http://blog.csdn.net/u010949962/article/details/41865777

最近要把Android 原生的View渲染到OpenGL GLSurfaceView中，起初想到的是截圖的方法，也就是把View截取成bitmap後，再把Bitmap渲染到OpenGL中；但是明顯這種方法是不可行的，面對一些高速動態更新的View，只有不停的對view 進行截圖才能渲染出原生View的效果。

通過大量的Google終於在國外的網站找到了一個做過類似的先例（鏈接:http://www.felixjones.co.uk/neo%20website/Android_View/）。不過經過測試該方法只能渲染直接父類為View的view，也就是只能渲染一層View（如progressbar，沒不能添加child的view），當該原生Android View包含很多子view時（也就是根View為FramLayout、或者linearLayout之類），無法實時的監聽到View動態改變，OpenGL中只能不停的渲染該view，才能渲染出原生View的效果。但是這樣一來不同的渲染會耗費大量的資源，降低應用程序的效率。理想中的話，是監聽到了該View的內容或者其子view 的內容發生了變化(如：View中的字幕發生滾動)才進行渲染。

經過接近兩周的努力我終於完美地實現了該效果，既然是站在別人的基礎上得來的成果，那麽該方法就應當被共享，所以產生了此文，不過只支持api 15以上的

步驟一:重寫根View

1.設置該View 繪制自己：

1. setWillNotDraw(false);

2.監聽View的變化，重寫View，用ViewTreeObServer來監聽，方法如下：

1. private void addOnPreDrawListener() {
3. if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.HONEYCOMB) {
5. final ViewTreeObserver mObserver = getViewTreeObserver();
6. if (mObserver != null) {
7. mObserver.addOnPreDrawListener(new OnPreDrawListener() {
9. @Override
10. public boolean onPreDraw() {
11. if (isDirty()) {//View或者子view發生變化
12. invalidate();
13. }
14. return true;
15. }
16. });
17. }
18. }
19. }

3.重寫該View的onDraw方法:

1. @Override
2. protected void onDraw(Canvas canvas) {
3. try {
4. if (mSurface != null) {
5. Canvas surfaceCanvas = mSurface.lockCanvas(null);
6. super.dispatchDraw(surfaceCanvas);
7. mSurface.unlockCanvasAndPost(surfaceCanvas);
9. mSurface.release();
10. mSurface = null;
11. mSurface = new Surface(mSurfaceTexture);
12. }
13. } catch (OutOfResourcesException e) {
14. e.printStackTrace();
15. }
16. }

