source: GTP/trunk/App/Demos/Illum/Ogre/Media/materials/programs/GameTools_Localized_EnvMap.hlsl @ 1724

//metal:
float3 n, k;    // R 700 nm, G 550 nm, B 435 nm 
float REDUCED_CUBEMAP_SIZE = 4;

float3 F0;
/*
        
        if (iWhichMetal == 1) { // copper       
                n = float3(0.21f, 0.96f, 1.17f);        
                k = float3(4.16f, 2.57f, 2.32f); }
        else if (iWhichMetal == 2) { // gold
                n = float3(0.16f, 0.35f, 1.6f);         
                k = float3(3.98f, 2.71f, 1.92f); }
        else if (iWhichMetal == 3) { // silver
                n = float3(0.142f, 0.124f, 0.158f);     
                k = float3(4.52f,  3.33f, 2.32f); }
        else if (iWhichMetal == 4) { // alu
                n = float3(1.83f, 0.96f, 0.577f);
                k = float3(8.31f,  6.69f, 5.288f); }

*/      

float4 readCubeMap(samplerCUBE cm, float3 coord)                
{
        float4 color = texCUBE( cm, float3(coord.xy, - coord.z) );
        color.a = 1;
        return color;
}

float readDistanceCubeMap(samplerCUBE dcm, float3 coord)                
{
        float dist = texCUBE(dcm, float3(coord.xy, - coord.z)).r;
        if(dist == 0) dist = 1000; ///sky
        return dist;
}



#define LIN_ITERATIONCOUNT 6
#define LIN_ITERATIONCOUNT_L0 5
#define LIN_ITERATIONCOUNT_L1 5
#define LIN_ITERATIONCOUNT_L2 3
#define LIN_ITERATIONCOUNT_L3 1
#define SECANT_ITERATIONCOUNT 2

float3 Hit(float3 x, float3 R, samplerCUBE mp, float cameraDistance = 0)
{
        return R + 0.000000001 *x;
        R = normalize(R);
        
        float3 Ra = abs(R);
        float3 xa = abs(x);
        float a = max(max(xa.x,xa.y),xa.z) / 
                          max(max(Ra.x,Ra.y),Ra.z);
        
        bool overshoot = false, undershoot = false;
        float dp, dl = 0, ppp, llp;
        float lR = readDistanceCubeMap(mp, R);
        float3 p = R;
        
        /*
        if(cameraDistance < 100)
                LIN_ITERATIONCOUNT  = (float) LIN_ITERATIONCOUNT_L0;
        else if(cameraDistance < 200)
                LIN_ITERATIONCOUNT  = (float) LIN_ITERATIONCOUNT_L1;
        else if(cameraDistance < 300)
                LIN_ITERATIONCOUNT  = (float) LIN_ITERATIONCOUNT_L2;
        else
                LIN_ITERATIONCOUNT  = (float) LIN_ITERATIONCOUNT_L3;
        */
        
        float dt = 1.0 / LIN_ITERATIONCOUNT;
        
        //linear iteration      
        float t = 0;
        while(t < 1.0 && !overshoot)
        {
                //if(!overshoot)
                //{
                        dp = a * t / (1 - t);
                        p = x + R * dp;
                        float dist = readDistanceCubeMap(mp, p);
                        if(dist > 0)
                        {
                                ppp = length(p) / dist;
                                if(ppp < 1)
                                {
                                        dl = dp;
                                        llp = ppp;              
                                        undershoot = true;              
                                }
                                else
                                {
                                        if (undershoot) 
                                           overshoot = true;
                                }
                        }
                        else 
                                undershoot = false;
                //}
                t += dt;                
        }
        
        if(overshoot)
        {
                float dnew;
                for(int i = 0; i < SECANT_ITERATIONCOUNT; i++ )
                {
                        dnew = dl + (dp - dl) * (1 - llp) / (ppp - llp);        
                            
                        p = x + R * dnew;
                        half pppnew = length(p) / readDistanceCubeMap(mp, p);
                        if(pppnew < 1)
                        {
                                llp = pppnew;
                                dl = dnew;
                        }
                        else
                        {
                                ppp = pppnew;
                                dp = dnew;
                        }
                }       
        }
        else
                p = float3(0,0,0);
         
        return p;
}
/*                      

float3 Hit( float3 x, float3 R, samplerCUBE mp )
{
        //return R  + 0.00000000001 * x;
        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
}
*/

