把Android原生的View渲染到OpenGL Texture _android

休言女子非英物，夜夜龙泉壁上鸣。这篇文章主要讲述把Android原生的View渲染到OpenGL Texture相关的知识，希望能为你提供帮助。
尊重原创请附上链接：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：

setWillNotDraw(false);

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

private void addOnPreDrawListener() {if (Build.VERSION.SDK_INT > = Build.VERSION_CODES.HONEYCOMB) {final ViewTreeObserver mObserver = getViewTreeObserver(); if (mObserver != null) { mObserver.addOnPreDrawListener(new OnPreDrawListener() {@Override public boolean onPreDraw() { if (isDirty()) {//View或者子view发生变化 invalidate(); } return true; } }); } } }

3.重写该View的onDraw方法:

@Override protected void onDraw(Canvas canvas) { try { if (mSurface != null) { Canvas surfaceCanvas = mSurface.lockCanvas(null); super.dispatchDraw(surfaceCanvas); mSurface.unlockCanvasAndPost(surfaceCanvas); mSurface.release(); mSurface = null; mSurface = new Surface(mSurfaceTexture); } } catch (OutOfResourcesException e) { e.printStackTrace(); } }

步骤二：GLSurfaceView.Renderer

class CustomRenderer implements GLSurfaceView.Renderer { int glSurfaceTex; private final int GL_TEXTURE_EXTERNAL_OES = 0x8D65; long currentTime; long previousTime; boolean b = false; int frameCount = 0; DirectDrawer mDirectDrawer; ActivityManager activityManager; MemoryInfo _memoryInfo; // Fixed values private int TEXTURE_WIDTH = 360; private int TEXTURE_HEIGHT = 360; Context context; private LauncherAppWidgetHostView addedWidgetView; private SurfaceTexture surfaceTexture = null; private Surface surface; float fps; public CustomRenderer(Context context, LauncherAppWidgetHostView addedWidgetView, Display mDisplay){ this.context = context; this.addedWidgetView = addedWidgetView; TEXTURE_WIDTH = mDisplay.getWidth(); TEXTURE_HEIGHT = mDisplay.getHeight(); _memoryInfo = new MemoryInfo(); activityManager = (ActivityManager) context.getApplicationContext().getSystemService(Context.ACTIVITY_SERVICE); } @Override public void onDrawFrame(GL10 gl) {synchronized (this) { surfaceTexture.updateTexImage(); }activityManager.getMemoryInfo(_memoryInfo); GLES20.glClearColor(0.0f, 0.0f, 1.0f, 1.0f); GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT); GLES20.glEnable(GLES20.GL_BLEND); GLES20.glBlendFunc(GLES20.GL_ONE, GLES20.GL_ONE_MINUS_SRC_ALPHA); float[] mtx = new float[16]; surfaceTexture.getTransformMatrix(mtx); mDirectDrawer.draw(mtx); calculateFps(); //getAppMemorySize(); //getRunningAppProcessInfo(); //Log.v(" onDrawFrame" , " FPS: " + Math.round(fps) + " , availMem: " + Math.round(_memoryInfo.availMem / 1048576) + " MB" ); } private void getAppMemorySize(){ ActivityManager mActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE); android.os.Debug.MemoryInfo[] memoryInfos = mActivityManager.getProcessMemoryInfo(new