OpenGL Insights

6. An Introduction to Tessellation Shaders 97

layout ( quads , fractional_even_spacing, cw) out;

// Declare inputs from tess control shader

in float tcFoo [];

// Declare per-patch inputs

patch in float tcSharedFoo;

// Declare per-vertex outputs

out float teFoo;

void main ()

{

vec3 tc = gl_TessCoord;

teFoo = ... ;

gl_Position = ... ;

}

Listing 6.2. Tessellation evaluation shader template.

Listing 6.2 presents a template for a tessellation evaluation shader. Unlike the

control shader, the outputs are not arrayed over the patch.

For a visualization of gl

TessCoord in quads mode, see Figure 6.6. The mean-

ing of gl

TessCoord varies according to the tessellation mode. ...