132 lines
3.2 KiB
C++
132 lines
3.2 KiB
C++
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#ifndef __MATH_RANDOM_H__
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#define __MATH_RANDOM_H__
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/*
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===============================================================================
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Random number generator
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===============================================================================
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*/
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class idRandom {
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public:
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idRandom( int seed = 0 );
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void SetSeed( int seed );
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int GetSeed( void ) const;
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int RandomInt( void ); // random integer in the range [0, MAX_RAND]
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int RandomInt( int max ); // random integer in the range [0, max[
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float RandomFloat( void ); // random number in the range [0.0f, 1.0f]
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float CRandomFloat( void ); // random number in the range [-1.0f, 1.0f]
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static const int MAX_RAND = 0x7fff;
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private:
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int seed;
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};
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ID_INLINE idRandom::idRandom( int seed ) {
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this->seed = seed;
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}
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ID_INLINE void idRandom::SetSeed( int seed ) {
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this->seed = seed;
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}
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ID_INLINE int idRandom::GetSeed( void ) const {
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return seed;
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}
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ID_INLINE int idRandom::RandomInt( void ) {
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seed = 69069 * seed + 1;
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return ( seed & idRandom::MAX_RAND );
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}
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ID_INLINE int idRandom::RandomInt( int max ) {
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if ( max == 0 ) {
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return 0; // avoid divide by zero error
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}
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return RandomInt() % max;
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}
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ID_INLINE float idRandom::RandomFloat( void ) {
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return ( RandomInt() / ( float )( idRandom::MAX_RAND + 1 ) );
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}
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ID_INLINE float idRandom::CRandomFloat( void ) {
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return ( 2.0f * ( RandomFloat() - 0.5f ) );
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}
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/*
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===============================================================================
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Random number generator
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===============================================================================
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*/
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class idRandom2 {
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public:
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idRandom2( unsigned long seed = 0 );
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void SetSeed( unsigned long seed );
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unsigned long GetSeed( void ) const;
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int RandomInt( void ); // random integer in the range [0, MAX_RAND]
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int RandomInt( int max ); // random integer in the range [0, max]
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float RandomFloat( void ); // random number in the range [0.0f, 1.0f]
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float CRandomFloat( void ); // random number in the range [-1.0f, 1.0f]
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static const int MAX_RAND = 0x7fff;
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private:
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unsigned long seed;
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static const unsigned long IEEE_ONE = 0x3f800000;
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static const unsigned long IEEE_MASK = 0x007fffff;
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};
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ID_INLINE idRandom2::idRandom2( unsigned long seed ) {
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this->seed = seed;
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}
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ID_INLINE void idRandom2::SetSeed( unsigned long seed ) {
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this->seed = seed;
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}
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ID_INLINE unsigned long idRandom2::GetSeed( void ) const {
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return seed;
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}
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ID_INLINE int idRandom2::RandomInt( void ) {
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seed = 1664525L * seed + 1013904223L;
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return ( (int) seed & idRandom2::MAX_RAND );
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}
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ID_INLINE int idRandom2::RandomInt( int max ) {
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if ( max == 0 ) {
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return 0; // avoid divide by zero error
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}
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return ( RandomInt() >> ( 16 - idMath::BitsForInteger( max ) ) ) % max;
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}
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ID_INLINE float idRandom2::RandomFloat( void ) {
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unsigned long i;
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seed = 1664525L * seed + 1013904223L;
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i = idRandom2::IEEE_ONE | ( seed & idRandom2::IEEE_MASK );
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return ( ( *(float *)&i ) - 1.0f );
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}
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ID_INLINE float idRandom2::CRandomFloat( void ) {
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unsigned long i;
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seed = 1664525L * seed + 1013904223L;
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i = idRandom2::IEEE_ONE | ( seed & idRandom2::IEEE_MASK );
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return ( 2.0f * ( *(float *)&i ) - 3.0f );
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}
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#endif /* !__MATH_RANDOM_H__ */
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