Support fot GPU image effects (#2)

Initial support of android.media.effects.
Note: Transitions are broken now, and must be fixed

Signed-off-by: Jorge Ruesga <jorge@ruesga.com>

19 files changed, 195 insertions, 396 deletions

diff --git a/res/values/arrays.xml b/res/values/arrays.xml
index ecfbb65..05157d7 100644
--- a/res/values/arrays.xml
+++ b/res/values/arrays.xml
@@ -65,7 +65,7 @@
     <string-array name="effects_labels" translatable="false">
         <item>@string/effects_none</item>
         <item>@string/effects_random</item>
-        <item>@string/effects_black_and_white</item>
+        <item>@string/effects_grayscale</item>
         <item>@string/effects_sepia</item>
     </string-array>
 
diff --git a/res/values/strings.xml b/res/values/strings.xml
index aff0185..dadde80 100644
--- a/res/values/strings.xml
+++ b/res/values/strings.xml
@@ -111,7 +111,7 @@
     <!-- Effects -->
     <string name="effects_none">None</string>
     <string name="effects_random">Random</string>
-    <string name="effects_black_and_white">Black &amp; White</string>
+    <string name="effects_grayscale">Grayscale</string>
     <string name="effects_sepia">Sepia</string>
 
     <!-- ColorPickerDialog -->
diff --git a/src/org/cyanogenmod/wallpapers/photophase/GLESUtil.java b/src/org/cyanogenmod/wallpapers/photophase/GLESUtil.java
index 25fe366..a6de6fd 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/GLESUtil.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/GLESUtil.java
@@ -21,12 +21,11 @@ import android.content.res.Resources;
 import android.graphics.Bitmap;
 import android.graphics.Color;
 import android.graphics.Rect;
+import android.media.effect.Effect;
 import android.opengl.GLES20;
 import android.opengl.GLUtils;
 import android.util.Log;
 
-import org.cyanogenmod.wallpapers.photophase.effects.Effect;
-
 import java.io.File;
 import java.io.IOException;
 import java.io.InputStream;
@@ -305,12 +304,13 @@ public final class GLESUtil {
      *
      * @param file The image file
      * @param dimensions The desired dimensions
-     * @param effect The effect to apply to the image
+     * @param effect The effect to apply to the image or null if no effect is needed
+     * @param screenDim The screen dimensions
      * @param recycle If the bitmap should be recycled
      * @return GLESTextureInfo The texture info
      */
     public static GLESTextureInfo loadTexture(
-            File file, Rect dimensions, Effect effect, boolean recycle) {
+            File file, Rect dimensions, Effect effect, Rect screenDim, boolean recycle) {
         Bitmap bitmap = null;
         try {
             // Decode and associate the bitmap (invert the desired dimensions)
@@ -320,10 +320,9 @@ public final class GLESUtil {
                 if (DEBUG) Log.e(TAG, msg);
                 return new GLESTextureInfo();
             }
-            bitmap = effect.apply(bitmap);
 
             if (DEBUG) Log.d(TAG, "image: " + file.getAbsolutePath());
-            GLESTextureInfo ti = loadTexture(bitmap);
+            GLESTextureInfo ti = loadTexture(bitmap, effect, screenDim);
             ti.path = file;
             return ti;
 
@@ -345,12 +344,13 @@ public final class GLESUtil {
      *
      * @param ctx The current context
      * @param resourceId The resource identifier
-     * @param effect The effect to apply to the image
+     * @param effect The effect to apply to the image or null if no effect is needed
+     * @param screenDim The screen dimensions
      * @param recycle If the bitmap should be recycled
      * @return GLESTextureInfo The texture info
      */
     public static GLESTextureInfo loadTexture(
-            Context ctx, int resourceId, Effect effect, boolean recycle) {
+            Context ctx, int resourceId, Effect effect, Rect screenDim, boolean recycle) {
         Bitmap bitmap = null;
         InputStream raw = null;
         try {
@@ -364,7 +364,7 @@ public final class GLESUtil {
             }
 
             if (DEBUG) Log.d(TAG, "resourceId: " + resourceId);
-            GLESTextureInfo ti = loadTexture(bitmap);
+            GLESTextureInfo ti = loadTexture(bitmap, effect, screenDim);
             return ti;
 
         } catch (Exception e) {
@@ -392,18 +392,22 @@ public final class GLESUtil {
      * Method that loads texture from a bitmap reference.
      *
      * @param bitmap The bitmap reference
+     * @param effect The effect to apply to the image or null if no effect is needed
+     * @param screenDim The screen dimensions
      * @return GLESTextureInfo The texture info
      */
-    public static GLESTextureInfo loadTexture(Bitmap bitmap) {
+    public static GLESTextureInfo loadTexture(Bitmap bitmap, Effect effect, Rect screenDim) {
         // Check that we have a valid image name reference
         if (bitmap == null) {
             return new GLESTextureInfo();
         }
 
-        int[] textureNames = new int[1];
-        GLES20.glGenTextures(1, textureNames, 0);
+        int num = effect == null ? 1 : 2;
+
+        int[] textureNames = new int[num];
+        GLES20.glGenTextures(num, textureNames, 0);
         GLESUtil.glesCheckError("glGenTextures");
-        if (textureNames[0] <= 0) {
+        if (textureNames[0] <= 0 || (effect != null && textureNames[1] <= 0)) {
             String msg = "Failed to generate a valid texture";
             if (DEBUG) Log.e(TAG, msg);
             return new GLESTextureInfo();
@@ -431,9 +435,23 @@ public final class GLESUtil {
             return new GLESTextureInfo();
         }
 
+        // Has a effect?
+        int handle = textureNames[0];
+        if (effect != null) {
+            // Apply the effect
+            effect.apply(textureNames[0], screenDim.width(), screenDim.height(), textureNames[1]);
+            effect.release();
+            handle = textureNames[1];
+
+            // Delete the unused texture
+            int[] textures = {textureNames[0]};
+            GLES20.glDeleteTextures(1, textures, 0);
+            GLESUtil.glesCheckError("glTexParameteri");
+        }
+
         // Return the texture handle identifier and the associated info
         GLESTextureInfo ti = new GLESTextureInfo();
-        ti.handle = textureNames[0];
+        ti.handle = handle;
         ti.bitmap = bitmap;
         ti.path = null;
         return ti;
diff --git a/src/org/cyanogenmod/wallpapers/photophase/PhotoFrame.java b/src/org/cyanogenmod/wallpapers/photophase/PhotoFrame.java
index 3cac77f..7e29a5a 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/PhotoFrame.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/PhotoFrame.java
@@ -25,7 +25,6 @@ import org.cyanogenmod.wallpapers.photophase.GLESUtil.GLESTextureInfo;
 import java.nio.ByteBuffer;
 import java.nio.ByteOrder;
 import java.nio.FloatBuffer;
-import java.nio.ShortBuffer;
 
 
 /**
@@ -38,26 +37,21 @@ public class PhotoFrame implements TextureRequestor {
      */
     public static final int COORDS_PER_VERTER = 3;
 
-    // The photo frame is always a rectangle, so here applies 2 triangle order
-    private static final short[] VERTEX_ORDER = { 0, 1, 2, 0, 2, 3 };
-
     // The default texture coordinates (fit to frame)
     private static final float[] DEFAULT_TEXTURE_COORDS = {
-                                                            0, 0, // top left
-                                                            0, 1, // bottom left
-                                                            1, 1, // bottom right
-                                                            1, 0  // top right
+                                                            0.0f, 1.0f,
+                                                            1.0f, 1.0f,
+                                                            0.0f, 0.0f,
+                                                            1.0f, 0.0f
                                                           };
 
+
     private final TextureManager mTextureManager;
 
     private final float mFrameWidth, mFrameHeight;
-    private final float mPictureWidth, mPictureHeight;
     private final float[] mFrameVertex;
-    private final float[] mPictureVertex;
 
-    private FloatBuffer mPictureVertexBuffer;
-    private ShortBuffer mVertexOrderBuffer;
+    private FloatBuffer mPositionBuffer;
     private FloatBuffer mTextureBuffer;
 
     private GLESTextureInfo mTextureInfo;
@@ -74,11 +68,10 @@ public class PhotoFrame implements TextureRequestor {
      * @param ctx The current context
      * @param textureManager The texture manager
      * @param frameVertex A 4 dimension array with the coordinates per vertex plus padding
-     * @param pictureVertex A 4 dimension array with the coordinates per vertex
      * @param color Background color
      */
     public PhotoFrame(Context ctx, TextureManager textureManager,
-            float[] frameVertex, float[] pictureVertex, GLColor color) {
+                float[] frameVertex, GLColor color) {
         super();
         mLoaded = false;
         mBackgroundColor = color;
@@ -86,25 +79,15 @@ public class PhotoFrame implements TextureRequestor {
 
         // Save dimensions
         mFrameVertex = frameVertex;
-        mFrameWidth = frameVertex[9] - frameVertex[0];
-        mFrameHeight = frameVertex[4] - frameVertex[1];
-        mPictureVertex = pictureVertex;
-        mPictureWidth = pictureVertex[9] - pictureVertex[0];
-        mPictureHeight = pictureVertex[4] - pictureVertex[1];
+        mFrameWidth = frameVertex[6] - frameVertex[4];
+        mFrameHeight = frameVertex[1] - frameVertex[5];
 
         // Initialize vertex byte buffer for shape coordinates
-        ByteBuffer bb = ByteBuffer.allocateDirect(pictureVertex.length * 4); // (# of coordinate values * 4 bytes per float)
-        bb.order(ByteOrder.nativeOrder());
-        mPictureVertexBuffer = bb.asFloatBuffer();
-        mPictureVertexBuffer.put(pictureVertex);
-        mPictureVertexBuffer.position(0);
-
-        // Initialize vertex byte buffer for shape coordinates order
-        bb = ByteBuffer.allocateDirect(VERTEX_ORDER.length * 2); // (# of coordinate values * 2 bytes per short)
+        ByteBuffer bb = ByteBuffer.allocateDirect(frameVertex.length * 4); // (# of coordinate values * 4 bytes per float)
         bb.order(ByteOrder.nativeOrder());
-        mVertexOrderBuffer = bb.asShortBuffer();
-        mVertexOrderBuffer.put(VERTEX_ORDER);
-        mVertexOrderBuffer.position(0);
+        mPositionBuffer = bb.asFloatBuffer();
+        mPositionBuffer.put(frameVertex);
+        mPositionBuffer.position(0);
 
         // Load the texture
         mTextureInfo = null;
@@ -147,7 +130,7 @@ public class PhotoFrame implements TextureRequestor {
         ByteBuffer bb = ByteBuffer.allocateDirect(textureCoords.length * 4); // (# of coordinate values * 4 bytes per float)
         bb.order(ByteOrder.nativeOrder());
         synchronized (mSync) {
-            // Synchronize buffer swap
+            // Swap buffers
             mTextureBuffer = bb.asFloatBuffer();
             mTextureBuffer.put(textureCoords);
             mTextureBuffer.position(0);
@@ -165,30 +148,12 @@ public class PhotoFrame implements TextureRequestor {
     }
 
     /**
-     * Method that returns the picture vertex
+     * Method that returns the position vertex buffer
      *
-     * @return float[] The picture vertex
+     * @return FloatBuffer The position vertex buffer
      */
-    public float[] getPictureVertex() {
-        return mPictureVertex;
-    }
-
-    /**
-     * Method that returns the picture vertex buffer
-     *
-     * @return FloatBuffer The picture vertex buffer
-     */
-    public FloatBuffer getPictureVertexBuffer() {
-        return mPictureVertexBuffer;
-    }
-
-    /**
-     * Method that returns the vertex order buffer
-     *
-     * @return ShortBuffer The vertex order buffer
-     */
-    public ShortBuffer getVertexOrderBuffer() {
-        return mVertexOrderBuffer;
+    public FloatBuffer getPositionBuffer() {
+        return mPositionBuffer;
     }
 
