source: GTP/branches/IllumWPdeliver2008dec/IlluminationWP/demos/OgreGames/CarGame/Media/materials/programs/DiffuseBump.hlsl @ 3255

float4x4 world_IT;
int REDUCED_CUBEMAP_SIZE = 8;


float4 readCubeMap(samplerCUBE cm, float3 coord)                
{
        float4 color = texCUBE( cm, float3(coord.xy, - coord.z) );
        return color;
}

float readDistanceCubeMap(samplerCUBE dcm, float3 coord)                
{
        float dist = texCUBE(dcm, float3(coord.xy, - coord.z)).r;
        if(dist == 0) dist = 4000; ///sky
        return dist;
}

// This function is called several times.
float3 Hit( float3 x, float3 R, samplerCUBE mp )
{
        float rl = readDistanceCubeMap( mp, R);                         // |r|
        
        float ppp = length( x ) /  readDistanceCubeMap( mp, x);                 // |p|/|p’|
        float dun = 0, pun = ppp, dov = 0, pov = 0;
        float dl = rl * ( 1 - ppp );                                                    // eq. 2
        float3 l = x + R * dl;                                                                  // ray equation

        // iteration
        for( int i = 0; i < 2; i++ )    // 2 !!!!!!!!!!!!!!!!!!!!!!!
        {
                float llp = length( l ) / readDistanceCubeMap( mp, l);          // |l|/|l’|
                if ( llp < 0.999f )                                                                     // undershooting
                {
                        dun = dl; pun = llp;                                                    // last undershooting
                        dl += ( dov == 0 ) ? rl * ( 1 - llp ) :                 // eq. 2
                                ( dl - dov ) * ( 1 - llp ) / ( llp - pov );     // eq. 3
                } else if ( llp > 1.001f )                                                      // overshooting
                {
                        dov = dl; pov = llp;                                                    // last overshooting
                        dl += ( dl -dun ) * ( 1 - llp ) / ( llp - pun );// eq. 3
                }
                l = x + R * dl;                                                                         // ray equation
        }
        return l;                                                                                               // computed hit point
}

float4 GetContibution(float3 L, float3 pos, float3 N, float3 V, samplerCUBE SmallEnvMapSampler, samplerCUBE DistanceEnvMapSampler)      // Phong-Blinn
// L: a hossza lényeges (az egységkocka faláig ér)
{
    REDUCED_CUBEMAP_SIZE = 4;
    float mindist = 1.0;
    
        float kd = 0.3; // 0.3
        float ks = 0;   // 0.5
        float shininess = 10;
        
        float l = length(L);
        L = normalize(L);

        //dw
        float dw = 4 / (REDUCED_CUBEMAP_SIZE*REDUCED_CUBEMAP_SIZE*l*l*l + 4/3.1416f);
        //Lin
        float4 Lin = readCubeMap(SmallEnvMapSampler, L);
        //r
        float doy = readDistanceCubeMap(DistanceEnvMapSampler, L);
        float dxy = length(L * doy - pos);
        
        dxy = max(mindist, dxy);
                

        //dws
        float dws = (doy*doy * dw) / (dxy*dxy*(1 - dw/3.1416f) + doy*doy*dw/3.1416f);   // localization:
        //float dws = dw;
        
        //L = L * doy - pos;    // L: x->y, az objektumtól induljon, ne a középpontból
        L = normalize(L);
        float3 H = normalize(L + V);    // felezõvektor

        float a = kd * max(dot(N,L),0) + 
                          ks * pow(max(dot(N,H),0), shininess); // diffuse + specular

