延迟着色天空盒，渲染后全屏四边形

Question

所以作为我延迟着色器的最后一步，我一直在尝试让一个天空盒工作。基本上，我经历了所有常规的延迟着色步骤，然后使用一些后期处理的东西，比如HDR和bloom，最后一步是使用前向着色器渲染到全屏四边形。现在，如果我只是单独渲染天空框或延迟着色结果，一切看起来都很正常。当我尝试最后渲染天空盒时，它不会在屏幕上结束。

所以基本上在我用结果渲染四边形之后，我想用几何通道的深度值渲染天空盒。我已经尝试过将深度缓冲作为延迟渲染Skybox OpenGL建议，但它没有任何效果，我认为问题是我如何为FBO设置深度缓冲，因为它共享一个模板附件。

我对skybox的渲染调用:

//draw skybox
glEnable(GL_DEPTH_TEST);
glBindFramebuffer(GL_READ_FRAMEBUFFER, mFBO);
glBindFramebuffer(GL_DRAW_FRAMEBUFFER, 0);
glBlitFramebuffer(0, 0, mWindowWidth, mWindowHeight, 0, 0, mWindowWidth, mWindowHeight, GL_DEPTH_BUFFER_BIT, GL_NEAREST);
glBindFramebuffer(GL_FRAMEBUFFER, 0);
// Draw skybox as last
glDepthFunc(GL_LEQUAL);  // Change depth function so depth test passes when values are equal to depth buffer's content
ShaderMan.bindShader(SKY_BOX_SHADER);
glm::mat4 view = glm::mat4(glm::mat3(CameraMan.getActiveCamera()->getViewMatrix()));    // Remove any translation component of the view matrix
glm::mat4 projection = CameraMan.getActiveCamera()->getProjectionMatrix();
glUniformMatrix4fv(ShaderMan.getActiveShader().getUniformLocation("viewMatrix"), 1, GL_FALSE, glm::value_ptr(view));
glUniformMatrix4fv(ShaderMan.getActiveShader().getUniformLocation("projectionMatrix"), 1, GL_FALSE, glm::value_ptr(projection));
// skybox cube
glUniform1i(ShaderMan.getActiveShader().getUniformLocation("skybox"), 0);
mSkybox.render();
glDepthFunc(GL_LESS); // Set depth function back to default
ShaderMan.unbindShader();

和如何设置延迟FBO

//POSIITON
glGenTextures(1, &mPositionTexture);
glBindTexture(GL_TEXTURE_2D, mPositionTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, mWindowWidth, mWindowHeight, 0, GL_RGB, GL_FLOAT, NULL);
//Nearest min mag filters since we dont want interpolated values
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_S, GL_CLAMP_TO_EDGE);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_WRAP_T, GL_CLAMP_TO_EDGE);
//glFrameBuffer attaches a texture as a color attachment, depth attachment or stencil etc
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, GL_TEXTURE_2D, mPositionTexture, 0);
glGenTextures(1, &mNormalTexture);
glBindTexture(GL_TEXTURE_2D, mNormalTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, mWindowWidth, mWindowHeight, 0, GL_RGB, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT1, GL_TEXTURE_2D, mNormalTexture, 0);
//Combined color and specular buffer
glGenTextures(1, &mSpecularAlbedoTexture);
glBindTexture(GL_TEXTURE_2D, mSpecularAlbedoTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGB32F, mWindowWidth, mWindowHeight, 0, GL_RGBA, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glFramebufferTexture2D(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT2, GL_TEXTURE_2D, mSpecularAlbedoTexture, 0);
//Depth & stencil texture for the FBO
glGenTextures(1, &mDepthTexture);
glBindTexture(GL_TEXTURE_2D, mDepthTexture);
glTexImage2D(GL_TEXTURE_2D, 0, GL_DEPTH32F_STENCIL8, mWindowWidth, mWindowHeight, 0, GL_DEPTH_COMPONENT, GL_FLOAT, NULL);
glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_DEPTH_STENCIL_ATTACHMENT, GL_TEXTURE_2D, mDepthTexture, 0);
// final
glGenTextures(1, &mFinalTexture);
glBindTexture(GL_TEXTURE_2D, mFinalTexture);
///Used to be GL_RGBA only
glTexImage2D(GL_TEXTURE_2D, 0, GL_RGBA32F, mWindowWidth, mWindowHeight, 0, GL_RGB, GL_FLOAT, NULL);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MIN_FILTER, GL_NEAREST);
glTexParameteri(GL_TEXTURE_2D, GL_TEXTURE_MAG_FILTER, GL_NEAREST);
glFramebufferTexture2D(GL_DRAW_FRAMEBUFFER, GL_COLOR_ATTACHMENT4, GL_TEXTURE_2D, mFinalTexture, 0);

我认为GL_DEPTH_STENCIL_ATTACHMENT是什么搞砸了一些东西，但我也看不出为什么你不应该能够blit深度附件，如果你指定它在blit函数

结果的图像，没有skybox: result

编辑

我试着搜索了一下，并将格式更改为GL_DEPTH_24_STENCIL8，以防主fbo有不同的浮动格式，但这也没有帮助。

Answer 1

您不应该尝试将FBO深度缓冲区blit到默认深度缓冲区。要从一个深度缓冲区移到另一个深度缓冲区，两者的内部格式必须完全相同。虽然您可以定义FBO的格式，但默认深度缓冲区是实现定义的。你也许可以通过反复试验推断出它的格式，但是这个解决方案是不可移植的。

一个解决方案是在几何通道期间将您的深度写入R32F纹理颜色附件。稍后，当你绘制你的天空盒到默认的framebuffer，你可以绑定R32F纹理到采样器，并读取该像素在片段着色器的深度。