source: GTP/branches/IllumWPdeliver2008dec/IlluminationWP/demos/Standalone/DepthOfField [DirectX]/shaders/illum.hlsl @ 3255

// material constants
const float3 ambientMaterial= float3(0.5, 0.5, 0.5);
const float3 diffuseMaterial = float3(1.0, 1.0, 1.0);   
const float3 specularMaterial = float3(0.3, 0.3, 0.3);

//------------------------------------------
// a fényerõt számító fv.
// l = light vector, r = reciprok négyzet radius: 1.0/(r*r)
//------------------------------------------
float SQR(float x) { return x*x; }
float Attenuation(float3 Light)
{
        return 10.0 / dot(Light, Light);
}

//-----------------------------------------------------------------------------
// Illumination function used in shading: all input vectors are normalized
//-----------------------------------------------------------------------------
float4 Illumination(float3 Light, float3 Normal, float3 View, float2 TexCoord, float Attenuation)
{
        // Blinn lighting
        float3 Half = normalize(Light + View);
        float Diffuse = dot(Normal, Light);
        float Specular = dot(Normal, Half);
        float4 Lighting = lit(Diffuse, Specular, 16);
        float4 Color= tex2D(ColorMapSampler, TexCoord);

        return float4(
                Lighting.x * ambientMaterial * Color +
                (Lighting.y * diffuseMaterial * Color +
                Lighting.z * specularMaterial) * Attenuation, 1);
}