     /**
@@ -242,24 +207,6 @@ public class PhotoFrame implements TextureRequestor {
     }
 
     /**
-     * Method that returns the picture width
-     *
-     * @return float The picture width
-     */
-    public float getPictureWidth() {
-        return mPictureWidth;
-    }
-
-    /**
-     * Method that returns the picture height
-     *
-     * @return float The picture height
-     */
-    public float getPictureHeight() {
-        return mPictureHeight;
-    }
-
-    /**
      * Method that returns the background color of the frame
      *
      * @return GLColor The background color
@@ -288,17 +235,13 @@ public class PhotoFrame implements TextureRequestor {
         }
         mTextureInfo = null;
 
-        if (mPictureVertexBuffer != null) {
-            mPictureVertexBuffer.clear();
-        }
-        if (mVertexOrderBuffer != null) {
-            mVertexOrderBuffer.clear();
+        if (mPositionBuffer != null) {
+            mPositionBuffer.clear();
         }
         if (mTextureBuffer != null) {
             mTextureBuffer.clear();
         }
-        mPictureVertexBuffer = null;
-        mVertexOrderBuffer = null;
+        mPositionBuffer = null;
         mTextureBuffer = null;
     }
 }
diff --git a/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseRenderer.java b/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseRenderer.java
index c1b40e7..5c2e2bf 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseRenderer.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseRenderer.java
@@ -27,6 +27,7 @@ import android.content.res.Configuration;
 import android.content.res.Resources.NotFoundException;
 import android.graphics.PointF;
 import android.graphics.Rect;
+import android.media.effect.EffectContext;
 import android.net.Uri;
 import android.opengl.GLES20;
 import android.opengl.GLException;
@@ -56,19 +57,20 @@ public class PhotoPhaseRenderer implements GLSurfaceView.Renderer {
     private final long mInstance;
     private static long sInstances;
 
-    final Context mContext;
+    /*package*/ final Context mContext;
+    /*package*/ EffectContext mEffectContext;
     private final Handler mHandler;
-    final GLESSurfaceDispatcher mDispatcher;
-    TextureManager mTextureManager;
+    /*package*/ final GLESSurfaceDispatcher mDispatcher;
+    /*package*/ TextureManager mTextureManager;
 
-    PhotoPhaseWallpaperWorld mWorld;
-    ColorShape mOverlay;
+    /*package*/ PhotoPhaseWallpaperWorld mWorld;
+    /*package*/ ColorShape mOverlay;
 
-    long mLastRunningTransition;
+    /*package*/ long mLastRunningTransition;
 
-    int mWidth = -1;
-    int mHeight = -1;
-    int mMeasuredHeight  = -1;
+    /*package*/ int mWidth = -1;
+    /*package*/ int mHeight = -1;
+    /*package*/ int mMeasuredHeight  = -1;
 
     private final float[] mMVPMatrix = new float[16];
     private final float[] mProjMatrix = new float[16];
@@ -76,7 +78,7 @@ public class PhotoPhaseRenderer implements GLSurfaceView.Renderer {
 
     private final Object mDrawing = new Object();
 
-    final Object mMediaSync = new Object();
+    /*package*/ final Object mMediaSync = new Object();
     private PendingIntent mMediaScanIntent;
 
     private final BroadcastReceiver mSettingsChangedReceiver = new BroadcastReceiver() {
@@ -216,6 +218,10 @@ public class PhotoPhaseRenderer implements GLSurfaceView.Renderer {
         // Register a receiver to listen for media reload request
         mContext.unregisterReceiver(mSettingsChangedReceiver);
         recycle();
+        if (mEffectContext != null) {
+            mEffectContext.release();
+        }
+        mEffectContext = null;
         mWidth = -1;
         mHeight = -1;
         mMeasuredHeight = -1;
@@ -401,6 +407,12 @@ public class PhotoPhaseRenderer implements GLSurfaceView.Renderer {
         GLES20.glDepthFunc(GLES20.GL_LEQUAL);
         GLESUtil.glesCheckError("glDepthFunc");
 
+        // Create an effect context
+        if (mEffectContext != null) {
+            mEffectContext.release();
+        }
+        mEffectContext = EffectContext.createWithCurrentGlContext();
+
         // Create the texture manager and recycle the old one
         if (mTextureManager == null) {
             // Precalculate the window size for the TextureManager. In onSurfaceChanged
@@ -415,8 +427,10 @@ public class PhotoPhaseRenderer implements GLSurfaceView.Renderer {
                         ? PreferencesProvider.Preferences.Layout.getPortraitDisposition().size()
                         : PreferencesProvider.Preferences.Layout.getLandscapeDisposition().size();
 
+            // Recycle the current texture manager and create a new one
             recycle();
-            mTextureManager = new TextureManager(mContext, mDispatcher, cc, dimensions);
+            mTextureManager = new TextureManager(
+                    mContext, mEffectContext, mDispatcher, cc, dimensions);
         }
     }
 
diff --git a/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaper.java b/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaper.java
index ea65f9d..0c9f23c 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaper.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaper.java
@@ -140,7 +140,7 @@ public class PhotoPhaseWallpaper
                     public void run() {
                         // Only if the wallpaper is visible after a long press and
                         // not in preview mode
-                        if(isVisible() && !isPreview()) {
+                        if (isVisible() && !isPreview()) {
                             List<ActivityManager.RunningTaskInfo> taskInfo =
                                                     mActivityManager.getRunningTasks(1);
                             String topActivity = taskInfo.get(0).topActivity.getClassName();
diff --git a/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaperWorld.java b/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaperWorld.java
index 8fc5934..2f31617 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaperWorld.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/PhotoPhaseWallpaperWorld.java
@@ -327,13 +327,12 @@ public class PhotoPhaseWallpaperWorld {
         for (Disposition disposition : dispositions) {
             // Create the photo frame
             float[] frameVertices = getVerticesFromDisposition(disposition, cellw, cellh);
-            float[] pictureVertices = getFramePadding(frameVertices, portrait ? w : h, portrait ? h : w);
+            frameVertices = getFramePadding(frameVertices, portrait ? w : h, portrait ? h : w);
             PhotoFrame frame =
                     new PhotoFrame(
                             mContext,
                             mTextureManager,
                             frameVertices,
-                            pictureVertices,
                             Colors.getBackground());
             mPhotoFrames.add(frame);
 
