diff --git a/app/src/main/java/com/asha/md360player4android/BitmapPlayerActivity.java b/app/src/main/java/com/asha/md360player4android/BitmapPlayerActivity.java
index 4fba5298..b7608ab8 100644
--- a/app/src/main/java/com/asha/md360player4android/BitmapPlayerActivity.java
+++ b/app/src/main/java/com/asha/md360player4android/BitmapPlayerActivity.java
@@ -12,7 +12,7 @@
 
 import com.asha.vrlib.MDVRLibrary;
 import com.asha.vrlib.model.MDRay;
-import com.asha.vrlib.plugins.IMDHotspot;
+import com.asha.vrlib.plugins.hotspot.IMDHotspot;
 import com.asha.vrlib.texture.MD360BitmapTexture;
 import com.squareup.picasso.Picasso;
 import com.squareup.picasso.Target;
diff --git a/app/src/main/java/com/asha/md360player4android/MD360PlayerActivity.java b/app/src/main/java/com/asha/md360player4android/MD360PlayerActivity.java
index d632da8e..d540ddd3 100644
--- a/app/src/main/java/com/asha/md360player4android/MD360PlayerActivity.java
+++ b/app/src/main/java/com/asha/md360player4android/MD360PlayerActivity.java
@@ -4,7 +4,6 @@
 import android.content.Context;
 import android.content.Intent;
 import android.content.res.Configuration;
-import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.BitmapFactory;
 import android.graphics.drawable.Drawable;
@@ -19,19 +18,22 @@
 import android.widget.Toast;
 
 import com.asha.vrlib.MDVRLibrary;
-import com.asha.vrlib.common.MDUtil;
 import com.asha.vrlib.model.MDHotspotBuilder;
 import com.asha.vrlib.model.MDPosition;
 import com.asha.vrlib.model.MDRay;
-import com.asha.vrlib.plugins.IMDHotspot;
+import com.asha.vrlib.model.MDViewBuilder;
+import com.asha.vrlib.model.position.MDMutablePosition;
 import com.asha.vrlib.plugins.MDAbsPlugin;
-import com.asha.vrlib.plugins.MDHotspotPlugin;
 import com.asha.vrlib.plugins.MDWidgetPlugin;
+import com.asha.vrlib.plugins.hotspot.IMDHotspot;
+import com.asha.vrlib.plugins.hotspot.MDAbsHotspot;
+import com.asha.vrlib.plugins.hotspot.MDSimpleHotspot;
+import com.asha.vrlib.plugins.hotspot.MDAbsView;
+import com.asha.vrlib.plugins.hotspot.MDView;
 import com.asha.vrlib.texture.MD360BitmapTexture;
 import com.squareup.picasso.Picasso;
 import com.squareup.picasso.Target;
 
-import java.io.File;
 import java.io.FileNotFoundException;
 import java.util.LinkedList;
 import java.util.List;
@@ -99,13 +101,15 @@ private static void start(Context context, Uri uri, Class<? extends Activity> cl
 
     private MDVRLibrary mVRLibrary;
 
+    // load resource from android drawable and remote url.
     private MDVRLibrary.IImageLoadProvider mImageLoadProvider = new ImageLoadProvider();
 
+    // load resource from android drawable only.
     private MDVRLibrary.IImageLoadProvider mAndroidProvider = new AndroidProvider(this);
 
     private List<MDAbsPlugin> plugins = new LinkedList<>();
 
-    private MDPosition logoPosition = MDPosition.newInstance().setY(-8.0f).setYaw(-90.0f);
+    private MDPosition logoPosition = MDMutablePosition.newInstance().setY(-8.0f).setYaw(-90.0f);
 
     private MDPosition[] positions = new MDPosition[]{
             MDPosition.newInstance().setZ(-8.0f).setYaw(-45.0f),
@@ -197,12 +201,12 @@ public void onSpinnerClicked(int index, int key, String value) {
             public void onClick(View v) {
                 final int index = (int) (Math.random() * 100) % positions.length;
                 MDPosition position = positions[index];
-                MDHotspotBuilder builder = MDHotspotBuilder.create(mAndroidProvider)
+                MDHotspotBuilder builder = MDHotspotBuilder.create(mImageLoadProvider)
                         .size(4f,4f)
-                        .provider(0, MDUtil.getDrawableUri(activity, android.R.drawable.star_off))
-                        .provider(1, MDUtil.getDrawableUri(activity, android.R.drawable.star_on))
-                        .provider(10, MDUtil.getDrawableUri(activity, android.R.drawable.checkbox_off_background))
-                        .provider(11, MDUtil.getDrawableUri(activity, android.R.drawable.checkbox_on_background))
+                        .provider(0, activity, android.R.drawable.star_off)
+                        .provider(1, activity, android.R.drawable.star_on)
+                        .provider(10, activity, android.R.drawable.checkbox_off_background)
+                        .provider(11, activity, android.R.drawable.checkbox_on_background)
                         .listenClick(new MDVRLibrary.ITouchPickListener() {
                             @Override
                             public void onHotspotHit(IMDHotspot hitHotspot, MDRay ray) {
@@ -228,9 +232,9 @@ public void onHotspotHit(IMDHotspot hitHotspot, MDRay ray) {
         findViewById(R.id.button_add_plugin_logo).setOnClickListener(new View.OnClickListener() {
             @Override
             public void onClick(View v) {
-                MDHotspotBuilder builder = MDHotspotBuilder.create(mAndroidProvider)
+                MDHotspotBuilder builder = MDHotspotBuilder.create(mImageLoadProvider)
                         .size(4f,4f)
-                        .provider(MDUtil.getDrawableUri(activity, R.drawable.moredoo_logo))
+                        .provider(activity, R.drawable.moredoo_logo)
                         .title("logo")
                         .position(logoPosition)
                         .listenClick(new MDVRLibrary.ITouchPickListener() {
@@ -239,9 +243,9 @@ public void onHotspotHit(IMDHotspot hitHotspot, MDRay ray) {
                                 Toast.makeText(MD360PlayerActivity.this, "click logo", Toast.LENGTH_SHORT).show();
                             }
                         });
-                MDHotspotPlugin plugin = new MDHotspotPlugin(builder);
-                plugins.add(plugin);
-                getVRLibrary().addPlugin(plugin);
+                MDAbsHotspot hotspot = new MDSimpleHotspot(builder);
+                plugins.add(hotspot);
+                getVRLibrary().addPlugin(hotspot);
                 Toast.makeText(MD360PlayerActivity.this, "add plugin logo" , Toast.LENGTH_SHORT).show();
             }
         });
@@ -264,6 +268,66 @@ public void onClick(View v) {
             }
         });
 
+        findViewById(R.id.button_add_hotspot_front).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                MDHotspotBuilder builder = MDHotspotBuilder.create(mImageLoadProvider)
+                        .size(4f,4f)
+                        .provider(activity, R.drawable.moredoo_logo)
+                        .title("front logo")
+                        .tag("tag-front")
+                        .position(MDPosition.newInstance().setZ(-12.0f).setY(-1.0f));
+                MDAbsHotspot hotspot = new MDSimpleHotspot(builder);
+                hotspot.rotateToCamera();
+                plugins.add(hotspot);
+                getVRLibrary().addPlugin(hotspot);
+            }
+        });
+
+        findViewById(R.id.button_rotate_to_camera_plugin).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                IMDHotspot hotspot = getVRLibrary().findHotspotByTag("tag-front");
+                if (hotspot != null){
+                    hotspot.rotateToCamera();
+                }
+            }
+        });
+
+        findViewById(R.id.button_add_md_view).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                TextView textView = new TextView(activity);
+                textView.setBackgroundColor(0x55FFCC11);
+                textView.setText("Hello world.");
+
+                MDViewBuilder builder = MDViewBuilder.create()
+                        .provider(textView, 400/*view width*/, 100/*view height*/)
+                        .size(4, 1)
+                        .position(MDPosition.newInstance().setZ(-12.0f))
+                        .title("md view")
+                        .tag("tag-md-text-view")
+                        ;
+
+                MDAbsView mdView = new MDView(builder);
+                plugins.add(mdView);
+                getVRLibrary().addPlugin(mdView);
+            }
+        });
+
+        findViewById(R.id.button_update_md_view).setOnClickListener(new View.OnClickListener() {
+            @Override
+            public void onClick(View v) {
+                MDAbsView mdView = getVRLibrary().findViewByTag("tag-md-text-view");
+                if (mdView != null){
+                    TextView textView = mdView.castAttachedView(TextView.class);
+                    textView.setText("Cheer up!");
+                    textView.setBackgroundColor(0x8800FF00);
+                    mdView.invalidate();
+                }
+            }
+        });
+
         final TextView hotspotText = (TextView) findViewById(R.id.hotspot_text);
         getVRLibrary().setEyePickChangedListener(new MDVRLibrary.IEyePickListener() {
             @Override
@@ -324,6 +388,7 @@ public void busy(){
         findViewById(R.id.progress).setVisibility(View.VISIBLE);
     }
 
+    // android impl
     private class AndroidProvider implements MDVRLibrary.IImageLoadProvider {
 
         Activity activity;
@@ -334,8 +399,6 @@ public AndroidProvider(Activity activity) {
 
         @Override
         public void onProvideBitmap(Uri uri, MD360BitmapTexture.Callback callback) {
-            //BitmapFactory.decodeStream()
-
             try {
                 Bitmap bitmap = BitmapFactory.decodeStream(activity.getContentResolver().openInputStream(uri));
                 callback.texture(bitmap);
@@ -346,13 +409,16 @@ public void onProvideBitmap(Uri uri, MD360BitmapTexture.Callback callback) {
         }
     }
 
+    // picasso impl
     private class ImageLoadProvider implements MDVRLibrary.IImageLoadProvider{
 
         private SimpleArrayMap<Uri,Target> targetMap = new SimpleArrayMap<>();
 
         @Override
         public void onProvideBitmap(final Uri uri, final MD360BitmapTexture.Callback callback) {
+
             final Target target = new Target() {
+
                 @Override
                 public void onBitmapLoaded(Bitmap bitmap, Picasso.LoadedFrom from) {
                     // texture
@@ -371,8 +437,7 @@ public void onPrepareLoad(Drawable placeHolderDrawable) {
                 }
             };
             targetMap.put(uri, target);
-            Picasso.with(getApplicationContext()).load(uri).resize(3072,2048).centerInside().memoryPolicy(NO_CACHE, NO_STORE).into(target);
-
+            Picasso.with(getApplicationContext()).load(uri).resize(callback.getMaxTextureSize(),callback.getMaxTextureSize()).onlyScaleDown().centerInside().memoryPolicy(NO_CACHE, NO_STORE).into(target);
         }
     }
 }
\ No newline at end of file
diff --git a/app/src/main/res/layout/activity_md_using_surface_view.xml b/app/src/main/res/layout/activity_md_using_surface_view.xml
index a2f0beb5..c90ded31 100644
--- a/app/src/main/res/layout/activity_md_using_surface_view.xml
+++ b/app/src/main/res/layout/activity_md_using_surface_view.xml
@@ -135,14 +135,75 @@
           android:background="@drawable/selector_button_background"
           android:layout_width="wrap_content"
           android:layout_height="42dp" />
+
    </LinearLayout>
 
    <LinearLayout
+       android:id="@+id/plugin_layout2"
        android:layout_below="@id/plugin_layout"
        android:layout_marginTop="8dp"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
+      <Button
+          android:id="@+id/button_add_hotspot_front"
+          android:textSize="13sp"
+          android:textColor="@android:color/white"
+          android:text="AddHotspotFront"
+          android:paddingLeft="8dp"
+          android:paddingRight="8dp"
+          android:includeFontPadding="false"
+          android:background="@drawable/selector_button_background"
+          android:layout_width="wrap_content"
+          android:layout_height="42dp" />
+
+      <Button
+          android:id="@+id/button_rotate_to_camera_plugin"
+          android:textSize="13sp"
+          android:textColor="@android:color/white"
+          android:layout_marginLeft="8dp"
+          android:text="RotateToCamera"
+          android:paddingLeft="8dp"
+          android:paddingRight="8dp"
+          android:includeFontPadding="false"
+          android:background="@drawable/selector_button_background"
+          android:layout_width="wrap_content"
+          android:layout_height="42dp" />
+
+      <Button
+          android:id="@+id/button_add_md_view"
+          android:textSize="13sp"
+          android:textColor="@android:color/white"
+          android:layout_marginLeft="8dp"
+          android:text="add MDView"
+          android:paddingLeft="8dp"
+          android:paddingRight="8dp"
+          android:includeFontPadding="false"
+          android:background="@drawable/selector_button_background"
+          android:layout_width="wrap_content"
+          android:layout_height="42dp" />
+
+      <Button
+          android:id="@+id/button_update_md_view"
+          android:textSize="13sp"
+          android:textColor="@android:color/white"
+          android:layout_marginLeft="8dp"
+          android:text="update MDView"
+          android:paddingLeft="8dp"
+          android:paddingRight="8dp"
+          android:includeFontPadding="false"
+          android:background="@drawable/selector_button_background"
+          android:layout_width="wrap_content"
+          android:layout_height="42dp" />
+
+   </LinearLayout>
+
+   <LinearLayout
+       android:layout_below="@id/plugin_layout2"
+       android:layout_marginTop="8dp"
+       android:orientation="horizontal"
+       android:layout_width="match_parent"
+       android:layout_height="wrap_content">
       <Button
           android:id="@+id/control_next"
           android:text="next"
diff --git a/vrlib/src/main/java/com/asha/vrlib/MD360Director.java b/vrlib/src/main/java/com/asha/vrlib/MD360Director.java
index b8b041a6..9fd82cfb 100644
--- a/vrlib/src/main/java/com/asha/vrlib/MD360Director.java
+++ b/vrlib/src/main/java/com/asha/vrlib/MD360Director.java
@@ -3,7 +3,9 @@
 import android.opengl.GLES20;
 import android.opengl.Matrix;
 
+import com.asha.vrlib.common.VRUtil;
 import com.asha.vrlib.model.MDPosition;
+import com.asha.vrlib.model.position.MDMutablePosition;
 
 /**
  * Created by hzqiujiadi on 16/1/22.
@@ -29,20 +31,22 @@ public class MD360Director {
     private float mLookY = 0f;
     private float mRatio = 0f;
     private float mNearScale = 0f;
-    private final MDPosition mCameraRotation;
+    private final MDPosition mCameraRotatePosition;
     private int mViewportWidth = 2;
     private int mViewportHeight = 1;
 
-    private float[] mCurrentRotation = new float[16];
+    private float[] mWorldRotationMatrix = new float[16];
+    private float[] mWorldRotationInvertMatrix = new float[16];
     private float[] mCurrentRotationPost = new float[16];
     private float[] mSensorMatrix = new float[16];
     private float[] mTempMatrix = new float[16];
-    private float[] mTempInvertMatrix = new float[16];
+    private float[] mCameraMatrix = new float[16];
 
     private float mDeltaX;
     private float mDeltaY;
 
-    private boolean mViewMatrixInvalidate = true;
+    private boolean mCameraMatrixInvalidate = true;
+    private boolean mWorldRotationMatrixInvalidate = true;
 
     protected MD360Director(Builder builder) {
         this.mRatio = builder.mRatio;
@@ -52,7 +56,7 @@ protected MD360Director(Builder builder) {
         this.mEyeZ = builder.mEyeZ;
         this.mLookX = builder.mLookX;
         this.mLookY = builder.mLookY;
-        this.mCameraRotation = builder.mRotation;
+        this.mCameraRotatePosition = builder.mRotation;
         initModel();
     }
 
@@ -62,7 +66,7 @@ public float getDeltaY() {
 
     public void setDeltaY(float mDeltaY) {
         this.mDeltaY = mDeltaY;
-        mViewMatrixInvalidate = true;
+        mWorldRotationMatrixInvalidate = true;
     }
 
     public float getDeltaX() {
@@ -71,32 +75,24 @@ public float getDeltaX() {
 
     public void setDeltaX(float mDeltaX) {
         this.mDeltaX = mDeltaX;
-        mViewMatrixInvalidate = true;
-    }
-
-    public float[] getTempInvertMatrix() {
-        return mTempInvertMatrix;
+        mWorldRotationMatrixInvalidate = true;
     }
 
     private void initModel(){
+        Matrix.setIdentityM(mViewMatrix, 0);
         Matrix.setIdentityM(mSensorMatrix, 0);
     }
 
-    public void shot(MD360Program program) {
-        shot(program, MDPosition.sOriginalPosition);
+    public void beforeShot(){
+        updateViewMatrixIfNeed();
     }
 
     public void shot(MD360Program program, MDPosition modelPosition) {
-
-        if (mViewMatrixInvalidate){
-            updateViewMatrix();
-            mViewMatrixInvalidate = false;
-        }
-
         // This multiplies the view matrix by the model matrix, and stores the result in the MVP matrix
         // (which currently contains model * view).
         Matrix.multiplyMM(mMVMatrix, 0, mViewMatrix, 0, modelPosition.getMatrix(), 0);
 
+
         // This multiplies the model view matrix by the projection matrix, and stores the result in the MVP matrix
         // (which now contains model * view * projection).
         Matrix.multiplyMM(mMVPMatrix, 0, mProjectionMatrix, 0, mMVMatrix, 0);
@@ -108,6 +104,22 @@ public void shot(MD360Program program, MDPosition modelPosition) {
         GLES20.glUniformMatrix4fv(program.getMVPMatrixHandle(), 1, false, mMVPMatrix, 0);
     }
 
+    private void updateViewMatrixIfNeed(){
+        if (mCameraMatrixInvalidate || mWorldRotationMatrixInvalidate){
+            if (mCameraMatrixInvalidate){
+                updateCameraMatrix();
+                mCameraMatrixInvalidate = false;
+            }
+
+            if (mWorldRotationMatrixInvalidate){
+                updateWorldRotationMatrix();
+                mWorldRotationMatrixInvalidate = false;
+            }
+
+            Matrix.multiplyMM(mViewMatrix, 0, mCameraMatrix, 0, mWorldRotationMatrix, 0);
+        }
+    }
+
     public void updateViewport(int width, int height){
         // Projection Matrix
         mViewportWidth = width;
@@ -155,7 +167,7 @@ public float[] getViewMatrix() {
         return mViewMatrix;
     }
 
-    private void updateViewMatrix() {
+    private void updateCameraMatrix() {
         final float eyeX = mEyeX;
         final float eyeY = mEyeY;
         final float eyeZ = mEyeZ;
@@ -165,41 +177,50 @@ private void updateViewMatrix() {
         final float upX = 0.0f;
         final float upY = 1.0f;
         final float upZ = 0.0f;
-        Matrix.setIdentityM(mViewMatrix, 0);
-        Matrix.setLookAtM(mViewMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY, lookZ, upX, upY, upZ);
+        Matrix.setIdentityM(mCameraMatrix, 0);
+        Matrix.setLookAtM(mCameraMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY, lookZ, upX, upY, upZ);
+    }
 
-        Matrix.setIdentityM(mCurrentRotation, 0);
-        Matrix.rotateM(mCurrentRotation, 0, -mDeltaY, 1.0f, 0.0f, 0.0f);
+    private void updateWorldRotationMatrix(){
+        Matrix.setIdentityM(mWorldRotationMatrix, 0);
+        Matrix.rotateM(mWorldRotationMatrix, 0, -mDeltaY, 1.0f, 0.0f, 0.0f);
         Matrix.setIdentityM(mCurrentRotationPost, 0);
         Matrix.rotateM(mCurrentRotationPost, 0, -mDeltaX, 0.0f, 1.0f, 0.0f);
 
         Matrix.setIdentityM(mTempMatrix, 0);
-        Matrix.multiplyMM(mTempMatrix, 0, mCurrentRotationPost, 0, mCameraRotation.getMatrix(), 0);
+        Matrix.multiplyMM(mTempMatrix, 0, mCurrentRotationPost, 0, mCameraRotatePosition.getMatrix(), 0);
         Matrix.multiplyMM(mCurrentRotationPost, 0, mSensorMatrix, 0, mTempMatrix, 0);
-        Matrix.multiplyMM(mTempMatrix, 0, mCurrentRotation, 0, mCurrentRotationPost, 0);
-        System.arraycopy(mTempMatrix, 0, mCurrentRotation, 0, 16);
+        Matrix.multiplyMM(mTempMatrix, 0, mWorldRotationMatrix, 0, mCurrentRotationPost, 0);
+        System.arraycopy(mTempMatrix, 0, mWorldRotationMatrix, 0, 16);
+
+        boolean success = VRUtil.invertM(mWorldRotationInvertMatrix, mWorldRotationMatrix);
+        if (!success){
+            Matrix.setIdentityM(mWorldRotationInvertMatrix, 0);
+        }
 
