hello world

neo/idlib/math/Random.h

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+/*
+===========================================================================
+
+Doom 3 GPL Source Code
+Copyright (C) 1999-2011 id Software LLC, a ZeniMax Media company. 
+
+This file is part of the Doom 3 GPL Source Code (?Doom 3 Source Code?).  
+
+Doom 3 Source Code is free software: you can redistribute it and/or modify
+it under the terms of the GNU General Public License as published by
+the Free Software Foundation, either version 3 of the License, or
+(at your option) any later version.
+
+Doom 3 Source Code is distributed in the hope that it will be useful,
+but WITHOUT ANY WARRANTY; without even the implied warranty of
+MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+GNU General Public License for more details.
+
+You should have received a copy of the GNU General Public License
+along with Doom 3 Source Code.  If not, see <http://www.gnu.org/licenses/>.
+
+In addition, the Doom 3 Source Code is also subject to certain additional terms. You should have received a copy of these additional terms immediately following the terms and conditions of the GNU General Public License which accompanied the Doom 3 Source Code.  If not, please request a copy in writing from id Software at the address below.
+
+If you have questions concerning this license or the applicable additional terms, you may contact in writing id Software LLC, c/o ZeniMax Media Inc., Suite 120, Rockville, Maryland 20850 USA.
+
+===========================================================================
+*/
+
+#ifndef __MATH_RANDOM_H__
+#define __MATH_RANDOM_H__
+
+/*
+===============================================================================
+
+	Random number generator
+
+===============================================================================
+*/
+
+class idRandom {
+public:
+						idRandom( int seed = 0 );
+
+	void				SetSeed( int seed );
+	int					GetSeed( void ) const;
+
+	int					RandomInt( void );			// random integer in the range [0, MAX_RAND]
+	int					RandomInt( int max );		// random integer in the range [0, max[
+	float				RandomFloat( void );		// random number in the range [0.0f, 1.0f]
+	float				CRandomFloat( void );		// random number in the range [-1.0f, 1.0f]
+
+	static const int	MAX_RAND = 0x7fff;
+
+private:
+	int					seed;
+};
+
+ID_INLINE idRandom::idRandom( int seed ) {
+	this->seed = seed;
+}
+
+ID_INLINE void idRandom::SetSeed( int seed ) {
+	this->seed = seed;
+}
+
+ID_INLINE int idRandom::GetSeed( void ) const {
+	return seed;
+}
+
+ID_INLINE int idRandom::RandomInt( void ) {
+	seed = 69069 * seed + 1;
+	return ( seed & idRandom::MAX_RAND );
+}
+
+ID_INLINE int idRandom::RandomInt( int max ) {
+	if ( max == 0 ) {
+		return 0;			// avoid divide by zero error
+	}
+	return RandomInt() % max;
+}
+
+ID_INLINE float idRandom::RandomFloat( void ) {
+	return ( RandomInt() / ( float )( idRandom::MAX_RAND + 1 ) );
+}
+
+ID_INLINE float idRandom::CRandomFloat( void ) {
+	return ( 2.0f * ( RandomFloat() - 0.5f ) );
+}
+
+
+/*
+===============================================================================
+
+	Random number generator
+
+===============================================================================
+*/
+
+class idRandom2 {
+public:
+							idRandom2( unsigned long seed = 0 );
+
+	void					SetSeed( unsigned long seed );
+	unsigned long			GetSeed( void ) const;
+
+	int						RandomInt( void );			// random integer in the range [0, MAX_RAND]
+	int						RandomInt( int max );		// random integer in the range [0, max]
+	float					RandomFloat( void );		// random number in the range [0.0f, 1.0f]
+	float					CRandomFloat( void );		// random number in the range [-1.0f, 1.0f]
+
+	static const int		MAX_RAND = 0x7fff;
+
+private:
+	unsigned long			seed;
+
+	static const unsigned long	IEEE_ONE = 0x3f800000;
+	static const unsigned long	IEEE_MASK = 0x007fffff;
+};
+
+ID_INLINE idRandom2::idRandom2( unsigned long seed ) {
+	this->seed = seed;
+}
+
+ID_INLINE void idRandom2::SetSeed( unsigned long seed ) {
+	this->seed = seed;
+}
+
+ID_INLINE unsigned long idRandom2::GetSeed( void ) const {
+	return seed;
+}
+
+ID_INLINE int idRandom2::RandomInt( void ) {
+	seed = 1664525L * seed + 1013904223L;
+	return ( (int) seed & idRandom2::MAX_RAND );
+}
+
+ID_INLINE int idRandom2::RandomInt( int max ) {
+	if ( max == 0 ) {
+		return 0;		// avoid divide by zero error
+	}
+	return ( RandomInt() >> ( 16 - idMath::BitsForInteger( max ) ) ) % max;
+}
+
+ID_INLINE float idRandom2::RandomFloat( void ) {
+	unsigned long i;
+	seed = 1664525L * seed + 1013904223L;
+	i = idRandom2::IEEE_ONE | ( seed & idRandom2::IEEE_MASK );
+	return ( ( *(float *)&i ) - 1.0f );
+}
+
+ID_INLINE float idRandom2::CRandomFloat( void ) {
+	unsigned long i;
+	seed = 1664525L * seed + 1013904223L;
+	i = idRandom2::IEEE_ONE | ( seed & idRandom2::IEEE_MASK );
+	return ( 2.0f * ( *(float *)&i ) - 3.0f );
+}
+
+#endif /* !__MATH_RANDOM_H__ */