52 lines
1.8 KiB
C++
52 lines
1.8 KiB
C++
#include "light/light.h"
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#include "scene/scene.h"
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#include "shader/cooktorranceshader.h"
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CookTorranceShader::CookTorranceShader(Color const &diffCol, Color const &ctCol, float IOR, float roughness,
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float diffCoeff, float ctCoeff) : diffuseColor(diffCol * diffCoeff),
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ctColor(ctCol * ctCoeff), F0(IOR),
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m(roughness) {}
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Color CookTorranceShader::shade(Scene const &scene, Ray const &ray) const {
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Color fragmentColor;
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// IMPLEMENT ME
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for (auto &light: scene.lights()) {
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auto illum = light->illuminate(scene, ray);
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auto N = ray.normal;
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auto V = ray.direction;
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auto L = illum.direction;
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auto H = normalized(V + L);
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auto NV = dotProduct(N, V);
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auto NL = dotProduct(N, L);
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auto NH = dotProduct(N, H);
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auto VH = dotProduct(V, H);
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float rhoD = 1.0f / PI;
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auto rhoS = F(VH) * D(NH) * G(NH, NV, VH, NL) / (4 * NV * NL);
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auto rhoPD = diffuseColor * rhoD + ctColor * rhoS;
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fragmentColor += illum.color * std::abs(NL) * rhoPD;
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}
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return diffuseColor * fragmentColor;
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}
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float CookTorranceShader::D(float NdotH) const {
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float divisor = 4.0f * m * m * std::pow(NdotH, 4.0f);
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float exponent = (NdotH * NdotH - 1.0f) / (m * m * NdotH * NdotH);
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return 1 / divisor * std::exp(exponent);
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}
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float CookTorranceShader::F(float VdotH) const {
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return F0 + (1.0f - F0) * std::pow(1.0f - VdotH, 5.0f);
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}
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float CookTorranceShader::G(float NdotH, float NdotV, float VdotH, float NdotL) const {
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return std::min(1.0f, std::min(2 * NdotH * NdotV / VdotH, 2 * NdotH * NdotL / VdotH));
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}
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