        // 1.: eddigi
        //return Lin * a * dws;
        
        float ctheta_in = dot(N,L);
        float ctheta_out = dot(N,V);    
        
        return Lin * a * dws;           
}

void DiffuseVS(float4 position : POSITION,
                float3 normal   : NORMAL,
                half3 tangent   : TEXCOORD1, 
                float2 texCoord : TEXCOORD0,
                out float2 otexCoord : TEXCOORD0,
                out float3 wPos : TEXCOORD1,                            
                out float3 mNormal  : TEXCOORD2,
                out half3 Tangent   : TEXCOORD3,         
                out half3 Binormal  : TEXCOORD4,         
                out float4 hPos : POSITION,             
                uniform float4x4 worldViewProj,
                uniform float4x4 world)
{
 
  hPos = mul(worldViewProj, position);
  wPos = mul(world, position).xyz;  
  //mNormal = mul(normal, world_IT);
  mNormal = normal;
  otexCoord = texCoord;
  Tangent = tangent;  
  Binormal = cross(tangent, normal); 
}

float4 DiffusePS( float2 Tex : TEXCOORD0,
           float3 pos : TEXCOORD1,
           float3 N : TEXCOORD2,
           half3 Tangent   : TEXCOORD3,  
                   half3 Binormal  : TEXCOORD4,
           uniform float3 cameraPos,
           uniform float3 lastCenter,
           uniform half3 lightPosition,                         
           uniform samplerCUBE SmallEnvMapSampler : register(s0),
           uniform samplerCUBE DistanceEnvMapSampler : register(s1),
                   uniform sampler2D ColorTexture : register(s2),
                   uniform sampler2D NormalMap : register(s3)                           
            ) : COLOR0
{
    REDUCED_CUBEMAP_SIZE = 4;
        
    //V = /*-*/normalize( V );
    float3 V = normalize(pos - cameraPos);      // 
    
    float3x3 ModelToTangent = float3x3(Tangent, Binormal, N); 
        half3 tNormal = tex2D(NormalMap, Tex).rgb;      
      
    N =mul(tNormal, ModelToTangent );
    N = mul( N, world_IT );
    N = normalize(N);
    
    float3 R = reflect(V, N);
    pos -= lastCenter;  
        
    float4 intens = 0;
    
        
        for (int x = 0; x < REDUCED_CUBEMAP_SIZE; x++)                  // az envmap minden texelére
         for (int y = 0; y < REDUCED_CUBEMAP_SIZE; y++)
         {
                // intenzitás kiolvasása az adott texelbõl 
                
                float2 p, tpos; 
            tpos.x = x/(float)REDUCED_CUBEMAP_SIZE;     // 0..1
            tpos.y = y/(float)REDUCED_CUBEMAP_SIZE;     // 0..1
            tpos.xy += float2(0.5/REDUCED_CUBEMAP_SIZE, 0.5/REDUCED_CUBEMAP_SIZE);      // az adott texel középpont uv koordinátái
            
            p.x = tpos.x; 
            p.y = 1-tpos.y;
            p.xy = 2*p.xy - 1;  // -1..1        // az adott texel középpont pozíciója
            
            float3 L;
            
                L = float3(p.x, p.y, 1);
                intens += GetContibution( L, pos, N, V, SmallEnvMapSampler, DistanceEnvMapSampler);
                
                L = float3(p.x, p.y, -1);
                intens += GetContibution( L, pos, N, V, SmallEnvMapSampler, DistanceEnvMapSampler);
                
                L = float3(p.x, 1, p.y);
                intens += GetContibution( L, pos, N, V, SmallEnvMapSampler, DistanceEnvMapSampler);
                
                L = float3(p.x, -1, p.y);
                intens += GetContibution( L, pos, N, V, SmallEnvMapSampler, DistanceEnvMapSampler);
                
                L = float3(1, p.x, p.y);
                intens += GetContibution( L, pos, N, V, SmallEnvMapSampler, DistanceEnvMapSampler);
                
                L = float3(-1, p.x, p.y);
                intens += GetContibution( L, pos, N, V, SmallEnvMapSampler, DistanceEnvMapSampler);
        }
        
        half3 light = lightPosition;
        half3 L = normalize(light);
        half3 H = normalize(L + V);
        half4 lighting = lit(dot(N, L),dot(N, H), 20);

        float4 retColor = intens;
        float4 texColor = tex2D(ColorTexture, Tex);
        retColor = intens * texColor * 1.5
                          + lighting.y * texColor * 0.15 
                          + lighting.z * 0.15                   
                         ;
        return retColor;
}