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Schlick reflection

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This commit is contained in:
Armin Friedl 2022-07-30 18:58:41 +02:00
parent 7ca342d5a4
commit 0a0080ce80
1 changed files with 22 additions and 13 deletions
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11
rtiww/src/material.h
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@ -67,7 +67,8 @@ public:
bool cannot_refract = refraction_ratio * sin_theta > 1.0; bool cannot_refract = refraction_ratio * sin_theta > 1.0;
vec3 direction; vec3 direction;
if (cannot_refract) if (cannot_refract ||
reflectance(cos_theta, refraction_ratio) > random_double())
direction = reflect(unit_direction, rec.normal); direction = reflect(unit_direction, rec.normal);
else else
direction = refract(unit_direction, rec.normal, refraction_ratio); direction = refract(unit_direction, rec.normal, refraction_ratio);
@ -78,6 +79,14 @@ public:
public: public:
double ir; double ir;
private:
static double reflectance(double cosine, double ref_idx) {
// Use Schlick's approximation for reflectance
auto r0 = (1 - ref_idx) / (1 + ref_idx);
r0 = r0 * r0;
return r0 + (1 - r0) * pow((1 - cosine), 5);
}
}; };
#endif // MATERIAL_H_ #endif // MATERIAL_H_