Clarify GlProgram parameter name.

PiperOrigin-RevId: 434441008

Author: hmsch

demos/gl/src/main/java/androidx/media3/demo/gl/BitmapOverlayVideoProcessor.java

@@ -119,8 +119,8 @@ public void draw(int frameTexture, long frameTimestampUs, float[] transformMatri
 
     // Run the shader program.
     GlProgram program = checkNotNull(this.program);
-    program.setSamplerTexIdUniform("uTexSampler0", frameTexture, /* unit= */ 0);
-    program.setSamplerTexIdUniform("uTexSampler1", textures[0], /* unit= */ 1);
+    program.setSamplerTexIdUniform("uTexSampler0", frameTexture, /* texUnitIndex= */ 0);
+    program.setSamplerTexIdUniform("uTexSampler1", textures[0], /* texUnitIndex= */ 1);
     program.setFloatUniform("uScaleX", bitmapScaleX);
     program.setFloatUniform("uScaleY", bitmapScaleY);
     program.setFloatsUniform("uTexTransform", transformMatrix);

libraries/common/src/main/java/androidx/media3/common/util/GlProgram.java

@@ -175,9 +175,16 @@ public void setBufferAttribute(String name, float[] values, int size) {
     checkNotNull(attributeByName.get(name)).setBuffer(values, size);
   }
 
-  /** Sets a texture sampler type uniform. */
-  public void setSamplerTexIdUniform(String name, int texId, int unit) {
-    checkNotNull(uniformByName.get(name)).setSamplerTexId(texId, unit);
+  /**
+   * Sets a texture sampler type uniform.
+   *
+   * @param name The uniform's name.
+   * @param texId The texture identifier.
+   * @param texUnitIndex The texture unit index. Use a different index (0, 1, 2, ...) for each
+   *     texture sampler in the program.
+   */
+  public void setSamplerTexIdUniform(String name, int texId, int texUnitIndex) {
+    checkNotNull(uniformByName.get(name)).setSamplerTexId(texId, texUnitIndex);
   }
 
   /** Sets a float type uniform. */
@@ -322,7 +329,7 @@ public static Uniform create(int programId, int index) {
     private final float[] value;
 
     private int texId;
-    private int unit;
+    private int texUnitIndex;
 
     private Uniform(String name, int location, int type) {
       this.name = name;
@@ -335,11 +342,11 @@ private Uniform(String name, int location, int type) {
      * Configures {@link #bind()} to use the specified {@code texId} for this sampler uniform.
      *
      * @param texId The GL texture identifier from which to sample.
-     * @param unit The GL texture unit index.
+     * @param texUnitIndex The GL texture unit index.
      */
-    public void setSamplerTexId(int texId, int unit) {
+    public void setSamplerTexId(int texId, int texUnitIndex) {
       this.texId = texId;
-      this.unit = unit;
+      this.texUnitIndex = texUnitIndex;
     }
 
     /** Configures {@link #bind()} to use the specified float {@code value} for this uniform. */
@@ -382,15 +389,15 @@ public void bind() {
       if (texId == 0) {
         throw new IllegalStateException("No call to setSamplerTexId() before bind.");
       }
-      GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + unit);
+      GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + texUnitIndex);
       if (type == GLES11Ext.GL_SAMPLER_EXTERNAL_OES || type == GL_SAMPLER_EXTERNAL_2D_Y2Y_EXT) {
         GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texId);
       } else if (type == GLES20.GL_SAMPLER_2D) {
         GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, texId);
       } else {
         throw new IllegalStateException("Unexpected uniform type: " + type);
       }
-      GLES20.glUniform1i(location, unit);
+      GLES20.glUniform1i(location, texUnitIndex);
       GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
       GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
       GLES20.glTexParameteri(

libraries/transformer/src/main/java/androidx/media3/transformer/ExternalCopyFrameProcessor.java

@@ -70,7 +70,7 @@ public void initialize(int inputTexId) throws IOException {
             ? FRAGMENT_SHADER_COPY_EXTERNAL_YUV_ES3_PATH
             : FRAGMENT_SHADER_COPY_EXTERNAL_PATH;
     glProgram = new GlProgram(context, vertexShaderFilePath, fragmentShaderFilePath);
-    glProgram.setSamplerTexIdUniform("uTexSampler", inputTexId, /* unit= */ 0);
+    glProgram.setSamplerTexIdUniform("uTexSampler", inputTexId, /* texUnitIndex= */ 0);
     // Draw the frame on the entire normalized device coordinate space, from -1 to 1, for x and y.
     glProgram.setBufferAttribute(
         "aFramePosition", GlUtil.getNormalizedCoordinateBounds(), GlUtil.RECTANGLE_VERTICES_COUNT);

libraries/transformer/src/main/java/androidx/media3/transformer/TransformationFrameProcessor.java

@@ -97,7 +97,7 @@ public void initialize(int inputTexId) throws IOException {
     // TODO(b/205002913): check the loaded program is consistent with the attributes and uniforms
     //  expected in the code.
     glProgram = new GlProgram(context, VERTEX_SHADER_TRANSFORMATION_PATH, FRAGMENT_SHADER_PATH);
-    glProgram.setSamplerTexIdUniform("uTexSampler", inputTexId, /* unit= */ 0);
+    glProgram.setSamplerTexIdUniform("uTexSampler", inputTexId, /* texUnitIndex= */ 0);
     // Draw the frame on the entire normalized device coordinate space, from -1 to 1, for x and y.
     glProgram.setBufferAttribute(
         "aFramePosition", GlUtil.getNormalizedCoordinateBounds(), GlUtil.RECTANGLE_VERTICES_COUNT);