@@ -395,25 +394,21 @@ public class PhotoPhaseWallpaperWorld {
             Disposition disposition, float cellw, float cellh) {
         return new float[]
                 {
-                     // top left
-                    -1.0f + (disposition.x * cellw),
-                     1.0f - (disposition.y * cellh),
-                     0.0f,
-
-                     // bottom left
+                    // bottom left
                     -1.0f + (disposition.x * cellw),
                      1.0f - ((disposition.y * cellh) + (disposition.h * cellh)),
-                     0.0f,
 
-                     // bottom right
+                    // bottom right
                     -1.0f + ((disposition.x * cellw) + (disposition.w * cellw)),
                      1.0f - ((disposition.y * cellh) + (disposition.h * cellh)),
-                     0.0f,
 
-                     // top right
-                    -1.0f + ((disposition.x * cellw) + (disposition.w * cellw)),
+                    // top left
+                    -1.0f + (disposition.x * cellw),
                      1.0f - (disposition.y * cellh),
-                     0.0f
+
+                    // top right
+                    -1.0f + ((disposition.x * cellw) + (disposition.w * cellw)),
+                     1.0f - (disposition.y * cellh)
                 };
     }
 
@@ -431,13 +426,13 @@ public class PhotoPhaseWallpaperWorld {
         final float pxw = (1 / (float)screenWidth) * PHOTO_FRAME_PADDING;
         final float pxh = (1 / (float)screenHeight) * PHOTO_FRAME_PADDING;
         paddingCoords[0] += pxw;
-        paddingCoords[1] -= pxh;
-        paddingCoords[3] += pxw;
-        paddingCoords[4] += pxh;
+        paddingCoords[1] += pxh;
+        paddingCoords[2] -= pxw;
+        paddingCoords[3] += pxh;
+        paddingCoords[4] += pxw;
+        paddingCoords[5] -= pxh;
         paddingCoords[6] -= pxw;
-        paddingCoords[7] += pxh;
-        paddingCoords[9] -= pxw;
-        paddingCoords[10] -= pxh;
+        paddingCoords[7] -= pxh;
         return paddingCoords;
     }
 }
diff --git a/src/org/cyanogenmod/wallpapers/photophase/TextureManager.java b/src/org/cyanogenmod/wallpapers/photophase/TextureManager.java
index ac05b77..9c0d3d0 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/TextureManager.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/TextureManager.java
@@ -18,6 +18,7 @@ package org.cyanogenmod.wallpapers.photophase;
 
 import android.content.Context;
 import android.graphics.Rect;
+import android.media.effect.EffectContext;
 import android.opengl.GLES20;
 import android.util.Log;
 
@@ -44,6 +45,7 @@ public class TextureManager implements OnMediaPictureDiscoveredListener {
     static final List<GLESTextureInfo> sRecycledBitmaps = new ArrayList<GLESTextureInfo>();
 
     final Context mContext;
+    final EffectContext mEffectContext;
     final Object mSync;
     final List<TextureRequestor> mPendingRequests;
     final FixedQueue<GLESTextureInfo> mQueue = new FixedQueue<GLESTextureInfo>(QUEUE_SIZE);
@@ -74,12 +76,14 @@ public class TextureManager implements OnMediaPictureDiscoveredListener {
                 if (sRecycledBitmaps.size() > 0) {
                     // Bind to the GLES context
                     GLESTextureInfo oldTextureInfo = sRecycledBitmaps.remove(0);
-                    ti = GLESUtil.loadTexture(oldTextureInfo.bitmap);
+                    ti = GLESUtil.loadTexture(oldTextureInfo.bitmap,
+                            Effects.getNextEffect(mEffectContext), mDimensions);
                     ti.path = oldTextureInfo.path;
                     oldTextureInfo.bitmap = null;
                 } else {
                     // Load and bind to the GLES context
-                    ti = GLESUtil.loadTexture(mImage, mDimensions, Effects.getNextEffect(), false);
+                    ti = GLESUtil.loadTexture(mImage, mDimensions,
+                            Effects.getNextEffect(mEffectContext), mDimensions, false);
                 }
 
