Specular for pixel shader 1.1 by Ashu Rege (NVIDIA)

//Per-Pixel Specular Lighting in HLSL (PS 1.1 Model)

sampler normalMap: register(s0);
sampler specularCubeMap: register(s3);
float4 vAmbient;
float4 vSpecular;

float4 main( float4 diffuse : COLOR,
      float2 TexCoord: TEXCOORD0,
      float4 EnvXform[3] : TEXCOORD1 ) : COLOR
{
   float3 N = tex2D(normalMap, TexCoord);
   float3 Nworld;
   Nworld.x= dot(N*2-1, EnvXform[0]);
   Nworld.y= dot(N*2-1, EnvXform[1]);
   Nworld.z= dot(N*2-1, EnvXform[2]);

   float3 Eye;
   Eye.x = EnvXform[0].w;
   Eye.y = EnvXform[1].w;
   Eye.z = EnvXform[2].w;
   float3 R = 2*dot(Nworld,Eye)*NworldEye*dot(Nworld,Nworld);
   float4 specular = texCUBE(specularCubeMap, R);
   return(specular * vSpecular+ diffuse + vAmbient);
}