Fix slide show animation so that cross fades work.

 Bug 7961297
 Removed the "Additive" blending, which didn't do anything, even in
 OpenGL ES 1.1 implementation. Modified the texturing to
 change the color of the pixels based on the supplied alpha
 rather than modifying the alpha. This appears to match the
 implementation in the OpenGL ES 1.1 pipeline.

Change-Id: I52491af1a8a2d727968e4e805bc4bc61647f5cf2

4 files changed, 52 insertions, 127 deletions

diff --git a/src/com/android/gallery3d/glrenderer/GLCanvas.java b/src/com/android/gallery3d/glrenderer/GLCanvas.java
index 4cf16892e..941002e8d 100644
--- a/src/com/android/gallery3d/glrenderer/GLCanvas.java
+++ b/src/com/android/gallery3d/glrenderer/GLCanvas.java
@@ -20,6 +20,8 @@ import android.graphics.Bitmap;
 import android.graphics.Rect;
 import android.graphics.RectF;
 
+import javax.microedition.khronos.opengles.GL11;
+
 //
 // GLCanvas gives a convenient interface to draw using OpenGL.
 //
@@ -27,9 +29,6 @@ import android.graphics.RectF;
 // [x, x+width) * [y, y+height)
 //
 public interface GLCanvas {
-    public enum Blending {
-        Additive, Mix,
-    }
 
     public GLId getGLId();
 
@@ -38,106 +37,106 @@ public interface GLCanvas {
     // This is called by GLRoot and should not be called by the clients
     // who only want to draw on the GLCanvas. Both width and height must be
     // nonnegative.
-    public void setSize(int width, int height);
+    public abstract void setSize(int width, int height);
 
     // Clear the drawing buffers. This should only be used by GLRoot.
-    public void clearBuffer();
+    public abstract void clearBuffer();
 
-    public void clearBuffer(float[] argb);
+    public abstract void clearBuffer(float[] argb);
 
     // Sets and gets the current alpha, alpha must be in [0, 1].
-    public void setAlpha(float alpha);
+    public abstract void setAlpha(float alpha);
 
-    public float getAlpha();
+    public abstract float getAlpha();
 
     // (current alpha) = (current alpha) * alpha
-    public void multiplyAlpha(float alpha);
+    public abstract void multiplyAlpha(float alpha);
 
     // Change the current transform matrix.
-    public void translate(float x, float y, float z);
+    public abstract void translate(float x, float y, float z);
 
-    public void translate(float x, float y);
+    public abstract void translate(float x, float y);
 
-    public void scale(float sx, float sy, float sz);
+    public abstract void scale(float sx, float sy, float sz);
 
-    public void rotate(float angle, float x, float y, float z);
+    public abstract void rotate(float angle, float x, float y, float z);
 
-    public void multiplyMatrix(float[] mMatrix, int offset);
+    public abstract void multiplyMatrix(float[] mMatrix, int offset);
 
     // Pushes the configuration state (matrix, and alpha) onto
     // a private stack.
-    public void save();
+    public abstract void save();
 
     // Same as save(), but only save those specified in saveFlags.
-    public void save(int saveFlags);
+    public abstract void save(int saveFlags);
 
     public static final int SAVE_FLAG_ALL = 0xFFFFFFFF;
     public static final int SAVE_FLAG_ALPHA = 0x01;
     public static final int SAVE_FLAG_MATRIX = 0x02;
-    public static final int SAVE_FLAG_BLEND = 0x04;
 
     // Pops from the top of the stack as current configuration state (matrix,
     // alpha, and clip). This call balances a previous call to save(), and is
     // used to remove all modifications to the configuration state since the
     // last save call.
-    public void restore();
+    public abstract void restore();
 
     // Draws a line using the specified paint from (x1, y1) to (x2, y2).
     // (Both end points are included).
-    public void drawLine(float x1, float y1, float x2, float y2, GLPaint paint);
+    public abstract void drawLine(float x1, float y1, float x2, float y2, GLPaint paint);
 
     // Draws a rectangle using the specified paint from (x1, y1) to (x2, y2).
     // (Both end points are included).
-    public void drawRect(float x1, float y1, float x2, float y2, GLPaint paint);
+    public abstract void drawRect(float x1, float y1, float x2, float y2, GLPaint paint);
 
