#version 450 layout(vertices = 1) out; in gl_PerVertex { vec4 gl_Position; } gl_in[gl_MaxPatchVertices]; out gl_PerVertex { vec4 gl_Position; } gl_out[1]; layout(location = 0) patch out vec3 vFoo; void main() { gl_TessLevelInner[0] = 8.9; gl_TessLevelInner[1] = 6.9; gl_TessLevelOuter[0] = 8.9; gl_TessLevelOuter[1] = 6.9; gl_TessLevelOuter[2] = 3.9; gl_TessLevelOuter[3] = 4.9; vFoo = vec3(1.0); gl_out[gl_InvocationID].gl_Position = gl_in[0].gl_Position + gl_in[1].gl_Position; }