virtualx-engine/core/math/random_pcg.cpp

/*************************************************************************/
/*  random_pcg.cpp                                                       */
/*************************************************************************/
/*                       This file is part of:                           */
/*                           GODOT ENGINE                                */
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/* Copyright (c) 2007-2020 Juan Linietsky, Ariel Manzur.                 */
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#include "random_pcg.h"

#include "core/os/os.h"

RandomPCG::RandomPCG(uint64_t p_seed, uint64_t p_inc) :
		pcg(),
		current_inc(p_inc) {
	seed(p_seed);
}

void RandomPCG::randomize() {
	seed(OS::get_singleton()->get_ticks_usec() * pcg.state + PCG_DEFAULT_INC_64);
}

double RandomPCG::random(double p_from, double p_to) {
	return randd() * (p_to - p_from) + p_from;
}

float RandomPCG::random(float p_from, float p_to) {
	return randf() * (p_to - p_from) + p_from;
}

int RandomPCG::random(int p_from, int p_to) {
	int range;
	int min;
	if (p_to > p_from) {
		range = p_to - p_from + 1;
		min = p_from;
	} else if (p_to < p_from) {
		range = p_from - p_to + 1;
		min = p_to;
	} else { // from == to
		return p_from;
	}
	return rand(range) + min;
}