historical/toontown-classic.git/panda/include/randomizer.I
2024-01-16 11:20:27 -06:00

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/**
* PANDA 3D SOFTWARE
* Copyright (c) Carnegie Mellon University. All rights reserved.
*
* All use of this software is subject to the terms of the revised BSD
* license. You should have received a copy of this license along
* with this source code in a file named "LICENSE."
*
* @file randomizer.I
* @author drose
* @date 2007-01-18
*/
/**
* If seed is nonzero, it is used to define the tables; if it is zero a random
* seed is generated.
*/
Randomizer::
Randomizer(unsigned long seed) :
_mersenne(seed != 0 ? seed : get_next_seed())
{
}
/**
*
*/
Randomizer::
Randomizer(const Randomizer &copy) :
_mersenne(copy._mersenne)
{
}
/**
*
*/
void Randomizer::
operator = (const Randomizer &copy) {
_mersenne = copy._mersenne;
}
/**
* Returns a random integer in the range [0, range).
*/
INLINE int Randomizer::
random_int(int range) {
return (int)floor(random_real((double)range));
}
/**
* Returns a random double in the range [0, range).
*/
INLINE double Randomizer::
random_real(double range) {
return (range * _mersenne.get_uint31()) / ((double)0x80000000);
}
/**
* Returns a random double in the range [-0.5, 0.5).
*/
INLINE double Randomizer::
random_real_unit() {
return random_real(1.0f) - 0.5f;
}
/**
* Returns a random seed value for the next global Randomizer object.
*/
INLINE unsigned long Randomizer::
get_next_seed() {
if (!_got_first_seed) {
_next_seed = Mersenne((unsigned long)time(nullptr));
_got_first_seed = true;
}
return _next_seed.get_uint31();
}
/**
* Returns a unique seed value based on the seed value passed to this
* Randomizer object (and on its current state).
*/
INLINE unsigned long Randomizer::
get_seed() {
return _mersenne.get_uint31();
}