40 lines
983 B
C
40 lines
983 B
C
struct Light
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{
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float4 color; // and radius
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float4 position; // and -cos(angle)
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float4 direction; // and falloff clamp
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};
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float3 DoDirLight(Light L, float3 N)
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{
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float l = max(0.0, dot(N, -L.direction.xyz));
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return l*L.color.xyz;
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}
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float3 DoPointLight(Light L, float3 V, float3 N)
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{
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// As on PS2
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float3 dir = V - L.position.xyz;
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float dist = length(dir);
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float atten = max(0.0, (1.0 - dist/L.color.w));
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float l = max(0.0, dot(N, -normalize(dir)));
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return l*L.color.xyz*atten;
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}
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float3 DoSpotLight(Light L, float3 V, float3 N)
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{
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// As on PS2
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float3 dir = V - L.position.xyz;
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float dist = length(dir);
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float atten = max(0.0, (1.0 - dist/L.color.w));
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dir /= dist;
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float l = max(0.0, dot(N, -dir));
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float pcos = dot(dir, L.direction.xyz); // cos to point
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float ccos = -L.position.w; // cos of cone
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float falloff = (pcos-ccos)/(1.0-ccos);
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if(falloff < 0) // outside of cone
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l = 0;
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l *= max(falloff, L.direction.w); // falloff clamp
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return l*L.color.xyz*atten;
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}
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