/*
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 < SECANT_ITERATIONCOUNT; i++ )
        {
                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
}
*/

void LocalizedVS(float4 position : POSITION,
                out float3 wPos : TEXCOORD1,                            
                float2 texCoord : TEXCOORD0,
                out float2 otexCoord : TEXCOORD0,
                float3 normal   : NORMAL,
                out float3 mNormal  : TEXCOORD2,
                out float4 hPos : POSITION,             
                uniform float4x4 worldViewProj,
                uniform float4x4 world,
                uniform float4x4 worldI
                )
{
 
  hPos = mul(worldViewProj, position);
  wPos = mul(world, position).xyz;  
  mNormal = mul(normal, worldI);  
  otexCoord = texCoord;
}
//////////////
//Localized reflection
//////////////
void LocalizedPS(  float2 texCoord : TEXCOORD0, 
                float3 wPos     : TEXCOORD1,    
                float3 mNormal  : TEXCOORD2,
                uniform float3 cameraPos,
                uniform samplerCUBE CubeMap : register(s0),
                uniform samplerCUBE DistanceMap : register(s1),
                uniform float3 lastCenter,
                uniform float3 lightPosition,           
                out float4 Color :COLOR0)
{
        
        Color = float4(1,1,1,1);
        
        mNormal = normalize(mNormal);
        float3 RR, TT;  
        float3 mPos = wPos - lastCenter;
        float3 V = normalize(wPos - cameraPos);
        float3 R = /*normalize*/(reflect( V, mNormal));
        
        float3 T = refract(V, mNormal, 0.9);
                
        RR = R; TT = T;
        //RR += 0.000001 * lastCenter.x;
        RR = Hit(mPos, R, DistanceMap);
        TT = Hit(mPos, T, DistanceMap);
        
        float4 reflectcolor = readCubeMap(CubeMap, RR );                
        float4 refractcolor = readCubeMap(CubeMap, TT );                
        
        float cos_theta = -dot(V, mNormal);
        float sFresnel = 0.1;
        float F = (sFresnel + pow(1-cos_theta, 5.0f) * (1-sFresnel));
    
    float3 L = normalize(lightPosition - wPos);
        float3 H = normalize(L+V);
        float4 lighting = lit(dot(mNormal, L),dot(mNormal, H), 30);
        Color = (F * reflectcolor + (1-F) * refractcolor) + lighting.z; 
}



//////////////
//Metal
//////////////
void LocalizedMetalPS(  float2 texCoord : TEXCOORD0, 
                float3 wPos     : TEXCOORD1,    
                float3 mNormal  : TEXCOORD2,
                uniform float3 cameraPos,
                uniform samplerCUBE CubeMap : register(s0),
                uniform samplerCUBE DistanceMap : register(s1),
                uniform float3 lastCenter,
                uniform float3 lightPosition,                           
                out float4 Color :COLOR0)
{
        
        Color = float4(1,1,1,1);
        
        mNormal = normalize(mNormal);
        float3 newTexCoord;     
        float3 mPos = wPos - lastCenter;
        float3 V  = (wPos - cameraPos);
        float cameraDistace = length(V);
        V = normalize(V);
        float3 R = normalize(reflect( V, mNormal));
                
        newTexCoord = R;        
        
        newTexCoord = Hit(mPos, R, DistanceMap);
        /*if(dot(newTexCoord,newTexCoord) == 0) 
                Color = float4(0.5,0.5,0.5,1);
        else*/
        Color = readCubeMap(CubeMap, newTexCoord );     
        
        float ctheta_in = dot(mNormal,R);
        float ctheta_out = dot(mNormal,-V);

        float3 F = 0;
        
        // F,P,G számítása
        if ( ctheta_in > 0 && ctheta_out > 0 )
        {
                float3 H = normalize(R - V);    // felezõvektor
                float cbeta  = dot(H,R);                
                //F = ( (n-1)*(n-1) + pow(1-cbeta,5) * 4*n + k*k) / ( (n+1)*(n+1) + k*k );
                //float3 F0 = ((n-1)*(n-1) + k*k) / ( (n+1)*(n+1) + k*k );
                //float3 F1 = float3(1.0f,1.0f,1.0f) - F0;
                F = F0 + (1-F0)*pow(1-cbeta,5);
        }       
        
