float4 variable; struct v2p { float2 texCoord : TEXCOORD0; }; struct p2f { float4 position : COLOR0; }; void ps( in v2p IN, out p2f OUT) { if(variable.g > 0) OUT.position = float4(1, 1, 0, 1); }; technique GridShader { pass VertexUpdates { PixelShader = compile ps_2_0 ps(); } }