                 synchronized (mSync) {
@@ -111,13 +115,16 @@ public class TextureManager implements OnMediaPictureDiscoveredListener {
      * Constructor of <code>TextureManager</code>
      *
      * @param ctx The current context
+     * @param effectCtx The current effect context
      * @param dispatcher The GLES dispatcher
      * @param requestors The number of requestors
      * @param dimensions The desired dimensions for the decoded bitmaps
      */
-    public TextureManager(final Context ctx, GLESSurfaceDispatcher dispatcher, int requestors, Rect dimensions) {
+    public TextureManager(final Context ctx, final EffectContext effectCtx,
+                        GLESSurfaceDispatcher dispatcher, int requestors, Rect dimensions) {
         super();
         mContext = ctx;
+        mEffectContext = effectCtx;
         mDispatcher = dispatcher;
         mDimensions = dimensions;
         mSync = new Object();
diff --git a/src/org/cyanogenmod/wallpapers/photophase/effects/BlackAndWhiteEffect.java b/src/org/cyanogenmod/wallpapers/photophase/effects/BlackAndWhiteEffect.java
deleted file mode 100644
index dbda330..0000000
--- a/src/org/cyanogenmod/wallpapers/photophase/effects/BlackAndWhiteEffect.java
+++ /dev/null
@@ -1,53 +0,0 @@
-/*
- * Copyright (C) 2013 The CyanogenMod Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.cyanogenmod.wallpapers.photophase.effects;
-
-import android.graphics.Bitmap;
-import android.graphics.Canvas;
-import android.graphics.ColorMatrix;
-import android.graphics.ColorMatrixColorFilter;
-import android.graphics.Paint;
-
-/**
- * This effect converts the source image to black and white color scheme.
- */
-public class BlackAndWhiteEffect extends Effect {
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Bitmap apply(Bitmap src) {
-        try {
-            final int height = src.getHeight();
-            final int width = src.getWidth();
-
-            Bitmap dst = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
-            final Canvas c = new Canvas(dst);
-            final Paint paint = new Paint();
-            final ColorMatrix cm = new ColorMatrix();
-            cm.setSaturation(0);
-            final ColorMatrixColorFilter f = new ColorMatrixColorFilter(cm);
-            paint.setColorFilter(f);
-            c.drawBitmap(src, 0, 0, paint);
-            return dst;
-        } finally {
-            src.recycle();
-        }
-    }
-
-}
diff --git a/src/org/cyanogenmod/wallpapers/photophase/effects/Effect.java b/src/org/cyanogenmod/wallpapers/photophase/effects/Effect.java
deleted file mode 100644
index 4ab4695..0000000
--- a/src/org/cyanogenmod/wallpapers/photophase/effects/Effect.java
+++ /dev/null
@@ -1,33 +0,0 @@
-/*
- * Copyright (C) 2013 The CyanogenMod Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.cyanogenmod.wallpapers.photophase.effects;
-
-import android.graphics.Bitmap;
-
-/**
- * The base class for all image effects.
- */
-public abstract class Effect {
-
-    /**
-     * Method that applies the effect
-     *
-     * @param src The source bitmap
-     * @return Bitmap The bitmap with the effect applied
-     */
-    public abstract Bitmap apply(Bitmap src);
-}
diff --git a/src/org/cyanogenmod/wallpapers/photophase/effects/Effects.java b/src/org/cyanogenmod/wallpapers/photophase/effects/Effects.java
index f8fd90d..c6a739d 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/effects/Effects.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/effects/Effects.java
@@ -16,6 +16,10 @@
 
 package org.cyanogenmod.wallpapers.photophase.effects;
 
+import android.media.effect.Effect;
+import android.media.effect.EffectContext;
+import android.media.effect.EffectFactory;
+
 import org.cyanogenmod.wallpapers.photophase.preferences.PreferencesProvider.Preferences;
 
 /**
@@ -32,15 +36,15 @@ public class Effects {
          */
         RANDOM,
         /**
-         * @see NullEffect
+         * No effect
          */
         NO_EFFECT,
         /**
-         * @see BlackAndWhiteEffect
+         * @see EffectFactory#EFFECT_GRAYSCALE
          */
-        BLACK_AND_WHITE,
+        GRAYSCALE,
         /**
-         * @see SepiaEffect
+         * @see EffectFactory#EFFECT_SEPIA
          */
         SEPIA;
     }
@@ -48,21 +52,32 @@ public class Effects {
     /**
      * Method that return the next effect to use with the picture.
      *
-     * @return Effect The next effect to use
+     * @param effectContext The android media effects context
+     * @return Effect The next effect to use or null if no need to apply any effect
      */
-    public static Effect getNextEffect() {
+    public static Effect getNextEffect(EffectContext effectContext) {
+        // Get a new instance of a effect factory
+        EffectFactory effectFactory = effectContext.getFactory();
+
+        // Get an effect based on the user preference
         int effect = Preferences.General.Effects.getEffectTypes();
         if (effect == EFFECTS.RANDOM.ordinal()) {
             int low = EFFECTS.NO_EFFECT.ordinal();
             int hight = EFFECTS.values().length - 1;
             effect = low + (int)(Math.random() * ((hight - low) + 1));
         }
-        if (effect == EFFECTS.BLACK_AND_WHITE.ordinal()) {
-            return new BlackAndWhiteEffect();
+
+        // Select the effect if is available
+        if (effect == EFFECTS.GRAYSCALE.ordinal()) {
+            if (EffectFactory.isEffectSupported(EffectFactory.EFFECT_GRAYSCALE)) {
+                return effectFactory.createEffect(EffectFactory.EFFECT_GRAYSCALE);
+            }
         }
         if (effect == EFFECTS.SEPIA.ordinal()) {
-            return new SepiaEffect();
+            if (EffectFactory.isEffectSupported(EffectFactory.EFFECT_SEPIA)) {
+                return effectFactory.createEffect(EffectFactory.EFFECT_SEPIA);
+            }
         }
-        return new NullEffect();
+        return null;
     }
 }
diff --git a/src/org/cyanogenmod/wallpapers/photophase/effects/NullEffect.java b/src/org/cyanogenmod/wallpapers/photophase/effects/NullEffect.java
deleted file mode 100644
index 0cd5e10..0000000
--- a/src/org/cyanogenmod/wallpapers/photophase/effects/NullEffect.java
+++ /dev/null
@@ -1,34 +0,0 @@
-/*
- * Copyright (C) 2013 The CyanogenMod Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.cyanogenmod.wallpapers.photophase.effects;
-
-import android.graphics.Bitmap;
-
-/**
- * A <code>null</code> effect. This class doesn't apply any filter to the bitmap
- */
-public class NullEffect extends Effect {
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Bitmap apply(Bitmap bitmap) {
-        return bitmap;
-    }
-
-}
diff --git a/src/org/cyanogenmod/wallpapers/photophase/effects/SepiaEffect.java b/src/org/cyanogenmod/wallpapers/photophase/effects/SepiaEffect.java
deleted file mode 100644
index 15aa894..0000000
--- a/src/org/cyanogenmod/wallpapers/photophase/effects/SepiaEffect.java
+++ /dev/null
@@ -1,56 +0,0 @@
-/*
- * Copyright (C) 2013 The CyanogenMod Project
- *
- * Licensed under the Apache License, Version 2.0 (the "License");
- * you may not use this file except in compliance with the License.
- * You may obtain a copy of the License at
- *
- *      http://www.apache.org/licenses/LICENSE-2.0
- *
- * Unless required by applicable law or agreed to in writing, software
- * distributed under the License is distributed on an "AS IS" BASIS,
- * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- * See the License for the specific language governing permissions and
- * limitations under the License.
- */
-
-package org.cyanogenmod.wallpapers.photophase.effects;
-
-import android.graphics.Bitmap;
-import android.graphics.Canvas;
-import android.graphics.ColorMatrix;
-import android.graphics.ColorMatrixColorFilter;
-import android.graphics.Paint;
-
-/**
- * This effect converts the source image to sepia color scheme.
- */
-public class SepiaEffect extends Effect {
-
-    /**
-     * {@inheritDoc}
-     */
-    @Override
-    public Bitmap apply(Bitmap src) {
-        try {
-            final int height = src.getHeight();
-            final int width = src.getWidth();
-
-            Bitmap dst = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
-            final Canvas c = new Canvas(dst);
-            final Paint paint = new Paint();
-            final ColorMatrix cmA = new ColorMatrix();
-            cmA.setSaturation(0);
-            final ColorMatrix cmB = new ColorMatrix();
-            cmB.setScale(1f, .95f, .82f, 1.0f);
-            cmA.setConcat(cmB, cmA);
-            final ColorMatrixColorFilter f = new ColorMatrixColorFilter(cmA);
-            paint.setColorFilter(f);
-            c.drawBitmap(src, 0, 0, paint);
-            return dst;
-        } finally {
-            src.recycle();
-        }
-    }
-
-}
diff --git a/src/org/cyanogenmod/wallpapers/photophase/transitions/FadeTransition.java b/src/org/cyanogenmod/wallpapers/photophase/transitions/FadeTransition.java
index d88aafc..c314a88 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/transitions/FadeTransition.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/transitions/FadeTransition.java
@@ -88,7 +88,7 @@ public class FadeTransition extends NullTransition {
     @Override
     public void select(PhotoFrame target) {
         super.select(target);
-        mOverlay = new ColorShape(mContext, target.getPictureVertex(), Colors.getBackground());
+        mOverlay = new ColorShape(mContext, target.getFrameVertex()/*target.getPictureVertex()*/, Colors.getBackground());
         mOverlay.setAlpha(0);
     }
 
