source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/shaders/combineSsao.cg @ 3123

#include "../shaderenv.h"


struct fragment
{
        float2 texCoord: TEXCOORD0; 
        float3 view: TEXCOORD1;
};


struct pixel
{
        float4 illum_col: COLOR0;
};



float Filter(float2 texCoord, 
                         uniform sampler2D ssaoTex,
                         uniform float2 filterOffs[NUM_SSAO_FILTERSAMPLES],
                         uniform float filterWeights[NUM_SSAO_FILTERSAMPLES])
{
        float average = .0f;
        float w = .0f;

        for (int i = 0; i < NUM_SSAO_FILTERSAMPLES; ++ i)
        {
                average += filterWeights[i] * tex2Dlod(ssaoTex, float4(texCoord + filterOffs[i], 0, 0)).x;
                w += filterWeights[i];
        }

        average *= 1.0f / (float)w;

        return average;
}


float Filter(float2 texCoord, 
                         uniform sampler2D ssaoTex,
                         uniform float2 filterOffs[NUM_SSAO_FILTERSAMPLES],
                         uniform float filterWeights[NUM_SSAO_FILTERSAMPLES],
                         float scale)
{
        float average = .0f;
        float w = .0f;

        for (int i = 0; i < NUM_SSAO_FILTERSAMPLES; ++ i)
        {       
                average += filterWeights[i] * tex2Dlod(ssaoTex, float4(texCoord + filterOffs[i] * scale, 0, 0)).x;
                w += filterWeights[i];
        }

        average *= 1.0f / (float)w;

        return average;
}


float DiscontinuityFilter(float2 texCoord,
                                                  float4 ao,
                                                  uniform sampler2D ssaoTex,
                                                  uniform sampler2D normalsTex,
                                                  uniform float2 filterOffs[NUM_SSAO_FILTERSAMPLES],
                                                  uniform float filterWeights[NUM_SSAO_FILTERSAMPLES],
                                                  float scale)
{
        float average = .0f;
        float total_w = .0f;

        const float eyeSpaceDepth = ao.w;
        const float3 norm = normalize(tex2Dlod(normalsTex, float4(texCoord, 0, 0)).xyz);

        float4 aoSample;
        float3 sampleNorm;
        float w;
        float4 offs;
        float depthFactor;
        float normalFactor;

        for (int i = 0; i < NUM_SSAO_FILTERSAMPLES; ++ i)
        {
                offs = float4(texCoord + filterOffs[i] * scale, 0, 0);
                aoSample = tex2Dlod(ssaoTex, offs);
                
                sampleNorm = normalize(tex2Dlod(normalsTex, offs).xyz);

                //depthFactor = clamp(1.0f - abs(1.0f - eyeSpaceDepth / aoSample.w), 1e-3f, 1.0f);
                
                depthFactor = max(step(5e-2f, 1.0f - abs(1.0f - eyeSpaceDepth / aoSample.w)), 1e-3f);
                normalFactor = max(step(0.5f, dot(sampleNorm, norm)), 1e-3f);

                w = filterWeights[i] * normalFactor * depthFactor;
                //w = filterWeights[i] * depthFactor;

                average += aoSample.x * w;
                total_w += w;
        }

        average *= 1.0f / max(total_w, 1e-6f);

        return average;
}


pixel combine(fragment IN, 
                          uniform sampler2D colorsTex,
                          uniform sampler2D ssaoTex,
                          uniform sampler2D normalsTex,
                          uniform float2 filterOffs[NUM_SSAO_FILTERSAMPLES],
                          uniform float filterWeights[NUM_SSAO_FILTERSAMPLES]
                          )
{
        pixel OUT;

        float4 col = tex2Dlod(colorsTex, float4(IN.texCoord, 0, 0));
        float4 ao = tex2Dlod(ssaoTex, float4(IN.texCoord, 0, 0));

        //if ((ao.y < 60.0f) && (col.w < 1e10f))
        if (col.w < 1e10f)
        {
                //const static float scaleFactor = 10.0f;
                const static float scaleFactor = 50.0f;

                //ao.x = Filter(IN.texCoord, ssaoTex, filterOffs, filterWeights);
                //ao.x = Filter(IN.texCoord, ssaoTex, filterOffs, filterWeights, 1.0f / (1.0f + ao.y));
                ao.x = DiscontinuityFilter(IN.texCoord, ao, ssaoTex, normalsTex, filterOffs, filterWeights, scaleFactor / (scaleFactor + ao.y));
                //ao.x = BilateralFilter(IN.texCoord, ao, ssaoTex, normalsTex, filterOffs, filterWeights, 1.0f);
        }

        OUT.illum_col = col * ao.x;
        //OUT.illum_col = float4(ao.x, ao.x, ao.x, col.w);
        //OUT.illum_col.xyz = float3(1.0f - ao.x, 1.0f - ao.y * 1e-2f, 1);
        OUT.illum_col.w = col.w;

        return OUT;
}