149 lines
3.3 KiB
C++
149 lines
3.3 KiB
C++
#ifndef VEC3_H
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#define VEC3_H
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#include <cmath>
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#include <iostream>
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#include "rtweekend.h"
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using std::sqrt;
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class vec3 {
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public:
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vec3() : e{0, 0, 0} {}
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vec3(double e0, double e1, double e2) : e{e0, e1, e2} {}
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double x() const { return e[0]; }
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double y() const { return e[1]; }
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double z() const { return e[2]; }
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vec3 operator-() const { return vec3(-e[0], -e[1], -e[2]); }
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double operator[](int i) const { return e[i]; }
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double& operator[](int i) { return e[i]; }
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vec3& operator+=(const vec3 &v) {
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e[0] += v.e[0];
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e[1] += v.e[1];
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e[2] += v.e[2];
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return *this;
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}
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vec3& operator*=(const double t) {
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e[0] *= t;
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e[1] *= t;
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e[2] *= t;
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return *this;
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}
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vec3& operator/=(const double t) {
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return *this *= 1/t;
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}
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double length() {
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return sqrt(length_squared());
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}
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double length_squared() {
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return e[0]*e[0] + e[1]*e[1] + e[2]*e[2];
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}
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inline static vec3 random() {
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return vec3(random_double(), random_double(), random_double());
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}
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inline static vec3 random(double min, double max) {
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return vec3(random_double(min, max), random_double(min, max), random_double(min, max));
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}
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bool near_zero() const {
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auto s = 1e-8;
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return fabs(e[0]) < s && fabs(e[1]) < s && fabs(e[2]) < s;
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}
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public:
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double e[3];
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};
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// Type aliases for vec3
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using point3 = vec3; // 3D point
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using color = vec3; // RGB color
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// vec3 utility functions
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inline std::ostream& operator<<(std::ostream& out, const vec3 &v) {
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return out<<v.e[0]<<" "<<v.e[1]<<" "<<v.e[2];
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}
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inline vec3 operator+(const vec3 &u, const vec3 &v) {
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return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
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}
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inline vec3 operator-(const vec3 &u, const vec3 &v) {
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return vec3(u.e[0] - v.e[0], u.e[1] - v.e[1], u.e[2] - v.e[2]);
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}
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inline vec3 operator*(const vec3 &u, const vec3 &v) {
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return vec3(u.e[0] * v.e[0], u.e[1] * v.e[1], u.e[2] * v.e[2]);
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}
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inline vec3 operator*(double t, const vec3 &v) {
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return vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
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}
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inline vec3 operator*(const vec3 &v, double t) {
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return t * v;
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}
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inline vec3 operator/(const vec3 &v, double t) {
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return (1/t) * v;
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}
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inline double dot(const vec3 &u, const vec3 &v) {
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return u.e[0] * v.e[0]
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+ u.e[1] * v.e[1]
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+ u.e[2] * v.e[2];
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}
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inline vec3 cross(const vec3 &u, const vec3 &v) {
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return vec3(u.e[1] * v.e[2] - u.e[2] * v.e[1],
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u.e[2] * v.e[0] - u.e[0] * v.e[2],
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u.e[0] * v.e[1] - u.e[1] * v.e[0]);
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}
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vec3 random_in_unit_sphere() {
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while(true) {
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auto p = vec3::random(-1, 1);
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if (p.length_squared() >= 1) continue;
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return p;
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}
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}
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inline vec3 unit_vector(vec3 v) {
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return v / v.length();
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}
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vec3 random_unit_vector() {
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return unit_vector(random_in_unit_sphere());
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}
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vec3 random_in_hemisphere(const vec3& normal) {
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vec3 in_unit_sphere = random_in_unit_sphere();
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if (dot(in_unit_sphere, normal) > 0.0) // In thesame hemisphere as the normal
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return in_unit_sphere;
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else
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return -in_unit_sphere;
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}
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vec3 reflect(const vec3& v, const vec3& n) {
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return v - 2*dot(v,n)*n;
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}
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vec3 refract(const vec3& uv, const vec3& n, double etai_over_etat) {
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auto cos_theta = fmin(dot(-uv, n), 1.0);
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vec3 r_out_perp = etai_over_etat * (uv + cos_theta*n);
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vec3 r_out_parrallel = -sqrt(fabs(1.0 - r_out_perp.length_squared())) * n;
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return r_out_perp + r_out_parrallel;
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}
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#endif
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