@@ -99,15 +99,13 @@ public class FadeTransition extends NullTransition {
     public void apply(float[] matrix) throws GLException {
         // Check internal vars
         if (mTarget == null ||
-            mTarget.getPictureVertexBuffer() == null ||
-            mTarget.getTextureBuffer() == null ||
-            mTarget.getVertexOrderBuffer() == null) {
+            mTarget.getPositionBuffer() == null ||
+            mTarget.getTextureBuffer() == null) {
             return;
         }
         if (mTransitionTarget == null ||
-            mTransitionTarget.getPictureVertexBuffer() == null ||
-            mTransitionTarget.getTextureBuffer() == null ||
-            mTransitionTarget.getVertexOrderBuffer() == null) {
+            mTransitionTarget.getPositionBuffer() == null ||
+            mTransitionTarget.getTextureBuffer() == null) {
             return;
         }
 
diff --git a/src/org/cyanogenmod/wallpapers/photophase/transitions/NullTransition.java b/src/org/cyanogenmod/wallpapers/photophase/transitions/NullTransition.java
index 0332bc5..e88689d 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/transitions/NullTransition.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/transitions/NullTransition.java
@@ -101,9 +101,8 @@ public class NullTransition extends Transition {
     public void apply(float[] matrix) throws GLException {
         // Check internal vars
         if (mTarget == null ||
-            mTarget.getPictureVertexBuffer() == null ||
-            mTarget.getTextureBuffer() == null ||
-            mTarget.getVertexOrderBuffer() == null) {
+            mTarget.getPositionBuffer() == null ||
+            mTarget.getTextureBuffer() == null) {
             return;
         }
 
@@ -114,54 +113,50 @@ public class NullTransition extends Transition {
     /**
      * Method that draws the picture texture
      *
-     * @param target
+     * @param target The target to draw
      * @param matrix The model-view-projection matrix
      */
     protected void draw(PhotoFrame target, float[] matrix) {
-        // Set the program
+        // Bind default FBO
+        GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
+
+        // Use our shader program
         useProgram(0);
 
-        // Bind the texture
-        int textureHandle = target.getTextureHandle();
-        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
-        GLESUtil.glesCheckError("glActiveTexture");
-        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle);
-        GLESUtil.glesCheckError("glBindTexture");
+        // Disable blending
+        GLES20.glDisable(GLES20.GL_BLEND);
 
-        // Position
-        FloatBuffer vertexBuffer = target.getPictureVertexBuffer();
-        vertexBuffer.position(0);
-        GLES20.glVertexAttribPointer(
-                mPositionHandlers[0],
-                PhotoFrame.COORDS_PER_VERTER,
-                GLES20.GL_FLOAT,
-                false,
-                PhotoFrame.COORDS_PER_VERTER * 4,
-                vertexBuffer);
-        GLESUtil.glesCheckError("glVertexAttribPointer");
-        GLES20.glEnableVertexAttribArray(mPositionHandlers[0]);
-        GLESUtil.glesCheckError("glEnableVertexAttribArray");
+        // Apply the projection and view transformation
+        GLES20.glUniformMatrix4fv(mMVPMatrixHandlers[0], 1, false, matrix, 0);
+        GLESUtil.glesCheckError("glUniformMatrix4fv");
 
