noise.cpp

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/* Copyright (c) 2014-2017, ARM Limited and Contributors
 *
 * SPDX-License-Identifier: MIT
 *
 * 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.
 */

#include "noise.h"
#include <random>

float clamp(float x, float min, float max)
{
        return x < min ? min : x > max ? max : x;
}

float max(float x, float y)
{
        return x > y ? x : y;
}

float min(float x, float y)
{
        return x < y ? x : y;
}

// See http://en.wikipedia.org/wiki/Xorshift
unsigned int xor128()
{
        static unsigned int x = 123456789;
        static unsigned int y = 362436069;
        static unsigned int z = 521288629;
        static unsigned int w = 88675123;
        unsigned int t;

        t = x ^ (x << 11);
        x = y; y = z; z = w;
        return w = w ^ (w >> 19) ^ (t ^ (t >>8));
}

float frand()
{
        return xor128() / float(4294967295.0f);
}