112 lines
3.6 KiB
C++
112 lines
3.6 KiB
C++
//===== Copyright (c) 1996-2005, Valve Corporation, All rights reserved. ======//
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//
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// Purpose: Random number generator
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//
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// $Workfile: $
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// $NoKeywords: $
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//===========================================================================//
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#ifndef VSTDLIB_RANDOM_H
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#define VSTDLIB_RANDOM_H
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#include "vstdlib/vstdlib.h"
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#include "tier0/basetypes.h"
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#include "tier0/threadtools.h"
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#include "tier1/interface.h"
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#define NTAB 32
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#pragma warning(push)
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#pragma warning( disable:4251 )
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//-----------------------------------------------------------------------------
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// A generator of uniformly distributed random numbers
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//-----------------------------------------------------------------------------
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class IUniformRandomStream
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{
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public:
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// Sets the seed of the random number generator
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virtual void SetSeed( int iSeed ) = 0;
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// Generates random numbers
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virtual float RandomFloat( float flMinVal = 0.0f, float flMaxVal = 1.0f ) = 0;
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virtual int RandomInt( int iMinVal, int iMaxVal ) = 0;
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virtual float RandomFloatExp( float flMinVal = 0.0f, float flMaxVal = 1.0f, float flExponent = 1.0f ) = 0;
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};
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//-----------------------------------------------------------------------------
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// The standard generator of uniformly distributed random numbers
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//-----------------------------------------------------------------------------
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class VSTDLIB_CLASS CUniformRandomStream : public IUniformRandomStream
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{
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public:
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CUniformRandomStream();
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// Sets the seed of the random number generator
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virtual void SetSeed( int iSeed );
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// Generates random numbers
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virtual float RandomFloat( float flMinVal = 0.0f, float flMaxVal = 1.0f );
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virtual int RandomInt( int iMinVal, int iMaxVal );
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virtual float RandomFloatExp( float flMinVal = 0.0f, float flMaxVal = 1.0f, float flExponent = 1.0f );
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private:
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int GenerateRandomNumber();
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int m_idum;
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int m_iy;
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int m_iv[NTAB];
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CThreadFastMutex m_mutex;
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};
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//-----------------------------------------------------------------------------
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// A generator of gaussian distributed random numbers
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//-----------------------------------------------------------------------------
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class VSTDLIB_CLASS CGaussianRandomStream
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{
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public:
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// Passing in NULL will cause the gaussian stream to use the
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// installed global random number generator
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CGaussianRandomStream( IUniformRandomStream *pUniformStream = NULL );
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// Attaches to a random uniform stream
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void AttachToStream( IUniformRandomStream *pUniformStream = NULL );
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// Generates random numbers
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float RandomFloat( float flMean = 0.0f, float flStdDev = 1.0f );
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private:
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IUniformRandomStream *m_pUniformStream;
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bool m_bHaveValue;
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float m_flRandomValue;
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CThreadFastMutex m_mutex;
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};
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//-----------------------------------------------------------------------------
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// A couple of convenience functions to access the library's global uniform stream
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//-----------------------------------------------------------------------------
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VSTDLIB_INTERFACE void RandomSeed( int iSeed );
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VSTDLIB_INTERFACE float RandomFloat( float flMinVal = 0.0f, float flMaxVal = 1.0f );
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VSTDLIB_INTERFACE float RandomFloatExp( float flMinVal = 0.0f, float flMaxVal = 1.0f, float flExponent = 1.0f );
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VSTDLIB_INTERFACE int RandomInt( int iMinVal, int iMaxVal );
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VSTDLIB_INTERFACE float RandomGaussianFloat( float flMean = 0.0f, float flStdDev = 1.0f );
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//-----------------------------------------------------------------------------
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// Installs a global random number generator, which will affect the Random functions above
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//-----------------------------------------------------------------------------
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VSTDLIB_INTERFACE void InstallUniformRandomStream( IUniformRandomStream *pStream );
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#pragma warning(pop)
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#endif // VSTDLIB_RANDOM_H
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