float4 gambient; sampler textureAlpha: register(s0); float4 main(float3 normal: TEXCOORD0, float3 lightVec: TEXCOORD1, float4 texCoord: TEXCOORD2) : COLOR { float depth = length(lightVec.xyz); if (tex2D(textureAlpha,texCoord).w > 0.0) { return float4(gambient.xyz,depth); } else { discard; } }