source: GTP/branches/IllumWPdeliver2008dec/IlluminationWP/demos/OgreDemos/media/MORIA/Fire.hlsl @ 3255

float farplane = 1000.0; //far plane
float nearplane = 0.1; //far plane
float width = 800;
float height = 600;

struct SBB_VS_OUT
{
        float4 hPosition        : POSITION;
        float4 texCoord         : TEXCOORD0;
        float3 P                : TEXCOORD1;
        float3 Q                : TEXCOORD2;
        float r                 : TEXCOORD3;
        float2 screenCoord      : TEXCOORD4;    
        float4 color            : COLOR0;
};

SBB_VS_OUT FireVS (float4 position : POSITION,  
                float4 texCoord : TEXCOORD0,
                float4 color    : COLOR,
                uniform float4x4 worldView,
                uniform float4x4 Proj,
                uniform float4x4 worldViewProj)
{
        SBB_VS_OUT OUT;
  
        float2 offset = texCoord.zw;
        float4 cPosition;   
        float4 wPosition = position;    
        cPosition = mul(worldView, wPosition);  
        OUT.P = cPosition.xyz;
        OUT.P.z = - 1 * OUT.P.z;
        cPosition.xy += offset;                         
        OUT.Q = cPosition.xyz;  
        OUT.Q.z = OUT.P.z;
        OUT.r = abs(texCoord.z);                

   /*texCoord.y = 1.0 - texCoord.y;
   float2 offset = texCoord.xy * 2.0 - 1.0;
   float4 cPosition = mul(worldView, position);
   OUT.P = cPosition.xyz;
   OUT.P.z = - 1 * OUT.P.z; // - texCoord.w;
   cPosition.xy += offset * texCoord.w;
   OUT.Q = cPosition.xyz;
   OUT.Q.z = OUT.P.z;
   OUT.r = texCoord.w;*/
  
   OUT.hPosition = mul( Proj, cPosition );
   OUT.screenCoord =  (OUT.hPosition.xy / OUT.hPosition.w + 1.0) / 2.0;
   OUT.screenCoord.y = 1.0 - OUT.screenCoord.y;
   OUT.screenCoord += float2(0.5/width, 0.5/height);   
   
   OUT.texCoord = texCoord;
   OUT.color = color;


  return OUT;
} 


void FirePS(SBB_VS_OUT IN ,
        //      in screenCoord : VPOS,
                uniform sampler2D colorTexture : register(s0),
                uniform sampler2D DepthMap : register(s1)
                ,uniform sampler2D PlanckMap : register(s2),
                uniform sampler2D gradTex : register(s3),
                uniform sampler2D heatTex : register(s4),
                uniform float frametime,
                out float4 Color : COLOR0,
                out float4 Heat: COLOR1)
{
        Color = IN.color;
        float alpha = 0;
        
        
        float d = length( IN.Q - IN.P );
        float Zs;
        
        Heat = float4(0,0,0,0.8);       
        
        if( d < IN.r )
        {        
                float w = sqrt( IN.r * IN.r - d * d );
                alpha = w / IN.r;
                float alpha2 = alpha * alpha;
                alpha = pow( alpha, 4);
        
                float F = IN.Q.z - w;
                float B = IN.Q.z + w;    

                Zs = tex2D( DepthMap, IN.screenCoord ).r;
                if(Zs == 0) Zs = farplane;
                float ds = min( Zs, B ) - max( nearplane, F );   
                
                alpha *=  ds / w * 0.5; 
                //alpha2 *=  ds / w * 0.5;
                
                Heat.rg = alpha2;       
        }
        if(alpha == 0)
                discard;
        
        alpha = saturate(alpha);
        Color.a = alpha * tex2D( colorTexture, IN.texCoord.xy).r ;
        Color.a *= IN.color.a;
        Color.rgb *= tex2D( PlanckMap, float2(Color.a, frametime)).rgb;
        float grad = tex2D(gradTex, IN.texCoord.xy).r;
        //Color.a *= grad;

        //Heat.rg *= (tex2D(heatTex, IN.texCoord.xy + frametime).rg * 2.0 - 1.0) * IN.color.a;
        Heat.rg *= /*grad **/ (tex2D(heatTex, IN.texCoord.xy + frametime).r * 2.0 - 1.0) * IN.color.a * 0.1;
        
        Color.a = pow(Color.a,5);
        Color.a *= 6.0;
        //Color = 1;
        //Heat = 1;
}

struct VS_OUT
{
        float4 hPosition        : POSITION;
        float2 texCoord         : TEXCOORD0;    
};


float4 FireHeatCompositorPS(VS_OUT IN,
                uniform float width,
                uniform float height,
                uniform sampler2D Scene: register(s0)
                ,uniform sampler2D FireColor: register(s1)
                ,uniform sampler2D FireHeatNoise: register(s2)
                 ):COLOR
{       
        float maxOffset = 0.045;
        float4 Color = 1;
        float2 halfpixel = float2(1.0 / width, 1.0 / height);
        float2 halfpixel2 = 2*halfpixel;

        float2 offset = tex2D(FireHeatNoise,IN.texCoord ).rg;
                
        offset *= maxOffset;
        float2 newTex = IN.texCoord + offset;
        float2 newTex2 = newTex + halfpixel2;
        newTex = newTex + halfpixel;

        newTex = saturate(newTex);
        float4 SceneSample = tex2D(Scene, newTex );
        float4 FireSample  = tex2D(FireColor, newTex2 );
        
        Color = SceneSample + FireSample;// + float4(offset,1,1);       
        Color.a = SceneSample.a;
        return Color;
        return float4(offset,0,1);
}