source: GTP/branches/IllumWPdeliver2008dec/IlluminationWP/demos/Standalone/DepthOfField [DirectX]/shaders/CameraEffects.fx @ 3255

// Number of outer filter taps
#define NUM_DOF_TAPS 12
float2 filterTaps[NUM_DOF_TAPS];


#define SAMPLER_LINEAR(g_samplerMap, g_txMap);  \
        sampler2D g_samplerMap = sampler_state {        \
    Texture = <g_txMap>;                                                \
    MinFilter = Linear;                                                 \
    MagFilter = Linear;                                                 \
    MipFilter = Linear;                                                 \
    AddressU  = WRAP;                                                   \
    AddressV  = WRAP;                                                   \
};

texture ColorMap;
SAMPLER_LINEAR(ColorMapSampler, ColorMap);
texture DepthMap;
SAMPLER_LINEAR(DepthMapSampler, DepthMap);

struct VS_INPUT {
                float3 Position : POSITION;
};

struct VS_OUTPUT {
        float4 hPosition : POSITION;     // point in normalized device space before homogeneous division
        float2 TexCoord  : TEXCOORD0;
};

VS_OUTPUT DepthVS(VS_INPUT IN)
{
        VS_OUTPUT output;
    
    output.hPosition = half4(IN.Position, 1);
    
    output.TexCoord = IN.Position.xy * 0.5f + 0.5f; 
    output.TexCoord.y *= -1;

    return output;
}
//------------------------------------------------------------------------------------
//
// 
//
//------------------------------------------------------------------------------------
const float maxCoC = 5;
float4 DepthPS(VS_OUTPUT IN) : COLOR
{
        // Get center sample
        float4 colorSum = tex2D(ColorMapSampler, IN.TexCoord);
        float2 centerDepthBlur = tex2D(DepthMapSampler, IN.TexCoord);

        // Compute CoC size based on blurriness
        float sizeCoC = centerDepthBlur.y * maxCoC;

        float totalContribution = 1.0f;

        // Run through all taps
        for (int i = 0; i < NUM_DOF_TAPS; i++)
        {
                // Compute tap coordinates
                float2 tapCoord = IN.TexCoord + filterTaps[i] * sizeCoC;

                // Fetch tap sample
                float4 tapColor = tex2D(ColorMapSampler, tapCoord);
                float2 tapDepthBlur = tex2D(DepthMapSampler, tapCoord);

                // Compute tap contribution
                float tapContribution = (tapDepthBlur.x > centerDepthBlur.x) ? 1.0f : tapDepthBlur.y;

                // Accumulate color and contribution
                colorSum += tapColor * tapContribution;
                totalContribution += tapContribution;
        }

        // Normalize to get proper luminance
        float4 finalColor = colorSum / totalContribution;

        return finalColor;
}
//------------------------------------------------------------------------------------
// Technique definitions
//------------------------------------------------------------------------------------
technique DepthOfField
{                                                                                                       
    pass p0                                                                                     
    {                                                                                           
            VertexShader = compile vs_3_0 DepthVS();    
            PixelShader  = compile ps_3_0 DepthPS();    
        }                                                                                               
}