-        Matrix.multiplyMM(mTempMatrix, 0, mViewMatrix, 0, mCurrentRotation, 0);
-        System.arraycopy(mTempMatrix, 0, mViewMatrix, 0, 16);
     }
 
     // call in gl thread
     public void updateSensorMatrix(float[] sensorMatrix) {
         System.arraycopy(sensorMatrix, 0, mSensorMatrix, 0, 16);
-        mViewMatrixInvalidate = true;
+        mWorldRotationMatrixInvalidate = true;
     }
 
     // call in gl thread
     public void reset(){
         mDeltaX = mDeltaY = 0;
         Matrix.setIdentityM(mSensorMatrix,0);
-        mViewMatrixInvalidate = true;
+        mWorldRotationMatrixInvalidate = true;
     }
 
     public static Builder builder(){
         return new Builder();
     }
 
+    public float[] getWorldRotationInvert() {
+        return mWorldRotationInvertMatrix;
+    }
+
     public static class Builder {
         private float mEyeX = 0f;
         private float mEyeY = 0f;
@@ -208,7 +229,7 @@ public static class Builder {
         private float mNearScale = 1f;
         private float mLookX = 0f;
         private float mLookY = 0f;
-        private MDPosition mRotation = MDPosition.newInstance();
+        private MDMutablePosition mRotation = MDMutablePosition.newInstance();
 
         public Builder setLookX(float mLookX) {
             this.mLookX = mLookX;
diff --git a/vrlib/src/main/java/com/asha/vrlib/MD360Program.java b/vrlib/src/main/java/com/asha/vrlib/MD360Program.java
index 8565f1ff..541b4c78 100644
--- a/vrlib/src/main/java/com/asha/vrlib/MD360Program.java
+++ b/vrlib/src/main/java/com/asha/vrlib/MD360Program.java
@@ -19,6 +19,7 @@ public class MD360Program {
     private int mTextureCoordinateHandle;
     private int mProgramHandle;
     private int mSTMatrixHandle;
+    private int mUseTextureTransformHandle;
     private int mContentType;
 
     public MD360Program(int type) {
@@ -51,6 +52,7 @@ public void build(Context context){
         mPositionHandle = GLES20.glGetAttribLocation(mProgramHandle, "a_Position");
         mTextureCoordinateHandle = GLES20.glGetAttribLocation(mProgramHandle, "a_TexCoordinate");
         mSTMatrixHandle = GLES20.glGetUniformLocation(mProgramHandle, "u_STMatrix");
+        mUseTextureTransformHandle = GLES20.glGetUniformLocation(mProgramHandle, "u_UseSTM");
     }
 
     protected String getVertexShader(Context context){
@@ -85,6 +87,10 @@ public int getSTMatrixHandle() {
         return mSTMatrixHandle;
     }
 
+    public int getUseTextureTransformHandle() {
+        return mUseTextureTransformHandle;
+    }
+
     public int getTextureCoordinateHandle() {
         return mTextureCoordinateHandle;
     }
diff --git a/vrlib/src/main/java/com/asha/vrlib/MD360Renderer.java b/vrlib/src/main/java/com/asha/vrlib/MD360Renderer.java
index 79d2ee9c..f9045e02 100644
--- a/vrlib/src/main/java/com/asha/vrlib/MD360Renderer.java
+++ b/vrlib/src/main/java/com/asha/vrlib/MD360Renderer.java
@@ -98,12 +98,12 @@ public void onDrawFrame(GL10 glUnused){
 		// main plugin
 		MDAbsPlugin mainPlugin = mProjectionModeManager.getMainPlugin();
 		if (mainPlugin != null){
-			mainPlugin.setup(mContext);
+			mainPlugin.setupInGL(mContext);
 			mainPlugin.beforeRenderer(this.mWidth, this.mHeight);
 		}
 
 		for (MDAbsPlugin plugin : mPluginManager.getPlugins()) {
-			plugin.setup(mContext);
+			plugin.setupInGL(mContext);
 			plugin.beforeRenderer(this.mWidth, this.mHeight);
 		}
 
diff --git a/vrlib/src/main/java/com/asha/vrlib/MDPickerManager.java b/vrlib/src/main/java/com/asha/vrlib/MDPickerManager.java
index 4deb6c2b..a6b5a72f 100644
--- a/vrlib/src/main/java/com/asha/vrlib/MDPickerManager.java
+++ b/vrlib/src/main/java/com/asha/vrlib/MDPickerManager.java
@@ -7,7 +7,7 @@
 import com.asha.vrlib.common.MDMainHandler;
 import com.asha.vrlib.common.VRUtil;
 import com.asha.vrlib.model.MDRay;
-import com.asha.vrlib.plugins.IMDHotspot;
+import com.asha.vrlib.plugins.hotspot.IMDHotspot;
 import com.asha.vrlib.plugins.MDAbsPlugin;
 import com.asha.vrlib.plugins.MDPluginManager;
 import com.asha.vrlib.strategy.display.DisplayModeManager;
@@ -60,7 +60,7 @@ public void onClick(MotionEvent e) {
 
     private MDAbsPlugin mEyePicker = new MDAbsPlugin() {
         @Override
-        protected void init(Context context) {
+        protected void initInGL(Context context) {
 
         }
 
@@ -78,7 +78,7 @@ public void renderer(int index, int width, int height, MD360Director director) {
         }
 
         @Override
-        public void destroy() {
+        public void destroyInGL() {
 
         }
 
@@ -103,6 +103,7 @@ public void setEyePickEnable(boolean eyePickEnable) {
         this.mEyePickEnable = eyePickEnable;
     }
 
+    // gl thread.
     private void rayPickAsTouch(float  x, float y) {
         int size = mDisplayModeManager.getVisibleSize();
         if (size == 0){
diff --git a/vrlib/src/main/java/com/asha/vrlib/MDVRLibrary.java b/vrlib/src/main/java/com/asha/vrlib/MDVRLibrary.java
index e538cee6..f60fc15f 100644
--- a/vrlib/src/main/java/com/asha/vrlib/MDVRLibrary.java
+++ b/vrlib/src/main/java/com/asha/vrlib/MDVRLibrary.java
@@ -20,9 +20,10 @@
 import com.asha.vrlib.model.MDMainPluginBuilder;
 import com.asha.vrlib.model.MDPinchConfig;
 import com.asha.vrlib.model.MDRay;
-import com.asha.vrlib.plugins.IMDHotspot;
+import com.asha.vrlib.plugins.hotspot.IMDHotspot;
 import com.asha.vrlib.plugins.MDAbsPlugin;
 import com.asha.vrlib.plugins.MDPluginManager;
+import com.asha.vrlib.plugins.hotspot.MDAbsView;
 import com.asha.vrlib.strategy.display.DisplayModeManager;
 import com.asha.vrlib.strategy.interactive.InteractiveModeManager;
 import com.asha.vrlib.strategy.projection.IMDProjectionFactory;
@@ -330,6 +331,14 @@ public void removePlugins(){
         mPluginManager.removeAll();
     }
 
+    public IMDHotspot findHotspotByTag(String tag){
+        return mPluginManager.findHotspotByTag(tag);
+    }
+
+    public MDAbsView findViewByTag(String tag){
+        return mPluginManager.findViewByTag(tag);
+    }
+
     public void onTextureResize(float width, float height){
         mTextureSize.set(0,0,width,height);
     }
@@ -360,19 +369,19 @@ public void run() {
                 fireDestroy();
             }
         });
-        mGLHandler.destroy();
+        mGLHandler.markAsDestroy();
     }
 
     private void fireDestroy(){
         Iterator<MDAbsPlugin> iterator = mPluginManager.getPlugins().iterator();
         while (iterator.hasNext()){
             MDAbsPlugin plugin = iterator.next();
-            plugin.destroy();
+            plugin.destroyInGL();
         }
 
         MDAbsPlugin mainPlugin = mProjectionModeManager.getMainPlugin();
         if (mainPlugin != null){
-            mainPlugin.destroy();
+            mainPlugin.destroyInGL();
         }
 
         if (mTexture != null){
diff --git a/vrlib/src/main/java/com/asha/vrlib/common/GLUtil.java b/vrlib/src/main/java/com/asha/vrlib/common/GLUtil.java
index f4fd417c..a358d76d 100644
--- a/vrlib/src/main/java/com/asha/vrlib/common/GLUtil.java
+++ b/vrlib/src/main/java/com/asha/vrlib/common/GLUtil.java
@@ -31,7 +31,7 @@ public class GLUtil {
     public static final float[] sIdentityMatrix = new float[16];
 
     static {
-        Matrix.setIdentityM(sIdentityMatrix,0);
+        Matrix.setIdentityM(sIdentityMatrix, 0);
     }
 
     public static float[] identityMatrix() {
diff --git a/vrlib/src/main/java/com/asha/vrlib/common/MDGLHandler.java b/vrlib/src/main/java/com/asha/vrlib/common/MDGLHandler.java
index d8b42aab..be6dd684 100644
--- a/vrlib/src/main/java/com/asha/vrlib/common/MDGLHandler.java
+++ b/vrlib/src/main/java/com/asha/vrlib/common/MDGLHandler.java
@@ -58,7 +58,7 @@ public void dealMessage(){
         }
     }
 
-    public void destroy() {
+    public void markAsDestroy() {
         died = true;
     }
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/common/VRUtil.java b/vrlib/src/main/java/com/asha/vrlib/common/VRUtil.java
index 486f2494..9c380c4a 100644
--- a/vrlib/src/main/java/com/asha/vrlib/common/VRUtil.java
+++ b/vrlib/src/main/java/com/asha/vrlib/common/VRUtil.java
@@ -4,6 +4,8 @@
 import android.hardware.SensorEvent;
 import android.hardware.SensorManager;
 import android.opengl.Matrix;
+import android.os.Looper;
+import android.util.Log;
 import android.view.Surface;
 
 import com.asha.vrlib.MD360Director;
@@ -17,10 +19,31 @@
 public class VRUtil {
 
     private static final String TAG = "VRUtil";
-    private static float[] mTmp = new float[16];
+    private static float[] sUIThreadTmp = new float[16];
+    private static float[] sGLThreadTmp = new float[16];
     public static final float sNotHit = Float.MAX_VALUE;
 
+    private static float[] sTruncatedVector = new float[4];
+    private static boolean sIsTruncated = false;
+
     public static void sensorRotationVector2Matrix(SensorEvent event, int rotation, float[] output) {
+        if (!sIsTruncated) {
+            try {
+                SensorManager.getRotationMatrixFromVector(sUIThreadTmp, event.values);
+            } catch (Exception e) {
+                // On some Samsung devices, SensorManager#getRotationMatrixFromVector throws an exception
+                // if the rotation vector has more than 4 elements. Since only the four first elements are used,
+                // we can truncate the vector without losing precision.
+                Log.e(TAG, "maybe Samsung bug, will truncate vector");
+                sIsTruncated = true;
+            }
+        }
+
+        if (sIsTruncated){
+            System.arraycopy(event.values, 0, sTruncatedVector, 0, 4);
+            SensorManager.getRotationMatrixFromVector(sUIThreadTmp, sTruncatedVector);
+        }
+
         float[] values = event.values;
         switch (rotation){
             case Surface.ROTATION_0:
@@ -28,19 +51,33 @@ public static void sensorRotationVector2Matrix(SensorEvent event, int rotation,
                 SensorManager.getRotationMatrixFromVector(output, values);
                 break;
             case Surface.ROTATION_90:
-                SensorManager.getRotationMatrixFromVector(mTmp, values);
-                SensorManager.remapCoordinateSystem(mTmp, SensorManager.AXIS_Y, SensorManager.AXIS_MINUS_X, output);
+                SensorManager.getRotationMatrixFromVector(sUIThreadTmp, values);
+                SensorManager.remapCoordinateSystem(sUIThreadTmp, SensorManager.AXIS_Y, SensorManager.AXIS_MINUS_X, output);
                 break;
             case Surface.ROTATION_270:
-                SensorManager.getRotationMatrixFromVector(mTmp, values);
-                SensorManager.remapCoordinateSystem(mTmp, SensorManager.AXIS_MINUS_Y, SensorManager.AXIS_X, output);
+                SensorManager.getRotationMatrixFromVector(sUIThreadTmp, values);
+                SensorManager.remapCoordinateSystem(sUIThreadTmp, SensorManager.AXIS_MINUS_Y, SensorManager.AXIS_X, output);
                 break;
         }
         Matrix.rotateM(output, 0, 90.0F, 1.0F, 0.0F, 0.0F);
     }
 
     public static void notNull(Object object, String error){
-        if (object == null) throw new RuntimeException(error);
+        if (object == null) {
+            throw new RuntimeException(error);
+        }
+    }
+
+    public static void checkMainThread(String error){
+        if (Looper.getMainLooper() != Looper.myLooper()) {
+            throw new RuntimeException(error);
+        }
+    }
+
+    public static void checkGLThread(String error){
+        if (Looper.getMainLooper() == Looper.myLooper()) {
+            throw new RuntimeException(error);
+        }
     }
 
     public static void barrelDistortion(double paramA, double paramB, double paramC, PointF src){
@@ -91,10 +128,19 @@ public static float vec3Dot(MDVector3D v1, MDVector3D v2){
         return v1.getX() * v2.getX() + v1.getY() * v2.getY() + v1.getZ() * v2.getZ();
     }
 
+    public static boolean invertM(float[] output, float[] input){
+        if (input == output){
+            return false;
+        }
+
+        return Matrix.invertM(output, 0, input, 0);
+    }
+
     public static MDRay point2Ray(float x, float y, MD360Director director){
+        checkGLThread("point2Ray must called in GLThread");
         float[] view = director.getViewMatrix();
-        float[] temp = director.getTempInvertMatrix();
-        boolean success = Matrix.invertM(temp,0,view,0);
+        float[] temp = sGLThreadTmp;
+        boolean success = invertM(temp, view);
         if (success){
             MDVector3D v = new MDVector3D();
             float[] projection = director.getProjectionMatrix();
diff --git a/vrlib/src/main/java/com/asha/vrlib/model/MDHotspotBuilder.java b/vrlib/src/main/java/com/asha/vrlib/model/MDHotspotBuilder.java
index e025a6b5..18b6a2db 100644
--- a/vrlib/src/main/java/com/asha/vrlib/model/MDHotspotBuilder.java
+++ b/vrlib/src/main/java/com/asha/vrlib/model/MDHotspotBuilder.java
@@ -1,9 +1,11 @@
 package com.asha.vrlib.model;
 
+import android.content.Context;
 import android.net.Uri;
 import android.util.SparseArray;
 
 import com.asha.vrlib.MDVRLibrary;
+import com.asha.vrlib.common.MDUtil;
 
 /**
  * Created by hzqiujiadi on 16/8/10.
@@ -11,15 +13,7 @@
  */
 public class MDHotspotBuilder {
 
-    public float width = 2;
-
-    public float height = 2;
-
-    public String title;
-
-    public MDVRLibrary.ITouchPickListener clickListener;
-
-    public MDPosition position;
+    public MDPluginBuilder builderDelegate;
 
     public SparseArray<Uri> uriList = new SparseArray<>(6);
 
@@ -35,6 +29,7 @@ public static MDHotspotBuilder create(MDVRLibrary.IImageLoadProvider imageLoadPr
 
     public MDHotspotBuilder(MDVRLibrary.IImageLoadProvider imageLoadProvider) {
         this.imageLoadProvider = imageLoadProvider;
+        this.builderDelegate = new MDPluginBuilder();
     }
 
     private MDHotspotBuilder status(int normal, int focused, int pressed){
@@ -63,19 +58,28 @@ public MDHotspotBuilder checkedStatus(int normal){
         return checkedStatus(normal, normal);
     }
 
-    public MDHotspotBuilder title(String title){
-        this.title = title;
+    public MDHotspotBuilder provider(Uri uri){
+        provider(0, uri);
+        return this;
+    }
+
+    public MDHotspotBuilder provider(String url){
+        provider(0, url);
         return this;
     }
 
-    public MDHotspotBuilder size(float width, float height){
-        this.width = width;
-        this.height = height;
+    public MDHotspotBuilder provider(Context context, int drawableRes){
+        provider(0, context, drawableRes);
         return this;
     }
 
-    public MDHotspotBuilder provider(Uri uri){
-        provider(0, uri);
+    public MDHotspotBuilder provider(int key, String url){
+        provider(key, Uri.parse(url));
+        return this;
+    }
+
+    public MDHotspotBuilder provider(int key, Context context, int drawableRes){
+        provider(key, MDUtil.getDrawableUri(context, drawableRes));
         return this;
     }
 
@@ -84,13 +88,30 @@ public MDHotspotBuilder provider(int key, Uri uri){
         return this;
     }
 
+    // delegate
+
+    public MDHotspotBuilder title(String title) {
+        builderDelegate.title(title);
+        return this;
+    }
+
+    public MDHotspotBuilder size(float width, float height) {
+        builderDelegate.size(width, height);
+        return this;
+    }
+
     public MDHotspotBuilder position(MDPosition position) {
-        this.position = position;
+        builderDelegate.position(position);
+        return this;
+    }
+
+    public MDHotspotBuilder listenClick(MDVRLibrary.ITouchPickListener listener) {
+        builderDelegate.listenClick(listener);
         return this;
     }
 
-    public MDHotspotBuilder listenClick(MDVRLibrary.ITouchPickListener listener){
-        this.clickListener = listener;
+    public MDHotspotBuilder tag(String tag) {
+        builderDelegate.tag(tag);
         return this;
     }
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/model/MDPluginBuilder.java b/vrlib/src/main/java/com/asha/vrlib/model/MDPluginBuilder.java
new file mode 100644
index 00000000..0896daec
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/model/MDPluginBuilder.java
@@ -0,0 +1,52 @@
+package com.asha.vrlib.model;
+
+import com.asha.vrlib.MDVRLibrary;
+
+/**
+ * Created by hzqiujiadi on 2017/4/12.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public class MDPluginBuilder {
+
+    public float width = 2;
+
+    public float height = 2;
+
+    public String tag;
+
+    public String title;
+
+    public MDVRLibrary.ITouchPickListener clickListener;
+
+    public MDPosition position;
+
+    public MDPluginBuilder() {
+    }
+
+    public MDPluginBuilder title(String title){
+        this.title = title;
+        return this;
+    }
+
+    public MDPluginBuilder size(float width, float height){
+        this.width = width;
+        this.height = height;
+        return this;
+    }
+
+    public MDPluginBuilder position(MDPosition position) {
+        this.position = position;
+        return this;
+    }
+
+    public MDPluginBuilder listenClick(MDVRLibrary.ITouchPickListener listener){
+        this.clickListener = listener;
+        return this;
+    }
+
+    public MDPluginBuilder tag(String tag) {
+        this.tag = tag;
+        return this;
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/model/MDPosition.java b/vrlib/src/main/java/com/asha/vrlib/model/MDPosition.java
index f651b37d..c3bf0a6f 100644
--- a/vrlib/src/main/java/com/asha/vrlib/model/MDPosition.java
+++ b/vrlib/src/main/java/com/asha/vrlib/model/MDPosition.java
@@ -1,164 +1,46 @@
 package com.asha.vrlib.model;
 
-import android.opengl.Matrix;
+import android.util.Log;
+
+import com.asha.vrlib.common.GLUtil;
+import com.asha.vrlib.model.position.MDMutablePosition;
+
+import static android.content.ContentValues.TAG;
 
