Rasterizer Block
The rasterizer block clips, sets up primitives, and determines how to call the pixel shader stage. The Direct3D runtime does not view the rasterizer block as a stage in the pipeline. Instead, the Direct3D runtime views the rasterizer block as an interface between pipeline stages that happens to perform a significant set of fixed function operations. Many of these fixed function operations can be adjusted by software developers.
The rasterizer always determines that input positions are provided in clip-space, performs clipping and perspective divide, and applies viewport scale and offset.
The Direct3D runtime calls the following driver functions to create, set up, and destroy the state of the rasterizer: