GPU Pro 5

50 I Rendering

3.4.1 Displaying Height

Tessellation shaders allow for adaptive subdivision of the surface geometry by

introducing two new shader stages after the vertex shader: a hull and a domain

shader. The hull shader is typically used to perform calculations for each control

point of a surface patch. In our case, both the vertex and hull shader by-pass po-

sitions, normals, and texture coordinates. The function

ConstantHS in Listing 3.9

is executed once per control patch to compute the distance-dependent tessellation

factors. Based on these factors, a fixed-function tessellation engine subdivides the

patches. The domain shader is executed for each ...