OpenGL Programming Guide: The Official Guide to Learning OpenGL, Version 4.3, Eighth Edition

Workgroups and Dispatch

Just as the graphics shaders fit into the pipeline at specific points and operate on graphics-specific elements, compute shaders effectively fit into the (single-stage) compute pipeline and operate on compute-specific elements. In this analogy, vertex shaders execute per vertex, geometry shaders execute per primitive and fragment shaders execute per fragment. Performance of graphics hardware is obtained through parallelism, which in turn is achieved through the very large number of vertices, primitives, or fragments, respectively, passing through each stage of the pipeline. In the context of compute shaders, this parallelism is more explicit, with work being launched in groups known as workgroups. Workgroups have a local ...