godot/core/math/random_pcg.h

79 lines
3.6 KiB
C++
Raw Normal View History

/*************************************************************************/
/* random_pcg.h */
/*************************************************************************/
/* This file is part of: */
/* GODOT ENGINE */
/* https://godotengine.org */
/*************************************************************************/
/* Copyright (c) 2007-2019 Juan Linietsky, Ariel Manzur. */
/* Copyright (c) 2014-2019 Godot Engine contributors (cf. AUTHORS.md) */
/* */
/* Permission is hereby granted, free of charge, to any person obtaining */
/* a copy of this software and associated documentation files (the */
/* "Software"), to deal in the Software without restriction, including */
/* without limitation the rights to use, copy, modify, merge, publish, */
/* distribute, sublicense, and/or sell copies of the Software, and to */
/* permit persons to whom the Software is furnished to do so, subject to */
/* the following conditions: */
/* */
/* The above copyright notice and this permission notice shall be */
/* included in all copies or substantial portions of the Software. */
/* */
/* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, */
/* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF */
/* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.*/
/* IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY */
/* CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, */
/* TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE */
/* SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. */
/*************************************************************************/
#ifndef RANDOM_PCG_H
#define RANDOM_PCG_H
#include <math.h>
#include "core/math/math_defs.h"
#include "thirdparty/misc/pcg.h"
class RandomPCG {
pcg32_random_t pcg;
uint64_t current_seed; // seed with this to get the same state
2019-03-17 17:51:51 +00:00
uint64_t current_inc;
public:
2019-01-19 23:12:50 +00:00
static const uint64_t DEFAULT_SEED = 12047754176567800795U;
static const uint64_t DEFAULT_INC = PCG_DEFAULT_INC_64;
2019-01-19 23:12:50 +00:00
static const uint64_t RANDOM_MAX = 0xFFFFFFFF;
2019-03-17 17:51:51 +00:00
RandomPCG(uint64_t p_seed = DEFAULT_SEED, uint64_t p_inc = DEFAULT_INC);
_FORCE_INLINE_ void seed(uint64_t p_seed) {
current_seed = p_seed;
2019-03-17 17:51:51 +00:00
pcg32_srandom_r(&pcg, current_seed, current_inc);
}
_FORCE_INLINE_ uint64_t get_seed() { return current_seed; }
void randomize();
_FORCE_INLINE_ uint32_t rand() {
current_seed = pcg.state;
return pcg32_random_r(&pcg);
}
_FORCE_INLINE_ double randd() { return (double)rand() / (double)RANDOM_MAX; }
_FORCE_INLINE_ float randf() { return (float)rand() / (float)RANDOM_MAX; }
_FORCE_INLINE_ double randfn(double p_mean, double p_deviation) {
return p_mean + p_deviation * (cos(Math_TAU * randd()) * sqrt(-2.0 * log(randd()))); // Box-Muller transform
}
_FORCE_INLINE_ float randfn(float p_mean, float p_deviation) {
return p_mean + p_deviation * (cos(Math_TAU * randf()) * sqrt(-2.0 * log(randf()))); // Box-Muller transform
}
double random(double p_from, double p_to);
float random(float p_from, float p_to);
real_t random(int p_from, int p_to) { return (real_t)random((real_t)p_from, (real_t)p_to); }
};
#endif // RANDOM_PCG_H