How to you define attaching a texture array to a FBO's color attachment point visually?
framebuffer, glsl, opengl, textures
Solution
A texture is a collection of images. You do not attach a texture to an FBO attachment point; you attach an image within the texture to an FBO attachment point.
So at no point do you attach multiple textures to a single attachment point.
Array textures are just textures that store an array of images within a mipmap level. A non array 2D texture only stores one image per mipmap level. A cubemap stores 6 images per mipmap. An array texture stores a user-provided number of images per mipmap.
However, you can attach a layered image to an attachment point. A mipmap level of an array texture is a layered image, as are several other things.
An FBO that is built from layered images can be used for layered rendering via a Geometry Shader. This allows the GS to pipe a particular primitive output to a specific layer index within the layered FBO.
How you visualize this is up to you.
Problem
I read that in layered rendering, we create a 2D texture array (GL_TEXTURE_2D_ARRAY): ``` glActiveTexture(GL_TEXTURE0); glBindTexture(GL_TEXTURE_2D_ARRAY, TextureColorbufferName); glTexParameteri(.... glTexImage3D(... ``` and can attach it to FBO: ``` glGenFramebuffers(1, &FramebufferName); glBindFramebuffer(GL_FRAMEBUFFER, FramebufferName); glFramebufferTexture(GL_FRAMEBUFFER, GL_COLOR_ATTACHMENT0, TextureColorbufferName, 0); ``` What i find hard to understand visually is how can a layer of textures be bound to a single color attachment point in FBO? Isnt color attachment 0 (or any of GL_COLOR_ATTACHMENTi ) a single "image" in themselves? In more detail: Before reading about texture arrays, this was my understanding of FBOS ``` +--------------+ +-----------+| FBO object ++--------------------------------------------+ | | +---------------------+ | | +--------------+ | | | + | | | | | | | | | | v v v v +-----------------+ +-----------------+ +-----------------+ +------------------+ |color attachment | |color attachment | |depth attachment | |stencil attachment| | 0 | | 1 | | | | | +-----------------+ +-----------------+ +-----------------+ +------------------+ (this too) (this is actually (this is also a (this too) one texture or texture of renderbuffer) one renderbuffer) ``` But after reading about texture arrays, is this how it really is? ``` +--------------+ +-----------+| FBO object ++--------------------------------------------+ | | +---------------------+ | | +--------------+ | | | + | | | | | | | | | | v v v v +-----------------+ +-----------------+ +-----------------+ +------------------+ |color attachment | |color attachment | |depth attachment | |stencil attachment| | 0 | | 1 | | | | | +-----+--+------+-+ +-----------------+ +-----------------+ +------------------+ | | | | | v+ | v+ +----------------------------------+ | +--------->+ v v | + +----------------+ +---v-------------+ | | | | | +---v------------+ |texture array[0]| |texture array[1] | |texture array[n]| | | | | | | | | | | | | | | | | | | +----------------+ +-----------------+ +----------------+ ``` i.e is each attachment itself a collection of various textures? This is hard for me to visualize how 1 color attachment point maps to multiple textures. What happens if i blit from 1 FBO (one that is bound to texture_2d_array) to another(one that is bound to texture_2d)