     // Fills the specified rectangle with the specified color.
-    public void fillRect(float x, float y, float width, float height, int color);
+    public abstract void fillRect(float x, float y, float width, float height, int color);
 
     // Draws a texture to the specified rectangle.
-    public void drawTexture(BasicTexture texture, int x, int y, int width, int height);
+    public abstract void drawTexture(
+            BasicTexture texture, int x, int y, int width, int height);
 
-    public void drawMesh(BasicTexture tex, int x, int y, int xyBuffer,
+    public abstract void drawMesh(BasicTexture tex, int x, int y, int xyBuffer,
             int uvBuffer, int indexBuffer, int indexCount);
 
     // Draws the source rectangle part of the texture to the target rectangle.
-    public void drawTexture(BasicTexture texture, RectF source, RectF target);
+    public abstract void drawTexture(BasicTexture texture, RectF source, RectF target);
 
     // Draw a texture with a specified texture transform.
-    public void drawTexture(BasicTexture texture, float[] mTextureTransform,
+    public abstract void drawTexture(BasicTexture texture, float[] mTextureTransform,
                 int x, int y, int w, int h);
 
     // Draw two textures to the specified rectangle. The actual texture used is
     // from * (1 - ratio) + to * ratio
     // The two textures must have the same size.
-    public void drawMixed(BasicTexture from, int toColor,
+    public abstract void drawMixed(BasicTexture from, int toColor,
             float ratio, int x, int y, int w, int h);
 
     // Draw a region of a texture and a specified color to the specified
     // rectangle. The actual color used is from * (1 - ratio) + to * ratio.
     // The region of the texture is defined by parameter "src". The target
     // rectangle is specified by parameter "target".
-    public void drawMixed(BasicTexture from, int toColor,
+    public abstract void drawMixed(BasicTexture from, int toColor,
             float ratio, RectF src, RectF target);
 
     // Unloads the specified texture from the canvas. The resource allocated
     // to draw the texture will be released. The specified texture will return
     // to the unloaded state. This function should be called only from
     // BasicTexture or its descendant
-    public boolean unloadTexture(BasicTexture texture);
+    public abstract boolean unloadTexture(BasicTexture texture);
 
     // Delete the specified buffer object, similar to unloadTexture.
-    public void deleteBuffer(int bufferId);
+    public abstract void deleteBuffer(int bufferId);
 
     // Delete the textures and buffers in GL side. This function should only be
     // called in the GL thread.
-    public void deleteRecycledResources();
+    public abstract void deleteRecycledResources();
 
     // Dump statistics information and clear the counters. For debug only.
-    public void dumpStatisticsAndClear();
+    public abstract void dumpStatisticsAndClear();
 
-    public void beginRenderTarget(RawTexture texture);
+    public abstract void beginRenderTarget(RawTexture texture);
 
-    public void endRenderTarget();
+    public abstract void endRenderTarget();
 
     /**
      * Sets texture parameters to use GL_CLAMP_TO_EDGE for both
@@ -147,7 +146,7 @@ public interface GLCanvas {
      *
      * @param texture The texture to set parameters on.
      */
-    public void setTextureParameters(BasicTexture texture);
+    public abstract void setTextureParameters(BasicTexture texture);
 
     /**
      * Initializes the texture to a size by calling texImage2D on it.
@@ -156,7 +155,7 @@ public interface GLCanvas {
      * @param format The texture format (e.g. GL_RGBA)
      * @param type The texture type (e.g. GL_UNSIGNED_BYTE)
      */
-    public void initializeTextureSize(BasicTexture texture, int format, int type);
+    public abstract void initializeTextureSize(BasicTexture texture, int format, int type);
 
     /**
      * Initializes the texture to a size by calling texImage2D on it.
@@ -164,7 +163,7 @@ public interface GLCanvas {
      * @param texture The texture to initialize the size.
      * @param bitmap The bitmap to initialize the bitmap with.
      */
-    public void initializeTexture(BasicTexture texture, Bitmap bitmap);
+    public abstract void initializeTexture(BasicTexture texture, Bitmap bitmap);
 
     /**
      * Calls glTexSubImage2D to upload a bitmap to the texture.
@@ -177,7 +176,8 @@ public interface GLCanvas {
      * @param format The texture format (e.g. GL_RGBA)
      * @param type The texture type (e.g. GL_UNSIGNED_BYTE)
      */
-    public void texSubImage2D(BasicTexture texture, int xOffset, int yOffset, Bitmap bitmap,
+    public abstract void texSubImage2D(BasicTexture texture, int xOffset, int yOffset,
+            Bitmap bitmap,
             int format, int type);
 
     /**
@@ -186,7 +186,7 @@ public interface GLCanvas {
      * @param buffer The buffer to upload
      * @return The buffer ID that was generated.
      */
-    public int uploadBuffer(java.nio.FloatBuffer buffer);
+    public abstract int uploadBuffer(java.nio.FloatBuffer buffer);
 
     /**
      * Generates buffers and uploads the element array buffer data.
@@ -194,36 +194,29 @@ public interface GLCanvas {
      * @param buffer The buffer to upload
      * @return The buffer ID that was generated.
      */
-    public int uploadBuffer(java.nio.ByteBuffer buffer);
-
-    /**
-     * Sets the blending algorithm if a texture is not opaque.
-     *
-     * @param blending Either mixing (overlay) or adding a texture.
-     */
-    public void setBlending(Blending blending);
+    public abstract int uploadBuffer(java.nio.ByteBuffer buffer);
 
     /**
      * Enable stencil test
      */
-    public void enableStencil();
+    public abstract void enableStencil();
 
     /**
      * Disable stencil.
      */
-    public void disableStencil();
+    public abstract void disableStencil();
 
     /**
      * Clears the stencil so that a new stencil can be generated.
      */
-    public void clearStencilBuffer();
+    public abstract void clearStencilBuffer();
 
     /**
      * Start/stop updating the stencil buffer.
      *
      * @param update True if the stencil should be updated, false otherwise.
      */
-    public void updateStencil(boolean update);
+    public abstract void updateStencil(boolean update);
 
     /**
      * Changes how the stencil buffer is used.
@@ -232,13 +225,13 @@ public interface GLCanvas {
      *            changed. If false, the area inside the stencil can be drawn to
      *            as well.
      */
-    public void drawOnlyOutsideStencil(boolean onlyOutside);
+    public abstract void drawOnlyOutsideStencil(boolean onlyOutside);
 
     /**
      * After LightCycle makes GL calls, this method is called to restore the GL
      * configuration to the one expected by GLCanvas.
      */
-    public void recoverFromLightCycle();
+    public abstract void recoverFromLightCycle();
 
     /**
      * Gets the bounds given by x, y, width, and height as well as the internal
@@ -251,5 +244,5 @@ public interface GLCanvas {
      * @param width The width of the input rectangle.
      * @param height The height of the input rectangle.
      */
-    public void getBounds(Rect bounds, int x, int y, int width, int height);
+    public abstract void getBounds(Rect bounds, int x, int y, int width, int height);
 }
diff --git a/src/com/android/gallery3d/glrenderer/GLES11Canvas.java b/src/com/android/gallery3d/glrenderer/GLES11Canvas.java
index a4ffa2a2c..efb9d80b9 100644
--- a/src/com/android/gallery3d/glrenderer/GLES11Canvas.java
+++ b/src/com/android/gallery3d/glrenderer/GLES11Canvas.java
@@ -86,7 +86,6 @@ public class GLES11Canvas implements GLCanvas {
     private static float[] sCropRect = new float[4];
 
     private RawTexture mTargetTexture;
-    private Blending mBlending = Blending.Mix;
 
     // Drawing statistics
     int mCountDrawLine;
@@ -775,12 +774,6 @@ public class GLES11Canvas implements GLCanvas {
             config.mAlpha = -1;
         }
 
