Sending rays into the scene

This commit is contained in:
Armin Friedl 2022-07-16 13:47:16 +02:00
parent 2e712043ec
commit a12fcfbe7b
5 changed files with 183 additions and 2 deletions

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@ -3,4 +3,4 @@ project(rtiww)
set(CMAKE_CXX_STANDARD 17) set(CMAKE_CXX_STANDARD 17)
add_executable(rtiww src/main.cpp) add_executable(rtiww src/main.cpp src/vec3.h src/color.h src/ray.h)

14
rtiww/src/color.h Normal file
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@ -0,0 +1,14 @@
#ifndef RTIWW_COLOR_H
#define RTIWW_COLOR_H
#include "vec3.h"
#include <iostream>
void write_color(std::ostream &out, color pixel_color) {
out << static_cast<int>(255.999 * pixel_color.x()) << ' '
<< static_cast<int>(255.999 * pixel_color.y()) << ' '
<< static_cast<int>(255.999 * pixel_color.z()) << '\n';
}
#endif //RTIWW_COLOR_H

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@ -1,6 +1,48 @@
#include "color.h"
#include "vec3.h"
#include "ray.h"
#include <iostream> #include <iostream>
color ray_color(const ray& r) {
vec3 unit_direction = unit_vector(r.direction());
auto t = 0.5 * (unit_direction.y() + 1.0);
return (1.0-t)*color(1.0, 1.0, 1.0) + t*color(0.5, 0.7, 1.0);
}
int main() { int main() {
std::cout << "Hello, World!" << std::endl;
// Image
const auto aspect_ratio = 16.0/9.0;
const int image_width = 400;
const int image_height = static_cast<int>(image_width / aspect_ratio);
// Camera
auto viewport_height = 2.0;
auto viewport_width = aspect_ratio*viewport_height;
auto focal_length = 1.0;
auto origin = point3(0, 0, 0);
auto horizontal = vec3(viewport_width, 0, 0);
auto vertical = vec3(0, viewport_height, 0);
auto lower_left_corner = origin - horizontal/2 - vertical/2 - vec3(0, 0, focal_length);
// Render
std::cout << "P3\n" << image_width << ' ' << image_height << "\n255\n";
for (int j = image_height - 1; j >= 0; --j) {
std::cerr << "\rScanlines remaining: " << j << ' ' << std::flush;
for (int i = 0; i < image_width; ++i) {
auto u = double(i)/(image_width-1);
auto v = double(j) / (image_height-1);
ray r(origin, lower_left_corner + u*horizontal + v*vertical - origin);
color pixel_color = ray_color(r);
write_color(std::cout, pixel_color);
}
}
std::cerr << "\nDone.\n";
return 0; return 0;
} }

24
rtiww/src/ray.h Normal file
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@ -0,0 +1,24 @@
#ifndef RTIWW_RAY_H
#define RTIWW_RAY_H
#include "vec3.h"
class ray {
public:
ray() {}
ray(const point3 &origin, const vec3 &direction) : orig(origin), dir(direction) {}
point3 origin() const { return orig; }
vec3 direction() const { return dir; }
point3 at(double t) const {
return orig + t*dir;
}
public:
point3 orig;
vec3 dir;
};
#endif //RTIWW_RAY_H

101
rtiww/src/vec3.h Normal file
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#ifndef RTIWW_VEC3_H
#define RTIWW_VEC3_H
#include <cmath>
#include <ostream>
class vec3 {
public:
vec3() : e{0, 0, 0} {}
vec3(double e0, double e1, double e2) : e{e0, e1, e2} {}
double x() const { return e[0]; }
double y() const { return e[1]; }
double z() const { return e[2]; }
vec3 operator-() const {return vec3(-e[0], -e[1], -e[2]);}
double operator[](int i) const { return e[i]; }
double& operator[](int i) {return e[i];}
vec3& operator+=(const vec3 &v) {
e[0] += v.e[0];
e[1] += v.e[1];
e[2] += v.e[2];
return *this;
}
vec3& operator*=(const double t) {
e[0] *= t;
e[1] *= t;
e[2] *= t;
return *this;
}
vec3& operator/=(const double t) {
return *this *= 1/t;
}
double length() const {
return sqrt(length_squared());
}
double length_squared() const {
return e[0]*e[0] + e[1]*e[1] + e[2]*e[2];
}
public:
double e[3];
};
using point3 = vec3;
using color = vec3;
inline std::ostream& operator<<(std::ostream &out, const vec3 &v) {
return out << v.e[0] << ' ' << v.e[1] << ' ' << v.e[2];
}
inline vec3 operator+(const vec3 &u, const vec3 &v) {
return vec3(u.e[0] + v.e[0], u.e[1] + v.e[1], u.e[2] + v.e[2]);
}
inline vec3 operator-(const vec3 &u, const vec3 &v) {
return vec3(u.e[0] - v.e[0], u.e[1] - v.e[1], u.e[2] + v.e[2]);
}
inline vec3 operator*(const vec3 &u, const vec3 &v) {
return vec3(u.e[0] * v.e[0], u.e[1] * v.e[1], u.e[2] * v.e[2]);
}
inline vec3 operator*(double t, const vec3 &v) {
return vec3(t*v.e[0], t*v.e[1], t*v.e[2]);
}
inline vec3 operator*(const vec3 &v, double t) {
return t*v;
}
inline vec3 operator/(vec3 v, double t) {
return (1/t) * v;
}
inline double dot(const vec3 &u, const vec3 &v) {
return u.e[0] * v.e[0]
+ u.e[1] * v.e[1]
+ u.e[2] * v.e[2];
}
inline vec3 cross(const vec3 &u, const vec3 &v) {
return vec3(u.e[1] * v.e[2] - u.e[2] * v.e[1],
u.e[2] * v.e[0] - u.e[0] * v.e[2],
u.e[0] * v.e[1] - u.e[1] * v.e[0]);
}
inline vec3 unit_vector(vec3 v) {
return v / v.length();
}
#endif //RTIWW_VEC3_H