Random.h

/*
 * Gamedev Framework (gf)
 * Copyright (C) 2016-2022 Julien Bernard
 *
 * This software is provided 'as-is', without any express or implied
 * warranty.  In no event will the authors be held liable for any damages
 * arising from the use of this software.
 *
 * Permission is granted to anyone to use this software for any purpose,
 * including commercial applications, and to alter it and redistribute it
 * freely, subject to the following restrictions:
 *
 * 1. The origin of this software must not be misrepresented; you must not
 *    claim that you wrote the original software. If you use this software
 *    in a product, an acknowledgment in the product documentation would be
 *    appreciated but is not required.
 * 2. Altered source versions must be plainly marked as such, and must not be
 *    misrepresented as being the original software.
 * 3. This notice may not be removed or altered from any source distribution.
 */
#ifndef GF_RANDOM_H
#define GF_RANDOM_H
 
#include <cstdint>
#include <limits>
#include <random>
 
#include "Circ.h"
#include "CoreApi.h"
#include "Id.h"
#include "Rect.h"
#include "Vector.h"
 
namespace gf {
#ifndef DOXYGEN_SHOULD_SKIP_THIS
inline namespace v1 {
#endif
 
  class GF_CORE_API RandomEngine {
  public:
    using result_type = uint64_t;
 
    RandomEngine();
 
    RandomEngine(result_type seed);
 
    static constexpr result_type min() {
      return std::numeric_limits<result_type>::min();
    }
 
    static constexpr result_type max() {
      return std::numeric_limits<result_type>::max();
    }
 
    result_type operator()();
 
    void shortJump();
    void longJump();
 
  private:
    uint64_t next();
 
  private:
    uint64_t m_state[4];
  };
 
  class GF_CORE_API Random {
  public:
    Random();
 
    Random(uint64_t seed)
    : m_engine(seed)
    {
 
    }
 
    template<typename T>
    T computeUniformInteger(T min, T max) {
      std::uniform_int_distribution<T> dist(min, max);
      return dist(m_engine);
    }
 
    template<typename T>
    T computeUniformFloat(T min, T max) {
      std::uniform_real_distribution<T> dist(min, max);
      return dist(m_engine);
    }
 
    template<typename T>
    T computeNormalFloat(T mean, T stddev) {
      std::normal_distribution<T> dist(mean, stddev);
      return dist(m_engine);
    }
 
    bool computeBernoulli(double p) {
      std::bernoulli_distribution dist(p);
      return dist(m_engine);
    }
 
    Vector2f computePosition(const RectF& area);
 
    Vector2i computePosition(const RectI& area);
 
    Vector2f computePosition(const CircF& area);
 
    float computeRadius(float radiusMin, float radiusMax);
 
    float computeAngle();
 
    gf::Id computeId();
 
    RandomEngine& getEngine() {
      return m_engine;
    }
 
  private:
    RandomEngine m_engine;
  };
 
#ifndef DOXYGEN_SHOULD_SKIP_THIS
}
#endif
}
 
#endif // GF_RANDOM_H