Renderbuffers

Renderbuffers are a type of image buffer used by graphics APIs such as OpenGL as render targets for framebuffers. They store color, depth, or stencil information and are optimized for rendering operations. Unlike textures, renderbuffers are not typically sampled in shaders; they are written by the GPU during rendering and are not intended to be read back as textures. They can be multisampled, providing multiple samples per pixel to support anti-aliasing, and can be resolved to a texture if needed.

Creation and attachment typically involve generating a renderbuffer, binding it, and allocating storage with functions that specify the desired format and size. The renderbuffer is then attached to a framebuffer as a color, depth, or stencil attachment. Supported formats include depth components (such as GL_DEPTH_COMPONENT24), depth-stencil combinations (such as GL_DEPTH24_STENCIL8), and color formats (such as GL_RGBA8, GL_RGB565, GL_RGBA4), depending on hardware capabilities.

Usage notes: In offscreen rendering, a framebuffer can use renderbuffers for its attachments. For multisample rendering, a multisample renderbuffer can be used for color and/or depth buffers. If the final result must be sampled later in a shader, or used in post-processing, the common approach is to render to a texture rather than a renderbuffer, or to resolve a multisample renderbuffer to a texture via a blit or copy operation.

Comparison with textures: Textures attached to framebuffers are typically used when the rendered results must be read or sampled in shaders, such as for post-processing or texture lookups. Renderbuffers, by contrast, are optimized for rendering performance and storage of depth and stencil data, and are preferable when sampling is not required. Renderbuffers remain a fundamental tool for offscreen rendering pipelines and multisample anti-aliasing setups.