 /**
  * Created by hzqiujiadi on 16/8/3.
  * hzqiujiadi ashqalcn@gmail.com
  */
-public class MDPosition {
-
-    public static final MDPosition sOriginalPosition = MDPosition.newInstance();
-
-    private float[] mCurrentRotation = new float[16];
-    private float mX;
-    private float mY;
-    private float mZ;
-    private float mAngleX;
-    private float mAngleY;
-    private float mAngleZ;
-    private float mPitch; // x-axis
-    private float mYaw; // y-axis
-    private float mRoll; // z-axis
-
-    private MDPosition() {
-        mX = mY = mZ = 0;
-        mAngleX = mAngleY = mAngleZ = 0;
-        mPitch = mYaw = mRoll = 0;
-    }
-
-    public float getPitch() {
-        return mPitch;
-    }
-
-    public MDPosition setPitch(float pitch) {
-        this.mPitch = pitch;
-        return this;
-    }
-
-    public float getYaw() {
-        return mYaw;
-    }
-
-    public MDPosition setYaw(float yaw) {
-        this.mYaw = yaw;
-        return this;
-    }
-
-    public float getRoll() {
-        return mRoll;
-    }
-
-    public MDPosition setRoll(float roll) {
-        this.mRoll = roll;
-        return this;
-    }
-
-    public float getX() {
-        return mX;
-    }
+public abstract class MDPosition {
 
-    public MDPosition setX(float x) {
-        this.mX = x;
-        return this;
-    }
-
-    public float getY() {
-        return mY;
-    }
-
-    public MDPosition setY(float y) {
-        this.mY = y;
-        return this;
-    }
-
-    public float getZ() {
-        return mZ;
-    }
-
-    public MDPosition setZ(float z) {
-        this.mZ = z;
-        return this;
-    }
-
-    public float getAngleX() {
-        return mAngleX;
-    }
+    private static final MDPosition sOriginalPosition = new MDOriginalPosition();
 
-    /**
-     * setAngleX
-     * @param angleX in degree
-     * @return self
-     */
-    public MDPosition setAngleX(float angleX) {
-        this.mAngleX = angleX;
-        return this;
+    public static MDPosition getOriginalPosition() {
+        return sOriginalPosition;
     }
 
-    public float getAngleY() {
-        return mAngleY;
+    public static MDMutablePosition newInstance() {
+        return MDMutablePosition.newInstance();
     }
 
-    /**
-     * setAngleY
-     * @param angleY in degree
-     * @return self
-     */
-    public MDPosition setAngleY(float angleY) {
-        this.mAngleY = angleY;
-        return this;
-    }
+    // abstract
+    public abstract float[] getMatrix();
 
-    public float getAngleZ() {
-        return mAngleZ;
-    }
+    // abstract
+    public abstract void setRotationMatrix(float[] rotation);
 
-    /**
-     * setAngleZ
-     * @param angleZ in degree
-     * @return self
-     */
-    public MDPosition setAngleZ(float angleZ) {
-        this.mAngleZ = angleZ;
-        return this;
-    }
+    private static class MDOriginalPosition extends MDPosition {
 
-    public static MDPosition newInstance(){
-        return new MDPosition();
-    }
+        @Override
+        public float[] getMatrix() {
+            return GLUtil.identityMatrix();
+        }
 
-    @Override
-    public String toString() {
-        return "MDPosition{" +
-                "mX=" + mX +
-                ", mY=" + mY +
-                ", mZ=" + mZ +
-                ", mAngleX=" + mAngleX +
-                ", mAngleY=" + mAngleY +
-                ", mAngleZ=" + mAngleZ +
-                ", mPitch=" + mPitch +
-                ", mYaw=" + mYaw +
-                ", mRoll=" + mRoll +
-                '}';
+        @Override
+        public void setRotationMatrix(float[] rotation) {
+            Log.e(TAG, "call setRotationMatrix to MDOriginalPosition");
+        }
     }
 
-    private void update(){
-        // model
-        Matrix.setIdentityM(mCurrentRotation, 0);
 
-        Matrix.rotateM(mCurrentRotation, 0, getAngleY(), 1.0f, 0.0f, 0.0f);
-        Matrix.rotateM(mCurrentRotation, 0, getAngleX(), 0.0f, 1.0f, 0.0f);
-        Matrix.rotateM(mCurrentRotation, 0, getAngleZ(), 0.0f, 0.0f, 1.0f);
-
-        Matrix.translateM(mCurrentRotation, 0, getX(),getY(),getZ());
-
-        Matrix.rotateM(mCurrentRotation, 0, getYaw(), 1.0f, 0.0f, 0.0f);
-        Matrix.rotateM(mCurrentRotation, 0, getPitch(), 0.0f, 1.0f, 0.0f);
-        Matrix.rotateM(mCurrentRotation, 0, getRoll(), 0.0f, 0.0f, 1.0f);
-    }
-
-    public float[] getMatrix() {
-        update();
-        return mCurrentRotation;
-    }
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/model/MDViewBuilder.java b/vrlib/src/main/java/com/asha/vrlib/model/MDViewBuilder.java
new file mode 100644
index 00000000..e24b3292
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/model/MDViewBuilder.java
@@ -0,0 +1,64 @@
+package com.asha.vrlib.model;
+
+import android.view.View;
+
+import com.asha.vrlib.MDVRLibrary;
+import com.asha.vrlib.plugins.hotspot.MDLayoutParams;
+
+/**
+ * Created by hzqiujiadi on 2017/4/12.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public class MDViewBuilder {
+
+    public MDPluginBuilder builderDelegate;
+
+    public View attachedView;
+
+    public MDLayoutParams layoutParams;
+
+    public MDViewBuilder() {
+        this.builderDelegate = new MDPluginBuilder();
+    }
+
+    public MDViewBuilder provider(View view, int widthInPx, int heightInPx){
+        return provider(view, new MDLayoutParams(widthInPx, heightInPx));
+    }
+
+    public MDViewBuilder provider(View view, MDLayoutParams layoutParams){
+        this.attachedView = view;
+        this.layoutParams = layoutParams;
+        return this;
+    }
+
+    // delegate builder
+    public MDViewBuilder title(String title) {
+        builderDelegate.title(title);
+        return this;
+    }
+
+    public MDViewBuilder size(float width, float height) {
+        builderDelegate.size(width, height);
+        return this;
+    }
+
+    public MDViewBuilder position(MDPosition position) {
+        builderDelegate.position(position);
+        return this;
+    }
+
+    public MDViewBuilder listenClick(MDVRLibrary.ITouchPickListener listener) {
+        builderDelegate.listenClick(listener);
+        return this;
+    }
+
+    public MDViewBuilder tag(String tag) {
+        builderDelegate.tag(tag);
+        return this;
+    }
+
+    public static MDViewBuilder create() {
+        return new MDViewBuilder();
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/model/position/MDMutablePosition.java b/vrlib/src/main/java/com/asha/vrlib/model/position/MDMutablePosition.java
new file mode 100644
index 00000000..0c42d664
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/model/position/MDMutablePosition.java
@@ -0,0 +1,212 @@
+package com.asha.vrlib.model.position;
+
+import android.opengl.Matrix;
+
+import com.asha.vrlib.model.MDPosition;
+
+import static com.asha.vrlib.common.VRUtil.checkGLThread;
+import static com.asha.vrlib.common.VRUtil.notNull;
+
+/**
+ * Created by hzqiujiadi on 2017/4/11.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public class MDMutablePosition extends MDPosition {
+
+    private float[] mModelMatrix = null;
+    private float[] mRotationMatrix = null;
+    private static final float[] sSharedTmpMatrix = new float[16];
+
+    private float mX;
+    private float mY;
+    private float mZ;
+    private float mAngleX;
+    private float mAngleY;
+    private float mAngleZ;
+    private float mPitch; // x-axis
+    private float mYaw; // y-axis
+    private float mRoll; // z-axis
+    private boolean changed;
+
+    private MDMutablePosition() {
+        mX = mY = mZ = 0;
+        mAngleX = mAngleY = mAngleZ = 0;
+        mPitch = mYaw = mRoll = 0;
+        changed = true;
+    }
+
+    public float getPitch() {
+        return mPitch;
+    }
+
+    public MDMutablePosition setPitch(float pitch) {
+        this.mPitch = pitch;
+        changed = true;
+        return this;
+    }
+
+    public float getYaw() {
+        return mYaw;
+    }
+
+    public MDMutablePosition setYaw(float yaw) {
+        this.mYaw = yaw;
+        changed = true;
+        return this;
+    }
+
+    public float getRoll() {
+        return mRoll;
+    }
+
+    public MDMutablePosition setRoll(float roll) {
+        this.mRoll = roll;
+        changed = true;
+        return this;
+    }
+
+    public float getX() {
+        return mX;
+    }
+
+    public MDMutablePosition setX(float x) {
+        this.mX = x;
+        changed = true;
+        return this;
+    }
+
+    public float getY() {
+        return mY;
+    }
+
+    public MDMutablePosition setY(float y) {
+        this.mY = y;
+        changed = true;
+        return this;
+    }
+
+    public float getZ() {
+        return mZ;
+    }
+
+    public MDMutablePosition setZ(float z) {
+        this.mZ = z;
+        changed = true;
+        return this;
+    }
+
+    public float getAngleX() {
+        return mAngleX;
+    }
+
+    /**
+     * setAngleX
+     * @param angleX in degree
+     * @return self
+     */
+    public MDMutablePosition setAngleX(float angleX) {
+        this.mAngleX = angleX;
+        changed = true;
+        return this;
+    }
+
+    public float getAngleY() {
+        return mAngleY;
+    }
+
+    /**
+     * setAngleY
+     * @param angleY in degree
+     * @return self
+     */
+    public MDMutablePosition setAngleY(float angleY) {
+        this.mAngleY = angleY;
+        changed = true;
+        return this;
+    }
+
+    public float getAngleZ() {
+        return mAngleZ;
+    }
+
+    /**
+     * setAngleZ
+     * @param angleZ in degree
+     * @return self
+     */
+    public MDMutablePosition setAngleZ(float angleZ) {
+        this.mAngleZ = angleZ;
+        changed = true;
+        return this;
+    }
+
+    public static MDMutablePosition newInstance(){
+        return new MDMutablePosition();
+    }
+
+    @Override
+    public String toString() {
+        return "MDPosition{" +
+                "mX=" + mX +
+                ", mY=" + mY +
+                ", mZ=" + mZ +
+                ", mAngleX=" + mAngleX +
+                ", mAngleY=" + mAngleY +
+                ", mAngleZ=" + mAngleZ +
+                ", mPitch=" + mPitch +
+                ", mYaw=" + mYaw +
+                ", mRoll=" + mRoll +
+                '}';
+    }
+
+    private void ensure(){
+        if (!changed){
+            return;
+        }
+
+        // model
+        if (mModelMatrix == null){
+            mModelMatrix = new float[16];
+        }
+
+        Matrix.setIdentityM(mModelMatrix, 0);
+
+        Matrix.rotateM(mModelMatrix, 0, getAngleY(), 1.0f, 0.0f, 0.0f);
+        Matrix.rotateM(mModelMatrix, 0, getAngleX(), 0.0f, 1.0f, 0.0f);
+        Matrix.rotateM(mModelMatrix, 0, getAngleZ(), 0.0f, 0.0f, 1.0f);
+
+        Matrix.translateM(mModelMatrix, 0, getX(),getY(),getZ());
+
+        Matrix.rotateM(mModelMatrix, 0, getYaw(), 1.0f, 0.0f, 0.0f);
+        Matrix.rotateM(mModelMatrix, 0, getPitch(), 0.0f, 1.0f, 0.0f);
+        Matrix.rotateM(mModelMatrix, 0, getRoll(), 0.0f, 0.0f, 1.0f);
+
+        // rotation
+        if (mRotationMatrix != null){
+            Matrix.multiplyMM(sSharedTmpMatrix, 0,  mRotationMatrix, 0, mModelMatrix, 0);
+            System.arraycopy(sSharedTmpMatrix, 0, mModelMatrix, 0, 16);
+        }
+
+        changed = false;
+    }
+
+    @Override
+    public void setRotationMatrix(float[] rotationMatrix){
+        notNull(rotationMatrix, "rotationMatrix can't be null!");
+        checkGLThread("setRotationMatrix must called in gl thread!");
+
+        if (mRotationMatrix == null){
+            mRotationMatrix = new float[16];
+        }
+
+        System.arraycopy(rotationMatrix, 0, mRotationMatrix, 0, 16);
+        changed = true;
+    }
+
+    @Override
+    public float[] getMatrix() {
+        ensure();
+        return mModelMatrix;
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/MDAbsPlugin.java b/vrlib/src/main/java/com/asha/vrlib/plugins/MDAbsPlugin.java
index 7cf46939..2b66003c 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/MDAbsPlugin.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/MDAbsPlugin.java
@@ -13,23 +13,23 @@ public abstract class MDAbsPlugin {
 
     private boolean mIsInit;
 
-    private MDPosition mPosition = MDPosition.sOriginalPosition;
+    private MDPosition mPosition = MDPosition.getOriginalPosition();
 
-    public final void setup(Context context){
+    public final void setupInGL(Context context){
         if (!mIsInit){
-            init(context);
+            initInGL(context);
             mIsInit = true;
         }
     }
 
-    abstract protected void init(Context context);
+    abstract protected void initInGL(Context context);
+
+    abstract public void destroyInGL();
 
     abstract public void beforeRenderer(int totalWidth, int totalHeight);
 
     abstract public void renderer(int index, int itemWidth, int itemHeight, MD360Director director);
 
-    abstract public void destroy();
-
     protected MDPosition getModelPosition(){
         return mPosition;
     }
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/MDBarrelDistortionLinePipe.java b/vrlib/src/main/java/com/asha/vrlib/plugins/MDBarrelDistortionLinePipe.java
index 3baebeeb..b114d502 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/MDBarrelDistortionLinePipe.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/MDBarrelDistortionLinePipe.java
@@ -10,6 +10,7 @@
 import com.asha.vrlib.MDVRLibrary;
 import com.asha.vrlib.common.VRUtil;
 import com.asha.vrlib.model.BarrelDistortionConfig;
+import com.asha.vrlib.model.MDPosition;
 import com.asha.vrlib.objects.MDAbsObject3D;
 import com.asha.vrlib.objects.MDObject3DHelper;
 import com.asha.vrlib.strategy.display.DisplayModeManager;
@@ -103,7 +104,8 @@ private void draw(int index){
         object3D.uploadTexCoordinateBufferIfNeed(mProgram, index);
 
         // Pass in the combined matrix.
-        mDirector.shot(mProgram);
+        mDirector.beforeShot();
+        mDirector.shot(mProgram, MDPosition.getOriginalPosition());
 
         GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
         GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, mDrawingCache.getTextureOutput());
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/MDHotspotPlugin.java b/vrlib/src/main/java/com/asha/vrlib/plugins/MDHotspotPlugin.java
index 104bd54a..68e09102 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/MDHotspotPlugin.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/MDHotspotPlugin.java
@@ -1,201 +1,20 @@
 package com.asha.vrlib.plugins;
 
-import android.content.Context;
-import android.graphics.RectF;
-import android.net.Uri;
-import android.opengl.GLES20;
-import android.util.SparseArray;
-
-import com.asha.vrlib.MD360Director;
-import com.asha.vrlib.MD360Program;
-import com.asha.vrlib.MDVRLibrary;
-import com.asha.vrlib.common.VRUtil;
 import com.asha.vrlib.model.MDHotspotBuilder;
-import com.asha.vrlib.model.MDPosition;
-import com.asha.vrlib.model.MDRay;
-import com.asha.vrlib.model.MDVector3D;
-import com.asha.vrlib.objects.MDAbsObject3D;
-import com.asha.vrlib.objects.MDObject3DHelper;
-import com.asha.vrlib.objects.MDPlane;
-import com.asha.vrlib.texture.MD360BitmapTexture;
-import com.asha.vrlib.texture.MD360Texture;
-
-import java.nio.FloatBuffer;
-import java.util.LinkedList;
-import java.util.List;
-
-import static com.asha.vrlib.common.GLUtil.glCheck;
-import static com.asha.vrlib.common.VRUtil.sNotHit;
+import com.asha.vrlib.plugins.hotspot.MDSimpleHotspot;
 
 /**
  * Created by hzqiujiadi on 16/8/2.
  * hzqiujiadi ashqalcn@gmail.com
+ *
+ * @deprecated MDHotspotPlugin
+ *
+ * Please use {@link MDSimpleHotspot} instead.
  */
-public class MDHotspotPlugin extends MDAbsPlugin implements IMDHotspot{
-
-    private static final String TAG = "MDSimplePlugin";
-
-    private MDVRLibrary.ITouchPickListener clickListener;
-
-    private MDAbsObject3D object3D;
-
-    private MD360Program program;
-
-    private SparseArray<Uri> uriList;
-
-    private RectF size;
-
-    private String title;
-
-    private int mPendingTextureKey = 0;
-
-    private int mCurrentTextureKey = 0;
-
-    private MD360Texture texture;
-
-    private MDVRLibrary.IImageLoadProvider provider;
+@Deprecated
+public class MDHotspotPlugin extends MDSimpleHotspot {
 
     public MDHotspotPlugin(MDHotspotBuilder builder) {
-        provider = builder.imageLoadProvider;
-        uriList = builder.uriList;
-        size = new RectF(0, 0, builder.width, builder.height);
-        clickListener = builder.clickListener;
-        setTitle(builder.title);
-        setModelPosition(builder.position == null ? MDPosition.sOriginalPosition : builder.position);
+        super(builder);
     }
-
-    @Override
-    public void init(Context context) {
-
-        program = new MD360Program(MDVRLibrary.ContentType.BITMAP);
-        program.build(context);
-
-        object3D = new MDPlane(size);
-        MDObject3DHelper.loadObj(context,object3D);
-
-        texture = new MD360BitmapTexture(new MDVRLibrary.IBitmapProvider() {
-            @Override
-            public void onProvideBitmap(MD360BitmapTexture.Callback callback) {
-                Uri uri = uriList.get(mCurrentTextureKey);
-                if (uri != null){
-                    provider.onProvideBitmap(uri, callback);
-                }
-            }
-        });
-        texture.create();
-    }
-
-    @Override
-    public void beforeRenderer(int totalWidth, int totalHeight) {
-
-    }
-
-    @Override
-    public void renderer(int index, int width, int height, MD360Director director) {
-        if (texture == null){
-            return;
-        }
-
-        if (mPendingTextureKey != mCurrentTextureKey){
-            mCurrentTextureKey = mPendingTextureKey;
-            texture.notifyChanged();
-        }
-
-        texture.texture(program);
-        if (texture.isReady()){
-            // Update Projection
-            director.updateViewport(width, height);
-
-            // Set our per-vertex lighting program.
-            program.use();
-            glCheck("MDSimplePlugin mProgram use");
-
-            object3D.uploadVerticesBufferIfNeed(program, index);
-
-            object3D.uploadTexCoordinateBufferIfNeed(program, index);
-
-            // Pass in the combined matrix.
-            director.shot(program, getModelPosition());
-
-            GLES20.glEnable(GLES20.GL_BLEND);
-            GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
-
-
-            object3D.draw();
-            GLES20.glDisable(GLES20.GL_BLEND);
-        }
-
-    }
-
-    @Override
-    public void destroy() {
-
-    }
-
-    @Override
-    protected boolean removable() {
-        return true;
-    }
-
-    @Override
-    public float hit(MDRay ray) {
-        if (object3D == null || object3D.getVerticesBuffer(0) == null){
-            return sNotHit;
-        }
-
-        MDPosition position = getModelPosition();
-        float[] model = position.getMatrix();
-
-        List<MDVector3D> points = new LinkedList<>();
-
-        FloatBuffer buffer = object3D.getVerticesBuffer(0);
-        int numPoints = buffer.capacity() / 3;
-
-        for (int i = 0; i < numPoints; i++){
-            MDVector3D v = new MDVector3D();
-            v.setX(buffer.get(i * 3)).setY(buffer.get(i * 3 + 1)).setZ(buffer.get(i * 3 + 2));
-            v.multiplyMV(model);
-            points.add(v);
-        }
-        float hit1 = sNotHit;
-        float hit2 = sNotHit;
-        if (points.size() == 4){
-            hit1 = VRUtil.intersectTriangle(ray, points.get(0), points.get(1), points.get(2));
-            hit2 = VRUtil.intersectTriangle(ray,points.get(1), points.get(2), points.get(3));
-        }
-
-        return Math.min(hit1,hit2);
-    }
-
-    @Override
-    public void onEyeHitIn(long timestamp) {
-
-    }
-
-    @Override
-    public void onEyeHitOut() {
-
-    }
-
-    @Override
-    public void onTouchHit(MDRay ray) {
-        if (clickListener != null){
-            clickListener.onHotspotHit(this, ray);
-        }
-    }
-
-    @Override
-    public String getTitle() {
-        return title;
-    }
-
-    @Override
-    public void useTexture(int key) {
-        mPendingTextureKey = key;
-    }
-
-    public void setTitle(String title) {
-        this.title = title;
-    }
-
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/MDMultiFishEyePlugin.java b/vrlib/src/main/java/com/asha/vrlib/plugins/MDMultiFishEyePlugin.java
index c2e2ac95..8c1b038f 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/MDMultiFishEyePlugin.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/MDMultiFishEyePlugin.java
@@ -55,7 +55,7 @@ public MDMultiFishEyePlugin(MDMainPluginBuilder builder, float radius, MDDirecti
     }
 