步驟二：GLSurfaceView.Renderer

1. class CustomRenderer implements GLSurfaceView.Renderer {
2. int glSurfaceTex;
3. private final int GL_TEXTURE_EXTERNAL_OES = 0x8D65;
4. long currentTime;
5. long previousTime;
6. boolean b = false;
7. int frameCount = 0;
8. DirectDrawer mDirectDrawer;
9. ActivityManager activityManager;
10. MemoryInfo _memoryInfo;
13. // Fixed values
14. private int TEXTURE_WIDTH = 360;
15. private int TEXTURE_HEIGHT = 360;
17. Context context;
19. private LauncherAppWidgetHostView addedWidgetView;
21. private SurfaceTexture surfaceTexture = null;
23. private Surface surface;
25. float fps;
27. public CustomRenderer(Context context, LauncherAppWidgetHostView addedWidgetView, Display mDisplay){
28. this.context = context;
29. this.addedWidgetView = addedWidgetView;
30. TEXTURE_WIDTH = mDisplay.getWidth();
31. TEXTURE_HEIGHT = mDisplay.getHeight();
32. _memoryInfo = new MemoryInfo();
33. activityManager = (ActivityManager) context.getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
34. }
36. @Override
37. public void onDrawFrame(GL10 gl) {
39. synchronized (this) {
40. surfaceTexture.updateTexImage();
41. }
43. activityManager.getMemoryInfo(_memoryInfo);
45. GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
46. GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
47. GLES20.glEnable(GLES20.GL_BLEND);
48. GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA);
50. float[] mtx = new float[16];
51. surfaceTexture.getTransformMatrix(mtx);
52. mDirectDrawer.draw(mtx);
54. calculateFps();
55. //getAppMemorySize();
56. //getRunningAppProcessInfo();
57. //Log.v("onDrawFrame", "FPS: " + Math.round(fps) + ", availMem: " + Math.round(_memoryInfo.availMem / 1048576) + "MB");
58. }
60. private void getAppMemorySize(){
61. ActivityManager mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
62. android.os.Debug.MemoryInfo[] memoryInfos = mActivityManager.getProcessMemoryInfo(new int[]{android.os.Process.myPid()});
63. int size = memoryInfos[0].dalvikPrivateDirty;
64. Log.w("getAppMemorySize", size / 1024 + " MB");
65. }
68. private void getRunningAppProcessInfo() {
69. ActivityManager mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
71. //獲得系統裏正在運行的所有進程
72. List<RunningAppProcessInfo> runningAppProcessesList = mActivityManager.getRunningAppProcesses();
74. for (RunningAppProcessInfo runningAppProcessInfo : runningAppProcessesList) {
75. // 進程ID號
76. int pid = runningAppProcessInfo.pid;
77. // 用戶ID
78. int uid = runningAppProcessInfo.uid;
79. // 進程名
80. String processName = runningAppProcessInfo.processName;
81. // 占用的內存
82. int[] pids = new int[] {pid};
83. Debug.MemoryInfo[] memoryInfo = mActivityManager.getProcessMemoryInfo(pids);
84. int memorySize = memoryInfo[0].dalvikPrivateDirty;
86. System.out.println("processName="+processName+",currentPid: "+ "pid= " +android.os.Process.myPid()+"----------->"+pid+",uid="+uid+",memorySize="+memorySize+"kb");
87. }
88. }
90. @Override
91. public void onSurfaceCreated(GL10 gl, EGLConfig config) {
93. surface = null;
94. surfaceTexture = null;
96. glSurfaceTex = Engine_CreateSurfaceTexture(TEXTURE_WIDTH, TEXTURE_HEIGHT);
97. Log.d("GLES20Ext", "glSurfaceTex" + glSurfaceTex);
98. if (glSurfaceTex > 0) {
99. surfaceTexture = new SurfaceTexture(glSurfaceTex);
100. surfaceTexture.setDefaultBufferSize(TEXTURE_WIDTH, TEXTURE_HEIGHT);
101. surface = new Surface(surfaceTexture);
102. addedWidgetView.setSurface(surface);
103. addedWidgetView.setSurfaceTexture(surfaceTexture);
104. //addedWidgetView.setSurfaceTexture(surfaceTexture);
105. mDirectDrawer = new DirectDrawer(glSurfaceTex);
106. }
107. }
109. float calculateFps() {
111. frameCount++;
112. if (!b) {
113. b = true;
114. previousTime = System.currentTimeMillis();
115. }
116. long intervalTime = System.currentTimeMillis() - previousTime;
118. if (intervalTime >= 1000) {
119. b = false;
120. fps = frameCount / (intervalTime / 1000f);
121. frameCount = 0;
122. Log.w("calculateFps", "FPS: " + fps);
123. }
125. return fps;
126. }
128. int Engine_CreateSurfaceTexture(int width, int height) {
129. /*
130. * Create our texture. This has to be done each time the surface is
131. * created.
132. */
134. int[] textures = new int[1];
135. GLES20.glGenTextures(1, textures, 0);
137. glSurfaceTex = textures[0];
139. if (glSurfaceTex > 0) {
140. GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, glSurfaceTex);
142. // Notice the use of GL_TEXTURE_2D for texture creation
143. GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB, width, height, 0, GLES20.GL_RGB, GLES20.GL_UNSIGNED_BYTE, null);
145. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
146. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);
148. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
149. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);
150. }
151. return glSurfaceTex;
152. }
154. @Override
155. public void onSurfaceChanged(GL10 gl, int width, int height) {
157. }
158. }

