source: GTP/branches/IllumWPdeliver2008dec/IlluminationWP/demos/OgreGames/SpaceStation/Media/GameTools_Blur.hlsl @ 3255

#define samplesU 3
#define samplesV 3

struct VS_INPUT {           
    float4 Position : POSITION;
};

struct VS_OUTPUT {         
    float4 hPosition : POSITION;
    float2 Position  : TEXCOORD0;
};

VS_OUTPUT BlurVS(VS_INPUT IN) {
        VS_OUTPUT OUT;
    OUT.hPosition = IN.Position;
    OUT.Position =(IN.Position.xy + 1.0) / 2.0;
    OUT.Position.y = 1.0 - OUT.Position.y;
    return OUT;
}

float4 BlurPS(VS_OUTPUT IN,
                        uniform sampler2D Texture : register(s0),
                        uniform float width,
                        uniform float height ) : COLOR
{  
/*
  float2 pixel = float2(1.0 / width, 1.0 / height);
  float2 uv = IN.Position + pixel * 0.5;

  float4 sum = float4(0,0,0,0);

        for(int i = 0; i < samplesU; i++)
         for(int j = 0; j < samplesU; j++)
                sum += tex2D(Texture, uv + float2(i - samplesU * 0.5,j - samplesV * 0.5) * pixel);

  sum /= samplesU * samplesV;
*/
  float du = 2.0 / width;
  float dv = 2.0 / height;
  float2 uv = IN.Position;
  float4 sum = float4(0,0,0,0);  
  sum += tex2D(Texture,uv);
  sum += tex2D(Texture,uv + float2(du,0));
  sum += tex2D(Texture,uv + float2(du,dv));
  sum += tex2D(Texture,uv + float2(0,dv));
  return sum / 4.0;
}

float4 CopyPS(VS_OUTPUT IN,
                        uniform sampler2D Texture : register(s0),
                        uniform float alpha,
                        uniform float width,
                        uniform float height ) : COLOR
{  
  float2 pixel = float2(1.0 / width, 1.0 / height);
  float2 uv = IN.Position + pixel * 0.5;

  float4 Color = tex2D(Texture, uv);
  Color.a = alpha;  
 // Color = float4(0,0,0,1);
  return Color;
}

VS_OUTPUT BlurCubeFaceVS(VS_INPUT IN) {
        VS_OUTPUT OUT;
    OUT.hPosition = IN.Position;   
    OUT.Position = OUT.hPosition;
    return OUT;
}

float4 BlurCubeFacePS(VS_OUTPUT IN,
                        uniform samplerCUBE Texture : register(s0),
                        uniform float width,
                        uniform float height,
                        uniform float face ) : COLOR
{
/*
  float2 pixel = float2(2.0 / width, 2.0 / height);
  float2 uv = IN.Position + pixel * 0.5;

  float4 sum = float4(0,0,0,0);

        for(int i = 0; i < samplesU; i++)
         for(int j = 0; j < samplesV; j++)
         {
                float3 dir;
                float2 pos = uv + float2(i - samplesU * 0.5,j - samplesV * 0.5) * pixel;
                if (face == 0) dir = float3(1, pos.y, -pos.x);
                if (face == 1) dir = float3(-1, pos.y, pos.x);
                if (face == 2) dir = float3(pos.x, 1, -pos.y);
                if (face == 3) dir = float3(pos.x, -1, pos.y);
                if (face == 4) dir = float3(pos.x, pos.y, 1);
                if (face == 5) dir = float3(-pos.x, pos.y,-1);
                
                sum += texCUBE(Texture, dir);
         }
                
*/
  float pixel = 2.0 / width;
  float2 uv = IN.Position;
  float3 u;
  float3 v;
  float3 pos;
  if (face == 0){u = float3(0,0,-1); v = float3(0,1,0); pos = float3(1,uv.y,-uv.x);}
  if (face == 1){u = float3(0,0,1); v = float3(0,1,0); pos = float3(-1,uv.y,uv.x);}
  if (face == 2){u = float3(1,0,0); v = float3(0,0,-1); pos = float3(uv.x,1,-uv.y);}
  if (face == 3){u = float3(1,0,0); v = float3(0,0,1); pos = float3(uv.x,-1,uv.y);}
  if (face == 4){u = float3(1,0,0); v = float3(0,1,0); pos = float3(uv.x,uv.y,1);}
  if (face == 5){u = float3(-1,0,0); v = float3(0,1,0); pos = float3(-uv.x,uv.y,-1);}
  u *= pixel;
  v *= pixel;
  float4 sum = float4(0,0,0,0);
  sum += texCUBE(Texture, pos);
  sum += texCUBE(Texture, pos + u);
  sum += texCUBE(Texture, pos + v);
  sum += texCUBE(Texture, pos + u + v);
  sum /= 4.0;

  return sum;
  //return texCUBE(Texture, float3(uv, 1)) + face * 0.0000001;
}