     @Override
-    public void init(Context context) {
+    public void initInGL(Context context) {
         mProgram.build(context);
         mBitmapProgram.build(context);
         mTexture.create();
@@ -93,12 +93,13 @@ public void renderer(int index, int width, int height, MD360Director director) {
         object3D.uploadTexCoordinateBufferIfNeed(mBitmapProgram, index);
 
         // Pass in the combined matrix.
+        director.beforeShot();
         director.shot(mBitmapProgram, getModelPosition());
         object3D.draw();
     }
 
     @Override
-    public void destroy() {
+    public void destroyInGL() {
         mTexture = null;
     }
 
@@ -130,7 +131,8 @@ private void drawConverter(int width, int height){
             mConverterObject3D.uploadTexCoordinateBufferIfNeed(mProgram, index);
 
             // Pass in the combined matrix.
-            mFixedDirector.shot(mProgram);
+            mFixedDirector.beforeShot();
+            mFixedDirector.shot(mProgram, MDPosition.getOriginalPosition());
 
             mConverterObject3D.draw();
 
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/MDPanoramaPlugin.java b/vrlib/src/main/java/com/asha/vrlib/plugins/MDPanoramaPlugin.java
index 5ad76d94..ce40ad6e 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/MDPanoramaPlugin.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/MDPanoramaPlugin.java
@@ -31,7 +31,7 @@ public MDPanoramaPlugin(MDMainPluginBuilder builder) {
     }
 
     @Override
-    public void init(Context context) {
+    public void initInGL(Context context) {
         mProgram.build(context);
         mTexture.create();
     }
@@ -63,13 +63,14 @@ public void renderer(int index, int width, int height, MD360Director director) {
 
         // Pass in the combined matrix.
         // model view projection matrix.
+        director.beforeShot();
         director.shot(mProgram, getModelPosition());
         object3D.draw();
 
     }
 
     @Override
-    public void destroy() {
+    public void destroyInGL() {
         mTexture = null;
     }
 
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/MDPluginManager.java b/vrlib/src/main/java/com/asha/vrlib/plugins/MDPluginManager.java
index bfa0c70f..f62c0ba4 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/MDPluginManager.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/MDPluginManager.java
@@ -1,6 +1,10 @@
 package com.asha.vrlib.plugins;
 
-import java.util.Iterator;
+import android.text.TextUtils;
+
+import com.asha.vrlib.plugins.hotspot.IMDHotspot;
+import com.asha.vrlib.plugins.hotspot.MDAbsView;
+
 import java.util.List;
 import java.util.concurrent.CopyOnWriteArrayList;
 
@@ -33,12 +37,34 @@ public void remove(MDAbsPlugin plugin) {
     }
 
     public void removeAll() {
-        Iterator<MDAbsPlugin> iterator = mList.iterator();
-        while (iterator.hasNext()){
-            MDAbsPlugin plugin = iterator.next();
-            if (plugin.removable()){
+        for (MDAbsPlugin plugin : mList) {
+            if (plugin.removable()) {
                 mList.remove(plugin);
             }
         }
     }
+
+    public IMDHotspot findHotspotByTag(String tag) {
+        for (MDAbsPlugin plugin : mList) {
+            if (plugin.removable() && plugin instanceof IMDHotspot) {
+                IMDHotspot hotspot = (IMDHotspot) plugin;
+                if (TextUtils.equals(tag, hotspot.getTag())){
+                    return hotspot;
+                }
+            }
+        }
+        return null;
+    }
+
+    public MDAbsView findViewByTag(String tag) {
+        for (MDAbsPlugin plugin : mList) {
+            if (plugin.removable() && plugin instanceof MDAbsView) {
+                MDAbsView mdView = (MDAbsView) plugin;
+                if (TextUtils.equals(tag, mdView.getTag())){
+                    return mdView;
+                }
+            }
+        }
+        return null;
+    }
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/IMDHotspot.java b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/IMDHotspot.java
similarity index 76%
rename from vrlib/src/main/java/com/asha/vrlib/plugins/IMDHotspot.java
rename to vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/IMDHotspot.java
index f9aad4a0..1130f8a9 100644
--- a/vrlib/src/main/java/com/asha/vrlib/plugins/IMDHotspot.java
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/IMDHotspot.java
@@ -1,4 +1,4 @@
-package com.asha.vrlib.plugins;
+package com.asha.vrlib.plugins.hotspot;
 
 import com.asha.vrlib.model.MDRay;
 
@@ -12,5 +12,6 @@ public interface IMDHotspot {
     void onEyeHitOut();
     void onTouchHit(MDRay ray);
     String getTitle();
-    void useTexture(int key);
+    String getTag();
+    void rotateToCamera();
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDAbsHotspot.java b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDAbsHotspot.java
new file mode 100644
index 00000000..71b0c616
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDAbsHotspot.java
@@ -0,0 +1,189 @@
+package com.asha.vrlib.plugins.hotspot;
+
+import android.content.Context;
+import android.graphics.RectF;
+import android.opengl.GLES20;
+
+import com.asha.vrlib.MD360Director;
+import com.asha.vrlib.MD360Program;
+import com.asha.vrlib.MDVRLibrary;
+import com.asha.vrlib.common.VRUtil;
+import com.asha.vrlib.model.MDPluginBuilder;
+import com.asha.vrlib.model.MDPosition;
+import com.asha.vrlib.model.MDRay;
+import com.asha.vrlib.model.MDVector3D;
+import com.asha.vrlib.objects.MDAbsObject3D;
+import com.asha.vrlib.objects.MDObject3DHelper;
+import com.asha.vrlib.objects.MDPlane;
+import com.asha.vrlib.plugins.MDAbsPlugin;
+
+import java.nio.FloatBuffer;
+import java.util.LinkedList;
+import java.util.List;
+import java.util.concurrent.atomic.AtomicBoolean;
+
+import static com.asha.vrlib.common.GLUtil.glCheck;
+import static com.asha.vrlib.common.VRUtil.sNotHit;
+
+/**
+ * Created by hzqiujiadi on 2017/4/12.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public abstract class MDAbsHotspot extends MDAbsPlugin implements IMDHotspot {
+
+    private RectF size;
+
+    private MDAbsObject3D object3D;
+
+    MD360Program program;
+
+    // hotspot
+    private String title;
+
+    private String tag;
+
+    private MDVRLibrary.ITouchPickListener clickListener;
+
+    private AtomicBoolean mPendingRotateToCamera = new AtomicBoolean(false);
+
+    public MDAbsHotspot(MDPluginBuilder builder) {
+        setTag(builder.tag);
+        setTitle(builder.title);
+        this.clickListener = builder.clickListener;
+        this.size = new RectF(0, 0, builder.width, builder.height);
+        setModelPosition(builder.position == null ? MDPosition.getOriginalPosition() : builder.position);
+    }
+
+    @Override
+    protected void initInGL(Context context) {
+        program = new MD360Program(MDVRLibrary.ContentType.BITMAP);
+        program.build(context);
+
+        // load obj
+        object3D = new MDPlane(size);
+        MDObject3DHelper.loadObj(context,object3D);
+    }
+
+    @Override
+    public void destroyInGL() {
+
+    }
+
+    @Override
+    public void beforeRenderer(int totalWidth, int totalHeight) {
+
+    }
+
+    @Override
+    public void renderer(int index, int width, int height, MD360Director director) {
+
+        // Update Projection
+        director.updateViewport(width, height);
+
+        // Set our per-vertex lighting program.
+        program.use();
+        glCheck("MDSimplePlugin mProgram use");
+
+        object3D.uploadVerticesBufferIfNeed(program, index);
+
+        object3D.uploadTexCoordinateBufferIfNeed(program, index);
+
+        // Pass in the combined matrix.
+        director.beforeShot();
+        consumePendingRotateToCamera(director);
+        director.shot(program, getModelPosition());
+
+        GLES20.glEnable(GLES20.GL_BLEND);
+        GLES20.glBlendFunc(GLES20.GL_SRC_ALPHA, GLES20.GL_ONE_MINUS_SRC_ALPHA);
+
+
+        object3D.draw();
+        GLES20.glDisable(GLES20.GL_BLEND);
+
+    }
+
+    @Override
+    protected boolean removable() {
+        return true;
+    }
+
+    @Override
+    public String getTitle() {
+        return title;
+    }
+
+    public void setTitle(String title) {
+        this.title = title;
+    }
+
+    @Override
+    public String getTag() {
+        return tag;
+    }
+
+    public void setTag(String tag) {
+        this.tag = tag;
+    }
+
+    @Override
+    public float hit(MDRay ray) {
+        if (object3D == null || object3D.getVerticesBuffer(0) == null){
+            return sNotHit;
+        }
+
+        MDPosition position = getModelPosition();
+        float[] model = position.getMatrix();
+
+        List<MDVector3D> points = new LinkedList<>();
+
+        FloatBuffer buffer = object3D.getVerticesBuffer(0);
+        int numPoints = buffer.capacity() / 3;
+
+        for (int i = 0; i < numPoints; i++){
+            MDVector3D v = new MDVector3D();
+            v.setX(buffer.get(i * 3)).setY(buffer.get(i * 3 + 1)).setZ(buffer.get(i * 3 + 2));
+            v.multiplyMV(model);
+            points.add(v);
+        }
+        float hit1 = sNotHit;
+        float hit2 = sNotHit;
+        if (points.size() == 4){
+            hit1 = VRUtil.intersectTriangle(ray, points.get(0), points.get(1), points.get(2));
+            hit2 = VRUtil.intersectTriangle(ray,points.get(1), points.get(2), points.get(3));
+        }
+
+        return Math.min(hit1,hit2);
+    }
+
+    @Override
+    public void onEyeHitIn(long timestamp) {
+
+    }
+
+    @Override
+    public void onEyeHitOut() {
+
+    }
+
+    @Override
+    public void onTouchHit(MDRay ray) {
+        if (clickListener != null){
+            clickListener.onHotspotHit(this, ray);
+        }
+    }
+
+    @Override
+    public void rotateToCamera(){
+        mPendingRotateToCamera.set(true);
+    }
+
+    private void consumePendingRotateToCamera(MD360Director director) {
+        if (mPendingRotateToCamera.get()){
+            MDPosition position = getModelPosition();
+            float[] rotation = director.getWorldRotationInvert();
+            position.setRotationMatrix(rotation);
+            mPendingRotateToCamera.set(false);
+        }
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDAbsView.java b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDAbsView.java
new file mode 100644
index 00000000..37c14a6a
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDAbsView.java
@@ -0,0 +1,127 @@
+package com.asha.vrlib.plugins.hotspot;
+
+import android.content.Context;
+import android.graphics.Bitmap;
+import android.graphics.Canvas;
+import android.graphics.Color;
+import android.graphics.PorterDuff;
+import android.view.View;
+
+import com.asha.vrlib.MD360Director;
+import com.asha.vrlib.MDVRLibrary;
+import com.asha.vrlib.model.MDViewBuilder;
+import com.asha.vrlib.texture.MD360BitmapTexture;
+import com.asha.vrlib.texture.MD360Texture;
+
+import static com.asha.vrlib.common.VRUtil.checkMainThread;
+import static com.asha.vrlib.common.VRUtil.notNull;
+
+/**
+ * Created by hzqiujiadi on 2017/4/12.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public abstract class MDAbsView extends MDAbsHotspot {
+
+    private boolean mInvalidate;
+
+    private MD360Texture mTexture;
+
+    private View mAttachedView;
+
+    private MDLayoutParams mLayoutParams;
+
+    private Canvas mCanvas;
+
+    private Bitmap mBitmap;
+
+    public MDAbsView(MDViewBuilder builder) {
+        super(builder.builderDelegate);
+        this.mAttachedView = builder.attachedView;
+        this.mLayoutParams = builder.layoutParams;
+        this.mAttachedView.setLayoutParams(this.mLayoutParams);
+
+        try {
+            this.mBitmap = Bitmap.createBitmap(mLayoutParams.width, mLayoutParams.height, Bitmap.Config.ARGB_8888);
+            this.mCanvas = new Canvas(mBitmap);
+        } catch (Exception e){
+            e.printStackTrace();
+        }
+
+        requestLayout();
+    }
+
+    public void invalidate(){
+        if (mBitmap == null){
+            return;
+        }
+
+        checkMainThread("invalidate must called in main thread.");
+        notNull(mLayoutParams, "layout params can't be null");
+        notNull(mAttachedView, "attached view can't be null");
+
+        mCanvas.drawColor(Color.TRANSPARENT, PorterDuff.Mode.CLEAR);
+        mAttachedView.draw(mCanvas);
+        mInvalidate = true;
+    }
+
+    public void requestLayout(){
+        if (mBitmap == null){
+            return;
+        }
+
+        checkMainThread("requestLayout must called in main thread.");
+        notNull(mLayoutParams, "layout params can't be null");
+        notNull(mAttachedView, "attached view can't be null");
+
+        mAttachedView.measure(
+                View.MeasureSpec.makeMeasureSpec(mLayoutParams.width, View.MeasureSpec.EXACTLY),
+                View.MeasureSpec.makeMeasureSpec(mLayoutParams.height, View.MeasureSpec.EXACTLY)
+        );
+        mAttachedView.layout(0, 0, mAttachedView.getMeasuredWidth(), mAttachedView.getMeasuredHeight());
+
+        invalidate();
+    }
+
+    @Override
+    protected void initInGL(Context context) {
+        super.initInGL(context);
+
+        mTexture = new MD360BitmapTexture(new MDVRLibrary.IBitmapProvider() {
+            @Override
+            public void onProvideBitmap(MD360BitmapTexture.Callback callback) {
+                if (mBitmap != null){
+                    callback.texture(mBitmap);
+                }
+            }
+        });
+        mTexture.create();
+    }
+
+    @Override
+    public void renderer(int index, int width, int height, MD360Director director) {
+        if (mTexture == null || mBitmap == null){
+            return;
+        }
+
+        if (mInvalidate){
+            mInvalidate = false;
+            mTexture.notifyChanged();
+        }
+
+        mTexture.texture(program);
+
+        if (mTexture.isReady()){
+            super.renderer(index, width, height, director);
+        }
+    }
+
+    public <T extends View> T castAttachedView(Class<T> clazz){
+        notNull(clazz, "param clz can't be null.");
+        return clazz.cast(mAttachedView);
+    }
+
+    public View getAttachedView() {
+        return mAttachedView;
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDLayoutParams.java b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDLayoutParams.java
new file mode 100644
index 00000000..3699faa7
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDLayoutParams.java
@@ -0,0 +1,19 @@
+package com.asha.vrlib.plugins.hotspot;
+
+import android.view.ViewGroup;
+
+/**
+ * Created by hzqiujiadi on 2017/4/12.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public class MDLayoutParams extends ViewGroup.LayoutParams {
+
+    public MDLayoutParams(int width, int height) {
+        super(width, height);
+    }
+
+    public MDLayoutParams(ViewGroup.LayoutParams source) {
+        super(source);
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDSimpleHotspot.java b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDSimpleHotspot.java
new file mode 100644
index 00000000..0e29e8ff
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDSimpleHotspot.java
@@ -0,0 +1,76 @@
+package com.asha.vrlib.plugins.hotspot;
+
+import android.content.Context;
+import android.net.Uri;
+import android.util.SparseArray;
+
+import com.asha.vrlib.MD360Director;
+import com.asha.vrlib.MDVRLibrary;
+import com.asha.vrlib.model.MDHotspotBuilder;
+import com.asha.vrlib.texture.MD360BitmapTexture;
+import com.asha.vrlib.texture.MD360Texture;
+
+/**
+ * Created by hzqiujiadi on 2017/4/12.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public class MDSimpleHotspot extends MDAbsHotspot {
+
+    private static final String TAG = "MDSimplePlugin";
+
+    private SparseArray<Uri> uriList;
+
+    private int mPendingTextureKey = 0;
+
+    private int mCurrentTextureKey = 0;
+
+    // plugin
+    private MDVRLibrary.IImageLoadProvider provider;
+
+    private MD360Texture texture;
+
+    public MDSimpleHotspot(MDHotspotBuilder builder) {
+        super(builder.builderDelegate);
+        this.provider = builder.imageLoadProvider;
+        this.uriList = builder.uriList;
+    }
+
+    @Override
+    protected void initInGL(Context context) {
+        super.initInGL(context);
+
+        texture = new MD360BitmapTexture(new MDVRLibrary.IBitmapProvider() {
+            @Override
+            public void onProvideBitmap(MD360BitmapTexture.Callback callback) {
+                Uri uri = uriList.get(mCurrentTextureKey);
+                if (uri != null){
+                    provider.onProvideBitmap(uri, callback);
+                }
+            }
+        });
+        texture.create();
+    }
+
+    @Override
+    public void renderer(int index, int width, int height, MD360Director director) {
+        if (texture == null){
+            return;
+        }
+
+        if (mPendingTextureKey != mCurrentTextureKey){
+            mCurrentTextureKey = mPendingTextureKey;
+            texture.notifyChanged();
+        }
+
+        texture.texture(program);
+
+        if (texture.isReady()){
+            super.renderer(index, width, height, director);
+        }
+    }
+
+    public void useTexture(int key) {
+        mPendingTextureKey = key;
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDView.java b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDView.java
new file mode 100644
index 00000000..320a78b8
--- /dev/null
+++ b/vrlib/src/main/java/com/asha/vrlib/plugins/hotspot/MDView.java
@@ -0,0 +1,15 @@
+package com.asha.vrlib.plugins.hotspot;
+
+import com.asha.vrlib.model.MDViewBuilder;
+
+/**
+ * Created by hzqiujiadi on 2017/4/13.
+ * hzqiujiadi ashqalcn@gmail.com
+ */
+
+public class MDView extends MDAbsView {
+
+    public MDView(MDViewBuilder builder) {
+        super(builder);
+    }
+}
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/IModeStrategy.java b/vrlib/src/main/java/com/asha/vrlib/strategy/IModeStrategy.java
index b30b6e9d..50e9e1b1 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/IModeStrategy.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/IModeStrategy.java
@@ -9,9 +9,9 @@
  */
 public interface IModeStrategy {
 
-    void on(Activity activity);
+    void turnOnInGL(Activity activity);
 
-    void off(Activity activity);
+    void turnOffInGL(Activity activity);
     
     boolean isSupport(Activity activity);
 
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/ModeManager.java b/vrlib/src/main/java/com/asha/vrlib/strategy/ModeManager.java
index ebce3b0d..e45a4f8a 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/ModeManager.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/ModeManager.java
@@ -8,6 +8,8 @@
 
 import java.util.Arrays;
 
+import static com.asha.vrlib.common.VRUtil.checkMainThread;
+
 /**
  * Created by hzqiujiadi on 16/3/19.
  * hzqiujiadi ashqalcn@gmail.com
@@ -45,12 +47,16 @@ private void initMode(Activity activity, final int mode){
             MDMainHandler.sharedHandler().post(new Runnable() {
                 @Override
                 public void run() {
-                    if (mCallback != null) mCallback.onNotSupport(mode);
+                    if (mCallback != null) {
+                        mCallback.onNotSupport(mode);
+                    }
                 }
             });
-        } else {
-            on(activity);
+            return;
         }
+
+        // t
+        on(activity);
     }
 
     public void switchMode(final Activity activity){
@@ -71,24 +77,28 @@ public void switchMode(final Activity activity, final int mode){
     }
 
     public void on(final Activity activity) {
+        checkMainThread("strategy on must call from main thread!");
+
         final T tmpStrategy = mStrategy;
         if (tmpStrategy.isSupport(activity)){
             getGLHandler().post(new Runnable() {
                 @Override
                 public void run() {
-                    tmpStrategy.on(activity);
+                    tmpStrategy.turnOnInGL(activity);
                 }
             });
         }
     }
 
     public void off(final Activity activity) {
+        checkMainThread("strategy off must call from main thread!");
+
         final T tmpStrategy = mStrategy;
         if (tmpStrategy.isSupport(activity)){
             getGLHandler().post(new Runnable() {
                 @Override
                 public void run() {
-                    tmpStrategy.off(activity);
+                    tmpStrategy.turnOffInGL(activity);
                 }
             });
         }
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/display/GlassStrategy.java b/vrlib/src/main/java/com/asha/vrlib/strategy/display/GlassStrategy.java
index 5b23883d..b7bb8811 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/display/GlassStrategy.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/display/GlassStrategy.java
@@ -12,10 +12,10 @@ public class GlassStrategy extends AbsDisplayStrategy {
     public GlassStrategy() {}
 
