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
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
|
#include "object.hpp"
#include <math.h>
#include <iostream>
#include "common.hpp"
void Color::clamp() {
if (m_x > 1) { m_x = 1; }
if (m_y > 1) { m_y = 1; }
if (m_z > 1) { m_z = 1; }
}
Material::Material(Color color, double defuse, double spectral, double spectral_pow, double emissive) {
m_color = color;
m_defuse = defuse;
m_emissive = emissive;
m_spectral = spectral;
m_spectral_pow = spectral_pow;
}
Color Material::reflect(const Vec3d &normal, const Vec3d &in, const Vec3d &out, const Color &incol) const {
// Emissive
Color c = Vec3d(m_color) * m_emissive;
// Defuse
c += (Vec3d(m_color) * Vec3d(incol)) * (in.dot(normal) * m_defuse);
// Spectral
if (m_spectral > 0) {
auto R = normal * (2 * normal.dot(in)) - in;
c += Vec3d(incol) * pow(out.dot(R) * m_spectral, m_spectral_pow);
}
return c;
}
Sphere::Sphere(const Material &mat, Vec3d center, double radius) : Shape(mat) {
m_center = center;
m_radius = radius;
}
Plane::Plane(const Material &mat, Vec3d start, Vec3d norm) : Shape(mat) {
m_start = start;
m_norm = norm;
m_norm.normalize();
}
Vec3d Sphere::norm_at(const Vec3d &point, const Vec3d&) const {
auto res = point - m_center;
res.normalize();
return res;
}
// https://www.scratchapixel.com/lessons/3d-basic-rendering/minimal-ray-tracer-rendering-simple-shapes/ray-sphere-intersection
double Sphere::intersect(const Ray &ray, bool skip_dist) const {
// Calculate O - C used multiple places
auto oc = ray.m_start - m_center;
// Calculate components of quadratic formula
// a = 1 when ray.direction is a unit vector
auto a = 1;
auto b = 2 * ray.m_direction.dot(oc);
auto c = oc.dot(oc) - m_radius * m_radius;
// Solve quadratic function
auto discr = b * b - 4 * a * c;
if (discr < 0) {
// No solution
return -1;
}
if (skip_dist) {
// Do not calculate distance
return 1;
}
auto q = (b > 0) ?
-0.5 * (b + sqrt(discr)):
-0.5 * (b - sqrt(discr));
auto t1 = q; // Assuming a = 1
auto t0 = c / q;
// Find correct result
if (t0 <= ZERO_APPROX) {
t0 = t1;
}
if (t0 <= ZERO_APPROX) {
return -1;
}
return t0;
}
Vec3d Plane::norm_at(const Vec3d&, const Vec3d &indir) const {
auto scale = m_norm.dot(indir);
return scale > 0 ? -m_norm : m_norm;
}
// https://www.scratchapixel.com/lessons/3d-basic-rendering/minimal-ray-tracer-rendering-simple-shapes/ray-plane-and-ray-disk-intersection
// Requires that vectors are normalized
// Skip dist is ignored as distance must be calculated
double Plane::intersect(const Ray &ray, bool) const {
// If ray is parallel
auto nr = m_norm.dot(ray.m_direction);
if (abs(nr) < ZERO_APPROX) {
return -1;
}
// Calculate distance
auto dist = m_norm.dot(m_start - ray.m_start) / nr;
if (dist < 0) {
return -1;
}
return dist;
}
|
