148 lines
3.6 KiB
C++
148 lines
3.6 KiB
C++
#pragma once
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#include <cmath>
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#include <iostream>
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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() const {
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return sqrt(length_squared());
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}
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double length_squared() const {
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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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const 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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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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// Utitility 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/(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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inline vec3 unit_vector(vec3 v){
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return v / v.length();
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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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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 the same 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_parallel = -sqrt(fabs(1.0 - r_out_perp.length_squared())) * n;
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return r_out_perp + r_out_parallel;
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}
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vec3 random_in_unit_disk(){
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while(true){
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auto p = vec3(random_double(-1,1) , random_double(-1,1), 0);
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if(p.length_squared() >= 1) continue;
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return p;
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}
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} |