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)).a;
	if(dist == 0) dist = 1000; ///sky
	return dist;
}

#define SECANT_ITERATIONCOUNT 20

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
}


struct Shaded_OUT
{
 float4 vPos : POSITION;
 float4 wNormal : TEXCOORD0;
 float4 wPos    : TEXCOORD1; 
};


float4 EnvMap_Default_PS(Shaded_OUT IN,
						uniform samplerCUBE CubeMap : register(s0),
						uniform float3 cameraPos) : COLOR0
{
	float3 N = normalize(IN.wNormal.xyz);
	float3 V = normalize(IN.wPos.xyz - cameraPos);
	float3 R = reflect( V, N);	
	
	return readCubeMap(CubeMap, R );	
}

float4 EnvMap_Refract_Default_PS
					(Shaded_OUT IN,
					uniform samplerCUBE CubeMap : register(s0),
					uniform float3 cameraPos,
					uniform float sRefraction,
					uniform float transparency ) : COLOR0
{
	float3 N = normalize(IN.wNormal.xyz);
	float3 V = normalize(IN.wPos.xyz - cameraPos);
	float3 R = reflect( V, N);	
	float3 R2 = refract( V, N, sRefraction);	
	
	return 0.5;//(1.0 - transparency) * readCubeMap(CubeMap, R ) + transparency * readCubeMap(CubeMap, R2);
}

float4  EnvMap_Localized_Reflection_PS( Shaded_OUT IN,
										uniform samplerCUBE CubeMap : register(s0),
										uniform samplerCUBE DistanceMap : register(s1),
										uniform float3 cameraPos,
										uniform float3 lastCenter,		
										uniform float sFresnel,
										uniform float sRefraction ) :COLOR0
{
	float3 N = normalize(IN.wNormal.xyz);
	float3 RR;	
	float3 V = normalize(IN.wPos.xyz - cameraPos);
	float3 cubePos = IN.wPos.xyz - lastCenter;
	float3 R = reflect( V, N);	
		
	RR = R;
	RR = Hit(cubePos, R, DistanceMap);
	
	return readCubeMap(CubeMap, RR );	
}

float4  EnvMap_Localized_Refraction_PS( Shaded_OUT IN,
										uniform samplerCUBE CubeMap : register(s0),
										uniform samplerCUBE DistanceMap : register(s1),
										uniform float3 cameraPos,
										uniform float3 lastCenter,		
										uniform float4 sFresnel,
										uniform float sRefraction ) :COLOR0
{
	float4 Color = 0;
	float3 N = normalize(IN.wNormal.xyz);
	float3 RR, TT;	
	float3 V = normalize(IN.wPos.xyz - cameraPos);
	float3 cubePos = IN.wPos.xyz - lastCenter;
	float3 R = reflect( V, N);	
	float3 T = refract(V, N, sRefraction);

		
	RR = R;	TT = T; 
	RR = Hit(cubePos, R, DistanceMap);
	float4 reflectcolor = readCubeMap(CubeMap, RR );		
	
	if(dot(T,T)!=0)
	{
		TT = Hit(cubePos, T, DistanceMap);
		float4 refractcolor = readCubeMap(CubeMap, TT );		
	
		float cos_theta = -dot(V, N);
		float F = (sFresnel + pow(1 - cos_theta, 5.0f) * (1 - sFresnel));
    		F = saturate(F);
		Color =  (F * reflectcolor + (1 - F) * refractcolor);
	}
	else
	{
		Color = reflectcolor;
	}
  return Color;
}


float4 EnvMap_LocalizedMetal_PS(  Shaded_OUT IN,
									uniform samplerCUBE CubeMap : register(s0),
									uniform samplerCUBE DistanceMap : register(s1),
									uniform float3 cameraPos,
									uniform float3 lastCenter,
									uniform float3 F0 ):COLOR0
{	
	float4 Color;
	float3 N = normalize(IN.wNormal.xyz);
	float3 RR;	
	float3 V = normalize(IN.wPos.xyz - cameraPos);
	float3 cubePos = IN.wPos.xyz - lastCenter;
	float3 R = reflect( V, N);
		
	RR = R;	
	RR = Hit(cubePos, R, DistanceMap);
	Color = readCubeMap(CubeMap, RR);
	//Color = readDistanceCubeMap(DistanceMap, cubePos)/300.0;
	//return Color;
	
	float ctheta_in = dot(N, R);
	float ctheta_out = dot(N, -V);

	float3 F = 0;
	
	// compute F,P,G
	//if ( ctheta_in > 0 && ctheta_out > 0 )
	{
		float3 H = normalize(R - V);	// felezővektor
		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);
	}
		
	return Color * float4(F,1);	
}