Shader

Previously, programmer uses Fixed Function Pipeline (FFP) to send instruction directly to the GPU. Shaders are program written in HSLS (MS) or Cg (C for Graphic) that are executed by GPU. Vertex Shader are run once for every vertex in the viewing frustum to set the position of the vertex based on the world and camera settings. Once the postion data is created, rasterization translate the triangles into a set of pixel. Pixel Shaders then run for each pixel to determine the colour. Then the data is output to the screen.