wip Move SurfaceTexture.updateTexImage() from video renderers into MediaCodecVideoDecoder

talk/app/webrtc/java/android/org/webrtc/RendererCommon.java

Index: talk/app/webrtc/java/android/org/webrtc/RendererCommon.java
diff --git a/talk/app/webrtc/java/android/org/webrtc/RendererCommon.java b/talk/app/webrtc/java/android/org/webrtc/RendererCommon.java
index 5195044a827a374b346fcfae41210312de660a5d..b771d5fb63818b01e0ffa61a00c6b4cc1aa4bdd9 100644
--- a/talk/app/webrtc/java/android/org/webrtc/RendererCommon.java
+++ b/talk/app/webrtc/java/android/org/webrtc/RendererCommon.java
@@ -61,36 +61,25 @@ public class RendererCommon {
   // The minimum fraction of the frame content that will be shown for |SCALE_ASPECT_BALANCED|.
   // This limits excessive cropping when adjusting display size.
   private static float BALANCED_VISIBLE_FRACTION = 0.5625f;
-  // Matrix with transform y' = 1 - y.
-  private static final float[] VERTICAL_FLIP = new float[] {
-      1,  0, 0, 0,
-      0, -1, 0, 0,
-      0,  0, 1, 0,
-      0,  1, 0, 1};
+  public static final float[] IDENTITY_MATRIX = new float[] {
+    1, 0, 0, 0,
+    0, 1, 0, 0,
+    0, 0, 1, 0,
+    0, 0, 0, 1
+  };
 
   /**
-   * Returns matrix that transforms standard coordinates to their proper sampling locations in
-   * the texture. This transform compensates for any properties of the video source that
-   * cause it to appear different from a normalized texture. If the video source is based on
-   * ByteBuffers, pass null in |surfaceTexture|.
+   * Rotates |textureMatrix| with |rotationDegree| and returns it in a new matrix. The rotation is
+   * done around (0.5, 0.5) to work with textures sampled from 0.0 to 1.0.
    */
-  public static float[] getSamplingMatrix(SurfaceTexture surfaceTexture, float rotationDegree) {
-    final float[] samplingMatrix;
-    if (surfaceTexture == null) {
-      // For ByteBuffers, row 0 specifies the top row, but for a texture, row 0 specifies the
-      // bottom row. Flip the image vertically to compensate for this.
-      samplingMatrix = VERTICAL_FLIP;
-    } else {
-      samplingMatrix = new float[16];
-      surfaceTexture.getTransformMatrix(samplingMatrix);
-    }
+  public static float[] rotateTextureMatrix(float[] textureMatrix, float rotationDegree) {
     // Clockwise rotation matrix in the XY-plane (around the Z-axis).
     final float[] rotationMatrix = new float[16];
     Matrix.setRotateM(rotationMatrix, 0, rotationDegree, 0, 0, 1);
     adjustOrigin(rotationMatrix);
     // Multiply matrices together.
     final float[] tmpMatrix = new float[16];
-    Matrix.multiplyMM(tmpMatrix, 0, samplingMatrix, 0, rotationMatrix, 0);
+    Matrix.multiplyMM(tmpMatrix, 0, textureMatrix, 0, rotationMatrix, 0);
     return tmpMatrix;
   }