3DRenderer/Material.cpp at master · yel0h/3DRenderer · GitHub

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
#include "Material.h"

bool Lambertian::scatter(const Ray &rIn, const HitRecord &rec, Vec3f &attenuation, Ray &scattered) const
{
    Vec3f scatterDirection = rec.normal + Vec3f::randomUnitVector();
    if (scatterDirection.nearZero())
    {
        scatterDirection = rec.normal;
    }

    scattered = {rec.p, scatterDirection};
    attenuation = albedo;
    return true;
}

bool Metal::scatter(const Ray &rIn, const HitRecord &rec, Vec3f &attenuation, Ray &scattered) const
{
    Vec3f reflected = rIn.dir.reflect(rec.normal);
    reflected = reflected.unitVector() + (fuzz * Vec3f::randomUnitVector());
    scattered = {rec.p, reflected};
    attenuation = albedo;
    return (scattered.dir.dot(rec.normal) > 0);
}

bool Dielectric::scatter(const Ray &rIn, const HitRecord &rec, Vec3f &attenuation, Ray &scattered) const
{
    attenuation = {1.0, 1.0, 1.0};
    float ri = rec.frontFace ? (1.0f / refractionIndex) : refractionIndex;
    Vec3f unitDirection = rIn.dir.unitVector();
    double cosTheta = std::fmin(-unitDirection.dot(rec.normal), 1.0);
    double sinTheta = std::sqrt(1.0 - (cosTheta * cosTheta));
    bool cannotRefract = ri * sinTheta > 1.0;
    Vec3f direction;
    if (cannotRefract || reflectance(cosTheta, ri) > randomFloat())
    {
        direction = unitDirection.reflect(rec.normal);
    }
    else
    {
        direction = unitDirection.refract(rec.normal, ri);
    }

    scattered = {rec.p, direction};
    return true;
}

double Dielectric::reflectance(double cosine, double refractionIndex)
{
    double r0 = (1 - refractionIndex) / (1 + refractionIndex);
    r0 *= r0;
    return r0 + ((1 - r0) * std::pow((1 - cosine),5));
}