feat: initial commit

.gitignore

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+main

README.md

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+# Ray Tracing in One Weekend
+
+## Quickstart
+
+```shell
+make
+./main > image.ppm
+sxiv image.ppm
+```
+
+## Resources
+* ["Ray Tracing in One Weekend" book](https://raytracing.github.io/books/RayTracingInOneWeekend.html)

color.h

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+#ifndef COLOR_H
+#define COLOR_H
+
+#include "vec3.h"
+
+#include <iostream>
+
+void write_color(std::ostream &out, color pixel_color) {
+	// Write the translated [0,255] value of each color component
+	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

main.cc

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+#include "color.h"
+#include "vec3.h"
+
+#include <iostream>
+
+int main() {
+	// Image
+	const int image_width = 256;
+	const int image_height = 256;
+
+	// 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) {
+			color pixel_color(double(i) / (image_width-1), double(j) / (image_height-1), 0.25);
+
+			write_color(std::cout, pixel_color);
+		}
+	}
+	std::cerr<<"\nDone.\n";
+}

makefile

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+CXX = g++
+
+.PHONY: default
+default: main;
+
+%: %.cpp
+	$(CXX) -o $@ $<

vec3.h

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+#ifndef VEC3_H
+#define VEC3_H
+
+#include <cmath>
+#include <iostream>
+
+using std::sqrt;
+
+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() {
+			return sqrt(length_squared());
+		}
+
+		double length_squared() {
+			return e[0]*e[0] + e[1]*e[1] + e[2]*e[2];
+		}
+
+	public:
+		double e[3];
+};
+
+// Type aliases for vec3
+using point3 = vec3;  // 3D point
+using color = vec3;   // RGB color
+
+
+// vec3 utility functions
+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/(const 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