-        if ((saveFlags & SAVE_FLAG_BLEND) != 0) {
-            config.mBlending = mBlending;
-        } else {
-            config.mBlending = null;
-        }
-
         if ((saveFlags & SAVE_FLAG_MATRIX) != 0) {
             System.arraycopy(mMatrixValues, 0, config.mMatrix, 0, 16);
         } else {
@@ -815,7 +808,6 @@ public class GLES11Canvas implements GLCanvas {
     private static class ConfigState {
         float mAlpha;
         float mMatrix[] = new float[16];
-        Blending mBlending;
         ConfigState mNextFree;
 
         public void restore(GLES11Canvas canvas) {
@@ -823,9 +815,6 @@ public class GLES11Canvas implements GLCanvas {
             if (mMatrix[0] != Float.NEGATIVE_INFINITY) {
                 System.arraycopy(mMatrix, 0, canvas.mMatrixValues, 0, 16);
             }
-            if (mBlending != null) {
-                canvas.setBlending(mBlending);
-            }
         }
     }
 
@@ -993,18 +982,6 @@ public class GLES11Canvas implements GLCanvas {
     }
 
     @Override
-    public void setBlending(Blending blending) {
-        if (mBlending == blending) {
-            return;
-        }
-        Assert.assertTrue(blending == Blending.Additive || blending == Blending.Mix);
-        mBlending = blending;
-        int srcFunc = GL11.GL_ONE;
-        int dstFunc = (blending == Blending.Additive) ? GL11.GL_ONE : GL11.GL_ONE_MINUS_SRC_ALPHA;
-        mGL.glBlendFunc(srcFunc, dstFunc);
-    }
-
-    @Override
     public void enableStencil() {
         mGL.glEnable(GL11.GL_STENCIL_TEST);
     }
diff --git a/src/com/android/gallery3d/glrenderer/GLES20Canvas.java b/src/com/android/gallery3d/glrenderer/GLES20Canvas.java
index 80f861b53..149b21efd 100644
--- a/src/com/android/gallery3d/glrenderer/GLES20Canvas.java
+++ b/src/com/android/gallery3d/glrenderer/GLES20Canvas.java
@@ -23,7 +23,6 @@ import android.opengl.GLUtils;
 import android.opengl.Matrix;
 import android.util.Log;
 
-import com.android.gallery3d.common.Utils;
 import com.android.gallery3d.util.IntArray;
 
 import java.nio.Buffer;
@@ -119,7 +118,7 @@ public class GLES20Canvas implements GLCanvas {
             + "uniform sampler2D " + TEXTURE_SAMPLER_UNIFORM + ";\n"
             + "void main() {\n"
             + "  gl_FragColor = texture2D(" + TEXTURE_SAMPLER_UNIFORM + ", vTextureCoord);\n"
-            + "  gl_FragColor.a *= " + ALPHA_UNIFORM + ";\n"
+            + "  gl_FragColor *= " + ALPHA_UNIFORM + ";\n"
             + "}\n";
 
     private static final String OES_TEXTURE_FRAGMENT_SHADER = ""
@@ -130,7 +129,7 @@ public class GLES20Canvas implements GLCanvas {
             + "uniform samplerExternalOES " + TEXTURE_SAMPLER_UNIFORM + ";\n"
             + "void main() {\n"
             + "  gl_FragColor = texture2D(" + TEXTURE_SAMPLER_UNIFORM + ", vTextureCoord);\n"
-            + "  gl_FragColor.a *= " + ALPHA_UNIFORM + ";\n"
+            + "  gl_FragColor *= " + ALPHA_UNIFORM + ";\n"
             + "}\n";
 
     private static final int INITIAL_RESTORE_STATE_SIZE = 8;
@@ -140,7 +139,6 @@ public class GLES20Canvas implements GLCanvas {
     private float[] mMatrices = new float[INITIAL_RESTORE_STATE_SIZE * MATRIX_SIZE];
     private float[] mAlphas = new float[INITIAL_RESTORE_STATE_SIZE];
     private IntArray mSaveFlags = new IntArray();
-    private ArrayList<Blending> mBlendings = new ArrayList<Blending>();
 
     private int mCurrentAlphaIndex = 0;
     private int mCurrentMatrixIndex = 0;
@@ -291,10 +289,8 @@ public class GLES20Canvas implements GLCanvas {
         mOesTextureProgram = assembleProgram(textureVertexShader, oesTextureFragmentShader,
                 mOesTextureParameters);
         mMeshProgram = assembleProgram(meshVertexShader, textureFragmentShader, mMeshParameters);
-
-        mBlendings.clear();
-        mBlendings.add(null);
-        setBlending(Blending.Mix);
+        GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA);
+        checkError();
     }
 
     private static FloatBuffer createBuffer(float[] values) {
@@ -463,10 +459,6 @@ public class GLES20Canvas implements GLCanvas {
             }
             System.arraycopy(mMatrices, currentIndex, mMatrices, mCurrentMatrixIndex, MATRIX_SIZE);
         }
-        boolean saveBlending = (saveFlags & SAVE_FLAG_BLEND) == SAVE_FLAG_BLEND;
-        if (saveBlending) {
-            mBlendings.add(mBlendings.get(mBlendings.size() - 1));
-        }
         mSaveFlags.add(saveFlags);
     }
 