     @Override
-    public void on(Activity activity) {}
+    public void turnOnInGL(Activity activity) {}
 
     @Override
-    public void off(Activity activity) {}
+    public void turnOffInGL(Activity activity) {}
 
     @Override
     public boolean isSupport(Activity activity) {
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/display/NormalStrategy.java b/vrlib/src/main/java/com/asha/vrlib/strategy/display/NormalStrategy.java
index 19c0441c..bb84bbc9 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/display/NormalStrategy.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/display/NormalStrategy.java
@@ -10,10 +10,10 @@
 public class NormalStrategy extends AbsDisplayStrategy {
 
     @Override
-    public void on(Activity activity) {}
+    public void turnOnInGL(Activity activity) {}
 
     @Override
-    public void off(Activity activity) {}
+    public void turnOffInGL(Activity activity) {}
 
     @Override
     public boolean isSupport(Activity activity) {
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/CardboardMotionStrategy.java b/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/CardboardMotionStrategy.java
index ca6446af..bdefe2ce 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/CardboardMotionStrategy.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/CardboardMotionStrategy.java
@@ -7,17 +7,14 @@
 import android.hardware.SensorEventListener;
 import android.hardware.SensorManager;
 import android.opengl.Matrix;
-import android.os.SystemClock;
 import android.util.Log;
-import android.view.Surface;
+import android.view.Display;
+import android.view.WindowManager;
 
 import com.asha.vrlib.MD360Director;
-import com.asha.vrlib.common.MDMainHandler;
-import com.asha.vrlib.common.VRUtil;
-import com.google.vrtoolkit.cardboard.sensors.internal.OrientationEKF;
-import com.google.vrtoolkit.cardboard.sensors.internal.Vector3d;
-
-import java.util.concurrent.TimeUnit;
+import com.google.vrtoolkit.cardboard.sensors.DeviceSensorLooper;
+import com.google.vrtoolkit.cardboard.sensors.HeadTracker;
+import com.google.vrtoolkit.cardboard.sensors.SystemClock;
 
 /**
  * Created by hzqiujiadi on 16/3/19.
@@ -27,29 +24,17 @@ public class CardboardMotionStrategy extends AbsInteractiveStrategy implements S
 
     private static final String TAG = "CardboardMotionStrategy";
 
-    private int mDeviceRotation;
-
-    private float[] mResultMatrix = new float[16];
-
-    private float[] mTmpMatrix = new float[16];
-
-    private float[] mRotateMatrix = new float[16];
-
-    private float[] mEkfToHeadTracker = new float[16];
-
     private boolean mRegistered = false;
 
     private Boolean mIsSupport = null;
 
-    private final OrientationEKF mTracker = new OrientationEKF();
-
-    private Vector3d mLatestAcc = new Vector3d();
+    private float[] mTmpMatrix = new float[16];
 
-    private long mLatestGyroEventClockTimeNs;
+    private final Object matrixLock = new Object();
 
-    private final Vector3d mGyroBias = new Vector3d();
+    private HeadTracker headTracker;
 
-    private final Vector3d mLatestGyro = new Vector3d();
+    private DeviceSensorLooper mDeviceSensorLooper;
 
     public CardboardMotionStrategy(InteractiveModeManager.Params params) {
         super(params);
@@ -72,20 +57,23 @@ public boolean handleDrag(int distanceX, int distanceY) {
 
     @Override
     public void onOrientationChanged(Activity activity) {
-        mDeviceRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
     }
 
     @Override
-    public void on(Activity activity) {
-        mDeviceRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
+    public void turnOnInGL(Activity activity) {
         for (MD360Director director : getDirectorList()){
             director.reset();
         }
     }
 
     @Override
-    public void off(Activity activity) {
-        unregisterSensor(activity);
+    public void turnOffInGL(final Activity activity) {
+        activity.runOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                unregisterSensor(activity);
+            }
+        });
     }
 
     @Override
@@ -100,11 +88,10 @@ public boolean isSupport(Activity activity) {
         return mIsSupport;
     }
 
-    protected void registerSensor(Context context){
+    private void registerSensor(Context context){
         if (mRegistered) return;
 
-        SensorManager mSensorManager = (SensorManager) context
-                .getSystemService(Context.SENSOR_SERVICE);
+        SensorManager mSensorManager = (SensorManager) context.getSystemService(Context.SENSOR_SERVICE);
         Sensor sensor1 = mSensorManager.getDefaultSensor(Sensor.TYPE_ACCELEROMETER);
         Sensor sensor2 = mSensorManager.getDefaultSensor(Sensor.TYPE_GYROSCOPE);
 
@@ -113,18 +100,28 @@ protected void registerSensor(Context context){
             return;
         }
 
-        mSensorManager.registerListener(this, sensor1, getParams().mMotionDelay, MDMainHandler.sharedHandler());
-        mSensorManager.registerListener(this, sensor2, getParams().mMotionDelay, MDMainHandler.sharedHandler());
+        if (mDeviceSensorLooper == null){
+            mDeviceSensorLooper = new DeviceSensorLooper(mSensorManager, getParams().mMotionDelay);
+        }
+
+        if (headTracker == null){
+            Display display = ((WindowManager)context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
+            headTracker = new HeadTracker(mDeviceSensorLooper, new SystemClock(), display);
+        }
+
+        // start the tracker
+        mDeviceSensorLooper.registerListener(this);
+        headTracker.startTracking();
 
         mRegistered = true;
     }
 
-    protected void unregisterSensor(Context context){
+    private void unregisterSensor(Context context){
         if (!mRegistered) return;
 
-        SensorManager mSensorManager = (SensorManager) context
-                .getSystemService(Context.SENSOR_SERVICE);
-        mSensorManager.unregisterListener(this);
+        // stop the tracker
+        mDeviceSensorLooper.unregisterListener(this);
+        headTracker.stopTracking();
 
         mRegistered = false;
     }
@@ -136,74 +133,40 @@ public void onSensorChanged(final SensorEvent event) {
                 getParams().mSensorListener.onSensorChanged(event);
             }
 
-            int type = event.sensor.getType();
-
-            if (type == Sensor.TYPE_ACCELEROMETER){
-                synchronized (mTracker){
-                    this.mLatestAcc.set(event.values[0], event.values[1], event.values[2]);
-                    this.mTracker.processAcc(this.mLatestAcc, event.timestamp);
-                }
-
-            } else if(type == Sensor.TYPE_GYROSCOPE){
-                synchronized (mTracker){
-                    this.mLatestGyroEventClockTimeNs = System.nanoTime();
-                    this.mLatestGyro.set(event.values[0], event.values[1], event.values[2]);
-                    Vector3d.sub(this.mLatestGyro, this.mGyroBias, this.mLatestGyro);
-                    this.mTracker.processGyro(this.mLatestGyro, event.timestamp);
-                }
+            synchronized (matrixLock){
+                Matrix.setIdentityM(mTmpMatrix, 0);
+                headTracker.getLastHeadView(mTmpMatrix, 0);
             }
 
             getParams().glHandler.post(updateSensorRunnable);
         }
     }
 
+    @Override
+    public void onAccuracyChanged(Sensor sensor, int accuracy) {
+        if (getParams().mSensorListener != null){
+            getParams().mSensorListener.onAccuracyChanged(sensor,accuracy);
+        }
+
+        synchronized (matrixLock){
+            Matrix.setIdentityM(mTmpMatrix, 0);
+            headTracker.getLastHeadView(mTmpMatrix, 0);
+        }
+
+        getParams().glHandler.post(updateSensorRunnable);
+    }
+
     private Runnable updateSensorRunnable = new Runnable() {
+
         @Override
         public void run() {
             if (!mRegistered) return;
 
-            // mTracker will be used in multi thread.
-            synchronized (mTracker){
-                final double secondsSinceLastGyroEvent = TimeUnit.NANOSECONDS.toSeconds(System.nanoTime() - mLatestGyroEventClockTimeNs);
-                final double secondsToPredictForward = secondsSinceLastGyroEvent + 1.0/60;
-                final double[] mat = mTracker.getPredictedGLMatrix(secondsToPredictForward);
-                for (int i = 0; i < mat.length; i++){
-                    mTmpMatrix[i] = (float) mat[i];
+            synchronized (matrixLock){
+                for (MD360Director director : getDirectorList()){
+                    director.updateSensorMatrix(mTmpMatrix);
                 }
             }
-
-            float rotation = 0;
-            switch (mDeviceRotation){
-                case Surface.ROTATION_0:
-                    rotation = 0;
-                    break;
-                case Surface.ROTATION_90:
-                    rotation = 90.0f;
-                    break;
-                case Surface.ROTATION_180:
-                    rotation = 180.0f;
-                    break;
-                case Surface.ROTATION_270:
-                    rotation = 270.0f;
-                    break;
-            }
-
-            Matrix.setRotateEulerM(mRotateMatrix, 0, 0.0f, 0.0f, -rotation);
-            Matrix.setRotateEulerM(mEkfToHeadTracker, 0, -90.0f, 0.0f, rotation);
-
-            Matrix.multiplyMM(mResultMatrix, 0, mRotateMatrix, 0, mTmpMatrix , 0);
-            Matrix.multiplyMM(mTmpMatrix, 0, mResultMatrix, 0, mEkfToHeadTracker, 0);
-
-            for (MD360Director director : getDirectorList()){
-                director.updateSensorMatrix(mTmpMatrix);
-            }
         }
     };
-
-    @Override
-    public void onAccuracyChanged(Sensor sensor, int accuracy) {
-        if (getParams().mSensorListener != null){
-            getParams().mSensorListener.onAccuracyChanged(sensor,accuracy);
-        }
-    }
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/MotionStrategy.java b/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/MotionStrategy.java
index e2c823c7..42063c28 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/MotionStrategy.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/MotionStrategy.java
@@ -57,7 +57,7 @@ public void onOrientationChanged(Activity activity) {
     }
 
     @Override
-    public void on(Activity activity) {
+    public void turnOnInGL(Activity activity) {
         mDeviceRotation = activity.getWindowManager().getDefaultDisplay().getRotation();
         for (MD360Director director : getDirectorList()){
             director.reset();
@@ -65,8 +65,13 @@ public void on(Activity activity) {
     }
 
     @Override
-    public void off(Activity activity) {
-        unregisterSensor(activity);
+    public void turnOffInGL(final Activity activity) {
+        activity.runOnUiThread(new Runnable() {
+            @Override
+            public void run() {
+                unregisterSensor(activity);
+            }
+        });
     }
 
     @Override
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/TouchStrategy.java b/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/TouchStrategy.java
index 590d7629..43169813 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/TouchStrategy.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/interactive/TouchStrategy.java
@@ -43,14 +43,14 @@ public void onOrientationChanged(Activity activity) {
     }
 
     @Override
-    public void on(Activity activity) {
+    public void turnOnInGL(Activity activity) {
         for (MD360Director director : getDirectorList()){
             director.reset();
         }
     }
 
     @Override
-    public void off(Activity activity) {
+    public void turnOffInGL(Activity activity) {
     }
 
     @Override
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/DomeProjection.java b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/DomeProjection.java
index 7f9baf91..887ed87b 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/DomeProjection.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/DomeProjection.java
@@ -32,13 +32,13 @@ public DomeProjection(RectF textureSize, float degree, boolean isUpper) {
     }
 
     @Override
-    public void on(Activity activity) {
+    public void turnOnInGL(Activity activity) {
         object3D = new MDDome3D(mTextureSize, mDegree, mIsUpper);
         MDObject3DHelper.loadObj(activity, object3D);
     }
 
     @Override
-    public void off(Activity activity) {
+    public void turnOffInGL(Activity activity) {
 
     }
 
@@ -54,7 +54,7 @@ public MDAbsObject3D getObject3D() {
 
     @Override
     public MDPosition getModelPosition() {
-        return MDPosition.sOriginalPosition;
+        return MDPosition.getOriginalPosition();
     }
 
     @Override
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/PlaneProjection.java b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/PlaneProjection.java
index d0e5b9cf..1eedbd2d 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/PlaneProjection.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/PlaneProjection.java
@@ -32,13 +32,13 @@ private PlaneProjection(PlaneScaleCalculator calculator) {
     }
 
     @Override
-    public void on(Activity activity) {
+    public void turnOnInGL(Activity activity) {
         object3D = new MDPlane(planeScaleCalculator);
         MDObject3DHelper.loadObj(activity, object3D);
     }
 
     @Override
-    public void off(Activity activity) {
+    public void turnOffInGL(Activity activity) {
 
     }
 
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/ProjectionModeManager.java b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/ProjectionModeManager.java
index f0359535..c7b5ffc1 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/ProjectionModeManager.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/ProjectionModeManager.java
@@ -17,6 +17,8 @@
 import java.util.LinkedList;
 import java.util.List;
 
+import static com.asha.vrlib.common.VRUtil.checkGLThread;
+
 /**
  * Created by hzqiujiadi on 16/6/25.
  * hzqiujiadi ashqalcn@gmail.com
@@ -71,7 +73,7 @@ public void on(Activity activity) {
 
         // destroy prev main plugin
         if( mMainPlugin != null){
-            mMainPlugin.destroy();
+            getGLHandler().post(new PluginDestroyTask(mMainPlugin));
             mMainPlugin = null;
         }
 
@@ -138,4 +140,23 @@ public MDAbsObject3D getObject3D() {
     public List<MD360Director> getDirectors() {
         return mDirectors;
     }
+
+    private static class PluginDestroyTask implements Runnable {
+
+        private MDAbsPlugin plugin;
+
+        public PluginDestroyTask(MDAbsPlugin plugin) {
+            this.plugin = plugin;
+        }
+
+        @Override
+        public void run() {
+            checkGLThread("must call in gl thread");
+
+            plugin.destroyInGL();
+            plugin = null;
+        }
+
+
+    }
 }
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/SphereProjection.java b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/SphereProjection.java
index 7077d904..295838b9 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/SphereProjection.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/SphereProjection.java
@@ -29,17 +29,17 @@ public MDAbsObject3D getObject3D() {
 
     @Override
     public MDPosition getModelPosition() {
-        return MDPosition.sOriginalPosition;
+        return MDPosition.getOriginalPosition();
     }
 
     @Override
-    public void on(Activity activity) {
+    public void turnOnInGL(Activity activity) {
         object3D = new MDSphere3D();
         MDObject3DHelper.loadObj(activity, object3D);
     }
 
     @Override
-    public void off(Activity activity) {
+    public void turnOffInGL(Activity activity) {
     }
 
     @Override
diff --git a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/StereoSphereProjection.java b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/StereoSphereProjection.java
index ba68e5c3..c02bf95c 100644
--- a/vrlib/src/main/java/com/asha/vrlib/strategy/projection/StereoSphereProjection.java
+++ b/vrlib/src/main/java/com/asha/vrlib/strategy/projection/StereoSphereProjection.java
@@ -35,13 +35,13 @@ public StereoSphereProjection(MDDirection direction) {
     }
 
     @Override
-    public void on(Activity activity) {
+    public void turnOnInGL(Activity activity) {
         object3D = new MDStereoSphere3D(direction);
         MDObject3DHelper.loadObj(activity, object3D);
     }
 
     @Override
-    public void off(Activity activity) {
+    public void turnOffInGL(Activity activity) {
 
     }
 
@@ -57,7 +57,7 @@ public MDAbsObject3D getObject3D() {
 
     @Override
     public MDPosition getModelPosition() {
-        return MDPosition.sOriginalPosition;
+        return MDPosition.getOriginalPosition();
     }
 
     @Override
diff --git a/vrlib/src/main/java/com/asha/vrlib/texture/MD360BitmapTexture.java b/vrlib/src/main/java/com/asha/vrlib/texture/MD360BitmapTexture.java
index 7bc27f79..dce57a9a 100644
--- a/vrlib/src/main/java/com/asha/vrlib/texture/MD360BitmapTexture.java
+++ b/vrlib/src/main/java/com/asha/vrlib/texture/MD360BitmapTexture.java
@@ -6,7 +6,6 @@
 
 import com.asha.vrlib.MD360Program;
 import com.asha.vrlib.MDVRLibrary;
-import com.asha.vrlib.common.GLUtil;
 import com.asha.vrlib.common.MDMainHandler;
 
 import java.lang.ref.SoftReference;
@@ -51,6 +50,7 @@ public boolean texture(MD360Program program) {
             mTextureDirty.set(false);
         }
 
+
         AsyncCallback asyncCallback = mTmpAsyncCallback;
         int textureId = getCurrentTextureId();
         if (asyncCallback != null && asyncCallback.hasBitmap()){
@@ -64,7 +64,6 @@ public boolean texture(MD360Program program) {
             GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
             GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);
             GLES20.glUniform1i(program.getTextureUniformHandle(), 0);
-            GLES20.glUniformMatrix4fv(program.getSTMatrixHandle(), 1, false, GLUtil.identityMatrix(), 0);
         }
         return true;
     }
@@ -116,7 +115,7 @@ public void release() {
     }
 
     private void textureInThread(int textureId, MD360Program program, Bitmap bitmap) {
-        notNull(bitmap,"bitmap can't be null!");
+        notNull(bitmap, "bitmap can't be null!");
 
         if (isEmpty(textureId)) return;
 
diff --git a/vrlib/src/main/java/com/asha/vrlib/texture/MD360VideoTexture.java b/vrlib/src/main/java/com/asha/vrlib/texture/MD360VideoTexture.java
index f0be501e..b5ce0a5f 100644
--- a/vrlib/src/main/java/com/asha/vrlib/texture/MD360VideoTexture.java
+++ b/vrlib/src/main/java/com/asha/vrlib/texture/MD360VideoTexture.java
@@ -22,6 +22,7 @@ public class MD360VideoTexture extends MD360Texture {
     private SurfaceTexture mSurfaceTexture;
     private MDVRLibrary.IOnSurfaceReadyCallback mOnSurfaceReadyListener;
     private float[] mTransformMatrix = new float[16];
+    private static final int[] sUseTransform = new int[]{1};
 
     public MD360VideoTexture(MDVRLibrary.IOnSurfaceReadyCallback onSurfaceReadyListener) {
         mOnSurfaceReadyListener = onSurfaceReadyListener;
@@ -101,6 +102,7 @@ public boolean texture(MD360Program program) {
 
