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Basic functional raytracer

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David 2021-08-23 00:37:57 +02:00
commit c37be6798f
5 changed files with 159 additions and 33 deletions
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43
material.hpp
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@ -54,4 +54,47 @@ struct metal : material {
}
};
struct dielectric : material
{
/* Attributes */
double ri; // refraction index
// Constructor
dielectric(double refraction_index) { ri = refraction_index; }
/* Methods */
// Schlick's approximation of reflectance
static double reflectance(double cosine, double ref_idx)
{
double r0 = (1-ref_idx) / (1+ref_idx);
r0 = r0*r0;
return r0 + (1-r0)*pow((1 - cosine), 5);
}
/* Virtual methods */
virtual bool scatter(const ray& r_in, const hit_record& rec, color& attenuation, ray& scattered) const override
{
attenuation = color(1,1,1);
double refraction_ratio = rec.front_face ? (1.0/ri) : ri;
vec3 unit_direction = normalize(r_in.direction);
double cos_theta = fmin(dot(-unit_direction, rec.normal), 1);
double sin_theta = sqrt(1.0 - cos_theta*cos_theta);
bool cannot_refract = refraction_ratio * sin_theta > 1.0;
vec3 direction;
if (cannot_refract || reflectance(cos_theta, refraction_ratio) > random_double())
direction = reflect(unit_direction, rec.normal);
else
direction = refract(unit_direction, rec.normal, refraction_ratio);
scattered = ray(rec.p, direction);
return true;
}
};
#endif