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dag_uint_noise.h
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dag_uint_noise.h
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/*
* Dagor Engine 4
* Copyright (C) 2003-2019 Gaijin Entertainment Corp. All rights reserved
*
* (for conditions of distribution and use, see EULA in "prog/eula.txt")
*/
#ifndef _DAGOR_PUBLIC_MATH_RANDOM_DAG_UINT_NOISE_H_
#define _DAGOR_PUBLIC_MATH_RANDOM_DAG_UINT_NOISE_H_
#pragma once
// Math for Game Programmers: Noise-Based RNG
// author: Squirrel Eiserloh
__forceinline unsigned int uint32_hash(unsigned int val)
{
constexpr unsigned int BIT_NOISE1 = 0x68E31DA4;
constexpr unsigned int BIT_NOISE2 = 0xB5297A4D;
constexpr unsigned int BIT_NOISE3 = 0x1B56C4E9;
unsigned int mangled = val;
mangled *= BIT_NOISE1;
mangled ^= (mangled>>8);
mangled += BIT_NOISE2;
mangled ^= (mangled<<8);
mangled *= BIT_NOISE3;
mangled ^= (mangled>>8);
return mangled;
}
__forceinline unsigned int uint_noise1D(int position, unsigned int seed)
{
constexpr unsigned int BIT_NOISE1 = 0x68E31DA4;
constexpr unsigned int BIT_NOISE2 = 0xB5297A4D;
constexpr unsigned int BIT_NOISE3 = 0x1B56C4E9;
unsigned int mangled = position;
mangled *= BIT_NOISE1;
mangled += seed;
mangled ^= (mangled>>8);
mangled += BIT_NOISE2;
mangled ^= (mangled<<8);
mangled *= BIT_NOISE3;
mangled ^= (mangled>>8);
return mangled;
}
__forceinline unsigned int uint_noise2D(int posX, int posY, unsigned int seed)
{
constexpr int PRIME_NUMBER = 198491317;
return uint_noise1D(posX + (PRIME_NUMBER*posY), seed);
}
__forceinline unsigned int uint_noise3D(int posX, int posY, int posZ, unsigned int seed)
{
constexpr int PRIME_NUMBER1 = 198491317;
constexpr int PRIME_NUMBER2 = 6542989;
return uint_noise1D(posX + (PRIME_NUMBER1*posY) + (PRIME_NUMBER2*posZ), seed);
}
#endif