         // surface transform get
         mSurfaceTexture.getTransformMatrix(mTransformMatrix);
+        GLES20.glUniform1iv(program.getUseTextureTransformHandle(), 1, sUseTransform, 0);
         GLES20.glUniformMatrix4fv(program.getSTMatrixHandle(), 1, false, mTransformMatrix, 0);
         return true;
     }
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/Clock.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/Clock.java
new file mode 100644
index 00000000..47b6ddbb
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/Clock.java
@@ -0,0 +1,10 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors;
+
+public interface Clock {
+    long nanoTime();
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/DeviceSensorLooper.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/DeviceSensorLooper.java
new file mode 100644
index 00000000..1f6aae73
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/DeviceSensorLooper.java
@@ -0,0 +1,113 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors;
+
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+import android.os.Build;
+import android.os.Handler;
+import android.os.HandlerThread;
+import android.os.Looper;
+import android.util.Log;
+
+import java.util.ArrayList;
+import java.util.Iterator;
+
+public class DeviceSensorLooper implements SensorEventProvider {
+    private static final String LOG_TAG = DeviceSensorLooper.class.getSimpleName();
+    private boolean isRunning;
+    private SensorManager sensorManager;
+    private Looper sensorLooper;
+    private SensorEventListener sensorEventListener;
+    private final ArrayList<SensorEventListener> registeredListeners = new ArrayList();
+    private int level;
+
+    public DeviceSensorLooper(SensorManager sensorManager, int level) {
+        this.sensorManager = sensorManager;
+        this.level = level;
+    }
+
+    public DeviceSensorLooper(SensorManager sensorManager) {
+        this(sensorManager, 0);
+    }
+
+    private Sensor getUncalibratedGyro() {
+        return Build.MANUFACTURER.equals("HTC")?null:this.sensorManager.getDefaultSensor(16);
+    }
+
+    public void start() {
+        if(!this.isRunning) {
+            this.sensorEventListener = new SensorEventListener() {
+                public void onSensorChanged(SensorEvent event) {
+                    synchronized(DeviceSensorLooper.this.registeredListeners) {
+                        Iterator var3 = DeviceSensorLooper.this.registeredListeners.iterator();
+
+                        while(var3.hasNext()) {
+                            SensorEventListener listener = (SensorEventListener)var3.next();
+                            listener.onSensorChanged(event);
+                        }
+
+                    }
+                }
+
+                public void onAccuracyChanged(Sensor sensor, int accuracy) {
+                    synchronized(DeviceSensorLooper.this.registeredListeners) {
+                        Iterator var4 = DeviceSensorLooper.this.registeredListeners.iterator();
+
+                        while(var4.hasNext()) {
+                            SensorEventListener listener = (SensorEventListener)var4.next();
+                            listener.onAccuracyChanged(sensor, accuracy);
+                        }
+
+                    }
+                }
+            };
+            HandlerThread sensorThread = new HandlerThread("sensor") {
+                protected void onLooperPrepared() {
+                    Handler handler = new Handler(Looper.myLooper());
+                    Sensor accelerometer = DeviceSensorLooper.this.sensorManager.getDefaultSensor(1);
+                    DeviceSensorLooper.this.sensorManager.registerListener(DeviceSensorLooper.this.sensorEventListener, accelerometer, level, handler);
+                    Sensor gyroscope = DeviceSensorLooper.this.getUncalibratedGyro();
+                    if(gyroscope == null) {
+                        Log.i(DeviceSensorLooper.LOG_TAG, "Uncalibrated gyroscope unavailable, default to regular gyroscope.");
+                        gyroscope = DeviceSensorLooper.this.sensorManager.getDefaultSensor(4);
+                    }
+
+                    DeviceSensorLooper.this.sensorManager.registerListener(DeviceSensorLooper.this.sensorEventListener, gyroscope, level, handler);
+                }
+            };
+            sensorThread.start();
+            this.sensorLooper = sensorThread.getLooper();
+            this.isRunning = true;
+        }
+    }
+
+    public void stop() {
+        if(this.isRunning) {
+            this.sensorManager.unregisterListener(this.sensorEventListener);
+            this.sensorEventListener = null;
+            this.sensorLooper.quit();
+            this.sensorLooper = null;
+            this.isRunning = false;
+        }
+    }
+
+    public void registerListener(SensorEventListener listener) {
+        ArrayList var2 = this.registeredListeners;
+        synchronized(this.registeredListeners) {
+            this.registeredListeners.add(listener);
+        }
+    }
+
+    public void unregisterListener(SensorEventListener listener) {
+        ArrayList var2 = this.registeredListeners;
+        synchronized(this.registeredListeners) {
+            this.registeredListeners.remove(listener);
+        }
+    }
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/HeadTracker.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/HeadTracker.java
new file mode 100644
index 00000000..276b58d7
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/HeadTracker.java
@@ -0,0 +1,249 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors;
+
+import android.content.Context;
+import android.hardware.Sensor;
+import android.hardware.SensorEvent;
+import android.hardware.SensorEventListener;
+import android.hardware.SensorManager;
+import android.opengl.Matrix;
+import android.view.Display;
+import android.view.WindowManager;
+
+import com.google.vrtoolkit.cardboard.sensors.internal.GyroscopeBiasEstimator;
+import com.google.vrtoolkit.cardboard.sensors.internal.Matrix3x3d;
+import com.google.vrtoolkit.cardboard.sensors.internal.OrientationEKF;
+import com.google.vrtoolkit.cardboard.sensors.internal.Vector3d;
+
+import java.util.concurrent.TimeUnit;
+
+public class HeadTracker implements SensorEventListener {
+    private static final float DEFAULT_NECK_HORIZONTAL_OFFSET = 0.08F;
+    private static final float DEFAULT_NECK_VERTICAL_OFFSET = 0.075F;
+    private static final float DEFAULT_NECK_MODEL_FACTOR = 1.0F;
+    private static final float PREDICTION_TIME_IN_SECONDS = 0.058F;
+    private final Display display;
+    private final float[] ekfToHeadTracker = new float[16];
+    private final float[] sensorToDisplay = new float[16];
+    private float displayRotation = -1.0F;
+    private final float[] neckModelTranslation = new float[16];
+    private final float[] tmpHeadView = new float[16];
+    private final float[] tmpHeadView2 = new float[16];
+    private float neckModelFactor = 1.0F;
+    private final Object neckModelFactorMutex = new Object();
+    private volatile boolean tracking;
+    private final OrientationEKF tracker;
+    private final Object gyroBiasEstimatorMutex = new Object();
+    private GyroscopeBiasEstimator gyroBiasEstimator;
+    private SensorEventProvider sensorEventProvider;
+    private Clock clock;
+    private long latestGyroEventClockTimeNs;
+    private volatile boolean firstGyroValue = true;
+    private float[] initialSystemGyroBias = new float[3];
+    private final Vector3d gyroBias = new Vector3d();
+    private final Vector3d latestGyro = new Vector3d();
+    private final Vector3d latestAcc = new Vector3d();
+
+    public static HeadTracker createFromContext(Context context) {
+        SensorManager sensorManager = (SensorManager)context.getSystemService(Context.SENSOR_SERVICE);
+        Display display = ((WindowManager)context.getSystemService(Context.WINDOW_SERVICE)).getDefaultDisplay();
+        return new HeadTracker(new DeviceSensorLooper(sensorManager), new SystemClock(), display);
+    }
+
+    public HeadTracker(SensorEventProvider sensorEventProvider, Clock clock, Display display) {
+        this.clock = clock;
+        this.sensorEventProvider = sensorEventProvider;
+        this.tracker = new OrientationEKF();
+        this.display = display;
+        this.setGyroBiasEstimationEnabled(true);
+        Matrix.setIdentityM(this.neckModelTranslation, 0);
+    }
+
+    public void onSensorChanged(SensorEvent event) {
+        Object var2;
+        if(event.sensor.getType() == 1) {
+            this.latestAcc.set((double)event.values[0], (double)event.values[1], (double)event.values[2]);
+            this.tracker.processAcc(this.latestAcc, event.timestamp);
+            var2 = this.gyroBiasEstimatorMutex;
+            synchronized(this.gyroBiasEstimatorMutex) {
+                if(this.gyroBiasEstimator != null) {
+                    this.gyroBiasEstimator.processAccelerometer(this.latestAcc, event.timestamp);
+                }
+            }
+        } else if(event.sensor.getType() == 4 || event.sensor.getType() == 16) {
+            this.latestGyroEventClockTimeNs = this.clock.nanoTime();
+            if(event.sensor.getType() == 16) {
+                if(this.firstGyroValue && event.values.length == 6) {
+                    this.initialSystemGyroBias[0] = event.values[3];
+                    this.initialSystemGyroBias[1] = event.values[4];
+                    this.initialSystemGyroBias[2] = event.values[5];
+                }
+
+                this.latestGyro.set((double)(event.values[0] - this.initialSystemGyroBias[0]), (double)(event.values[1] - this.initialSystemGyroBias[1]), (double)(event.values[2] - this.initialSystemGyroBias[2]));
+            } else {
+                this.latestGyro.set((double)event.values[0], (double)event.values[1], (double)event.values[2]);
+            }
+
+            this.firstGyroValue = false;
+            var2 = this.gyroBiasEstimatorMutex;
+            synchronized(this.gyroBiasEstimatorMutex) {
+                if(this.gyroBiasEstimator != null) {
+                    this.gyroBiasEstimator.processGyroscope(this.latestGyro, event.timestamp);
+                    this.gyroBiasEstimator.getGyroBias(this.gyroBias);
+                    Vector3d.sub(this.latestGyro, this.gyroBias, this.latestGyro);
+                }
+            }
+
+            this.tracker.processGyro(this.latestGyro, event.timestamp);
+        }
+
+    }
+
+    public void onAccuracyChanged(Sensor sensor, int accuracy) {
+    }
+
+    public void startTracking() {
+        if(!this.tracking) {
+            this.tracker.reset();
+            Object var1 = this.gyroBiasEstimatorMutex;
+            synchronized(this.gyroBiasEstimatorMutex) {
+                if(this.gyroBiasEstimator != null) {
+                    this.gyroBiasEstimator.reset();
+                }
+            }
+
+            this.firstGyroValue = true;
+            this.sensorEventProvider.registerListener(this);
+            this.sensorEventProvider.start();
+            this.tracking = true;
+        }
+    }
+
+    public void resetTracker() {
+        this.tracker.reset();
+    }
+
+    public void stopTracking() {
+        if(this.tracking) {
+            this.sensorEventProvider.unregisterListener(this);
+            this.sensorEventProvider.stop();
+            this.tracking = false;
+        }
+    }
+
+    public void setNeckModelEnabled(boolean enabled) {
+        if(enabled) {
+            this.setNeckModelFactor(1.0F);
+        } else {
+            this.setNeckModelFactor(0.0F);
+        }
+
+    }
+
+    public float getNeckModelFactor() {
+        Object var1 = this.neckModelFactorMutex;
+        synchronized(this.neckModelFactorMutex) {
+            return this.neckModelFactor;
+        }
+    }
+
+    public void setNeckModelFactor(float factor) {
+        Object var2 = this.neckModelFactorMutex;
+        synchronized(this.neckModelFactorMutex) {
+            if(factor >= 0.0F && factor <= 1.0F) {
+                this.neckModelFactor = factor;
+            } else {
+                throw new IllegalArgumentException("factor should be within [0.0, 1.0]");
+            }
+        }
+    }
+
+    public void setGyroBiasEstimationEnabled(boolean enabled) {
+        Object var2 = this.gyroBiasEstimatorMutex;
+        synchronized(this.gyroBiasEstimatorMutex) {
+            if(!enabled) {
+                this.gyroBiasEstimator = null;
+            } else if(this.gyroBiasEstimator == null) {
+                this.gyroBiasEstimator = new GyroscopeBiasEstimator();
+            }
+
+        }
+    }
+
+    public boolean getGyroBiasEstimationEnabled() {
+        Object var1 = this.gyroBiasEstimatorMutex;
+        synchronized(this.gyroBiasEstimatorMutex) {
+            return this.gyroBiasEstimator != null;
+        }
+    }
+
+    public void getLastHeadView(float[] headView, int offset) {
+        if(offset + 16 > headView.length) {
+            throw new IllegalArgumentException("Not enough space to write the result");
+        } else {
+            float rotation = 0.0F;
+            switch(this.display.getRotation()) {
+                case 0:
+                    rotation = 0.0F;
+                    break;
+                case 1:
+                    rotation = 90.0F;
+                    break;
+                case 2:
+                    rotation = 180.0F;
+                    break;
+                case 3:
+                    rotation = 270.0F;
+            }
+
+            if(rotation != this.displayRotation) {
+                this.displayRotation = rotation;
+                Matrix.setRotateEulerM(this.sensorToDisplay, 0, 0.0F, 0.0F, -rotation);
+                Matrix.setRotateEulerM(this.ekfToHeadTracker, 0, -90.0F, 0.0F, rotation);
+            }
+
+            OrientationEKF var4 = this.tracker;
+            synchronized(this.tracker) {
+                if(!this.tracker.isReady()) {
+                    return;
+                }
+
+                double secondsSinceLastGyroEvent = (double)TimeUnit.NANOSECONDS.toSeconds(this.clock.nanoTime() - this.latestGyroEventClockTimeNs);
+                double secondsToPredictForward = secondsSinceLastGyroEvent + 0.057999998331069946D;
+                double[] mat = this.tracker.getPredictedGLMatrix(secondsToPredictForward);
+                int i = 0;
+
+                while(true) {
+                    if(i >= headView.length) {
+                        break;
+                    }
+
+                    this.tmpHeadView[i] = (float)mat[i];
+                    ++i;
+                }
+            }
+
+            Matrix.multiplyMM(this.tmpHeadView2, 0, this.sensorToDisplay, 0, this.tmpHeadView, 0);
+            Matrix.multiplyMM(headView, offset, this.tmpHeadView2, 0, this.ekfToHeadTracker, 0);
+            Matrix.setIdentityM(this.neckModelTranslation, 0);
+            Matrix.translateM(this.neckModelTranslation, 0, 0.0F, -this.neckModelFactor * 0.075F, this.neckModelFactor * 0.08F);
+            Matrix.multiplyMM(this.tmpHeadView, 0, this.neckModelTranslation, 0, headView, offset);
+            Matrix.translateM(headView, offset, this.tmpHeadView, 0, 0.0F, this.neckModelFactor * 0.075F, 0.0F);
+        }
+    }
+
+    Matrix3x3d getCurrentPoseForTest() {
+        return new Matrix3x3d(this.tracker.getRotationMatrix());
+    }
+
+    void setGyroBiasEstimator(GyroscopeBiasEstimator estimator) {
+        Object var2 = this.gyroBiasEstimatorMutex;
+        synchronized(this.gyroBiasEstimatorMutex) {
+            this.gyroBiasEstimator = estimator;
+        }
+    }
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/SensorEventProvider.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/SensorEventProvider.java
new file mode 100644
index 00000000..e5651569
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/SensorEventProvider.java
@@ -0,0 +1,18 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors;
+
+import android.hardware.SensorEventListener;
+
+public interface SensorEventProvider {
+    void start();
+
+    void stop();
+
+    void registerListener(SensorEventListener var1);
+
+    void unregisterListener(SensorEventListener var1);
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/SystemClock.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/SystemClock.java
new file mode 100644
index 00000000..e3501661
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/SystemClock.java
@@ -0,0 +1,17 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors;
+
+import com.google.vrtoolkit.cardboard.sensors.Clock;
+
+public class SystemClock implements Clock {
+    public SystemClock() {
+    }
+
+    public long nanoTime() {
+        return System.nanoTime();
+    }
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/GyroBiasEstimator.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/GyroBiasEstimator.java
deleted file mode 100644
index 3f2c93b7..00000000
--- a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/GyroBiasEstimator.java
+++ /dev/null
@@ -1,142 +0,0 @@
-package com.google.vrtoolkit.cardboard.sensors.internal;
-
-public class GyroBiasEstimator {
-    private static final float GYRO_SMOOTHING_FACTOR = 0.01f;
-    private static final float ACC_SMOOTHING_FACTOR = 0.1f;
-    private static final Vector3d UP_VECTOR;
-    private static final float MIN_ACCEL_DOT_WITH_UP;
-    private static final float MIN_ACCEL_LENGTH = 1.0E-4f;
-    private static final float MAX_GYRO_DIFF = 0.01f;
-    private static final long CALIBRATION_DURATION_NS = 5000000000L;
-    private static final long MAX_DELAY_BETWEEN_EVENTS_NS = 100000000L;
-    private final Vector3d mLastGyro;
-    private final Vector3d mCurrGyro;
-    private final Vector3d mGyroDiff;
-    private final Vector3d mCurrAcc;
-    private final Vector3d mAccSmoothed;
-    private final Vector3d mAccNormalizedTmp;
-    private float mGyroMagnitudeDiffSmoothed;
-    private final Estimate mBiasEstimate;
-    private long mCalibrationStartTimeNs;
-    private long mLastGyroTimeNs;
-    private long mLastAccTimeNs;
-    
-    public GyroBiasEstimator() {
-        super();
-        this.mLastGyro = new Vector3d();
-        this.mCurrGyro = new Vector3d();
-        this.mGyroDiff = new Vector3d();
-        this.mCurrAcc = new Vector3d();
-        this.mAccSmoothed = new Vector3d();
-        this.mAccNormalizedTmp = new Vector3d();
-        this.mBiasEstimate = new Estimate();
-        this.mCalibrationStartTimeNs = -1L;
-        this.mLastGyroTimeNs = -1L;
-        this.mLastAccTimeNs = -1L;
-    }
-    
-    public void processGyroscope(final Vector3d gyro, final long sensorTimeStamp) {
-        if (this.mBiasEstimate.mState == Estimate.State.CALIBRATED) {
-            return;
-        }
-        this.mCurrGyro.set(gyro);
-        Vector3d.sub(this.mCurrGyro, this.mLastGyro, this.mGyroDiff);
-        final float mCurrDiff = (float)this.mGyroDiff.length();
-        this.mGyroMagnitudeDiffSmoothed = MAX_GYRO_DIFF * mCurrDiff + (1-MAX_GYRO_DIFF) * this.mGyroMagnitudeDiffSmoothed;
-        this.mLastGyro.set(this.mCurrGyro);
-        final boolean eventIsDelayed = sensorTimeStamp > this.mLastGyroTimeNs + MAX_DELAY_BETWEEN_EVENTS_NS;
-        this.mLastGyroTimeNs = sensorTimeStamp;
-        if (eventIsDelayed) {
-            this.resetCalibration();
-            return;
-        }
-        if (this.mBiasEstimate.mState == Estimate.State.CALIBRATING && sensorTimeStamp > this.mCalibrationStartTimeNs + CALIBRATION_DURATION_NS) {
-            this.mBiasEstimate.mState = Estimate.State.CALIBRATED;
-            return;
-        }
-        if (!this.canCalibrateGyro()) {
-            this.resetCalibration();
-            return;
-        }
-        this.startCalibration(sensorTimeStamp);
-    }
-    
-    private void resetCalibration() {
-        this.mBiasEstimate.mState = Estimate.State.UNCALIBRATED;
-        this.mBiasEstimate.mBias.set(0.0, 0.0, 0.0);
-        this.mCalibrationStartTimeNs = -1L;
-    }
-    
-    private void startCalibration(final long gyroTimeStamp) {
-        if (this.mBiasEstimate.mState != Estimate.State.CALIBRATING) {
-            this.mBiasEstimate.mBias.set(this.mCurrGyro);
-            this.mBiasEstimate.mState = Estimate.State.CALIBRATING;
-            this.mCalibrationStartTimeNs = gyroTimeStamp;
-        }
-        else {
-            smooth(this.mBiasEstimate.mBias, this.mCurrGyro, GYRO_SMOOTHING_FACTOR);
-        }
-    }
-    
-    public void processAccelerometer(final Vector3d acc, final long sensorTimeStamp) {
-        if (this.mBiasEstimate.mState == Estimate.State.CALIBRATED) {
-            return;
-        }
-        this.mCurrAcc.set(acc);
-        final boolean eventIsDelayed = sensorTimeStamp > this.mLastAccTimeNs + MAX_DELAY_BETWEEN_EVENTS_NS;
-        this.mLastAccTimeNs = sensorTimeStamp;
-        if (eventIsDelayed) {
-            this.resetCalibration();
-            return;
-        }
-        smooth(this.mAccSmoothed, this.mCurrAcc, ACC_SMOOTHING_FACTOR);
-    }
-    
-    public void getEstimate(final Estimate output) {
-        output.set(this.mBiasEstimate);
-    }
-    
-    private boolean canCalibrateGyro() {
-        if (this.mAccSmoothed.length() < MIN_ACCEL_LENGTH) {
-            return false;
-        }
-        this.mAccNormalizedTmp.set(this.mAccSmoothed);
-        this.mAccNormalizedTmp.normalize();
-        return Vector3d.dot(this.mAccNormalizedTmp, GyroBiasEstimator.UP_VECTOR) >= GyroBiasEstimator.MIN_ACCEL_DOT_WITH_UP && this.mGyroMagnitudeDiffSmoothed <= 0.01f;
-    }
-    
-    private static void smooth(final Vector3d smoothed, final Vector3d newValue, final float smoothingFactor) {
-        smoothed.x = smoothingFactor * newValue.x + (1.0f - smoothingFactor) * smoothed.x;
-        smoothed.y = smoothingFactor * newValue.y + (1.0f - smoothingFactor) * smoothed.y;
-        smoothed.z = smoothingFactor * newValue.z + (1.0f - smoothingFactor) * smoothed.z;
-    }
-    
-    static {
-        UP_VECTOR = new Vector3d(0.0, 0.0, 1.0);
-        MIN_ACCEL_DOT_WITH_UP = (float)Math.cos(Math.toRadians(10.0));
-    }
-    
-    public static class Estimate
-    {
-        public State mState;
-        public final Vector3d mBias;
-        
-        public Estimate() {
-            super();
-            this.mState = State.UNCALIBRATED;
-            this.mBias = new Vector3d();
-        }
-        
-        public void set(final Estimate from) {
-            this.mState = from.mState;
-            this.mBias.set(from.mBias);
-        }
-        
-        public enum State
-        {
-            UNCALIBRATED, 
-            CALIBRATING, 
-            CALIBRATED;
-        }
-    }
-}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/GyroscopeBiasEstimator.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/GyroscopeBiasEstimator.java
new file mode 100644
index 00000000..cbb2c520
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/GyroscopeBiasEstimator.java
@@ -0,0 +1,96 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors.internal;
+
+public class GyroscopeBiasEstimator {
+    private static final float ACCEL_LOWPASS_FREQ = 1.0F;
+    private static final float GYRO_LOWPASS_FREQ = 10.0F;
+    private static final float GYRO_BIAS_LOWPASS_FREQ = 0.15F;
+    private static final int NUM_GYRO_BIAS_SAMPLES_THRESHOLD = 30;
+    private static final int NUM_GYRO_BIAS_SAMPLES_INITIAL_SMOOTHING = 100;
+    private LowPassFilter accelLowPass;
+    private LowPassFilter gyroLowPass;
+    private LowPassFilter gyroBiasLowPass;
+    private static final float ACCEL_DIFF_STATIC_THRESHOLD = 0.5F;
+    private static final float GYRO_DIFF_STATIC_THRESHOLD = 0.008F;
+    private Vector3d smoothedGyroDiff;
+    private Vector3d smoothedAccelDiff;
+    private static final float GYRO_FOR_BIAS_THRESHOLD = 0.35F;
+    private static final int IS_STATIC_NUM_FRAMES_THRESHOLD = 10;
+    private GyroscopeBiasEstimator.IsStaticCounter isAccelStatic;
+    private GyroscopeBiasEstimator.IsStaticCounter isGyroStatic;
+
+    public GyroscopeBiasEstimator() {
+        this.reset();
+    }
+
+    public void reset() {
+        this.smoothedGyroDiff = new Vector3d();
+        this.smoothedAccelDiff = new Vector3d();
+        this.accelLowPass = new LowPassFilter(1.0D);
+        this.gyroLowPass = new LowPassFilter(10.0D);
+        this.gyroBiasLowPass = new LowPassFilter(0.15000000596046448D);
+        this.isAccelStatic = new GyroscopeBiasEstimator.IsStaticCounter(10);
+        this.isGyroStatic = new GyroscopeBiasEstimator.IsStaticCounter(10);
+    }
+
+    public void processGyroscope(Vector3d gyro, long sensorTimestampNs) {
+        this.gyroLowPass.addSample(gyro, sensorTimestampNs);
+        Vector3d.sub(gyro, this.gyroLowPass.getFilteredData(), this.smoothedGyroDiff);
+        this.isGyroStatic.appendFrame(this.smoothedGyroDiff.length() < 0.00800000037997961D);
+        if(this.isGyroStatic.isRecentlyStatic() && this.isAccelStatic.isRecentlyStatic()) {
+            this.updateGyroBias(gyro, sensorTimestampNs);
+        }
+
+    }
+
+    public void processAccelerometer(Vector3d accel, long sensorTimestampNs) {
+        this.accelLowPass.addSample(accel, sensorTimestampNs);
+        Vector3d.sub(accel, this.accelLowPass.getFilteredData(), this.smoothedAccelDiff);
+        this.isAccelStatic.appendFrame(this.smoothedAccelDiff.length() < 0.5D);
+    }
+
+    public void getGyroBias(Vector3d result) {
+        if(this.gyroBiasLowPass.getNumSamples() < 30) {
+            result.setZero();
+        } else {
+            result.set(this.gyroBiasLowPass.getFilteredData());
+            double rampUpRatio = Math.min(1.0D, (double)(this.gyroBiasLowPass.getNumSamples() - 30) / 100.0D);
+            result.scale(rampUpRatio);
+        }
+
+    }
+
+    private void updateGyroBias(Vector3d gyro, long sensorTimestampNs) {
+        if(gyro.length() < 0.3499999940395355D) {
+            double updateWeight = Math.max(0.0D, 1.0D - gyro.length() / 0.3499999940395355D);
+            updateWeight *= updateWeight;
+            this.gyroBiasLowPass.addWeightedSample(this.gyroLowPass.getFilteredData(), sensorTimestampNs, updateWeight);
+        }
+    }
+
+    private static class IsStaticCounter {
+        private final int minStaticFrames;
+        private int consecutiveIsStatic;
+
+        IsStaticCounter(int minStaticFrames) {
+            this.minStaticFrames = minStaticFrames;
+        }
+
+        void appendFrame(boolean isStatic) {
+            if(!isStatic) {
+                this.consecutiveIsStatic = 0;
+            } else {
+                ++this.consecutiveIsStatic;
+            }
+
+        }
+
+        boolean isRecentlyStatic() {
+            return this.consecutiveIsStatic >= this.minStaticFrames;
+        }
+    }
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/LowPassFilter.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/LowPassFilter.java
new file mode 100644
index 00000000..4730d9b2
--- /dev/null
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/LowPassFilter.java
@@ -0,0 +1,53 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
+package com.google.vrtoolkit.cardboard.sensors.internal;
+
+import java.util.concurrent.TimeUnit;
+
+public class LowPassFilter {
+    private static final double NANOS_TO_SECONDS;
+    private final double timeConstantSecs;
+    private final Vector3d filteredData = new Vector3d();
+    private long lastTimestampNs;
+    private int numSamples;
+    private final Vector3d temp = new Vector3d();
+
+    public LowPassFilter(double cutoffFrequency) {
+        this.timeConstantSecs = 1.0D / (6.283185307179586D * cutoffFrequency);
+    }
+
+    public int getNumSamples() {
+        return this.numSamples;
+    }
+
+    public void addSample(Vector3d sampleData, long timestampNs) {
+        this.addWeightedSample(sampleData, timestampNs, 1.0D);
+    }
+
+    public void addWeightedSample(Vector3d sampleData, long timestampNs, double weight) {
+        ++this.numSamples;
+        if(this.numSamples == 1) {
+            this.filteredData.set(sampleData);
+            this.lastTimestampNs = timestampNs;
+        } else {
+            double weightedDeltaSecs = weight * (double)(timestampNs - this.lastTimestampNs) * NANOS_TO_SECONDS;
+            double alpha = weightedDeltaSecs / (this.timeConstantSecs + weightedDeltaSecs);
+            this.filteredData.scale(1.0D - alpha);
+            this.temp.set(sampleData);
+            this.temp.scale(alpha);
+            Vector3d.add(this.temp, this.filteredData, this.filteredData);
+            this.lastTimestampNs = timestampNs;
+        }
+    }
+
+    public Vector3d getFilteredData() {
+        return this.filteredData;
+    }
+
+    static {
+        NANOS_TO_SECONDS = 1.0D / (double)TimeUnit.NANOSECONDS.convert(1L, TimeUnit.SECONDS);
+    }
+}
diff --git a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/OrientationEKF.java b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/OrientationEKF.java
index 60bc3777..3d187efa 100644
--- a/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/OrientationEKF.java
+++ b/vrlib/src/main/java/com/google/vrtoolkit/cardboard/sensors/internal/OrientationEKF.java
@@ -1,137 +1,89 @@
+//
+// Source code recreated from a .class file by IntelliJ IDEA
+// (powered by Fernflower decompiler)
+//
+
 package com.google.vrtoolkit.cardboard.sensors.internal;
 
