mirror of
https://github.com/love2d/love.git
synced 2026-08-16 08:11:02 +02:00
Alex Szpakowski
152 lines
3.2 KiB
C++
152 lines
3.2 KiB
C++
/**
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* Copyright (c) 2006-2013 LOVE Development Team
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*
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* This software is provided 'as-is', without any express or implied
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* warranty. In no event will the authors be held liable for any damages
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* arising from the use of this software.
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*
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* Permission is granted to anyone to use this software for any purpose,
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* including commercial applications, and to alter it and redistribute it
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* freely, subject to the following restrictions:
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*
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* 1. The origin of this software must not be misrepresented; you must not
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* claim that you wrote the original software. If you use this software
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* in a product, an acknowledgment in the product documentation would be
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* appreciated but is not required.
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* 2. Altered source versions must be plainly marked as such, and must not be
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* misrepresented as being the original software.
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* 3. This notice may not be removed or altered from any source distribution.
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**/
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#ifndef LOVE_MATH_RANDOM_GENERATOR_H
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#define LOVE_MATH_RANDOM_GENERATOR_H
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// LOVE
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#include "common/config.h"
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#include "common/Exception.h"
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#include "common/math.h"
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#include "common/int.h"
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#include "common/Object.h"
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// STL
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#include <limits>
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namespace love
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{
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namespace math
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{
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class RandomGenerator : public Object
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{
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public:
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union State
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{
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uint64 b64;
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struct
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{
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uint32 a;
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uint32 b;
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} b32;
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};
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RandomGenerator();
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virtual ~RandomGenerator() {}
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/**
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* Set pseudo-random state.
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* It's up to the implementation how to use this.
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**/
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void setState(State state);
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/**
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* Separately set the low and high parts of the pseudo-random state.
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**/
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inline void setState(uint32 low, uint32 high)
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{
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State newstate;
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#ifdef LOVE_BIG_ENDIAN
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newstate.b32.a = high;
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newstate.b32.b = low;
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#else
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newstate.b32.b = high;
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newstate.b32.a = low;
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#endif
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setState(newstate);
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}
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inline State getState() const
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{
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return rng_state;
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}
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inline void getState(uint32 &low, uint32 &high) const
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{
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#ifdef LOVE_BIG_ENDIAN
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high = rng_state.b32.a;
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low = rng_state.b32.b;
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#else
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high = rng_state.b32.b;
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low = rng_state.b32.a;
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#endif
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}
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/**
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* Return uniformly distributed pseudo random integer.
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*
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* @return Pseudo random integer in [0,2^64).
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**/
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uint64 rand();
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/**
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* Get uniformly distributed pseudo random number in [0,1).
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*
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* @return Pseudo random number in [0,1).
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**/
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inline double random()
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{
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return double(rand()) / (double(std::numeric_limits<uint64>::max()) + 1.0);
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}
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/**
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* Get uniformly distributed pseudo random number in [0,max).
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*
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* @return Pseudo random number in [0,max).
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**/
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inline double random(double max)
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{
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return random() * max;
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}
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/**
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* Get uniformly distributed pseudo random number in [min, max).
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*
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* @return Pseudo random number in [min, max).
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**/
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inline double random(double min, double max)
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{
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return random() * (max - min) + min;
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}
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/**
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* Get normally distributed pseudo random number.
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*
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* @param stddev Standard deviation of the distribution.
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* @return Normally distributed random number with mean 0 and variance (stddev)².
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**/
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double randomNormal(double stddev);
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private:
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State rng_state;
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double last_randomnormal;
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}; // RandomGenerator
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} // math
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} // love
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#endif // LOVE_MATH_RANDOM_GENERATOR_H
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