Merge pull request #420 from KhronosGroup/fix/uncaught_type_error

Fix uncaught type error

source/gltf/accessor.js

@@ -88,6 +88,10 @@ class gltfAccessor extends GltfObject
                 break;
             }
         }
+        else if (this.sparse !== undefined)
+        {
+            this.typedView = this.createView();
+        }
 
         if (this.typedView === undefined)
         {
@@ -175,6 +179,10 @@ class gltfAccessor extends GltfObject
                 this.filteredView[i] = dv[func](offset, true);
             }
         }
+        else if (this.sparse !== undefined)
+        {
+            this.filteredView = this.createView();
+        }
 
         if (this.filteredView === undefined)
         {
@@ -188,6 +196,18 @@ class gltfAccessor extends GltfObject
         return this.filteredView;
     }
 
+    createView()
+    {
+        const size = this.count * this.getComponentCount(this.type);
+        if (this.componentType == GL.BYTE) return new Int8Array(size);
+        if (this.componentType == GL.UNSIGNED_BYTE) return new Uint8Array(size);
+        if (this.componentType == GL.SHORT) return new Int16Array(size);
+        if (this.componentType == GL.UNSIGNED_SHORT) return new Uint16Array(size);
+        if (this.componentType == GL.UNSIGNED_INT) return new Uint32Array(size);
+        if (this.componentType == GL.FLOAT) return new Float32Array(size);
+        return undefined;
+    }
+
     // getNormalizedDeinterlacedView provides an alternative view to the accessors data,
     // where quantized data is already normalized. This is useful if the data is not passed
     // to vertexAttribPointer but used immediately (like e.g. animations)