android opengl fbo模式

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;}