        Color = Color * float4(F,1);    
}
//////////////
//PhotonMap
//////////////
/*void PhotonMapPS(  float2 texCoord : TEXCOORD0, 
                float3 wPos     : TEXCOORD1,    
                float3 mNormal  : TEXCOORD2,
                uniform float3 cameraPos,
                uniform samplerCUBE UVMap : register(s0),
                uniform samplerCUBE DistanceMap : register(s1),
                uniform float3 lastCenter,
                out float4 Color :COLOR0)
{
        
        Color = float4(1,1,1,1);
        
        mNormal = normalize(mNormal);
        float3 newTexCoord;     
        float3 mPos = wPos - lastCenter;
        float3 V = normalize(wPos - cameraPos);
        float3 R = normalize(reflect( V, mNormal));
                
        newTexCoord = R;        
        
        newTexCoord = Hit(mPos, R, DistanceMap);
        
        Color = readCubeMap(UVMap, newTexCoord );
        //Color = float4(1,0,0,1);              
}*/

float4 PhotonMapCausticPS(  float2 texCoord : TEXCOORD0, 
                float3 wPos     : TEXCOORD1,    
                float3 mNormal  : TEXCOORD2,
                uniform float3 cameraPos,
                uniform samplerCUBE DistanceMap : register(s0),
                uniform float3 lastCenter):COLOR0
{
        
        float4 Color = float4(1,1,1,1);
        
        mNormal = normalize(mNormal);
        float3 newTexCoord;     
        float3 mPos = wPos - lastCenter;
        float3 V = normalize(wPos - cameraPos);
                
        float3 R = refract(V, mNormal, 0.85);           
        //float3 R = V; 
        newTexCoord = R;        
                
        newTexCoord = Hit(mPos, R, DistanceMap);
                
        Color = float4(newTexCoord, 1);
        
        //Color = 0.0001 * Color +  float4(0,0,1,1);
        //Color += 0.0001 * lastCenter.x;
        if(dot(V,mNormal)>0)
        {
                Color = float4(1,0,0,0);                
        }               
        return Color;
}



/////////////////////
///// Diffuse
///////////////////

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 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);      

        //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,
                float2 Tex : TEXCOORD0,
                uniform float4x4 worldViewProj,
                                uniform float4x4 world,
                                //uniform float3 lastCenter,    //LI//
                                out float4 hposition : POSITION,
                out float2 oTex : TEXCOORD0,
                out float3 Normal : TEXCOORD1,
                out float3 pos : TEXCOORD2 )
{
        pos = /*lastCenter + 0.01 * */mul( world, position ).xyz;
        Normal = normal;
    oTex = Tex;    
    hposition = mul( worldViewProj, position );
}


float4 DiffusePS( float2 Tex : TEXCOORD0,
           float3 N : TEXCOORD1,
           float3 pos : TEXCOORD2,
           uniform float3 cameraPos,
           uniform float3 lastCenter,   //LI//
           uniform samplerCUBE SmallEnvMapSampler : register(s0),
           uniform samplerCUBE DistanceEnvMapSampler : register(s1)
            ) : COLOR0
{
    REDUCED_CUBEMAP_SIZE = 4;
        
    //V = /*-*/normalize( V );
    float3 V = normalize(pos - cameraPos);      // 
    N = normalize( N ); 
        float3 R = reflect(V, N);
    pos -= lastCenter;

        
    //return float4(N,1);
    //return float4(V,1);
    //return float4(R,1);
                
        //return readCubeMap(SmallEnvMapSampler,R);
        
    //pos.xy += float2(1.0/LIGHT_TEXTURE_SIZE, -1.0/LIGHT_TEXTURE_SIZE);        // eltolás a pixel/texel középpontba
    // x, y = -1..1
    // z = 1
    
    float4 intens = 0;
    /*
        intens += GetContibution( R, pos, N, V, SmallEnvMapSampler);
        intens = readCubeMap(SmallEnvMapSampler, R);
        return intens;*/
        
        for (int x = 0; x < REDUCED_CUBEMAP_SIZE; x++)                  // az envmap minden texelére
         for (int y = 0; y < REDUCED_CUBEMAP_SIZE; y++)
        //int x = 0;            // az envmap 1 texelére
        //int y = 0; 
        //if (x==LIGHT_TEXTURE_SIZE/2 && y==LIGHT_TEXTURE_SIZE/2)
         {
                // 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);
        }

        return intens;
}