// This is C3E6f_twoTextures from "The Cg Tutorial" (Addison-Wesley, ISBN // 0321194969) by Randima Fernando and Mark J. Kilgard. See page 85. void C3E6f_twoTextures(float2 leftTexCoord : TEXCOORD0, float2 rightTexCoord : TEXCOORD1, out float4 color : COLOR, uniform sampler2D decal) { float4 leftColor = tex2D(decal, leftTexCoord); float4 rightColor = tex2D(decal, rightTexCoord); color = lerp(leftColor, rightColor, 0.5); }