         // Texture
         FloatBuffer textureBuffer = target.getTextureBuffer();
         textureBuffer.position(0);
-        GLES20.glVertexAttribPointer(
-                mTextureCoordHandlers[0],
-                2,
-                GLES20.GL_FLOAT,
-                false,
-                2 * 4,
-                textureBuffer);
+        GLES20.glVertexAttribPointer(mTextureCoordHandlers[0], 2, GLES20.GL_FLOAT, false, 0, textureBuffer);
         GLESUtil.glesCheckError("glVertexAttribPointer");
         GLES20.glEnableVertexAttribArray(mTextureCoordHandlers[0]);
         GLESUtil.glesCheckError("glEnableVertexAttribArray");
 
-        // Apply the projection and view transformation
-        GLES20.glUniformMatrix4fv(mMVPMatrixHandlers[0], 1, false, matrix, 0);
-        GLESUtil.glesCheckError("glUniformMatrix4fv");
+        // Position
+        FloatBuffer positionBuffer = target.getPositionBuffer();
+        positionBuffer.position(0);
+        GLES20.glVertexAttribPointer(mPositionHandlers[0], 2, GLES20.GL_FLOAT, false, 0, positionBuffer);
+        GLESUtil.glesCheckError("glVertexAttribPointer");
+        GLES20.glEnableVertexAttribArray(mPositionHandlers[0]);
+        GLESUtil.glesCheckError("glEnableVertexAttribArray");
+
+        // Set the input texture
+        int textureHandle = target.getTextureHandle();
+        GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
+        GLESUtil.glesCheckError("glActiveTexture");
+        GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureHandle);
+        GLESUtil.glesCheckError("glBindTexture");
+        GLES20.glUniform1i(mTextureHandlers[0], 0);
+        GLESUtil.glesCheckError("glBindTexture");
 
-        // Draw the photo frame
-        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_FAN, 0, 4);
+        // Draw
+        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
         GLESUtil.glesCheckError("glDrawElements");
 
         // Disable attributes
diff --git a/src/org/cyanogenmod/wallpapers/photophase/transitions/SwapTransition.java b/src/org/cyanogenmod/wallpapers/photophase/transitions/SwapTransition.java
index d100110..d5cf15f 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/transitions/SwapTransition.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/transitions/SwapTransition.java
@@ -84,15 +84,13 @@ public class SwapTransition extends NullTransition {
     public void apply(float[] matrix) throws GLException {
         // Check internal vars
         if (mTarget == null ||
-            mTarget.getPictureVertexBuffer() == null ||
-            mTarget.getTextureBuffer() == null ||
-            mTarget.getVertexOrderBuffer() == null) {
+            mTarget.getPositionBuffer() == null ||
+            mTarget.getTextureBuffer() == null) {
             return;
         }
         if (mTransitionTarget == null ||
-            mTransitionTarget.getPictureVertexBuffer() == null ||
-            mTransitionTarget.getTextureBuffer() == null ||
-            mTransitionTarget.getVertexOrderBuffer() == null) {
+            mTransitionTarget.getPositionBuffer() == null ||
+            mTransitionTarget.getTextureBuffer() == null) {
             return;
         }
 
diff --git a/src/org/cyanogenmod/wallpapers/photophase/transitions/Transition.java b/src/org/cyanogenmod/wallpapers/photophase/transitions/Transition.java
index 315a9f8..cd24b54 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/transitions/Transition.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/transitions/Transition.java
@@ -35,6 +35,7 @@ public abstract class Transition {
     private final TextureManager mTextureManager;
 
     protected int[] mProgramHandlers;
+    protected int[] mTextureHandlers;
     protected int[] mPositionHandlers;
     protected int[] mTextureCoordHandlers;
     protected int[] mMVPMatrixHandlers;
@@ -64,6 +65,7 @@ public abstract class Transition {
         assert mVertexShader.length != mFragmentShader.length;
         int cc = mVertexShader.length;
         mProgramHandlers = new int[cc];
+        mTextureHandlers = new int[cc];
         mPositionHandlers = new int[cc];
         mTextureCoordHandlers = new int[cc];
         mMVPMatrixHandlers = new int[cc];
@@ -86,7 +88,6 @@ public abstract class Transition {
                             mContext,
                             mTextureManager,
                             mTarget.getFrameVertex(),
-                            mTarget.getPictureVertex(),
                             mTarget.getBackgroundColor());
         }
     }
@@ -157,6 +158,8 @@ public abstract class Transition {
         mProgramHandlers[index] =
                 GLESUtil.createProgram(
                         mContext.getResources(), mVertexShader[index], mFragmentShader[index]);
+        mTextureHandlers[index] =
+                GLES20.glGetAttribLocation(mProgramHandlers[index], "sTexture");
         mPositionHandlers[index] =
                 GLES20.glGetAttribLocation(mProgramHandlers[index], "aPosition");
         GLESUtil.glesCheckError("glGetAttribLocation");
@@ -192,6 +195,7 @@ public abstract class Transition {
                 GLESUtil.glesCheckError("glDeleteProgram");
             }
             mProgramHandlers[i] = 0;
+            mTextureHandlers[i] = 0;
             mPositionHandlers[i] = 0;
             mTextureCoordHandlers[i] = 0;
             mMVPMatrixHandlers[i] = 0;
diff --git a/src/org/cyanogenmod/wallpapers/photophase/transitions/TranslateTransition.java b/src/org/cyanogenmod/wallpapers/photophase/transitions/TranslateTransition.java
index 4e32a4a..33e69d7 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/transitions/TranslateTransition.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/transitions/TranslateTransition.java
@@ -29,7 +29,6 @@ import org.cyanogenmod.wallpapers.photophase.TextureManager;
 import org.cyanogenmod.wallpapers.photophase.transitions.Transitions.TRANSITIONS;
 
 import java.nio.FloatBuffer;
-import java.nio.ShortBuffer;
 import java.util.ArrayList;
 import java.util.Arrays;
 import java.util.List;
@@ -120,16 +119,16 @@ public class TranslateTransition extends Transition {
                 new ArrayList<TranslateTransition.TRANSLATE_MODES>(
                         Arrays.asList(TRANSLATE_MODES.values()));
         float[] vertex = target.getFrameVertex();
-        if (vertex[0] != -1.0f) {
+        if (vertex[4] != -1.0f) {
             modes.remove(TRANSLATE_MODES.RIGHT_TO_LEFT);
         }
-        if (vertex[9] != 1.0f) {
+        if (vertex[6] != 1.0f) {
             modes.remove(TRANSLATE_MODES.LEFT_TO_RIGHT);
         }
-        if (vertex[1] != 1.0f) {
+        if (vertex[5] != 1.0f) {
             modes.remove(TRANSLATE_MODES.DOWN_TO_UP);
         }
-        if (vertex[4] != -1.0f) {
+        if (vertex[1] != -1.0f) {
             modes.remove(TRANSLATE_MODES.UP_TO_DOWN);
         }
 
