source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/shaders/deferred.cg @ 2895

struct fragment
{
         // normalized screen position
        float4 pos: WPOS;
        float4 texCoord: TEXCOORD0; 
        float3 view: COLOR0;
};


struct pixel
{
        float4 color: COLOR0;
};



/** function for standard deferred shading
*/
float4 shade(fragment IN, 
                         uniform float4 color,
                         uniform float4 position,
                         uniform float3 normal,
                         uniform float amb)
{
        float4 lightDir = float4(0.8f, -1.0f, 0.7f, 0.0f);
        //float4 lightDir = float4(0.0f, 1.0f, 0.0f, 0.0f);
        float4 lightDir2 = float4(-0.5f, 0.5f, 0.4f, 0.0f);

        // global ambient
        const float4 ambient = 0.25f;

        // float3 L = normalize(lightPosition - position);
        float3 light = normalize(lightDir.xyz);
        float3 light2 = normalize(lightDir2.xyz);

        float diffuseLight = saturate(dot(normal, light));
        float diffuseLight2 = saturate(dot(normal, light2));

        float diffuse = diffuseLight + diffuseLight2;

        return (ambient + diffuse) * color * (1.0f - amb) + amb * color;
}



/** The mrt shader for standard rendering
*/
pixel main(fragment IN, 
                   uniform sampler2D colors,
                   uniform sampler2D positions,
                   uniform sampler2D normals    
                   )
{
        pixel OUT;

        float4 norm = tex2D(normals, IN.texCoord.xy);
        float4 color = tex2Dlod(colors, float4(IN.texCoord.xy, 0, 0));
        float4 position = tex2D(positions, IN.texCoord.xy);

        // an ambient color term
        float amb = norm.w;

        // expand normal
        float3 normal = normalize(norm.xyz);// * 2.0f - float4(1.0f));

        float4 col = shade(IN, color, position, normal, amb);
        
        //OUT.color = float4(1.0f);
        OUT.color = col;
        OUT.color.w = color.w;

        return OUT;
}

/** The mrt shader for standard rendering
*/
pixel main_shadow(fragment IN, 
                                  uniform sampler2D colors,
                                  uniform sampler2D positions,
                                  uniform sampler2D normals,               
                                  uniform sampler2D shadowMap,
                                  uniform float4x4 shadowMatrix,
                                  uniform float maxDepth,
                                  uniform float sampleWidth
                                  )
{
        pixel OUT;

        float4 norm = tex2D(normals, IN.texCoord.xy);
        float4 color = tex2Dlod(colors, float4(IN.texCoord.xy, 0, 0));
        float4 position = tex2D(positions, IN.texCoord.xy);


        // an ambient color term
        float amb = norm.w;

        float3 normal = normalize(norm.xyz);
        float4 col = shade(IN, color, position, normal, amb);
        
        position *= maxDepth;
        position.w = 1.0f;
        
        float4 lightSpacePos = mul(shadowMatrix, position);

        float shadowDepth[9];

        float w = sampleWidth;

        // pcf sampling using 3 x 3 tab

        shadowDepth[0] = tex2D(shadowMap, lightSpacePos.xy).x;
        
        shadowDepth[1] = tex2D(shadowMap, lightSpacePos.xy + float2( w,  w)).x;
        shadowDepth[2] = tex2D(shadowMap, lightSpacePos.xy - float2( w, -w)).x;
        shadowDepth[3] = tex2D(shadowMap, lightSpacePos.xy - float2(-w, -w)).x;
        shadowDepth[4] = tex2D(shadowMap, lightSpacePos.xy - float2(-w,  w)).x;

        shadowDepth[5] = tex2D(shadowMap, lightSpacePos.xy - float2( w,  0)).x;
        shadowDepth[6] = tex2D(shadowMap, lightSpacePos.xy - float2( 0,  w)).x;
        shadowDepth[7] = tex2D(shadowMap, lightSpacePos.xy - float2(-w,  0)).x;
        shadowDepth[8] = tex2D(shadowMap, lightSpacePos.xy - float2( 0, -w)).x;

        OUT.color = col;
        
        float depth = lightSpacePos.z / lightSpacePos.w;

        float d = 0.0f;

        for (int i = 0; i < 9; ++ i)
        {
                d += step(shadowDepth[i], depth);
        }

        d /= 9.0f;
        
        /*if ((amb < 0.9) && // hack: prevent shadowing the sky 
                (lightSpacePos.z / lightSpacePos.w > shadowDepth))
        {
                OUT.color *= 0.1f;
        }*/
        
        if (amb < 0.9) // hack: prevent shadowing the sky       
        {
                const float x = 0.1f;
                OUT.color *= x + (1.0f - x) * (1.0f - d);
        }
        
        //OUT.color = lightSpacePos;//float4(lightSpacePos.z / lightSpacePos.w);
        //OUT.color = float4(shadowDepth);
        OUT.color.w = color.w;

        return OUT;
}