Tessellation Shader

+After the tessellation factors are determined, a fixed-function **Tessellator** stage subdivides the geometry based on these factors, generating a higher density of vertices. These new vertices are then passed to the [Domain Shader](/wiki/domain_shader) (DirectX) or [Tessellation Evaluation Shader](/wiki/tessellation_evaluation_shader) (OpenGL). This final programmable stage is where fine-grain details are applied, often by displacing the newly created vertices based on data like [Height Map](/wiki/height_map)s or normal maps, creating realistic surfaces like terrain, character models, and organic shapes without increasing the base mesh complexity.

+This process is crucial for implementing technologies like [Adaptive Tessellation](/wiki/adaptive_tessellation), where the level of detail changes dynamically based on the camera's distance to an object, optimizing performance by only applying high detail where it's most visible.

+- [Hull Shader](/wiki/hull_shader)

+- [Domain Shader](/wiki/domain_shader)

+- [Graphics Pipeline](/wiki/graphics_pipeline)

+The core of tessellation involves defining *tessellation factors* that control the level of subdivision. These factors are often set in a specialized shader stage, such as the [Hull Shader](/wiki/hull_shader) in DirectX or the [Tessellation Control Shader](/wiki/tessellation_control_shader) in OpenGL:

+```cpp

+// Example: Setting tessellation factors for a triangle patch

+float tessFactorEdge0 = 4.0f; // Subdivision for the first edge

+float tessFactorEdge1 = 4.0f; // Subdivision for the second edge

+A **tessellation shader** dynamically refines coarse geometry, transforming simple forms into intricate detail. Part of the [Graphics Pipeline](/wiki/graphics_pipeline), it enables artists to create smoother surfaces and rich complexity with minimal initial data, enhancing visual realism on the [GPU](/wiki/gpu).

+## See also

+- [Vertex Shader](/wiki/vertex_shader)

+- [Fragment Shader](/wiki/fragment_shader)

+- [DirectX](/wiki/directx)