Question

因此，作为延迟着色器的最后一步，我一直试图让天空盒工作。基本上我会经历所有常规延迟着色器步骤，然后使用一些后处理内容，如HDR和bloom，这个最后一步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盒或延迟着色结果，一切看起来都很正常。当我尝试最后渲染天空盒时，它并没有在屏幕上结束。

所以基本上在我用结果渲染四边形后，我想使用几何图形的深度值渲染天空盒。我试图按照Deferred Rendering Skybox OpenGL的建议对深度缓冲区进行blitting，但它没有任何效果，我认为问题在于如何为FBO设置我的深度缓冲区，因为它共享一个模板附件

我对天空盒的渲染调用：

//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();

以及我如何设置延期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会让人感到困惑，但如果你在blit函数中指定它，我也无法理解为什么你不能对深度附件进行blit

结果图片，没有天空盒：result

修改

我试着搜索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，但这也无济于事。

Answer 1

您不应尝试将FBO深度缓冲区blit到默认深度缓冲区。要从一个深度缓冲区blit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。您可以通过反复试验来推断其格式，但解决方案将无法移植。

一种解决方案是在几何过程中将您的深度写出到R32F纹理颜色附件。稍后，当您将天空盒绘制到默认帧缓冲区时，可以将R32F纹理绑定到采样器，并在片段着色器中读取该像素的深度。仅将天空盒输出到深度为0.0f的片段。

延迟着色天空盒，在全屏四边形后渲染

1 个答案: