本文主要是介绍android opengl fbo模式，希望对大家解决编程问题提供一定的参考价值，需要的开发者们随着小编来一起学习吧！
opengl 有好多o啊,还有ibo,vbo和vao,我都被搞糊涂了...
试了试fbo和vbo。fbo是挺有用的，用它实现了多线程渲染,vbo听说能提高效率
贴代码
public class GLRenderer implements GLSurfaceView.Renderer {private int programId; //vertexData和textureVertexData数组基本固定不变 private final float[] vertexData = {1f, -1f, 0f, -1f, -1f, 0f, 1f, 1f, 0f, -1f, 1f, 0f }; private FloatBuffer vertexBuffer; private FloatBuffer textureVertexBuffer; private int aPositionHandle; private int uTextureSamplerHandle; private int aTextureCoordHandle; private int[] textures; private int[] frameBuffers; private int[] vertexBuffers; private Context context; private Bitmap bitmap; public GLRenderer(Context context){this.context = context; bitmap = BitmapFactory.decodeResource(context.getResources(),R.drawable.plane_image); final float[] textureVertexData = {1f, 0f, 0f, 0f, 1f, 1f, 0f, 1f }; vertexBuffer = ByteBuffer.allocateDirect(vertexData.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer().put(vertexData); vertexBuffer.position(0); textureVertexBuffer = ByteBuffer.allocateDirect(textureVertexData.length * 4).order(ByteOrder.nativeOrder()).asFloatBuffer().put(textureVertexData); textureVertexBuffer.position(0); }@Override public void onSurfaceCreated(GL10 gl10, EGLConfig eglConfig) {String vertexShader = ShaderUtils.readRawTextFile(context, R.raw.bitmap_vertext_shader); String fragmentShader = ShaderUtils.readRawTextFile(context, R.raw.bitmap_fragment_sharder); programId = ShaderUtils.createProgram(vertexShader, fragmentShader); aPositionHandle = GLES20.glGetAttribLocation(programId, "aPosition"); uTextureSamplerHandle = GLES20.glGetUniformLocation(programId, "sTexture"); aTextureCoordHandle = GLES20.glGetAttribLocation(programId, "aTexCoord"); //初始化vbo vertexBuffers = new int[1]; GLES20.glGenBuffers(1,vertexBuffers,0); GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vertexBuffers[0]); GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, vertexData.length*4, vertexBuffer,GLES20.GL_STATIC_DRAW); GLES20.glBufferSubData(GLES20.GL_ARRAY_BUFFER,0,vertexData.length*4,vertexBuffer); //初始化fbo frameBuffers = new int[1]; GLES20.glGenFramebuffers(1, frameBuffers, 0); GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBuffers[0]); //初始化纹理 textures = new int[2]; GLES20.glGenTextures(2, textures, 0); //给fbo用的纹理，不是fbo纹理 GLES20.glActiveTexture(GLES20.GL_TEXTURE0); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[0]); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR); GLUtils.texImage2D(GLES20.GL_TEXTURE_2D,0,GLES20.GL_RGBA,bitmap,0); GLES20.glUseProgram(programId); //绑定vbo GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, vertexBuffers[0]); GLES20.glEnableVertexAttribArray(aPositionHandle); GLES20.glVertexAttribPointer(aPositionHandle, 3, GLES20.GL_FLOAT, false, 12, 0); GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, 0); //这是原来写法，没有glBindBuffer和vertexBuffers[0] //GLES20.glEnableVertexAttribArray(aPositionHandle); //GLES20.glVertexAttribPointer(aPositionHandle, 3, GLES20.GL_FLOAT, false,12, vertexBuffer); GLES20.glEnableVertexAttribArray(aTextureCoordHandle); GLES20.glVertexAttribPointer(aTextureCoordHandle, 2, GLES20.GL_FLOAT, false, 8, textureVertexBuffer); //*这是关键步，当时看别人的例子就是不成功，当时对opengl理解还不深，把它移到下边就清楚了 GLES20.glUniform1i(uTextureSamplerHandle,0); //初始化fbo纹理 GLES20.glActiveTexture(GLES20.GL_TEXTURE1); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[1]); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_NEAREST); GLES20.glTexParameterf(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR); //创建一个只有宽高，没有数据的纹理 GLES20.glTexImage2D(GLES20.GL_TEXTURE_2D, 0, GLES20.GL_RGBA, bitmap.getWidth(), bitmap.getHeight(), 0, GLES20.GL_RGBA, GLES20.GL_UNSIGNED_BYTE, null); //绑定 GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D, textures[1], 0); if(GLES20.glCheckFramebufferStatus(GLES20.GL_FRAMEBUFFER) == GLES20.GL_FRAMEBUFFER_COMPLETE){}GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, 0); GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0); }@Override public void onSurfaceChanged(GL10 gl10, int screenWidth, int screenHeight) {//还是没用矩阵，而且数学还不好，就凑合着用吧 int bitmapWidth = bitmap.getWidth(); int bitmapHeight = bitmap.getHeight(); int left,top,viewWidth,viewHeight; if(screenHeight > screenWidth){left = 0; viewWidth = screenWidth; viewHeight = (int)(bitmapHeight*1.0f/bitmapWidth*viewWidth); top = (screenHeight - viewHeight)/2; }else{top = 0; viewHeight = screenHeight; viewWidth = (int)(bitmapWidth*1.0f/bitmapHeight*viewHeight); left = (screenWidth - viewWidth)/2; }rect.left = left; rect.top = top; rect.right = left + viewWidth; rect.bottom = top + viewHeight; }private Rect rect = new Rect(); @Override public void onDrawFrame(GL10 gl10) {//*把给fbo用的纹理传入shader里，把上边的代码可以移到这里 GLES20.glActiveTexture(GLES20.GL_TEXTURE0); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[0]); GLES20.glUniform1i(uTextureSamplerHandle,0); GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, frameBuffers[0]); GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT); GLES20.glViewport(0, 0, bitmap.getWidth(), bitmap.getHeight()); GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4); //GLES20.glDrawElements()听说适合绘制复杂图形 //fbo用完后换回显示窗口 GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0); //*渲染fbo纹理，这次把fbo纹理传入shader内 GLES20.glActiveTexture(GLES20.GL_TEXTURE1); GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textures[1]); GLES20.glUniform1i(uTextureSamplerHandle,1); GLES20.glClear(GLES20.GL_DEPTH_BUFFER_BIT | GLES20.GL_COLOR_BUFFER_BIT); GLES20.glViewport(rect.left, rect.top, rect.width(), rect.height()); GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4); } }
配合GLSurfaceView使用
bitmap_fragment_sharder
precision mediump float;
varying vec2 vTexCoord;
uniform sampler2D sTexture;
void main() {gl_FragColor = texture2D(sTexture, vTexCoord);//
}
bitmap_vertext_sharder
attribute vec4 aPosition;
attribute vec2 aTexCoord;
varying vec2 vTexCoord;
void main() {vTexCoord = vec2(aTexCoord.x,1.0-aTexCoord.y);gl_Position = aPosition;
}
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