ray-tracer/src/colour.h

#pragma once

#include <cassert>
#include <iomanip>
#include <ios>
#include <ostream>

#include "util.h"

class Colour {
   public:
    static const Colour kBlack;
    static const Colour kWhite;

    constexpr Colour() = default;
    constexpr Colour(double r, double g, double b) : r_{r}, g_{g}, b_{b} {
        assert(0.0 <= r && r <= 1.0);
        assert(0.0 <= g && g <= 1.0);
        assert(0.0 <= b && b <= 1.0);
    }

    constexpr double& r() { return r_; }
    constexpr double& g() { return g_; }
    constexpr double& b() { return b_; }

    constexpr double r() const { return r_; }
    constexpr double g() const { return g_; }
    constexpr double b() const { return b_; }

   private:
    double r_;
    double g_;
    double b_;
};

constexpr Colour Colour::kBlack{0.0, 0.0, 0.0};

constexpr Colour operator*(double t, Colour col) {
    return {t * col.r(), t * col.g(), t * col.b()};
}

constexpr Colour operator+(Colour c1, Colour c2) {
    return {c1.r() + c2.r(), c1.g() + c2.g(), c1.b() + c2.b()};
}

inline std::ostream& operator<<(std::ostream& out, Colour colour) {
    out << '#';

    out << std::hex << std::setfill('0') << std::setw(2) << FToU8(colour.r());
    out << std::hex << std::setfill('0') << std::setw(2) << FToU8(colour.g());
    out << std::hex << std::setfill('0') << std::setw(2) << FToU8(colour.b());

    return out;
}