51 lines
1.3 KiB
GLSL
51 lines
1.3 KiB
GLSL
const float PI = 3.14159265359;
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//ue4 falloff model
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float CalculateAttenuation(vec3 lp, float lr, vec3 FragPos) {
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float distance = distance(lp, FragPos);
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float saturated = pow(clamp(1 - pow(distance / lr, 4), 0.0, 1.0), 2);
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return saturated / (pow(distance, 2) + 1);
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}
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//pbr functions from learnopengl.com
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vec3 fresnelSchlickRoughness(float cosTheta, vec3 F0, float roughness)
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{
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return F0 + (max(vec3(1.0 - roughness), F0) - F0) * pow(1.0 - cosTheta, 5.0);
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}
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float DistributionGGX(vec3 N, vec3 H, float roughness)
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{
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float a = roughness*roughness;
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float a2 = a*a;
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float NdotH = max(dot(N, H), 0.0);
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float NdotH2 = NdotH*NdotH;
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float nom = a2;
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float denom = (NdotH2 * (a2 - 1.0) + 1.0);
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denom = PI * denom * denom;
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return nom / denom;
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}
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float GeometrySchlickGGX(float NdotV, float roughness)
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{
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float r = (roughness + 1.0);
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float k = (r*r) / 8.0;
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float nom = NdotV;
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float denom = NdotV * (1.0 - k) + k;
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return nom / denom;
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}
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float GeometrySmith(vec3 N, vec3 V, vec3 L, float roughness)
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{
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float NdotV = max(dot(N, V), 0.0);
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float NdotL = max(dot(N, L), 0.0);
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float ggx2 = GeometrySchlickGGX(NdotV, roughness);
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float ggx1 = GeometrySchlickGGX(NdotL, roughness);
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return ggx1 * ggx2;
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}
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