把Android原生的View渲染到OpenGL Texture

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

最近要把Android 原生的View渲染到OpenGL GLSurfaceView中，起初想到的是截图的方法，也就是把View截取成bitmap后，再把Bitmap渲染到OpenGL中；但是明显这种方法是不可行的，面对一些高速动态更新的View，只有不停的对view 进行截图才能渲染出原生View的效果。

通过大量的Google终于在国外的网站找到了一个做过类似的先例（链接:http://www.felixjones.co.uk/neo%20website/Android_View/）。不过经过测试该方法只能渲染直接父类为View的view，也就是只能渲染一层View（如progressbar，没不能添加child的view），当该原生Android View包含很多子view时（也就是根View为FramLayout、或者linearLayout之类），无法实时的监听到View动态改变，OpenGL中只能不停的渲染该view，才能渲染出原生View的效果。但是这样一来不同的渲染会耗费大量的资源，降低应用程序的效率。理想中的话，是监听到了该View的内容或者其子view 的内容发生了变化(如：View中的字幕发生滚动)才进行渲染。

经过接近两周的努力我终于完美地实现了该效果，既然是站在别人的基础上得来的成果，那么该方法就应当被共享，所以产生了此文，不过只支持api 15以上的

步骤一:重写根View

1.设置该View 绘制自己：

1. setWillNotDraw(false);

2.监听View的变化，重写View，用ViewTreeObServer来监听，方法如下：

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

3.重写该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);
8. mSurface.release();
9. mSurface = null;
10. mSurface = new Surface(mSurfaceTexture);
11. }
12. } catch (OutOfResourcesException e) {
13. e.printStackTrace();
14. }
15. }

