st-random.h

Go to the documentation of this file.

#pragma once
 
namespace StyyxUtil
{
 
struct RandomiserUtil
{
    static int GetRandomInt(const int a_min, const int a_max)
    {
        std::uniform_int_distribution<int> distrib(a_min, a_max);
        return distrib(GetRNG());
    }

    static float GetRandomFloat(const float a_min, const float a_max)
    {
        std::uniform_real_distribution<float> distrib(a_min, a_max);
        return distrib(GetRNG());
    }

    static float GetRandomRoundedFloat(const float a_min, const float a_max, const int decimals = 2)
    {
        const auto value    = GetRandomFloat(a_min, a_max);
        const double factor = std::pow(10.0, static_cast<double>(decimals));
        return static_cast<float>(std::round(value * factor) / factor);
    }

    static double GetRandomDouble(const double a_min, const double a_max)
    {
        std::uniform_real_distribution<double> distrib(a_min, a_max);
        return distrib(GetRNG());
    }

    static bool GetRandomBool()
    {
        std::bernoulli_distribution distrib(0.5);
        return distrib(GetRNG());
    }

    static bool GetWeightedRandomBool(const float p = 0.5)
    {
        std::bernoulli_distribution distrib(p);
        return distrib(GetRNG());
    }

    static bool IsPercentageChanceFloat(const float a_chancePercent)
    {
        const auto chance = std::clamp(a_chancePercent, 0.0f, 100.0f);
 
        if (chance <= 0.0f)
            return false;
        if (chance >= 100.0f)
            return true;
        return GetRandomFloat(0.0, 100.0) <= a_chancePercent;
    }
 
  private:
    static std::mt19937& GetRNG()
    {
        static std::mt19937 gen(std::random_device{}());
        return gen;
    }
};
} // namespace StyyxUtil