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#pragma once
#include <cstdint>
#include <Containers/ArrayView.h>
using namespace Death;
namespace nCine
{
/// Random number generator (PCG32)
class RandomGenerator
{
public:
/// Creates a new generator with default seeds
RandomGenerator() noexcept;
/// Creates a new generator with the specified seeds
RandomGenerator(std::uint64_t initState, std::uint64_t initSequence) noexcept;
/// Initializes the generator with the specified seeds
void Init(std::uint64_t initState, std::uint64_t initSequence) noexcept;
/// Generates a uniformly distributed 32-bit number
std::uint32_t Next() noexcept;
/// Generates a uniformly distributed 32-bit number, r, where min <= r < max
std::uint32_t Next(std::uint32_t min, std::uint32_t max) noexcept;
/// Generates a uniformly distributed float number, r, where 0 <= r < 1
float NextFloat() noexcept;
/// Generates a uniformly distributed float number, r, where min <= r < max
float NextFloat(float min, float max) noexcept;
/// Generates a uniformly distributed boolean
bool NextBool() noexcept;
/// Faster but less uniform version of @ref Next()
std::uint32_t Fast(std::uint32_t min, std::uint32_t max) noexcept;
/// Faster but less uniform version of @ref NextFloat()
float FastFloat() noexcept;
/// Faster but less uniform version of @ref NextFloat()
float FastFloat(float min, float max) noexcept;
/// Gnerates a 128-bit unique identifier
void Uuid(Containers::StaticArrayView<16, std::uint8_t> result);
/// Shuffles the specified array
template<class T>
void Shuffle(Containers::ArrayView<T> data) noexcept
{
for (std::size_t i = data.size() - 1; i > 0; --i) {
std::swap(data[i], data[Next(0, (std::uint32_t)i + 1)]);
}
}
private:
std::uint64_t _state;
std::uint64_t _increment;
};
/// Returns random number generator instance
extern RandomGenerator& Random() noexcept;
}
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