glFramebufferTexture2DEXT

glFramebufferTexture glFramebufferTexture1D glFramebufferTexture2D glFramebufferTexture3D glFramebufferTextureLayer are all functions in the OpenGL API that are used to attach a texture to a framebuffer object. Framebuffer objects, often referred to as FBOs, allow for off-screen rendering. Instead of rendering directly to the screen, rendering commands can be directed to a texture or renderbuffer object attached to an FBO. This is essential for techniques such as deferred rendering, post-processing effects, and generating mipmaps dynamically.

The general concept behind these functions is to associate a specific texture image or a slice of a 3D texture with a particular attachment point of the framebuffer. The attachment points include color buffers (GL_COLOR_ATTACHMENT0, GL_COLOR_ATTACHMENT1, etc.), depth buffer (GL_DEPTH_ATTACHMENT), and stencil buffer (GL_STENCIL_ATTACHMENT).

glFramebufferTexture is the most general of these functions. It allows attaching a texture object to a specified attachment point. glFramebufferTexture1D, glFramebufferTexture2D, and glFramebufferTexture3D are older, more specific functions that were used before glFramebufferTexture was widely adopted. They are still valid but are often superseded by the more flexible glFramebufferTexture. glFramebufferTexture1D attaches a 1D texture, glFramebufferTexture2D attaches a 2D texture (or a face of a cube map), and glFramebufferTexture3D attaches a 3D texture or a specific layer of a 3D texture. glFramebufferTextureLayer is specifically designed to attach a single 2D layer from a 3D texture or texture array to a framebuffer attachment.

When a texture is attached to an FBO, it becomes the rendering target for subsequent drawing operations. After rendering to the FBO, the contents of the attached texture can be read back or used as input for further rendering passes, effectively enabling a powerful rendering pipeline.