int[]{android.os.Process.myPid()}); int size = memoryInfos[0].dalvikPrivateDirty; Log.w(" getAppMemorySize" , size / 1024 + " MB" ); } private void getRunningAppProcessInfo() { ActivityManagermActivityManager = (ActivityManager) context.getSystemService(Context.ACTIVITY_SERVICE); //获得系统里正在运行的所有进程 List< RunningAppProcessInfo> runningAppProcessesList = mActivityManager.getRunningAppProcesses(); for (RunningAppProcessInfo runningAppProcessInfo : runningAppProcessesList) { // 进程ID号 int pid = runningAppProcessInfo.pid; // 用户ID int uid = runningAppProcessInfo.uid; // 进程名 String processName = runningAppProcessInfo.processName; // 占用的内存 int[] pids = new int[] {pid}; Debug.MemoryInfo[] memoryInfo = mActivityManager.getProcessMemoryInfo(pids); int memorySize = memoryInfo[0].dalvikPrivateDirty; System.out.println(" processName=" +processName+" ,currentPid: " +" pid= " +android.os.Process.myPid()+" -----------> " +pid+" ,uid=" +uid+" ,memorySize=" +memorySize+" kb" ); } } @Override public void onSurfaceCreated(GL10 gl, EGLConfig config) {surface = null; surfaceTexture = null; glSurfaceTex = Engine_CreateSurfaceTexture(TEXTURE_WIDTH, TEXTURE_HEIGHT); Log.d(" GLES20Ext" , " glSurfaceTex" + glSurfaceTex); if (glSurfaceTex > 0) { surfaceTexture = new SurfaceTexture(glSurfaceTex); surfaceTexture.setDefaultBufferSize(TEXTURE_WIDTH, TEXTURE_HEIGHT); surface = new Surface(surfaceTexture); addedWidgetView.setSurface(surface); addedWidgetView.setSurfaceTexture(surfaceTexture); //addedWidgetView.setSurfaceTexture(surfaceTexture); mDirectDrawer = new DirectDrawer(glSurfaceTex); } } float calculateFps() {frameCount++; if (!b) { b = true; previousTime = System.currentTimeMillis(); } long intervalTime = System.currentTimeMillis() - previousTime; if (intervalTime > = 1000) { b = false; fps = frameCount / (intervalTime / 1000f); frameCount = 0; Log.w(" calculateFps" , " FPS: " + fps); }return fps; } int Engine_CreateSurfaceTexture(int width, int height) { /* * Create our texture. This has to be done each time the surface is * created. */int[] textures = new int[1]; GLES20.glGenTextures(1, textures, 0); glSurfaceTex = textures[0]; if (glSurfaceTex > 0) { GLES20.glBindTexture(GL_TEXTURE_EXTERNAL_OES, glSurfaceTex); // Notice the use of GL_TEXTURE_2D for texture creation GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGB, width, height, 0, GLES20.GL_RGB, GLES20.GL_UNSIGNED_BYTE, null); GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST); GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_NEAREST); GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE); GLES20.glTexParameteri(GL_TEXTURE_EXTERNAL_OES, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE); } return glSurfaceTex; } @Override public void onSurfaceChanged(GL10 gl, int width, int height) { } }

