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