多采样帧渲染对象和深度缓冲区

Question

我正在尝试使用我的帧缓冲区进行多重采样（用于 post-处理）。通过忽略深度缓冲区，我几乎可以让它正常工作，但我遇到了面部未渲染的问题。

我这样设置我的普通帧缓冲区

glBindTexture(GL_TEXTURE_2D, m_Texture);
    glTexImage2D(
        GL_TEXTURE_2D, 0, GL_RGB, 1280, 720, 0, GL_RGB, GL_UNSIGNED_BYTE, 0
    );

    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
    glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);


    glFramebufferTexture2D(
        GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, m_Texture, 0
    );

    // Create color render buffer
    glGenRenderbuffers(1, &m_TexColorBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, m_TexColorBuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_RGB, 1280, 720);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, m_TexColorBuffer);

    // Create depth render buffer (This is optional)
    glGenRenderbuffers(1, &m_RBODepthBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, m_RBODepthBuffer);
    glRenderbufferStorage(GL_RENDERBUFFER, GL_DEPTH_COMPONENT24, 1280, 720);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_RBODepthBuffer);

然后我也像这样创建一个多采样帧缓冲区。

glEnable(GL_MULTISAMPLE);
    glBindTexture(GL_TEXTURE_2D_MULTISAMPLE, m_Texture);
    glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, GL_RGB, 1280, 720, GL_FALSE);
    glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D_MULTISAMPLE, m_Texture, 0);

    glGenRenderbuffers(1, &m_TexColorBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, m_TexColorBuffer);
    glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, GL_RGB, 1280, 720);
    glFramebufferRenderbuffer(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_RENDERBUFFER, m_TexColorBuffer);

/*  glGenRenderbuffers(1, &m_RBODepthBuffer);
    glBindRenderbuffer(GL_RENDERBUFFER, m_RBODepthBuffer);
    glRenderbufferStorageMultisample(GL_RENDERBUFFER, samples, GL_DEPTH_COMPONENT24, 1280, 720);
    glFramebufferRenderbuffer(
        GL_FRAMEBUFFER, GL_DEPTH_ATTACHMENT, GL_RENDERBUFFER, m_RBODepthBuffer
    );*/

    glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, m_Texture, 0);

这段代码（在深度缓冲区上注释掉的部分）确实产生了一个正确显示但没有深度的多采样纹理，我得到的面没有渲染或法线方向错误（所以从我看到的角度看里面该模型）。但是，如果我取消对该部分的注释，那么

glCheckFramebufferStatus(GL_FRAMEBUFFER)

returns

其次是

Error 00000506 after convex fill

最终黑屏。

我正在使用 glBlitFramebuffer 将多样本 fbo 复制到单样本 fbo（可行，但存在前面提到的问题）。

真的卡在这了，找不到解决办法！

Answer 1

所以我找到了答案，这要归功于 source forge 上随机项目的一些过时文档。

我的错误是 GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE

根据这些信息，我找到了错误的含义，即

GL_FRAMEBUFFER_INCOMPLETE_MULTISAMPLE is also returned if the value of GL_TEXTURE_FIXED_SAMPLE_LOCATIONS is not the same for all attached textures; or, if the attached images are a mix of renderbuffers and textures, the value of GL_TEXTURE_FIXED_SAMPLE_LOCATIONS is not GL_TRUE for all attached textures.

因此更改

末尾的 GL_FALSE

glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, GL_RGB, 1280, 720, GL_FALSE);

到 GL_TRUE 修复了它。所以

glTexImage2DMultisample(GL_TEXTURE_2D_MULTISAMPLE, samples, GL_RGB, 1280, 720, GL_TRUE);

多采样帧渲染对象和深度缓冲区

Multi-sampling Frame Render Objects and Depth Buffers

c++

opengl

framebuffer

depth-buffer

post-processing