Graphics Pipeline

The stages of the graphics pipeline are

• IA ::Input Assembler Stage
• VS ::Vertex Shader Stage
• GS ::Geometry Shader Stage
• RS ::Rasterization Stage
• PS / FS ::Pixel/Fragment Shader Stage
• OM ::Output Merger Stage

Shaders are executed on the GPU using SIMT (single instruction multiple threads). Multiple computation units on the GPU execute the same shader code at the same time using different data. Because of that, branches can become expensive. If some processing units have to execute branched code and other processing units don’t, they would still have to wait for the others to finish before they can continue.