步骤二：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;
11. // Fixed values
12. private int TEXTURE_WIDTH = 360;
13. private int TEXTURE_HEIGHT = 360;
14. Context context;
15. private LauncherAppWidgetHostView addedWidgetView;
16. private SurfaceTexture surfaceTexture = null;
17. private Surface surface;
18. float fps;
19. public CustomRenderer(Context context, LauncherAppWidgetHostView addedWidgetView, Display mDisplay){
20. this.context = context;
21. this.addedWidgetView = addedWidgetView;
22. TEXTURE_WIDTH = mDisplay.getWidth();
23. TEXTURE_HEIGHT = mDisplay.getHeight();
24. _memoryInfo = new MemoryInfo();
25. activityManager = (ActivityManager) context.getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE);
26. }
27. @Override
28. public void onDrawFrame(GL10 gl) {
29. synchronized (this) {
30. surfaceTexture.updateTexImage();
31. }
32. activityManager.getMemoryInfo(_memoryInfo);
33. GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f);
34. GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT);
35. GLES20.glEnable(GLES20.GL_BLEND);
36. GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA);
37. float[] mtx = new float[16];
38. surfaceTexture.getTransformMatrix(mtx);
39. mDirectDrawer.draw(mtx);
40. calculateFps();
41. //getAppMemorySize();
42. //getRunningAppProcessInfo();
43. //Log.v("onDrawFrame", "FPS: " + Math.round(fps) + ", availMem: " + Math.round(_memoryInfo.availMem / 1048576) + "MB");
44. }
45. private void getAppMemorySize(){
46. ActivityManager mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
47. android.os.Debug.MemoryInfo[] memoryInfos = mActivityManager.getProcessMemoryInfo(new int[]{android.os.Process.myPid()});
48. int size = memoryInfos[0].dalvikPrivateDirty;
49. Log.w("getAppMemorySize", size / 1024 + " MB");
50. }
51. private void getRunningAppProcessInfo() {
52. ActivityManager  mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE);
53. //获得系统里正在运行的所有进程
54. List<RunningAppProcessInfo> runningAppProcessesList = mActivityManager.getRunningAppProcesses();
55. for (RunningAppProcessInfo runningAppProcessInfo : runningAppProcessesList) {
56. // 进程ID号
57. int pid = runningAppProcessInfo.pid;
58. // 用户ID
59. int uid = runningAppProcessInfo.uid;
60. // 进程名
61. String processName = runningAppProcessInfo.processName;
62. // 占用的内存
63. int[] pids = new int[] {pid};
64. Debug.MemoryInfo[] memoryInfo = mActivityManager.getProcessMemoryInfo(pids);
65. int memorySize = memoryInfo[0].dalvikPrivateDirty;
66. System.out.println("processName="+processName+",currentPid: "+  "pid= " +android.os.Process.myPid()+"----------->"+pid+",uid="+uid+",memorySize="+memorySize+"kb");
67. }
68. }
69. @Override
70. public void onSurfaceCreated(GL10 gl, EGLConfig config) {
71. surface = null;
72. surfaceTexture = null;
73. glSurfaceTex = Engine_CreateSurfaceTexture(TEXTURE_WIDTH, TEXTURE_HEIGHT);
74. Log.d("GLES20Ext", "glSurfaceTex" + glSurfaceTex);
75. if (glSurfaceTex > 0) {
76. surfaceTexture = new SurfaceTexture(glSurfaceTex);
77. surfaceTexture.setDefaultBufferSize(TEXTURE_WIDTH, TEXTURE_HEIGHT);
78. surface = new Surface(surfaceTexture);
79. addedWidgetView.setSurface(surface);
80. addedWidgetView.setSurfaceTexture(surfaceTexture);
81. //addedWidgetView.setSurfaceTexture(surfaceTexture);
82. mDirectDrawer = new DirectDrawer(glSurfaceTex);
83. }
84. }
85. float calculateFps() {
86. frameCount++;
87. if (!b) {
88. b = true;
89. previousTime = System.currentTimeMillis();
90. }
91. long intervalTime = System.currentTimeMillis() - previousTime;
92. if (intervalTime >= 1000) {
93. b = false;
94. fps = frameCount / (intervalTime / 1000f);
95. frameCount = 0;
96. Log.w("calculateFps", "FPS: " + fps);
97. }
98. return fps;
99. }
100. int Engine_CreateSurfaceTexture(int width, int height) {
101. /*
102. * Create our texture. This has to be done each time the surface is
103. * created.
104. */
105. int[] textures = new int[1];
106. GLES20.glGenTextures(1, textures, 0);
107. glSurfaceTex = textures[0];
108. if (glSurfaceTex > 0) {
109. GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, glSurfaceTex);
110. // Notice the use of GL_TEXTURE_2D for texture creation
111. GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB, width, height, 0, GLES20.GL_RGB, GLES20.GL_UNSIGNED_BYTE, null);
112. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST);
113. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST);
114. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
115. GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);
116. }
117. return glSurfaceTex;
118. }
119. @Override
120. public void onSurfaceChanged(GL10 gl, int width, int height) {
121. }
122. }

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. "}";
11. private final String fragmentShaderCode =
12. "#extension GL_OES_EGL_image_external : require\n"+
13. "precision mediump float;" +
14. "varying vec2 textureCoordinate;\n" +
15. "uniform samplerExternalOES s_texture;\n" +
16. "void main() {" +
17. "  gl_FragColor = texture2D( s_texture, textureCoordinate );\n" +
18. "}";
19. private FloatBuffer vertexBuffer, textureVerticesBuffer;
20. private ShortBuffer drawListBuffer;
21. private final int mProgram;
22. private int mPositionHandle;
23. private int mTextureCoordHandle;
24. private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices
25. // number of coordinates per vertex in this array
26. private static final int COORDS_PER_VERTEX = 2;
27. private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex
28. static float squareCoords[] = {
29. -1.0f,  0.0f,
30. -1.0f, -2.2f,
31. 1.0f, -2.2f,
32. 1.0f,  0.0f,
33. };
34. static float textureVertices[] = {
35. 0f,  0f,
36. 0f,  1f,
37. 1f,  1f,
38. 1f,  0f,
39. };
40. private int texture;
41. public DirectDrawer(int texture)
42. {
43. this.texture = texture;
44. // initialize vertex byte buffer for shape coordinates
45. ByteBuffer bb = ByteBuffer.allocateDirect(squareCoords.length * 4);
46. bb.order(ByteOrder.nativeOrder());
47. vertexBuffer = bb.asFloatBuffer();
48. vertexBuffer.put(squareCoords);
49. vertexBuffer.position(0);
50. // initialize byte buffer for the draw list
51. ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2);
52. dlb.order(ByteOrder.nativeOrder());
53. drawListBuffer = dlb.asShortBuffer();
54. drawListBuffer.put(drawOrder);
55. drawListBuffer.position(0);
56. ByteBuffer bb2 = ByteBuffer.allocateDirect(textureVertices.length * 4);
57. bb2.order(ByteOrder.nativeOrder());
58. textureVerticesBuffer = bb2.asFloatBuffer();
59. textureVerticesBuffer.put(textureVertices);
60. textureVerticesBuffer.position(0);
61. int vertexShader    = loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode);
62. int fragmentShader  = loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode);
63. mProgram = GLES20.glCreateProgram();             // create empty OpenGL ES Program
64. GLES20.glAttachShader(mProgram, vertexShader);   // add the vertex shader to program
65. GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program
66. GLES20.glLinkProgram(mProgram);                  // creates OpenGL ES program executables
67. }
68. public void draw(float[] mtx)
69. {
70. GLES20.glUseProgram(mProgram);
71. GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
72. GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture);
73. // get handle to vertex shader's vPosition member
74. mPositionHandle = GLES20.glGetAttribLocation(mProgram, "vPosition");
75. // Enable a handle to the triangle vertices
76. GLES20.glEnableVertexAttribArray(mPositionHandle);
77. // Prepare the <insert shape here> coordinate data
78. GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer);
79. mTextureCoordHandle = GLES20.glGetAttribLocation(mProgram, "inputTextureCoordinate");
80. GLES20.glEnableVertexAttribArray(mTextureCoordHandle);
81. // textureVerticesBuffer.clear();
82. // textureVerticesBuffer.put( transformTextureCoordinates(
83. // textureVertices, mtx ));
84. // textureVerticesBuffer.position(0);
85. GLES20.glVertexAttribPointer(mTextureCoordHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, textureVerticesBuffer);
86. GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer);
87. // Disable vertex array
88. GLES20.glDisableVertexAttribArray(mPositionHandle);
89. GLES20.glDisableVertexAttribArray(mTextureCoordHandle);
90. }
91. private  int loadShader(int type, String shaderCode){
92. // create a vertex shader type (GLES20.GL_VERTEX_SHADER)
93. // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER)
94. int shader = GLES20.glCreateShader(type);
95. // add the source code to the shader and compile it
96. GLES20.glShaderSource(shader, shaderCode);
97. GLES20.glCompileShader(shader);
98. return shader;
99. }
100. private float[] transformTextureCoordinates( float[] coords, float[] matrix)
101. {
102. float[] result = new float[ coords.length ];
103. float[] vt = new float[4];
104. for ( int i = 0 ; i < coords.length ; i += 2 ) {
105. float[] v = { coords[i], coords[i+1], 0 , 1  };
106. Matrix.multiplyMV(vt, 0, matrix, 0, v, 0);
107. result[i] = vt[0];
108. result[i+1] = vt[1];
109. }
110. return result;
111. }
112. }

步骤三：配置GLSurfaceView：

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

效果如图所示，上面是猎豹清理大师的widget，下面是GLSurfaceView的Texture，原生的Widget和OpenGL中渲染的一模一样。并且点击widget进行清理时也能达到实时渲染的Veiw动画清理效果，源码链接：https://github.com/MrHuangXin/RenderViewToOpenGL/tree/master