Initial commit.

.gitignore

@@ -0,0 +1,3 @@
+*.o
+wtracer
+image.ppm

Makefile

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+CXX = g++
+
+CXXFLAGS  = -Wall -Wextra -O2 -std=c++14
+
+DEPS = vec3.h color.h
+OBJ = wtracer.o
+
+TARGET = wtracer
+
+all: $(TARGET) run
+
+run:
+	./wtracer > image.ppm
+	eog image.ppm
+
+%.o: %.cpp $(DEPS)
+	$(CXX) $(CXXFLAGS) -c -o $@ $<
+
+$(TARGET): $(OBJ)
+	$(CXX) $(CXXFLAGS) -o $@ $^
+
+clean:
+	$(RM) $(TARGET) $(OBJ) image.ppm
+

color.h

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+#ifndef COLOR_H
+#define COLOR_H
+
+#include <iostream>
+
+#include "vec3.h"
+
+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 // COLOR_H

vec3.h

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+#ifndef VEC3_H
+#define VEC3_H
+
+#include <cmath>
+#include <iostream>
+
+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 std::sqrt(length_squared()); }
+
+    double length_squared() const {
+        return e[0] * e[0] + e[1] * e[1] + e[2] * e[2];
+    }
+
+   private:
+    double e[3];
+    
+    friend std::ostream& operator<<(std::ostream&, const Vec3&);
+    friend Vec3 operator+(const Vec3&, const Vec3&);
+    friend Vec3 operator-(const Vec3&, const Vec3&);
+    friend Vec3 operator*(const Vec3&, const Vec3&);
+    friend Vec3 operator*(double, const Vec3&);
+    friend Vec3 operator*(const Vec3&, double);
+    friend Vec3 operator/(const Vec3&, double);
+    friend double dot(const Vec3&, const Vec3&);
+    friend Vec3 cross(const Vec3&, const Vec3&);
+    friend Vec3 unit_vector(const Vec3);
+};
+
+using Point3 = Vec3;
+using Color = Vec3;
+
+// 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 Vec3(t * v.e[0], t * v.e[1], t * v.e[2]);
+}
+
+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[1];
+}
+
+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  // VEC3_H

wtracer.cpp

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+#include <iostream>
+
+#include "color.h"
+#include "vec3.h"
+
+int main() {
+    const int image_width = 256;
+    const int image_height = 256;
+
+    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";
+}