// This is C8E2f_bumpSurf from "The Cg Tutorial" (Addison-Wesley, ISBN
// 0321194969) by Randima Fernando and Mark J. Kilgard.  See page 206.

float3 expand(float3 v)
{
  return (v-0.5)*2;  // Expand a range-compressed vector
}

void C8E2f_bumpSurf(float2 normalMapTexCoord : TEXCOORD0,
                    float3 lightDir          : TEXCOORD1,

                out float4 color : COLOR,

            uniform sampler2D   normalMap,
            uniform samplerCUBE normalizeCube)
{
  // Normalizes light vector with normalization cube map
  float3 lightTex = texCUBE(normalizeCube, lightDir).xyz;
  float3 light = expand(lightTex);
  // Sample and expand the normal map texture	
  float3 normalTex = tex2D(normalMap, normalMapTexCoord).xyz;
  float3 normal = expand(normalTex);
  // Diffuse lighting
  color = dot(normal,light);
}