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