@@ -145,8 +144,8 @@ public class TranslateTransition extends Transition {
     @Override
     public boolean isSelectable(PhotoFrame frame) {
         float[] vertex = frame.getFrameVertex();
-        if (vertex[0] == -1.0f || vertex[9] == 1.0f ||
-            vertex[1] == 1.0f || vertex[4] == -1.0f) {
+        if (vertex[4] == -1.0f || vertex[6] == 1.0f ||
+            vertex[5] == 1.0f || vertex[1] == -1.0f) {
             return true;
         }
         return false;
@@ -168,15 +167,13 @@ public class TranslateTransition extends Transition {
     public void apply(float[] matrix) throws GLException {
         // Check internal vars
         if (mTarget == null ||
-            mTarget.getPictureVertexBuffer() == null ||
-            mTarget.getTextureBuffer() == null ||
-            mTarget.getVertexOrderBuffer() == null) {
+            mTarget.getPositionBuffer() == null ||
+            mTarget.getTextureBuffer() == null) {
             return;
         }
         if (mTransitionTarget == null ||
-            mTransitionTarget.getPictureVertexBuffer() == null ||
-            mTransitionTarget.getTextureBuffer() == null ||
-            mTransitionTarget.getVertexOrderBuffer() == null) {
+            mTransitionTarget.getPositionBuffer() == null ||
+            mTransitionTarget.getTextureBuffer() == null) {
             return;
         }
 
@@ -218,7 +215,7 @@ public class TranslateTransition extends Transition {
         GLESUtil.glesCheckError("glBindTexture");
 
         // Position
-        FloatBuffer vertexBuffer = mTarget.getPictureVertexBuffer();
+        FloatBuffer vertexBuffer = mTarget.getPositionBuffer();
         vertexBuffer.position(0);
         GLES20.glVertexAttribPointer(
                 mPositionHandlers[0],
@@ -248,8 +245,8 @@ public class TranslateTransition extends Transition {
         // Calculate the delta distance
         float distance =
            (mMode.compareTo(TRANSLATE_MODES.LEFT_TO_RIGHT) == 0 || mMode.compareTo(TRANSLATE_MODES.RIGHT_TO_LEFT) == 0)
-           ? mTarget.getPictureWidth()
-           : mTarget.getPictureHeight();
+           ? mTarget.getFrameWidth()
+           : mTarget.getFrameHeight();
         if (mMode.compareTo(TRANSLATE_MODES.RIGHT_TO_LEFT) == 0 || mMode.compareTo(TRANSLATE_MODES.DOWN_TO_UP) == 0) {
             distance *= -1;
         }
@@ -267,13 +264,7 @@ public class TranslateTransition extends Transition {
         GLESUtil.glesCheckError("glUniformMatrix4fv");
 
         // Draw the photo frame
-        ShortBuffer vertexOrderBuffer = mTarget.getVertexOrderBuffer();
-        vertexOrderBuffer.position(0);
-        GLES20.glDrawElements(
-                GLES20.GL_TRIANGLE_FAN,
-                6,
-                GLES20.GL_UNSIGNED_SHORT,
-                vertexOrderBuffer);
+        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
         GLESUtil.glesCheckError("glDrawElements");
 
         // Disable attributes
@@ -301,7 +292,7 @@ public class TranslateTransition extends Transition {
         GLESUtil.glesCheckError("glBindTexture");
 
         // Position
-        FloatBuffer vertexBuffer = mTransitionTarget.getPictureVertexBuffer();
+        FloatBuffer vertexBuffer = mTransitionTarget.getPositionBuffer();
         vertexBuffer.position(0);
         GLES20.glVertexAttribPointer(
                 mPositionHandlers[1],
@@ -335,13 +326,7 @@ public class TranslateTransition extends Transition {
         GLESUtil.glesCheckError("glUniformMatrix4fv");
 
         // Draw the photo frame
-        ShortBuffer vertexOrderBuffer = mTransitionTarget.getVertexOrderBuffer();
-        vertexOrderBuffer.position(0);
-        GLES20.glDrawElements(
-                GLES20.GL_TRIANGLE_FAN,
-                6,
-                GLES20.GL_UNSIGNED_SHORT,
-                vertexOrderBuffer);
+        GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);
         GLESUtil.glesCheckError("glDrawElements");
 
         // Disable attributes
diff --git a/src/org/cyanogenmod/wallpapers/photophase/utils/MERAlgorithm.java b/src/org/cyanogenmod/wallpapers/photophase/utils/MERAlgorithm.java
index bd29235..8e793ae 100644
--- a/src/org/cyanogenmod/wallpapers/photophase/utils/MERAlgorithm.java
+++ b/src/org/cyanogenmod/wallpapers/photophase/utils/MERAlgorithm.java
@@ -23,6 +23,9 @@ import java.util.Stack;
  * The maximal empty rectangle algorithm that allows to find the rectangle with the maximal
  * area that could be create in empty areas (in this case 0 in a byte matrix)
  */
+//
+// Based on the source discussed at http://discuss.leetcode.com/questions/260/maximal-rectangle
+//
 public final class MERAlgorithm {
 
     /**