random.hpp

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#pragma once

 
#include <cstdint>
#include <limits>
#include <random>
 
#include "orrery/core/types.hpp"
#include "orrery/core/vec3.hpp"
 
namespace orrery::core {

class RandomSource {
public:
    explicit RandomSource(std::uint64_t seed) noexcept;

    [[nodiscard]] std::uint64_t seed() const noexcept { return seed_; }

    [[nodiscard]] Real uniform() noexcept;

    [[nodiscard]] Real uniform(Real low, Real high) noexcept;

    [[nodiscard]] Vec3 unit_vector() noexcept;
 
private:
    static constexpr int kMantissaBits = std::numeric_limits<Real>::digits;

    static constexpr Real kScale = Real{1} / static_cast<Real>(std::uint64_t{1} << kMantissaBits);
 
    std::uint64_t seed_;
    std::mt19937_64 engine_;
};
 
} // namespace orrery::core