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