Android: Framebuffer缺少附件

Question

我正在尝试创建一个render to texture类，它有一个用于位置的帧缓冲区和一个用于旋转的帧缓冲区。这部分工作得很好。但当我切换到我的应用程序时，它崩溃了，因为检查帧缓冲区状态会返回framebuffer不完整的缺失附件。

public void setup(Context context) {
    final float eyeX = 0.0f;
    final float eyeY = 0.0f;
    final float eyeZ = 1.5f;

    final float lookX = 0.0f;
    final float lookY = 0.0f;
    final float lookZ = -5.0f;

    final float upX = 0.0f;
    final float upY = 1.0f;
    final float upZ = 0.0f;

    Matrix.setLookAtM(mViewMatrix, 0, eyeX, eyeY, eyeZ, lookX, lookY, lookZ, upX, upY, upZ);

    int vertexShaderHandle = ShaderHelper.compileShader(GLES20.GL_VERTEX_SHADER,
            ShaderHelper.readShader(context, R.raw.vertex_shader));     
    int fragmentShaderHandle = ShaderHelper.compileShader(GLES20.GL_FRAGMENT_SHADER,
            ShaderHelper.readShader(context, R.raw.fragment_shader));

    mProgramHandle = ShaderHelper.createAndLinkProgram(vertexShaderHandle, fragmentShaderHandle, 
            new String[] {"a_Position", "a_TexCoord"});

    vertexShaderHandle = ShaderHelper.compileShader(GLES20.GL_VERTEX_SHADER,
            ShaderHelper.readShader(context, R.raw.particle_vertex_shader));        
    fragmentShaderHandle = ShaderHelper.compileShader(GLES20.GL_FRAGMENT_SHADER,
            ShaderHelper.readShader(context, R.raw.particle_fragment_shader));

    mPartProgramHandle = ShaderHelper.createAndLinkProgram(vertexShaderHandle, fragmentShaderHandle, 
            new String[] {"a_Position"});

    // create the ints for the framebuffer, depth render buffer and texture
    final int[] fb = new int[2];
    // generate
    GLES20.glGenFramebuffers(2, fb, 0);

    if (!setup) {
        posTex = ShaderHelper.genTexture(texW, texH, null);
        velTex = ShaderHelper.genTexture(texW, texH, null);
        rotTex = ShaderHelper.genTexture(texW, texH, null);
        rotVelTex = ShaderHelper.genTexture(texW, texH, null);
        atlasTex = ShaderHelper.loadTexture(context, R.drawable.ship_atlas);
    }
    posFb = fb[0];
    rotFb = fb[1];

    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, posFb);
    GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D, posTex, 0);     
    GLES20.glBindFramebuffer(GLES20.GL_FRAMEBUFFER, rotFb);
    GLES20.glFramebufferTexture2D(GLES20.GL_FRAMEBUFFER, GLES20.GL_COLOR_ATTACHMENT0, GLES20.GL_TEXTURE_2D, rotTex, 0);


    final int buffers[] = new int[2];
    GLES20.glGenBuffers(2, buffers, 0);
    GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, buffers[0]);
    GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, spriteBuffer.capacity() * BYTES_PER_FLOAT, spriteBuffer, GLES20.GL_STATIC_DRAW);
    GLES20.glBindBuffer(GLES20.GL_ARRAY_BUFFER, buffers[1]);
    GLES20.glBufferData(GLES20.GL_ARRAY_BUFFER, renderQuad.capacity() * BYTES_PER_FLOAT, renderQuad, GLES20.GL_STATIC_DRAW);

    mMVPMatrixHandle = GLES20.glGetUniformLocation(mProgramHandle, "u_MVPMatrix");
    mAtlasTexHandle = GLES20.glGetUniformLocation(mProgramHandle, "u_TexAtlas");
    mPosTexHandle = GLES20.glGetUniformLocation(mProgramHandle, "u_PosTexture");
    mPositionHandle = GLES20.glGetAttribLocation(mProgramHandle, "a_Position"); 
    mTexCoordHandle = GLES20.glGetAttribLocation(mProgramHandle, "a_TexCoord");

    mXTexHandle = GLES20.glGetUniformLocation(mPartProgramHandle, "u_Values");
    mDXTexHandle = GLES20.glGetUniformLocation(mPartProgramHandle, "u_Transforms");
    mPassHandle = GLES20.glGetUniformLocation(mPartProgramHandle, "u_Pass");
    mFBPositionHandle = GLES20.glGetAttribLocation(mPartProgramHandle, "a_Position"); 

    spriteBufferIdx = buffers[0];
    fbQuadBufferIdx = buffers[1];
    setup = true;

}

根据我的研究，纹理不需要重新加载，只有帧缓冲区需要重新加载。这很好，因为我必须以某种方式将旧纹理中的像素放入新纹理中。但是如果不重做纹理，它就会崩溃，并出现帧缓冲区错误。为了清楚起见，每次调用onSurfaceChanged时都会运行代码。

如何才能避免每次调用onSurfaceChanged时都生成新的纹理，而不会出现FrameBuffer不完整缺失附件错误？

Answer 1

由于android在每次暂停时都会重新创建上下文，因此我需要添加下面这一行

glSurfaceView.setPreserveEGLContextOnPause(true);