2019-08-04 19:54:08 +00:00
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//https://gamedev.stackexchange.com/questions/92015/optimized-linear-to-srgb-glsl
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vec3 srgb_to_linear(vec3 srgb) {
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bvec3 cutoff = lessThan(srgb, vec3(0.04045));
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vec3 higher = pow((srgb + vec3(0.055))/vec3(1.055), vec3(2.4));
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vec3 lower = srgb/vec3(12.92);
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return mix(higher, lower, cutoff);
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2020-04-04 00:32:39 +00:00
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}
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// Phong reflection.
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//
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// Note: norm, dir, light_dir must all be normalizd.
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vec3 light_reflection_factor(vec3 norm, vec3 dir, vec3 light_dir, vec3 k_d, vec3 k_s, float alpha) {
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float ndotL = max(dot(-norm, light_dir), 0.0);
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if (ndotL > 0.0) {
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vec3 H = normalize(-light_dir + dir);
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// (k_d * (L ⋅ N) + k_s * (R ⋅ V)^α)
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return k_d * ndotL + k_s * pow(max(dot(norm, H), 0.0), alpha * 4.0);
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}
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return vec3(0.0);
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}
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