position the clicked object. However, since the screen and the mouse have only two dimensions, the third is unknown. Therefore, a ray is projected at the cursor position into the world and then the intersection of this ray with the polygons in the world is determined. Shader Classic graphics cards are still relatively close to the graphics pipeline. With increasing demands on the GPU, restrictions were gradually removed to create more flexibility. Modern graphics cards use a freely programmable, shader-controlled pipeline, which allows direct access to individual processing steps. To relieve the main processor, additional processing steps have been moved to the pipeline and the GPU. The most important shader units are vertex shaders, geometry shaders, and pixel shaders. The Unified Shader has been introduced to take full advantage of all units. This gives you a single large pool of shader units. As required, the pool is divided into different groups of shaders. A strict separation between the shader types is therefore no longer useful. It is also possible to use a so-called compute-shader to perform any calculations off the display of a graphic on the GPU. The advantage is that they run very parallel, but there are limitations. These universal calculations are also called general-purpose computing on graphics processing units, or GPGPU for short. See also Pipeline (computing) Instruction pipelining Hardware acceleration Sources References External links ExtremeTech 3D Pipeline Tutorial 3D rendering Graphics hardware