% Semantics can be used in uniforms even though they are ignored. [pixel shader] float a : SEMANTIC; float4 main() : sv_target { return a; } [test] uniform 0 float 3.5 todo(glsl) draw quad probe all rgba (3.5, 3.5, 3.5, 3.5) [pixel shader] float2 a : sv_position; float4 main() : sv_target { return float4(a, a); } [test] uniform 0 float4 4.0 5.0 6.0 7.0 todo(glsl) draw quad probe all rgba (4.0, 5.0, 4.0, 5.0)