 public class OrientationEKF {
-    private static final String TAG = "OrientationEKF";
-
-    private static final float NS2S = 1.0E-9f;
-    private static final double MIN_ACCEL_NOISE_SIGMA = 0.75;
-    private static final double MAX_ACCEL_NOISE_SIGMA = 7.0;
-    private double[] rotationMatrix;
-    private Matrix3x3d so3SensorFromWorld;
-    private Matrix3x3d so3LastMotion;
-    private Matrix3x3d mP;
-    private Matrix3x3d mQ;
-    private Matrix3x3d mR;
-    private Matrix3x3d mRaccel;
-    private Matrix3x3d mS;
-    private Matrix3x3d mH;
-    private Matrix3x3d mK;
-    private Vector3d mNu;
-    private Vector3d mz;
-    private Vector3d mh;
-    private Vector3d mu;
-    private Vector3d mx;
-    private Vector3d down;
-    private Vector3d north;
+    private static final float NS2S = 1.0E-9F;
+    private static final double MIN_ACCEL_NOISE_SIGMA = 0.75D;
+    private static final double MAX_ACCEL_NOISE_SIGMA = 7.0D;
+    private double[] rotationMatrix = new double[16];
+    private Matrix3x3d so3SensorFromWorld = new Matrix3x3d();
+    private Matrix3x3d so3LastMotion = new Matrix3x3d();
+    private Matrix3x3d mP = new Matrix3x3d();
+    private Matrix3x3d mQ = new Matrix3x3d();
+    private Matrix3x3d mR = new Matrix3x3d();
+    private Matrix3x3d mRaccel = new Matrix3x3d();
+    private Matrix3x3d mS = new Matrix3x3d();
+    private Matrix3x3d mH = new Matrix3x3d();
+    private Matrix3x3d mK = new Matrix3x3d();
+    private Vector3d mNu = new Vector3d();
+    private Vector3d mz = new Vector3d();
+    private Vector3d mh = new Vector3d();
+    private Vector3d mu = new Vector3d();
+    private Vector3d mx = new Vector3d();
+    private Vector3d down = new Vector3d();
+    private Vector3d north = new Vector3d();
     private long sensorTimeStampGyro;
-    private final Vector3d lastGyro;
-    private double previousAccelNorm;
-    private double movingAverageAccelNormChange;
+    private final Vector3d lastGyro = new Vector3d();
+    private double previousAccelNorm = 0.0D;
+    private double movingAverageAccelNormChange = 0.0D;
     private float filteredGyroTimestep;
-    private boolean timestepFilterInit;
+    private boolean timestepFilterInit = false;
     private int numGyroTimestepSamples;
-    private boolean gyroFilterValid;
-    private Matrix3x3d getPredictedGLMatrixTempM1;
-    private Matrix3x3d getPredictedGLMatrixTempM2;
-    private Vector3d getPredictedGLMatrixTempV1;
-    private Matrix3x3d setHeadingDegreesTempM1;
-    private Matrix3x3d processGyroTempM1;
-    private Matrix3x3d processGyroTempM2;
-    private Matrix3x3d processAccTempM1;
-    private Matrix3x3d processAccTempM2;
-    private Matrix3x3d processAccTempM3;
-    private Matrix3x3d processAccTempM4;
-    private Matrix3x3d processAccTempM5;
-    private Vector3d processAccTempV1;
-    private Vector3d processAccTempV2;
-    private Vector3d processAccVDelta;
-    private Vector3d processMagTempV1;
-    private Vector3d processMagTempV2;
-    private Vector3d processMagTempV3;
-    private Vector3d processMagTempV4;
-    private Vector3d processMagTempV5;
-    private Matrix3x3d processMagTempM1;
-    private Matrix3x3d processMagTempM2;
-    private Matrix3x3d processMagTempM4;
-    private Matrix3x3d processMagTempM5;
-    private Matrix3x3d processMagTempM6;
-    private Matrix3x3d updateCovariancesAfterMotionTempM1;
-    private Matrix3x3d updateCovariancesAfterMotionTempM2;
-    private Matrix3x3d accObservationFunctionForNumericalJacobianTempM;
-    private Matrix3x3d magObservationFunctionForNumericalJacobianTempM;
+    private boolean gyroFilterValid = true;
+    private Matrix3x3d getPredictedGLMatrixTempM1 = new Matrix3x3d();
+    private Matrix3x3d getPredictedGLMatrixTempM2 = new Matrix3x3d();
+    private Vector3d getPredictedGLMatrixTempV1 = new Vector3d();
+    private Matrix3x3d setHeadingDegreesTempM1 = new Matrix3x3d();
+    private Matrix3x3d processGyroTempM1 = new Matrix3x3d();
+    private Matrix3x3d processGyroTempM2 = new Matrix3x3d();
+    private Matrix3x3d processAccTempM1 = new Matrix3x3d();
+    private Matrix3x3d processAccTempM2 = new Matrix3x3d();
+    private Matrix3x3d processAccTempM3 = new Matrix3x3d();
+    private Matrix3x3d processAccTempM4 = new Matrix3x3d();
+    private Matrix3x3d processAccTempM5 = new Matrix3x3d();
+    private Vector3d processAccTempV1 = new Vector3d();
+    private Vector3d processAccTempV2 = new Vector3d();
+    private Vector3d processAccVDelta = new Vector3d();
+    private Vector3d processMagTempV1 = new Vector3d();
+    private Vector3d processMagTempV2 = new Vector3d();
+    private Vector3d processMagTempV3 = new Vector3d();
+    private Vector3d processMagTempV4 = new Vector3d();
+    private Vector3d processMagTempV5 = new Vector3d();
+    private Matrix3x3d processMagTempM1 = new Matrix3x3d();
+    private Matrix3x3d processMagTempM2 = new Matrix3x3d();
+    private Matrix3x3d processMagTempM4 = new Matrix3x3d();
+    private Matrix3x3d processMagTempM5 = new Matrix3x3d();
+    private Matrix3x3d processMagTempM6 = new Matrix3x3d();
+    private Matrix3x3d updateCovariancesAfterMotionTempM1 = new Matrix3x3d();
+    private Matrix3x3d updateCovariancesAfterMotionTempM2 = new Matrix3x3d();
+    private Matrix3x3d accObservationFunctionForNumericalJacobianTempM = new Matrix3x3d();
+    private Matrix3x3d magObservationFunctionForNumericalJacobianTempM = new Matrix3x3d();
     private boolean alignedToGravity;
     private boolean alignedToNorth;
-    
+
     public OrientationEKF() {
-        super();
-        this.rotationMatrix = new double[16];
-        this.so3SensorFromWorld = new Matrix3x3d();
-        this.so3LastMotion = new Matrix3x3d();
-        this.mP = new Matrix3x3d();
-        this.mQ = new Matrix3x3d();
-        this.mR = new Matrix3x3d();
-        this.mRaccel = new Matrix3x3d();
-        this.mS = new Matrix3x3d();
-        this.mH = new Matrix3x3d();
-        this.mK = new Matrix3x3d();
-        this.mNu = new Vector3d();
-        this.mz = new Vector3d();
-        this.mh = new Vector3d();
-        this.mu = new Vector3d();
-        this.mx = new Vector3d();
-        this.down = new Vector3d();
-        this.north = new Vector3d();
-        this.lastGyro = new Vector3d();
-        this.previousAccelNorm = 0.0;
-        this.movingAverageAccelNormChange = 0.0;
-        this.timestepFilterInit = false;
-        this.gyroFilterValid = true;
-        this.getPredictedGLMatrixTempM1 = new Matrix3x3d();
-        this.getPredictedGLMatrixTempM2 = new Matrix3x3d();
-        this.getPredictedGLMatrixTempV1 = new Vector3d();
-        this.setHeadingDegreesTempM1 = new Matrix3x3d();
-        this.processGyroTempM1 = new Matrix3x3d();
-        this.processGyroTempM2 = new Matrix3x3d();
-        this.processAccTempM1 = new Matrix3x3d();
-        this.processAccTempM2 = new Matrix3x3d();
-        this.processAccTempM3 = new Matrix3x3d();
-        this.processAccTempM4 = new Matrix3x3d();
-        this.processAccTempM5 = new Matrix3x3d();
-        this.processAccTempV1 = new Vector3d();
-        this.processAccTempV2 = new Vector3d();
-        this.processAccVDelta = new Vector3d();
-        this.processMagTempV1 = new Vector3d();
-        this.processMagTempV2 = new Vector3d();
-        this.processMagTempV3 = new Vector3d();
-        this.processMagTempV4 = new Vector3d();
-        this.processMagTempV5 = new Vector3d();
-        this.processMagTempM1 = new Matrix3x3d();
-        this.processMagTempM2 = new Matrix3x3d();
-        this.processMagTempM4 = new Matrix3x3d();
-        this.processMagTempM5 = new Matrix3x3d();
-        this.processMagTempM6 = new Matrix3x3d();
-        this.updateCovariancesAfterMotionTempM1 = new Matrix3x3d();
-        this.updateCovariancesAfterMotionTempM2 = new Matrix3x3d();
-        this.accObservationFunctionForNumericalJacobianTempM = new Matrix3x3d();
-        this.magObservationFunctionForNumericalJacobianTempM = new Matrix3x3d();
         this.reset();
     }
-    
-    public void reset() {
+
+    public synchronized void reset() {
         this.sensorTimeStampGyro = 0L;
         this.so3SensorFromWorld.setIdentity();
         this.so3LastMotion.setIdentity();
-        final double initialSigmaP = 5.0;
+        double initialSigmaP = 5.0D;
         this.mP.setZero();
-        this.mP.setSameDiagonal(25.0);
-        final double initialSigmaQ = 1.0;
+        this.mP.setSameDiagonal(25.0D);
+        double initialSigmaQ = 1.0D;
         this.mQ.setZero();
-        this.mQ.setSameDiagonal(1.0);
-        final double initialSigmaR = 0.25;
+        this.mQ.setSameDiagonal(1.0D);
+        double initialSigmaR = 0.25D;
         this.mR.setZero();
-        this.mR.setSameDiagonal(0.0625);
+        this.mR.setSameDiagonal(0.0625D);
         this.mRaccel.setZero();
-        this.mRaccel.setSameDiagonal(0.5625);
+        this.mRaccel.setSameDiagonal(0.5625D);
         this.mS.setZero();
         this.mH.setZero();
         this.mK.setZero();
@@ -140,135 +92,143 @@ public void reset() {
         this.mh.setZero();
         this.mu.setZero();
         this.mx.setZero();
-        this.down.set(0.0, 0.0, 9.81);
-        this.north.set(0.0, 1.0, 0.0);
+        this.down.set(0.0D, 0.0D, 9.81D);
+        this.north.set(0.0D, 1.0D, 0.0D);
         this.alignedToGravity = false;
         this.alignedToNorth = false;
     }
-    
+
     public boolean isReady() {
         return this.alignedToGravity;
     }
-    
+
     public double getHeadingDegrees() {
-        final double x = this.so3SensorFromWorld.get(2, 0);
-        final double y = this.so3SensorFromWorld.get(2, 1);
-        final double mag = Math.sqrt(x * x + y * y);
-        if (mag < 0.1) {
-            return 0.0;
-        }
-        double heading = -90.0 - Math.atan2(y, x) / 3.141592653589793 * 180.0;
-        if (heading < 0.0) {
-            heading += 360.0;
-        }
-        if (heading >= 360.0) {
-            heading -= 360.0;
+        double x = this.so3SensorFromWorld.get(2, 0);
+        double y = this.so3SensorFromWorld.get(2, 1);
+        double mag = Math.sqrt(x * x + y * y);
+        if(mag < 0.1D) {
+            return 0.0D;
+        } else {
+            double heading = -90.0D - Math.atan2(y, x) / 3.141592653589793D * 180.0D;
+            if(heading < 0.0D) {
+                heading += 360.0D;
+            }
+
+            if(heading >= 360.0D) {
+                heading -= 360.0D;
+            }
+
+            return heading;
         }
-        return heading;
     }
-    
-    public synchronized void setHeadingDegrees(final double heading) {
-        final double currentHeading = this.getHeadingDegrees();
-        final double deltaHeading = heading - currentHeading;
-        final double s = Math.sin(deltaHeading / 180.0 * 3.141592653589793);
-        final double c = Math.cos(deltaHeading / 180.0 * 3.141592653589793);
-        final double[][] deltaHeadingRotationVals = { { c, -s, 0.0 }, { s, c, 0.0 }, { 0.0, 0.0, 1.0 } };
+
+    public synchronized void setHeadingDegrees(double heading) {
+        double currentHeading = this.getHeadingDegrees();
+        double deltaHeading = heading - currentHeading;
+        double s = Math.sin(deltaHeading / 180.0D * 3.141592653589793D);
+        double c = Math.cos(deltaHeading / 180.0D * 3.141592653589793D);
+        double[][] deltaHeadingRotationVals = new double[][]{{c, -s, 0.0D}, {s, c, 0.0D}, {0.0D, 0.0D, 1.0D}};
         arrayAssign(deltaHeadingRotationVals, this.setHeadingDegreesTempM1);
         Matrix3x3d.mult(this.so3SensorFromWorld, this.setHeadingDegreesTempM1, this.so3SensorFromWorld);
     }
-    
+
     public double[] getGLMatrix() {
         return this.glMatrixFromSo3(this.so3SensorFromWorld);
     }
-    
-    public double[] getPredictedGLMatrix(final double secondsAfterLastGyroEvent) {
-        final Vector3d pmu = this.getPredictedGLMatrixTempV1;
+
+    public double[] getPredictedGLMatrix(double secondsAfterLastGyroEvent) {
+        Vector3d pmu = this.getPredictedGLMatrixTempV1;
         pmu.set(this.lastGyro);
         pmu.scale(-secondsAfterLastGyroEvent);
-        final Matrix3x3d so3PredictedMotion = this.getPredictedGLMatrixTempM1;
+        Matrix3x3d so3PredictedMotion = this.getPredictedGLMatrixTempM1;
         So3Util.sO3FromMu(pmu, so3PredictedMotion);
-        final Matrix3x3d so3PredictedState = this.getPredictedGLMatrixTempM2;
+        Matrix3x3d so3PredictedState = this.getPredictedGLMatrixTempM2;
         Matrix3x3d.mult(so3PredictedMotion, this.so3SensorFromWorld, so3PredictedState);
         return this.glMatrixFromSo3(so3PredictedState);
     }
-    
+
     public Matrix3x3d getRotationMatrix() {
         return this.so3SensorFromWorld;
     }
-    
-    public static void arrayAssign(final double[][] data, final Matrix3x3d m) {
+
+    public static void arrayAssign(double[][] data, Matrix3x3d m) {
         assert 3 == data.length;
+
         assert 3 == data[0].length;
+
         assert 3 == data[1].length;
+
         assert 3 == data[2].length;
+
         m.set(data[0][0], data[0][1], data[0][2], data[1][0], data[1][1], data[1][2], data[2][0], data[2][1], data[2][2]);
     }
-    
+
     public boolean isAlignedToGravity() {
         return this.alignedToGravity;
     }
-    
+
     public boolean isAlignedToNorth() {
         return this.alignedToNorth;
     }
-    
-    public synchronized void processGyro(final Vector3d gyro, final long sensorTimeStamp) {
-        final float kTimeThreshold = 0.04f;
-        final float kdTDefault = 0.01f;
-        if (this.sensorTimeStampGyro != 0L) {
-            float dT = (sensorTimeStamp - this.sensorTimeStampGyro) * 1.0E-9f;
-            if (dT > kTimeThreshold) {
-                dT = (this.gyroFilterValid ? this.filteredGyroTimestep : kdTDefault );
-            }
-            else {
+
+    public synchronized void processGyro(Vector3d gyro, long sensorTimeStamp) {
+        float kTimeThreshold = 0.04F;
+        float kdTdefault = 0.01F;
+        if(this.sensorTimeStampGyro != 0L) {
+            float dT = (float)(sensorTimeStamp - this.sensorTimeStampGyro) * 1.0E-9F;
+            if(dT > 0.04F) {
+                dT = this.gyroFilterValid?this.filteredGyroTimestep:0.01F;
+            } else {
                 this.filterGyroTimestep(dT);
             }
+
             this.mu.set(gyro);
-            this.mu.scale(-dT);
+            this.mu.scale((double)(-dT));
             So3Util.sO3FromMu(this.mu, this.so3LastMotion);
-            Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.so3SensorFromWorld);
+            this.processGyroTempM1.set(this.so3SensorFromWorld);
+            Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.processGyroTempM1);
+            this.so3SensorFromWorld.set(this.processGyroTempM1);
             this.updateCovariancesAfterMotion();
             this.processGyroTempM2.set(this.mQ);
-            this.processGyroTempM2.scale(dT * dT);
+            this.processGyroTempM2.scale((double)(dT * dT));
             this.mP.plusEquals(this.processGyroTempM2);
         }
+
         this.sensorTimeStampGyro = sensorTimeStamp;
         this.lastGyro.set(gyro);
     }
-    
-    private void updateAccelCovariance(final double currentAccelNorm) {
-        final double currentAccelNormChange = Math.abs(currentAccelNorm - this.previousAccelNorm);
+
+    private void updateAccelCovariance(double currentAccelNorm) {
+        double currentAccelNormChange = Math.abs(currentAccelNorm - this.previousAccelNorm);
         this.previousAccelNorm = currentAccelNorm;
-        final double kSmoothingFactor = 0.5;
-        this.movingAverageAccelNormChange = kSmoothingFactor * currentAccelNormChange
-                + kSmoothingFactor * this.movingAverageAccelNormChange;
-        final double kMaxAccelNormChange = 0.15;
-        final double kMinAccelNoiseSigma = 0.75;
-        final double kMaxAccelNoiseSigma = 7.0;
-        final double normChangeRatio = this.movingAverageAccelNormChange / kMaxAccelNormChange;
-        final double accelNoiseSigma = Math.min(kMaxAccelNoiseSigma,
-                kMinAccelNoiseSigma + normChangeRatio * (kMaxAccelNoiseSigma - kMinAccelNoiseSigma));
+        double kSmoothingFactor = 0.5D;
+        this.movingAverageAccelNormChange = 0.5D * currentAccelNormChange + 0.5D * this.movingAverageAccelNormChange;
+        double kMaxAccelNormChange = 0.15D;
+        double normChangeRatio = this.movingAverageAccelNormChange / 0.15D;
+        double accelNoiseSigma = Math.min(7.0D, 0.75D + normChangeRatio * 6.25D);
         this.mRaccel.setSameDiagonal(accelNoiseSigma * accelNoiseSigma);
     }
-    
-    public synchronized void processAcc(final Vector3d acc, final long sensorTimeStamp) {
+
+    public synchronized void processAcc(Vector3d acc, long sensorTimeStamp) {
         this.mz.set(acc);
         this.updateAccelCovariance(this.mz.length());
-        if (this.alignedToGravity) {
+        if(this.alignedToGravity) {
             this.accObservationFunctionForNumericalJacobian(this.so3SensorFromWorld, this.mNu);
-            final double eps = 1.0E-7;
-            for (int dof = 0; dof < 3; ++dof) {
-                final Vector3d delta = this.processAccVDelta;
+            double eps = 1.0E-7D;
+
+            for(int dof = 0; dof < 3; ++dof) {
+                Vector3d delta = this.processAccVDelta;
                 delta.setZero();
                 delta.setComponent(dof, eps);
                 So3Util.sO3FromMu(delta, this.processAccTempM1);
                 Matrix3x3d.mult(this.processAccTempM1, this.so3SensorFromWorld, this.processAccTempM2);
                 this.accObservationFunctionForNumericalJacobian(this.processAccTempM2, this.processAccTempV1);
-                final Vector3d withDelta = this.processAccTempV1;
+                Vector3d withDelta = this.processAccTempV1;
                 Vector3d.sub(this.mNu, withDelta, this.processAccTempV2);
-                this.processAccTempV2.scale(1.0 / eps);
+                this.processAccTempV2.scale(1.0D / eps);
                 this.mH.setColumn(dof, this.processAccTempV2);
             }
+
             this.mH.transpose(this.processAccTempM3);
             Matrix3x3d.mult(this.mP, this.processAccTempM3, this.processAccTempM4);
             Matrix3x3d.mult(this.mH, this.processAccTempM4, this.processAccTempM5);
@@ -286,120 +246,116 @@ public synchronized void processAcc(final Vector3d acc, final long sensorTimeSta
             So3Util.sO3FromMu(this.mx, this.so3LastMotion);
             Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.so3SensorFromWorld);
             this.updateCovariancesAfterMotion();
-        }
-        else {
+        } else {
             So3Util.sO3FromTwoVec(this.down, this.mz, this.so3SensorFromWorld);
             this.alignedToGravity = true;
         }
+
     }
-    
-    public synchronized void processMag(final float[] mag, final long sensorTimeStamp) {
-        if (!this.alignedToGravity) {
-            return;
-        }
-        this.mz.set(mag[0], mag[1], mag[2]);
-        this.mz.normalize();
-        final Vector3d downInSensorFrame = new Vector3d();
-        this.so3SensorFromWorld.getColumn(2, downInSensorFrame);
-        Vector3d.cross(this.mz, downInSensorFrame, this.processMagTempV1);
-        final Vector3d perpToDownAndMag = this.processMagTempV1;
-        perpToDownAndMag.normalize();
-        Vector3d.cross(downInSensorFrame, perpToDownAndMag, this.processMagTempV2);
-        final Vector3d magHorizontal = this.processMagTempV2;
-        magHorizontal.normalize();
-        this.mz.set(magHorizontal);
-        if (this.alignedToNorth) {
-            this.magObservationFunctionForNumericalJacobian(this.so3SensorFromWorld, this.mNu);
-            final double eps = 1.0E-7;
-            for (int dof = 0; dof < 3; ++dof) {
-                final Vector3d delta = this.processMagTempV3;
-                delta.setZero();
-                delta.setComponent(dof, eps);
-                So3Util.sO3FromMu(delta, this.processMagTempM1);
-                Matrix3x3d.mult(this.processMagTempM1, this.so3SensorFromWorld, this.processMagTempM2);
-                this.magObservationFunctionForNumericalJacobian(this.processMagTempM2, this.processMagTempV4);
-                final Vector3d withDelta = this.processMagTempV4;
-                Vector3d.sub(this.mNu, withDelta, this.processMagTempV5);
-                this.processMagTempV5.scale(1.0 / eps);
-                this.mH.setColumn(dof, this.processMagTempV5);
+
+    public synchronized void processMag(float[] mag, long sensorTimeStamp) {
+        if(this.alignedToGravity) {
+            this.mz.set((double)mag[0], (double)mag[1], (double)mag[2]);
+            this.mz.normalize();
+            Vector3d downInSensorFrame = new Vector3d();
+            this.so3SensorFromWorld.getColumn(2, downInSensorFrame);
+            Vector3d.cross(this.mz, downInSensorFrame, this.processMagTempV1);
+            Vector3d perpToDownAndMag = this.processMagTempV1;
+            perpToDownAndMag.normalize();
+            Vector3d.cross(downInSensorFrame, perpToDownAndMag, this.processMagTempV2);
+            Vector3d magHorizontal = this.processMagTempV2;
+            magHorizontal.normalize();
+            this.mz.set(magHorizontal);
+            if(this.alignedToNorth) {
+                this.magObservationFunctionForNumericalJacobian(this.so3SensorFromWorld, this.mNu);
+                double eps = 1.0E-7D;
+
+                for(int dof = 0; dof < 3; ++dof) {
+                    Vector3d delta = this.processMagTempV3;
+                    delta.setZero();
+                    delta.setComponent(dof, eps);
+                    So3Util.sO3FromMu(delta, this.processMagTempM1);
+                    Matrix3x3d.mult(this.processMagTempM1, this.so3SensorFromWorld, this.processMagTempM2);
+                    this.magObservationFunctionForNumericalJacobian(this.processMagTempM2, this.processMagTempV4);
+                    Vector3d withDelta = this.processMagTempV4;
+                    Vector3d.sub(this.mNu, withDelta, this.processMagTempV5);
+                    this.processMagTempV5.scale(1.0D / eps);
+                    this.mH.setColumn(dof, this.processMagTempV5);
+                }
+
+                this.mH.transpose(this.processMagTempM4);
+                Matrix3x3d.mult(this.mP, this.processMagTempM4, this.processMagTempM5);
+                Matrix3x3d.mult(this.mH, this.processMagTempM5, this.processMagTempM6);
+                Matrix3x3d.add(this.processMagTempM6, this.mR, this.mS);
+                this.mS.invert(this.processMagTempM4);
+                this.mH.transpose(this.processMagTempM5);
+                Matrix3x3d.mult(this.processMagTempM5, this.processMagTempM4, this.processMagTempM6);
+                Matrix3x3d.mult(this.mP, this.processMagTempM6, this.mK);
+                Matrix3x3d.mult(this.mK, this.mNu, this.mx);
+                Matrix3x3d.mult(this.mK, this.mH, this.processMagTempM4);
+                this.processMagTempM5.setIdentity();
+                this.processMagTempM5.minusEquals(this.processMagTempM4);
+                Matrix3x3d.mult(this.processMagTempM5, this.mP, this.processMagTempM4);
+                this.mP.set(this.processMagTempM4);
+                So3Util.sO3FromMu(this.mx, this.so3LastMotion);
+                Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.processMagTempM4);
+                this.so3SensorFromWorld.set(this.processMagTempM4);
+                this.updateCovariancesAfterMotion();
+            } else {
+                this.magObservationFunctionForNumericalJacobian(this.so3SensorFromWorld, this.mNu);
+                So3Util.sO3FromMu(this.mNu, this.so3LastMotion);
+                Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.processMagTempM4);
+                this.so3SensorFromWorld.set(this.processMagTempM4);
+                this.updateCovariancesAfterMotion();
+                this.alignedToNorth = true;
             }
-            this.mH.transpose(this.processMagTempM4);
-            Matrix3x3d.mult(this.mP, this.processMagTempM4, this.processMagTempM5);
-            Matrix3x3d.mult(this.mH, this.processMagTempM5, this.processMagTempM6);
-            Matrix3x3d.add(this.processMagTempM6, this.mR, this.mS);
-            this.mS.invert(this.processMagTempM4);
-            this.mH.transpose(this.processMagTempM5);
-            Matrix3x3d.mult(this.processMagTempM5, this.processMagTempM4, this.processMagTempM6);
-            Matrix3x3d.mult(this.mP, this.processMagTempM6, this.mK);
-            Matrix3x3d.mult(this.mK, this.mNu, this.mx);
-            Matrix3x3d.mult(this.mK, this.mH, this.processMagTempM4);
-            this.processMagTempM5.setIdentity();
-            this.processMagTempM5.minusEquals(this.processMagTempM4);
-            Matrix3x3d.mult(this.processMagTempM5, this.mP, this.processMagTempM4);
-            this.mP.set(this.processMagTempM4);
-            So3Util.sO3FromMu(this.mx, this.so3LastMotion);
-            Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.processMagTempM4);
-            this.so3SensorFromWorld.set(this.processMagTempM4);
-            this.updateCovariancesAfterMotion();
-        }
-        else {
-            this.magObservationFunctionForNumericalJacobian(this.so3SensorFromWorld, this.mNu);
-            So3Util.sO3FromMu(this.mNu, this.so3LastMotion);
-            Matrix3x3d.mult(this.so3LastMotion, this.so3SensorFromWorld, this.processMagTempM4);
-            this.so3SensorFromWorld.set(this.processMagTempM4);
-            this.updateCovariancesAfterMotion();
-            this.alignedToNorth = true;
+
         }
     }
-    
-    private double[] glMatrixFromSo3(final Matrix3x3d so3) {
-        for (int r = 0; r < 3; ++r) {
-            for (int c = 0; c < 3; ++c) {
+
+    private double[] glMatrixFromSo3(Matrix3x3d so3) {
+        for(int r = 0; r < 3; ++r) {
+            for(int c = 0; c < 3; ++c) {
                 this.rotationMatrix[4 * c + r] = so3.get(r, c);
             }
         }
 
