source: GTP/trunk/App/Demos/Illum/Ogre/Media/materials/programs/GameTools_Cau.hlsl @ 777

float CauSpriteSize;
float CauSpriteIntens;

struct VS_OUT
{
        float4 hPosition        : POSITION;
        float4 texCoord         : TEXCOORD0;
        float4 color            : COLOR0;
        float2 r                        : TEXCOORD1;
        float2 center           : TEXCOORD2;
        float4 position         : TEXCOORD3;
};

VS_OUT CauVS(float4 position : POSITION,        
                float4 texCoord : TEXCOORD0,
                float4 color    : COLOR0,
                uniform float4x4 worldView,
                uniform float4x4 Proj,
                uniform float4x4 worldViewProj,
                uniform float resolution,
                uniform sampler2D PhotonHitMap : register(s0))
{
  VS_OUT OUT;
     
   float radius = CauSpriteSize;
   float2 offset = 2.0 * texCoord.zw * radius;
   
   float4 cPosition;  

   float4 pos = tex2Dlod(PhotonHitMap, float4(position.x, 1.0 - position.y,0,0)).rgba;
   if(pos.a != 1)//no photon hit
   {
                OUT.center = 1000.0f;
                OUT.position = OUT.hPosition = 1000.0f; //transform out of view
   }
   else
   {
                float4 wPosition = float4(normalize(pos.xyz),1); 
    
                cPosition = mul(worldView, wPosition);
                OUT.center = cPosition.xy;
                cPosition.xy += offset;                         
                OUT.position = cPosition;       
                OUT.hPosition = mul(Proj, cPosition);
                
                /* 
                //rotate to camera
                cPosition = mul(worldView, wPosition);
                                
                float3 C = cPosition.xyz;
                float3 right = cross(C, float3(0,1,0));
                float3 up = cross(right, C);
                
                float3 cOffset = offset.x * right + offset.y * up;
                cPosition.xy += float2(-0.5/resolution, -0.5/resolution);
                OUT.center = cPosition.xy;
                cPosition.xyz += cOffset;                               
                OUT.position = cPosition;       
                OUT.hPosition = mul(Proj, cPosition);
                */
         }      
  
   OUT.r.x = abs(offset.x);
   OUT.r.y = radius;
   OUT.texCoord = texCoord;
   OUT.color = 1;       
   
   return OUT;
}


float4 CauPS(VS_OUT IN,
                uniform sampler2D intensityTex : register(s1)
                 ):COLOR
{

  float2 texcoord = (IN.center - IN.position.xy) / IN.r.x;
  texcoord = (texcoord + 1.0) * 0.5;
  float intens = tex2D(intensityTex, texcoord).r;
  IN.color.a = intens * CauSpriteIntens;
 
  return IN.color;
  
}