source: GTP/trunk/App/Demos/Vis/FriendlyCulling/src/shaders/deferred.cg @ 3005

#include "../shaderenv.h"


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


struct pixel
{
        float4 color: COLOR0;
};


float2 myreflect(float2 pt, float2 n)
{
        // distance to plane
        float d = dot(n, pt);
        // reflect around plane
        float2 rpt = pt - d * 2.0f * n;

        return rpt;
}


/** function for standard deferred shading
*/
float4 shade(fragment IN, 
                         uniform float4 color,
                         uniform float4 position,
                         uniform float3 normal,
                         uniform float emmisive,
                         float3 lightDir)
{
        // diffuse intensity
        const float angle = saturate(dot(normal, lightDir)); 
        
        float4 lightDiffuse = glstate.light[0].diffuse;
        float4 diffuse = angle * lightDiffuse;

        // global ambient
        const float4 ambient = glstate.light[0].ambient;
        
        float4 outColor;

        // hack: prevent shading the sky
        if (position.z > 1e19f) outColor = color;
        //if (emmisive > 1.5f) outColor = color;
        else outColor = (ambient + diffuse) * color;

        return outColor;
}



/** The mrt shader for standard rendering
*/
pixel main(fragment IN, 
                   uniform sampler2D colors,
                   uniform sampler2D positions,
                   uniform sampler2D normals,
                   uniform float3 lightDir
                  //, uniform sampler2D oldColors
                   )
{
        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 = color.w;
        float3 normal = normalize(norm.xyz);
        float4 col = shade(IN, color, position, normal, amb, lightDir);
        
        OUT.color = col;
        
#if 1

        OUT.color.w = color.w;

#else

        ////////////
        //-- write out logaritmic luminance for tone mapping

        // the old loglum is stored in the hightest mipmap-level
        float oldLogLum = tex2Dlod(colors, float4(IN.texCoord.xy, 0, MAX_LOD_LEVEL)).w;

        const float3 w = float3(0.299f, 0.587f, 0.114f);

        float lum = dot(OUT.color.rgb, w);
        float logLum = log(1e-5f + lum);

        float logLumOffset = MINLOGLUM * INV_LOGLUM_RANGE;
        float logLumScaled = logLum * INV_LOGLUM_RANGE - logLumOffset;

        if (oldLogLum > 0)
                OUT.color.w = lerp(oldLogLum, logLumScaled, 0.1f);
        else
                OUT.color.w = logLumScaled;

#endif

        return OUT;
}


float CalcShadowTerm(fragment IN,
                                         uniform sampler2D shadowMap,
                                         uniform float w,
                                         uniform float2 lightSpacePos,
                                         uniform float depth,
                                         uniform float2 samples[NUM_PCF_TABS],
                                         uniform sampler2D noiseTexture
                                         )
{
        //float shadowDepth = tex2D(shadowMap, lightSpacePos).x;
        //return step(depth, shadowDepth);

        float total_d = 0.0;
        
        for (int i = 0; i < NUM_PCF_TABS; ++ i) 
        {
                const float2 offset = samples[i];

#if 1
                ////////////////////
                //-- add random noise: reflect around random normal vector (warning: slow!)

                float2 mynoise = tex2D(noiseTexture, IN.texCoord.xy).xy;
                const float2 offsetTransformed = myreflect(offset, mynoise);
#else
                const float2 offsetTransformed = offset;
#endif
                // weight with projected coordinate to reach similar kernel size for near and far
                float2 texcoord = lightSpacePos + offsetTransformed * w;

                float shadowDepth = tex2D(shadowMap, texcoord).x;

                total_d += step(depth, shadowDepth);
        }

        total_d /= (float)NUM_PCF_TABS;

        return total_d;
}


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,
                                  uniform sampler2D noiseTexture,
                                  uniform float2 samples[NUM_PCF_TABS],
                                  uniform float3 lightDir
                                  //, uniform sampler2D oldColors
                                  )
{
        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);
        
        const float3 normal = normalize(norm.xyz);
        
        // hack: an emmisive color term
        float emmisive = color.w;

        // diffuse intensity
        const float angle = saturate(dot(normal, lightDir)); 
        //float4 lightDiffuse = float4(1.0f, 1.0f, 0.9f, 1.0f);
        const float4 lightDiffuse = glstate.light[0].diffuse;
        //float4(1.0f, 1.0f, 0.9f, 1.0f);

        float4 diffuse = lightDiffuse * angle;

        // calc diffuse illumination + shadow term
        //if ((emmisive < 1.5f) // hack: prevent shadowing the sky      
        if ((position.z < 1e19f)
                && (angle > 1e-3f) // shadow only if diffuse color has some minimum intensity
                )
        {
                position *= maxDepth;
                position.w = 1.0f;

                float4 lightSpacePos = mul(shadowMatrix, position);
                lightSpacePos /= lightSpacePos.w;

                float shadowTerm = CalcShadowTerm(IN, shadowMap, sampleWidth, lightSpacePos.xy, lightSpacePos.z, samples, noiseTexture);

                diffuse *= shadowTerm;
        }

        // light ambient term
        const float4 ambient = glstate.light[0].ambient;
        
        // base lighting
        //OUT.color = (emmisive > 1.5f) ? color: (ambient + diffuse) * color;
        OUT.color = (position.z > 1e19f) ? color: (ambient + diffuse) * color;


        ////////////
        //-- write out logaritmic luminance for tone mapping

#if 1
        OUT.color.w = color.w;
#else

        float oldLogLum = tex2Dlod(colors, float4(IN.texCoord.xy, 0, MAX_LOD_LEVEL)).w;

        const float3 w = float3(0.299f, 0.587f, 0.114f);

        float lum = dot(OUT.color.rgb, w);
        float logLum = log(1e-5f + lum);

        float logLumOffset = MINLOGLUM * INV_LOGLUM_RANGE;
        float logLumScaled = logLum * INV_LOGLUM_RANGE - logLumOffset;

        if (oldLogLum > 0)
                OUT.color.w = lerp(oldLogLum, logLumScaled, 0.1f);
        else
                OUT.color.w = logLumScaled;
#endif  
        return OUT;
}