public class DirectDrawer { private final String vertexShaderCode = " attribute vec4 vPosition; " + " attribute vec2 inputTextureCoordinate; " + " varying vec2 textureCoordinate; " + " void main()" + " {" + " gl_Position = vPosition; " + " textureCoordinate = inputTextureCoordinate; " + " }" ; private final String fragmentShaderCode = " #extension GL_OES_EGL_image_external : require\n" + " precision mediump float; " + " varying vec2 textureCoordinate; \n" + " uniform samplerExternalOES s_texture; \n" + " void main() {" + " gl_FragColor = texture2D( s_texture, textureCoordinate ); \n" + " }" ; private FloatBuffer vertexBuffer, textureVerticesBuffer; private ShortBuffer drawListBuffer; private final int mProgram; private int mPositionHandle; private int mTextureCoordHandle; private short drawOrder[] = { 0, 1, 2, 0, 2, 3 }; // order to draw vertices // number of coordinates per vertex in this array private static final int COORDS_PER_VERTEX = 2; private final int vertexStride = COORDS_PER_VERTEX * 4; // 4 bytes per vertex static float squareCoords[] = { -1.0f,0.0f, -1.0f, -2.2f, 1.0f, -2.2f, 1.0f,0.0f, }; static float textureVertices[] = { 0f,0f, 0f,1f, 1f,1f, 1f,0f, }; private int texture; public DirectDrawer(int texture) { this.texture = texture; // initialize vertex byte buffer for shape coordinates ByteBuffer bb = ByteBuffer.allocateDirect(squareCoords.length * 4); bb.order(ByteOrder.nativeOrder()); vertexBuffer = bb.asFloatBuffer(); vertexBuffer.put(squareCoords); vertexBuffer.position(0); // initialize byte buffer for the draw list ByteBuffer dlb = ByteBuffer.allocateDirect(drawOrder.length * 2); dlb.order(ByteOrder.nativeOrder()); drawListBuffer = dlb.asShortBuffer(); drawListBuffer.put(drawOrder); drawListBuffer.position(0); ByteBuffer bb2 = ByteBuffer.allocateDirect(textureVertices.length * 4); bb2.order(ByteOrder.nativeOrder()); textureVerticesBuffer = bb2.asFloatBuffer(); textureVerticesBuffer.put(textureVertices); textureVerticesBuffer.position(0); int vertexShader= loadShader(GLES20.GL_VERTEX_SHADER, vertexShaderCode); int fragmentShader= loadShader(GLES20.GL_FRAGMENT_SHADER, fragmentShaderCode); mProgram = GLES20.glCreateProgram(); // create empty OpenGL ES Program GLES20.glAttachShader(mProgram, vertexShader); // add the vertex shader to program GLES20.glAttachShader(mProgram, fragmentShader); // add the fragment shader to program GLES20.glLinkProgram(mProgram); // creates OpenGL ES program executables } public void draw(float[] mtx) { GLES20.glUseProgram(mProgram); GLES20.glActiveTexture(GLES20.GL_TEXTURE0); GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, texture); // get handle to vertex shader' s vPosition member mPositionHandle = GLES20.glGetAttribLocation(mProgram, " vPosition" ); // Enable a handle to the triangle vertices GLES20.glEnableVertexAttribArray(mPositionHandle); // Prepare the < insert shape here> coordinate data GLES20.glVertexAttribPointer(mPositionHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, vertexBuffer); mTextureCoordHandle = GLES20.glGetAttribLocation(mProgram, " inputTextureCoordinate" ); GLES20.glEnableVertexAttribArray(mTextureCoordHandle); // textureVerticesBuffer.clear(); // textureVerticesBuffer.put( transformTextureCoordinates( // textureVertices, mtx )); // textureVerticesBuffer.position(0); GLES20.glVertexAttribPointer(mTextureCoordHandle, COORDS_PER_VERTEX, GLES20.GL_FLOAT, false, vertexStride, textureVerticesBuffer); GLES20.glDrawElements(GLES20.GL_TRIANGLES, drawOrder.length, GLES20.GL_UNSIGNED_SHORT, drawListBuffer); // Disable vertex array GLES20.glDisableVertexAttribArray(mPositionHandle); GLES20.glDisableVertexAttribArray(mTextureCoordHandle); }privateint loadShader(int type, String shaderCode){ // create a vertex shader type (GLES20.GL_VERTEX_SHADER) // or a fragment shader type (GLES20.GL_FRAGMENT_SHADER) int shader = GLES20.glCreateShader(type); // add the source code to the shader and compile it GLES20.glShaderSource(shader, shaderCode); GLES20.glCompileShader(shader); return shader; } private float[] transformTextureCoordinates( float[] coords, float[] matrix) { float[] result = new float[ coords.length ]; float[] vt = new float[4]; for ( int i = 0 ; i < coords.length ; i += 2 ) { float[] v = { coords[i], coords[i+1], 0 , 1}; Matrix.multiplyMV(vt, 0, matrix, 0, v, 0); result[i] = vt[0]; result[i+1] = vt[1]; } return result; } }

步骤三：配置GLSurfaceView：

GLSurfaceView glSurfaceView = new GLSurfaceView(getApplicationContext()); // Setup the surface view for drawing toglSurfaceView.setEGLContextClientVersion(2); glSurfaceView.setEGLConfigChooser(8, 8, 8, 8, 16, 0); glSurfaceView.setRenderer(renderer); //glSurfaceView.setZOrderOnTop(true); // Add our WebView to the Android View hierarchy 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

【把Android原生的View渲染到OpenGL Texture】