Geometry shader

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A geometry shader is a possible element of the graphics pipeline that is used to generate three-dimensional computer graphics in a graphics engine . As a shader in the classic graphics pipeline, the geometry shader is called after the vertex shader . He can create new simple or so-called primitive geometries from existing primitives (points, lines, triangles) and insert them again into the graphics pipeline. Since the creation of new nodes is not actually part of the rendering (transformation, lighting, texturing), the geometry shader takes on a special role.

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Typical applications are, for example, the generation of shadow volumes, the distribution of the geometry on the sides of a cube map or the generation of fur or hair geometry. Although the Geometry shader can produce any geometry within a certain limit, it is not recommended that it produce large amounts of it. In Direct3D 11 for the Tesselationseinheit was introduced in OpenGL 4.0 of tessellation shaders .

Geometry shading is nVidia's GPUs GeForce 8-series and ATI GPUs Radeon HD2000-series supported. On the software side, geometry shaders are programmed either via the Direct3D 10 or higher interface offered by Windows Vista or higher or via OpenGL 3.2 . They enable effects such as point sprite expansion (replacement of individual points / particles with volume data) or shadow volume generation (voluminous shadow replaces “flat” shadow images).

literature

  • DirectX Software Development Kit Documentation

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