Android: Refactor renderers to allow apps to inject custom shaders

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

Index: talk/app/webrtc/java/android/org/webrtc/GlRectDrawer.java
diff --git a/talk/app/webrtc/java/android/org/webrtc/GlRectDrawer.java b/talk/app/webrtc/java/android/org/webrtc/GlRectDrawer.java
index 2cb8af754d324ddb71667c640a5cdfd9fb629c52..6d3d5d256399876cb9b1c93957f3b41a03d29f2d 100644
--- a/talk/app/webrtc/java/android/org/webrtc/GlRectDrawer.java
+++ b/talk/app/webrtc/java/android/org/webrtc/GlRectDrawer.java
@@ -40,13 +40,13 @@ import java.util.IdentityHashMap;
 import java.util.Map;
 
 /**
- * Helper class to draw a quad that covers the entire viewport. Rotation, mirror, and cropping is
- * specified using a 4x4 texture coordinate transform matrix. The frame input can either be an OES
- * texture or YUV textures in I420 format. The GL state must be preserved between draw calls, this
- * is intentional to maximize performance. The function release() must be called manually to free
- * the resources held by this object.
+ * Helper class to draw an opaque quad on the target viewport location. Rotation, mirror, and
+ * cropping is specified using a 4x4 texture coordinate transform matrix. The frame input can either
+ * be an OES texture or YUV textures in I420 format. The GL state must be preserved between draw
+ * calls, this is intentional to maximize performance. The function release() must be called
+ * manually to free the resources held by this object.
  */
-public class GlRectDrawer {
+public class GlRectDrawer implements RendererCommon.GlDrawer {
   // Simple vertex shader, used for both YUV and OES.
   private static final String VERTEX_SHADER_STRING =
         "varying vec2 interp_tc;\n"
@@ -118,67 +118,31 @@ public class GlRectDrawer {
             1.0f, 1.0f   // Top right.
           });
 
-  // The keys are one of the fragments shaders above.
-  private final Map<String, GlShader> shaders = new IdentityHashMap<String, GlShader>();
-  private GlShader currentShader;
-  private float[] currentTexMatrix;
-  private int texMatrixLocation;
-  // Intermediate copy buffer for uploading yuv frames that are not packed, i.e. stride > width.
-  // TODO(magjed): Investigate when GL_UNPACK_ROW_LENGTH is available, or make a custom shader that
-  // handles stride and compare performance with intermediate copy.
-  private ByteBuffer copyBuffer;
+  private static class Shader {
+    public final GlShader glShader;
+    public final int texMatrixLocation;
 
-  /**
-   * Upload |planes| into |outputYuvTextures|, taking stride into consideration. |outputYuvTextures|
-   * must have been generated in advance.
-   */
-  public void uploadYuvData(
-      int[] outputYuvTextures, int width, int height, int[] strides, ByteBuffer[] planes) {
-    // Make a first pass to see if we need a temporary copy buffer.
-    int copyCapacityNeeded = 0;
-    for (int i = 0; i < 3; ++i) {
-      final int planeWidth = (i == 0) ? width : width / 2;
-      final int planeHeight = (i == 0) ? height : height / 2;
-      if (strides[i] > planeWidth) {
-        copyCapacityNeeded = Math.max(copyCapacityNeeded, planeWidth * planeHeight);
-      }
-    }
-    // Allocate copy buffer if necessary.
-    if (copyCapacityNeeded > 0
-        && (copyBuffer == null || copyBuffer.capacity() < copyCapacityNeeded)) {
-      copyBuffer = ByteBuffer.allocateDirect(copyCapacityNeeded);
-    }
-    // Upload each plane.
-    for (int i = 0; i < 3; ++i) {
-      GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + i);
-      GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, outputYuvTextures[i]);
-      final int planeWidth = (i == 0) ? width : width / 2;
-      final int planeHeight = (i == 0) ? height : height / 2;
-      // GLES only accepts packed data, i.e. stride == planeWidth.
-      final ByteBuffer packedByteBuffer;
-      if (strides[i] == planeWidth) {
-        // Input is packed already.
-        packedByteBuffer = planes[i];
-      } else {
-        VideoRenderer.nativeCopyPlane(
-            planes[i], planeWidth, planeHeight, strides[i], copyBuffer, planeWidth);
-        packedByteBuffer = copyBuffer;
-      }
-      GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_LUMINANCE, planeWidth, planeHeight, 0,
-          GLES20.GL_LUMINANCE, GLES20.GL_UNSIGNED_BYTE, packedByteBuffer);
+    public Shader(String fragmentShader) {
+      this.glShader = new GlShader(VERTEX_SHADER_STRING, fragmentShader);
+      this.texMatrixLocation = glShader.getUniformLocation("texMatrix");
     }
   }
 
+  // The keys are one of the fragments shaders above.
+  private final Map<String, Shader> shaders = new IdentityHashMap<String, Shader>();
+
   /**
    * Draw an OES texture frame with specified texture transformation matrix. Required resources are
    * allocated at the first call to this function.
    */
-  public void drawOes(int oesTextureId, float[] texMatrix) {
-    prepareShader(OES_FRAGMENT_SHADER_STRING);
+  @Override
+  public void drawOes(int oesTextureId, float[] texMatrix, int x, int y, int width, int height) {
+    prepareShader(OES_FRAGMENT_SHADER_STRING, texMatrix);
+    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
     // updateTexImage() may be called from another thread in another EGL context, so we need to
     // bind/unbind the texture in each draw call so that GLES understads it's a new texture.
     GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, oesTextureId);
-    drawRectangle(texMatrix);
+    drawRectangle(x, y, width, height);
     GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, 0);
   }
 
@@ -186,10 +150,12 @@ public class GlRectDrawer {
    * Draw a RGB(A) texture frame with specified texture transformation matrix. Required resources
    * are allocated at the first call to this function.
    */
-  public void drawRgb(int textureId, float[] texMatrix) {
-    prepareShader(RGB_FRAGMENT_SHADER_STRING);
+  @Override
+  public void drawRgb(int textureId, float[] texMatrix, int x, int y, int width, int height) {
+    prepareShader(RGB_FRAGMENT_SHADER_STRING, texMatrix);
+    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
     GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);
-    drawRectangle(texMatrix);
+    drawRectangle(x, y, width, height);
     // Unbind the texture as a precaution.
     GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0);
   }
@@ -198,14 +164,15 @@ public class GlRectDrawer {
    * Draw a YUV frame with specified texture transformation matrix. Required resources are
    * allocated at the first call to this function.
    */
-  public void drawYuv(int[] yuvTextures, float[] texMatrix) {
-    prepareShader(YUV_FRAGMENT_SHADER_STRING);
+  @Override
+  public void drawYuv(int[] yuvTextures, float[] texMatrix, int x, int y, int width, int height) {
+    prepareShader(YUV_FRAGMENT_SHADER_STRING, texMatrix);
     // Bind the textures.
     for (int i = 0; i < 3; ++i) {
       GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + i);
       GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, yuvTextures[i]);
     }
-    drawRectangle(texMatrix);
+    drawRectangle(x, y, width, height);
     // Unbind the textures as a precaution..
     for (int i = 0; i < 3; ++i) {
       GLES20.glActiveTexture(GLES20.GL_TEXTURE0 + i);
@@ -213,60 +180,51 @@ public class GlRectDrawer {
     }
   }
 
-  private void drawRectangle(float[] texMatrix) {
-    // Try avoid uploading the texture if possible.
-    if (!Arrays.equals(currentTexMatrix, texMatrix)) {
-      currentTexMatrix = texMatrix.clone();
-      // Copy the texture transformation matrix over.
-      GLES20.glUniformMatrix4fv(texMatrixLocation, 1, false, texMatrix, 0);
-    }
+  private void drawRectangle(int x, int y, int width, int height) {
     // Draw quad.
+    GLES20.glViewport(x, y, width, height);
     GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
   }
 
-  private void prepareShader(String fragmentShader) {
-    // Lazy allocation.
-    if (!shaders.containsKey(fragmentShader)) {
-      final GlShader shader = new GlShader(VERTEX_SHADER_STRING, fragmentShader);
+  private void prepareShader(String fragmentShader, float[] texMatrix) {
+    final Shader shader;
+    if (shaders.containsKey(fragmentShader)) {
+      shader = shaders.get(fragmentShader);
+    } else {
+      // Lazy allocation.
+      shader = new Shader(fragmentShader);
       shaders.put(fragmentShader, shader);
-      shader.useProgram();
+      shader.glShader.useProgram();
       // Initialize fragment shader uniform values.
       if (fragmentShader == YUV_FRAGMENT_SHADER_STRING) {
-        GLES20.glUniform1i(shader.getUniformLocation("y_tex"), 0);
-        GLES20.glUniform1i(shader.getUniformLocation("u_tex"), 1);
-        GLES20.glUniform1i(shader.getUniformLocation("v_tex"), 2);
+        GLES20.glUniform1i(shader.glShader.getUniformLocation("y_tex"), 0);
+        GLES20.glUniform1i(shader.glShader.getUniformLocation("u_tex"), 1);
+        GLES20.glUniform1i(shader.glShader.getUniformLocation("v_tex"), 2);
       } else if (fragmentShader == RGB_FRAGMENT_SHADER_STRING) {
-        GLES20.glUniform1i(shader.getUniformLocation("rgb_tex"), 0);
+        GLES20.glUniform1i(shader.glShader.getUniformLocation("rgb_tex"), 0);
       } else if (fragmentShader == OES_FRAGMENT_SHADER_STRING) {
-        GLES20.glUniform1i(shader.getUniformLocation("oes_tex"), 0);
+        GLES20.glUniform1i(shader.glShader.getUniformLocation("oes_tex"), 0);
       } else {
         throw new IllegalStateException("Unknown fragment shader: " + fragmentShader);
       }
       GlUtil.checkNoGLES2Error("Initialize fragment shader uniform values.");
       // Initialize vertex shader attributes.
-      shader.setVertexAttribArray("in_pos", 2, FULL_RECTANGLE_BUF);
-      shader.setVertexAttribArray("in_tc", 2, FULL_RECTANGLE_TEX_BUF);
-    }
-
-    // Update GLES state if shader is not already current.
-    final GlShader shader = shaders.get(fragmentShader);
-    if (currentShader != shader) {
-      currentShader = shader;
-      shader.useProgram();
-      GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
-      currentTexMatrix = null;
-      texMatrixLocation = shader.getUniformLocation("texMatrix");
+      shader.glShader.setVertexAttribArray("in_pos", 2, FULL_RECTANGLE_BUF);
+      shader.glShader.setVertexAttribArray("in_tc", 2, FULL_RECTANGLE_TEX_BUF);
     }
+    shader.glShader.useProgram();
+    // Copy the texture transformation matrix over.
+    GLES20.glUniformMatrix4fv(shader.texMatrixLocation, 1, false, texMatrix, 0);
   }
 
   /**
    * Release all GLES resources. This needs to be done manually, otherwise the resources are leaked.
    */
+  @Override
   public void release() {
-    for (GlShader shader : shaders.values()) {
-      shader.release();
+    for (Shader shader : shaders.values()) {
+      shader.glShader.release();
     }
     shaders.clear();
-    copyBuffer = null;
   }
 }