Shader#Geometry shaders

A Geometry shader is a possible element of the graphics pipeline. As a shader in the classic graphics pipeline of the Geometry Shader is called after the vertex shader. It can generate new primitive geometries from existing primitives ( points, lines, triangles) and insert them back into the graphics pipeline. Since the creation of new nodes in the strict sense is not a part of the renderings ( transformation, lighting, texturing ), the Geometry Shader plays a special role.

Typical applications include the production of shadow volume distribution of the geometry of the sides of a cube map or the generation of fur or hair geometry. Although the geometry shader can generate any geometry within a budgetary limit, is not recommended to produce large amounts of it through him. In Direct3D 11 for the Tesselationseinheit was introduced in OpenGL 4.0 and the tessellation shader.

Geometry Shading is supported by nVidia's GeForce 8 series and ATI Radeon HD2000 series graphics processors. From the software side programming Geometry shaders either the Windows Vista / 7 interface provided Direct3D 10 (see DirectX) or OpenGL 3.2. They allow effects such as point sprite expansion ( replacing individual points / particles by volume data ) or Volume Shadow generation ( volume shadow poorly trained replaced "flat" silhouettes ).