Tessellation shader
A part of the graphics pipeline in 3D computer graphics is referred to as a tessellation shader (from the English tessellation for "mosaic") . Technically, it consists of two separate shaders and a fixed-function tessellator. The tessellation shaders are called after the vertex shader and before the geometry shader . The task of the tessellation shader is to break down areas, so-called patches , into smaller areas (usually triangles or squares).
function
First, the tessellation control shader is called, this works on so-called "patches". A patch consists of a number of points (vertices) as well as other data assigned to the patch. a. determine the fineness of the tesellation (subdivision). The fixed-function tessellator now divides each input patch into (usually several) output patches, usually triangles or squares. The second shader, the tessellation evaluation shader, can now move the newly created vertices. In Direct3D, these two shaders are called Hull shaders or domain shaders .
support
OpenGL supports tessellation shaders from version 4.0. Programs for the shader can be written in the OpenGL Shading Language (GLSL). Direct3D supports tessellation shaders from version 10.
Vulkan (API) supports tessellation shaders from version 1.0.