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Area Light Implementation with directx9 or DX11


I want to implement AreaLight Using Directx 9 Plz help me that how I can start. I Studies Two three link but enable to implement in RenderMonkey or Direct With Sample


Solution

  • Spherical area light HLSL

    float specTrowbridgeReitz(float HoN,float a,float aP)
    {
       float a2 = a*a;
       float ap2 = aP*aP;
       return ( a2 * ap2 ) / pow( HoN * HoN * ( a2 - 1.0 ) + 1.0, 2.0 );
    }
    
    float visSchlickSmithMod( float NoL, float NoV, float r )
    {
        float k = pow( r * 0.5 + 0.5, 2.0 ) * 0.5;
        float l = NoL * ( 1.0 - k ) + k;
        float v = NoV * ( 1.0 - k ) + k;
        return 1.0 / ( 4.0 * l * v );
    }
    
    float fresSchlickSmith( float HoV, float f0 )
    {
       return f0 + ( 1.0 - f0 ) * pow( 1.0 - HoV, 5.0 );
    }
    
    float sphereLight(float3 pos,float3 N,float3 V,float3 r,float f0,float 
    roughness,float NoV,out float NoL)
    {
       float3 L = lightPositions - pos;
       float3 centerToRay = dot(L,r)*r-L;
       float3 closestPoint = L + centerToRay * clamp( fLightRadius / length( 
       centerToRay ), 0.0, 1.0 );
       float3 l = normalize(closestPoint);
       float3 h = normalize(V+l);
       NoL = clamp(dot(N,l),0.0,1.0);
       float HoN = clamp(dot(h,N),0.0,1.0);
       float HoV = dot(h,V);
       float distL = length(L);
       float alpha = roughness * roughness;
       float alphaPrime = clamp(fLightRadius/(distL*2.0)+alpha,0.0,1.0);
       float specD = specTrowbridgeReitz( HoN, alpha, alphaPrime );
       float specF = fresSchlickSmith( HoV, f0 );
       float specV = visSchlickSmithMod( NoL, NoV, roughness );
       return specD * specF * specV*NoL;
    }
    
    float3 areaLights(float3 pos,float3 nor,float3 V)
    {
       float f0 = FO;
       float NoV = clamp(dot(nor,V),0.0,1.0);
       float3 r = reflect(-V,nor);
       float NdotLSphere;
       float specSph = sphereLight(pos,nor,V,r,f0,roughness,NoV,NdotLSphere);
       float3 color = 0.3183*(NdotLSphere*lightcolor)+
       (specSph*lightcolor)+albedo;
       return pow(color,1.0/2.2);
    }
    
    float4 ps_main( PS_INPUT Input ) : COLOR0
    {  
        float3 N = normalize(Input.Normal);
        float3 viewDir = normalize(campos.xyz - 
        float3(Input.WSPosition.xyz));
        float3 color = areaLights(Input.WSPosition,N,viewDir);
        return float4(color,0.0);
     }