android opengl模糊,Android：双重渲染使用OpenGL渲染到SurfaceTexture

要实现模糊效果，可以使用双重渲染技术，即将OpenGL渲染到SurfaceTexture，再将SurfaceTexture渲染到屏幕上。

下面是一个简单的示例代码：

1. 首先，在XML布局文件中添加一个TextureView：

<TextureView
    android:id="@+id/textureView"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />

2. 在Activity中获取TextureView并设置监听器：

private TextureView textureView;
private SurfaceTexture surfaceTexture;
private int textureId;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    textureView = findViewById(R.id.textureView);
    textureView.setSurfaceTextureListener(surfaceTextureListener);
}

private TextureView.SurfaceTextureListener surfaceTextureListener = new TextureView.SurfaceTextureListener() {
    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
        surfaceTexture = surface;
        textureId = createTexture();
        startRender();
    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
        stopRender();
        surfaceTexture = null;
        return true;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surface) {

    }
};

3. 创建OpenGL纹理：

private int createTexture() {
    int[] textures = new int[1];
    GLES20.glGenTextures(1, textures, 0);
    int textureId = textures[0];

    GLES20.glBindTexture(GLES20.GL_TEXTURE_2D, textureId);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MIN_FILTER, GLES20.GL_LINEAR);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_MAG_FILTER, GLES20.GL_LINEAR);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_S, GLES20.GL_CLAMP_TO_EDGE);
    GLES20.glTexParameteri(GLES20.GL_TEXTURE_2D, GLES20.GL_TEXTURE_WRAP_T, GLES20.GL_CLAMP_TO_EDGE);

    return textureId;
}

4. 开始渲染：

private RenderThread renderThread;

private void startRender() {
    if (renderThread == null) {
        renderThread = new RenderThread();
        renderThread.start();
    }
}

private void stopRender() {
    if (renderThread != null) {
        renderThread.stopRender();
        renderThread = null;
    }
}

private class RenderThread extends Thread {
    private volatile boolean isRender = true;

    @Override
    public void run() {
        super.run();

        EglCore eglCore = new EglCore();
        WindowSurface windowSurface = new WindowSurface(eglCore, surfaceTexture);

        GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);

        while (isRender) {
            GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);

            // 在这里进行OpenGL渲染操作

            windowSurface.swapBuffers();
        }

        windowSurface.release();
        eglCore.release();
    }

    public void stopRender() {
        isRender = false;
    }
}

5. 最后，在onDrawFrame方法中进行双重渲染：

@Override
public void onDrawFrame(GL10 gl) {
    GLES20.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    GLES20.glClear(GLES20.GL_COLOR_BUFFER_BIT);

    // 在这里进行OpenGL渲染操作

    SurfaceTexture surfaceTexture = textureView.getSurfaceTexture();
    surfaceTexture.updateTexImage();

    // 将SurfaceTexture渲染到屏幕上
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, 0);
    GLES20.glViewport(0, 0, getWidth(), getHeight());
    GLES20.glUseProgram(programId);

    int uTextureSamplerLocation = GLES20.glGetUniformLocation(programId, "uTextureSampler");
    GLES20.glActiveTexture(GLES20.GL_TEXTURE0);
    GLES20.glBindTexture(GLES11Ext.GL_TEXTURE_EXTERNAL_OES, textureId);
    GLES20.glUniform1i(uTextureSamplerLocation, 0);

    GLES20.glEnableVertexAttribArray(aPositionLocation);
    GLES20.glVertexAttribPointer(aPositionLocation, 2, GLES20.GL_FLOAT, false, 0, vertexBuffer);

    GLES20.glEnableVertexAttribArray(aTextureCoordLocation);
    GLES20.glVertexAttribPointer(aTextureCoordLocation, 2, GLES20.GL_FLOAT, false, 0, textureBuffer);

    GLES20.glDrawArrays(GLES20.GL_TRIANGLE_STRIP, 0, 4);

    GLES20.glDisableVertexAttribArray(aPositionLocation);
    GLES20.glDisableVertexAttribArray(aTextureCoordLocation);
}