-        this.rotationMatrix[3] = 0.0;
-        this.rotationMatrix[7] = 0.0;
-        this.rotationMatrix[11] = 0.0;
-
-        this.rotationMatrix[12] = 0.0;
-        this.rotationMatrix[13] = 0.0;
-        this.rotationMatrix[14] = 0.0;
-        this.rotationMatrix[15] = 1.0;
+        this.rotationMatrix[3] = this.rotationMatrix[7] = this.rotationMatrix[11] = 0.0D;
+        this.rotationMatrix[12] = this.rotationMatrix[13] = this.rotationMatrix[14] = 0.0D;
+        this.rotationMatrix[15] = 1.0D;
         return this.rotationMatrix;
     }
-    
-    private void filterGyroTimestep(final float timeStep) {
-        final float kFilterCoeff = 0.95f;
-        final int kMinSamples = 10;
-        if (!this.timestepFilterInit) {
+
+    private void filterGyroTimestep(float timeStep) {
+        float kFilterCoeff = 0.95F;
+        float kMinSamples = 10.0F;
+        if(!this.timestepFilterInit) {
             this.filteredGyroTimestep = timeStep;
             this.numGyroTimestepSamples = 1;
             this.timestepFilterInit = true;
-        }
-        else {
-            this.filteredGyroTimestep = kFilterCoeff * this.filteredGyroTimestep + (1 - kFilterCoeff) * timeStep;
-            if (++this.numGyroTimestepSamples > kMinSamples) {
+        } else {
+            this.filteredGyroTimestep = 0.95F * this.filteredGyroTimestep + 0.050000012F * timeStep;
+            if((float)(++this.numGyroTimestepSamples) > 10.0F) {
                 this.gyroFilterValid = true;
             }
         }
+
     }
-    
+
     private void updateCovariancesAfterMotion() {
         this.so3LastMotion.transpose(this.updateCovariancesAfterMotionTempM1);
         Matrix3x3d.mult(this.mP, this.updateCovariancesAfterMotionTempM1, this.updateCovariancesAfterMotionTempM2);
         Matrix3x3d.mult(this.so3LastMotion, this.updateCovariancesAfterMotionTempM2, this.mP);
         this.so3LastMotion.setIdentity();
     }
-    
-    private void accObservationFunctionForNumericalJacobian(final Matrix3x3d so3SensorFromWorldPred, final Vector3d result) {
+
+    private void accObservationFunctionForNumericalJacobian(Matrix3x3d so3SensorFromWorldPred, Vector3d result) {
         Matrix3x3d.mult(so3SensorFromWorldPred, this.down, this.mh);
         So3Util.sO3FromTwoVec(this.mh, this.mz, this.accObservationFunctionForNumericalJacobianTempM);
         So3Util.muFromSO3(this.accObservationFunctionForNumericalJacobianTempM, result);
     }
-    
-    private void magObservationFunctionForNumericalJacobian(final Matrix3x3d so3SensorFromWorldPred, final Vector3d result) {
+
+    private void magObservationFunctionForNumericalJacobian(Matrix3x3d so3SensorFromWorldPred, Vector3d result) {
         Matrix3x3d.mult(so3SensorFromWorldPred, this.north, this.mh);
         So3Util.sO3FromTwoVec(this.mh, this.mz, this.magObservationFunctionForNumericalJacobianTempM);
         So3Util.muFromSO3(this.magObservationFunctionForNumericalJacobianTempM, result);
diff --git a/vrlib/src/main/res/raw/per_pixel_vertex_shader.glsl b/vrlib/src/main/res/raw/per_pixel_vertex_shader.glsl
index 4a1d8aed..6f7849ab 100644
--- a/vrlib/src/main/res/raw/per_pixel_vertex_shader.glsl
+++ b/vrlib/src/main/res/raw/per_pixel_vertex_shader.glsl
@@ -1,6 +1,7 @@
 uniform mat4 u_MVPMatrix;		// A constant representing the combined model/view/projection matrix.      		       
 uniform mat4 u_MVMatrix;		// A constant representing the combined model/view matrix.
 uniform mat4 u_STMatrix;
+uniform bool u_UseSTM;
 		  			
 attribute vec4 a_Position;		// Per-vertex position information we will pass in.   				
 //attribute vec4 a_Color;			// Per-vertex color information we will pass in.
@@ -22,7 +23,12 @@ void main()
 	//v_Color = a_Color;
 	
 	// Pass through the texture coordinate.
-	v_TexCoordinate = (u_STMatrix * a_TexCoordinate).xy;
+	if(u_UseSTM){
+	    v_TexCoordinate = (u_STMatrix * a_TexCoordinate).xy;
+	} else {
+	    v_TexCoordinate = a_TexCoordinate.xy;
+	}
+
 	
 	// Transform the normal's orientation into eye space.
     //v_Normal = vec3(u_MVMatrix * vec4(a_Normal, 0.0));