1. public class DirectDrawer {
2. private final String vertexShaderCode =
3. "attribute vec4 vPosition;" +
4. "attribute vec2 inputTextureCoordinate;" +
5. "varying vec2 textureCoordinate;" +
6. "void main()" +
7. "{"+
8. "gl_Position = vPosition;"+
9. "textureCoordinate = inputTextureCoordinate;" +
10. "}";
12. private final String fragmentShaderCode =
13. "#extension GL_OES_EGL_image_external : require\n"+
14. "precision mediump float;" +
15. "varying vec2 textureCoordinate;\n" +
16. "uniform samplerExternalOES s_texture;\n" +
17. "void main() {" +
18. " gl_FragColor = texture2D( s_texture, textureCoordinate );\n" +
19. "}";
21. private FloatBuffer vertexBuffer, textureVerticesBuffer;
22. private ShortBuffer drawListBuffer;
23. private final int mProgram;
24. private int mPositionHandle;
25. private int mTextureCoordHandle;
27. private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices
29. // number of coordinates per vertex in this array
30. private static final int COORDS_PER_VERTEX = 2;
32. private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
34. static float squareCoords[] = {
35. -1.0f, 0.0f,
36. -1.0f, -2.2f,
37. 1.0f, -2.2f,
38. 1.0f, 0.0f,
39. };
41. static float textureVertices[] = {
42. 0f, 0f,
43. 0f, 1f,
44. 1f, 1f,
45. 1f, 0f,
46. };
48. private int texture;
50. public DirectDrawer(int texture)
51. {
52. this.texture = texture;
53. // initialize vertex byte buffer for shape coordinates
54. ByteBuffer bb = ByteBuffer.allocateDirect(squareCoords.length * 4);
55. bb.order(ByteOrder.nativeOrder());
56. vertexBuffer = bb.asFloatBuffer();
57. vertexBuffer.put(squareCoords);
58. vertexBuffer.position(0);
60. // initialize byte buffer for the draw list
61. ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2);
62. dlb.order(ByteOrder.nativeOrder());
63. drawListBuffer = dlb.asShortBuffer();
64. drawListBuffer.put(drawOrder);
65. drawListBuffer.position(0);
67. ByteBuffer bb2 = ByteBuffer.allocateDirect(textureVertices.length * 4);
68. bb2.order(ByteOrder.nativeOrder());
69. textureVerticesBuffer = bb2.asFloatBuffer();
70. textureVerticesBuffer.put(textureVertices);
71. textureVerticesBuffer.position(0);
73. int vertexShader = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
74. int fragmentShader = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);
76. mProgram = GLES20.glCreateProgram(); // create empty OpenGL ES Program
77. GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program
78. GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
79. GLES20.glLinkProgram(mProgram); // creates OpenGL ES program executables
80. }
82. public void draw(float[] mtx)
83. {
84. GLES20.glUseProgram(mProgram);
86. GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
87. GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture);
89. // get handle to vertex shader‘s vPosition member
90. mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
92. // Enable a handle to the triangle vertices
93. GLES20.glEnableVertexAttribArray(mPositionHandle);
95. // Prepare the <insert shape here> coordinate data
96. GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer);
98. mTextureCoordHandle = GLES20.glGetAttribLocation(mProgram, "inputTextureCoordinate");
99. GLES20.glEnableVertexAttribArray(mTextureCoordHandle);
101. // textureVerticesBuffer.clear();
102. // textureVerticesBuffer.put( transformTextureCoordinates(
103. // textureVertices, mtx ));
104. // textureVerticesBuffer.position(0);
106. GLES20.glVertexAttribPointer(mTextureCoordHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, textureVerticesBuffer);
108. GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
110. // Disable vertex array
111. GLES20.glDisableVertexAttribArray(mPositionHandle);
112. GLES20.glDisableVertexAttribArray(mTextureCoordHandle);
113. }
115. private int loadShader(int type, String shaderCode){
117. // create a vertex shader type (GLES20.GL_VERTEX_SHADER)
118. // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
119. int shader = GLES20.glCreateShader(type);
121. // add the source code to the shader and compile it
122. GLES20.glShaderSource(shader, shaderCode);
123. GLES20.glCompileShader(shader);
125. return shader;
126. }
127. private float[] transformTextureCoordinates( float[] coords, float[] matrix)
128. {
129. float[] result = new float[ coords.length ];
130. float[] vt = new float[4];
132. for ( int i = 0 ; i < coords.length ; i += 2 ) {
133. float[] v = { coords[i], coords[i+1], 0 , 1 };
134. Matrix.multiplyMV(vt, 0, matrix, 0, v, 0);
135. result[i] = vt[0];
136. result[i+1] = vt[1];
137. }
138. return result;
139. }
140. }

步驟三：配置GLSurfaceView：

1. GLSurfaceView glSurfaceView = new GLSurfaceView(getApplicationContext());
2. // Setup the surface view for drawing to
4. glSurfaceView.setEGLContextClientVersion(2);
5. glSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0);
6. glSurfaceView.setRenderer(renderer);
7. //glSurfaceView.setZOrderOnTop(true);
9. // Add our WebView to the Android View hierarchy
10. glSurfaceView.setLayoutParams(new FrameLayout.LayoutParams(FrameLayout.LayoutParams.MATCH_PARENT, FrameLayout.LayoutParams.MATCH_PARENT));

效果如圖所示，上面是獵豹清理大師的widget，下面是GLSurfaceView的Texture，原生的Widget和OpenGL中渲染的一模一樣。並且點擊widget進行清理時也能達到實時渲染的Veiw動畫清理效果，源碼鏈接：https://github.com/MrHuangXin/RenderViewToOpenGL/tree/master

把Android原生的View渲染到OpenGL Texture