@@ -481,11 +473,6 @@ public class GLES20Canvas implements GLCanvas {
         if (restoreMatrix) {
             mCurrentMatrixIndex -= MATRIX_SIZE;
         }
-        boolean restoreBlending = (restoreFlags & SAVE_FLAG_BLEND) == SAVE_FLAG_BLEND;
-        if (restoreBlending) {
-            setBlending(mBlendings.get(mBlendings.size() - 2));
-            mBlendings.remove(mBlendings.size() - 1);
-        }
     }
 
     @Override
@@ -965,32 +952,6 @@ public class GLES20Canvas implements GLCanvas {
     }
 
     @Override
-    public void setBlending(Blending blending) {
-        Blending currentBlending = mBlendings.get(mBlendings.size() - 1);
-        if (currentBlending == blending) {
-            return; // nothing to change
-        }
-        mBlendings.set(mBlendings.size() - 1, blending);
-        int srcFunc = GLES20.GL_ONE;
-        int dstFunc;
-        switch (blending) {
-            case Additive:
-                dstFunc = GLES20.GL_ONE;
-                break;
-            case Mix:
-                dstFunc = GLES20.GL_ONE_MINUS_SRC_ALPHA;
-                break;
-            default:
-                Utils.fail("Unknown blend: " + blending);
-                dstFunc = GLES20.GL_ONE_MINUS_SRC_ALPHA;
-                break;
-        }
-        GLES20.glBlendFunc(srcFunc, dstFunc);
-        checkError();
-    }
-
-
-    @Override
     public void enableStencil() {
         GLES20.glEnable(GLES20.GL_STENCIL_TEST);
     }
@@ -1041,11 +1002,9 @@ public class GLES20Canvas implements GLCanvas {
     @Override
     public void recoverFromLightCycle() {
         GLES20.glViewport(0, 0, mWidth, mHeight);
-        int blendingIndex = mBlendings.size() - 1;
-        Blending currentBlending = mBlendings.get(blendingIndex);
-        mBlendings.set(blendingIndex, null);
-        setBlending(currentBlending);
         GLES20.glDisable(GLES20.GL_DEPTH_TEST);
+        GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA);
+        checkError();
     }
 
     @Override
diff --git a/src/com/android/gallery3d/ui/SlideshowView.java b/src/com/android/gallery3d/ui/SlideshowView.java
index b215c6661..43784232d 100644
--- a/src/com/android/gallery3d/ui/SlideshowView.java
+++ b/src/com/android/gallery3d/ui/SlideshowView.java
@@ -23,7 +23,6 @@ import com.android.gallery3d.anim.CanvasAnimation;
 import com.android.gallery3d.anim.FloatAnimation;
 import com.android.gallery3d.glrenderer.BitmapTexture;
 import com.android.gallery3d.glrenderer.GLCanvas;
-import com.android.gallery3d.glrenderer.GLCanvas.Blending;
 
 import java.util.Random;
 
@@ -94,8 +93,6 @@ public class SlideshowView extends GLView {
     protected void render(GLCanvas canvas) {
         long animTime = AnimationTime.get();
         boolean requestRender = mTransitionAnimation.calculate(animTime);
-        canvas.save(GLCanvas.SAVE_FLAG_BLEND);
-        canvas.setBlending(Blending.Additive);
         float alpha = mPrevTexture == null ? 1f : mTransitionAnimation.get();
 
         if (mPrevTexture != null && alpha != 1f) {
@@ -119,7 +116,6 @@ public class SlideshowView extends GLView {
             canvas.restore();
         }
         if (requestRender) invalidate();
-        canvas.restore();
     }
 
     private class SlideshowAnimation extends CanvasAnimation {