77 lines
1.8 KiB
C++
77 lines
1.8 KiB
C++
// Copyright (C) 2015 Rémi Bèges
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// This file is part of the "Nazara Engine - Noise module"
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// For conditions of distribution and use, see copyright notice in Config.hpp
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#include <Nazara/Noise/NoiseBase.hpp>
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#include <Nazara/Core/Error.hpp>
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#include <Nazara/Noise/Config.hpp>
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#include <Nazara/Noise/Debug.hpp>
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NzNoiseBase::NzNoiseBase(unsigned int seed)
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{
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Ua = 16807;
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Uc = 0;
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Um = 2147483647;
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UcurrentSeed = 0;
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Uprevious = 0;
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SetNewSeed(seed);
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for(int i(0) ; i < 512 ; i++)
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perm[i] = i & 255;
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}
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void NzNoiseBase::SetNewSeed(unsigned int seed)
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{
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Uprevious = seed;
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UcurrentSeed = seed;
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}
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unsigned int NzNoiseBase::GetUniformRandomValue()
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{
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Ulast = Ua*Uprevious + Uc%Um;
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Uprevious = Ulast;
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return Ulast;
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}
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void NzNoiseBase::ShufflePermutationTable()
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{
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int xchanger;
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unsigned int ncase;
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for(unsigned int i(0) ; i < 256 ; i++)
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perm[i] = i;
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for(unsigned int j(0) ; j < 20 ; ++j)
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for (unsigned int i(0); i < 256 ; ++i)
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{
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ncase = this->GetUniformRandomValue() & 255;
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xchanger = perm[i];
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perm[i] = perm[ncase];
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perm[ncase] = xchanger;
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}
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for(unsigned int i(256) ; i < 512; ++i)
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perm[i] = perm[i & 255];
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}
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int NzNoiseBase::fastfloor(float n)
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{
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return (n >= 0) ? static_cast<int>(n) : static_cast<int>(n-1);
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}
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int NzNoiseBase::JenkinsHash(int a, int b, int c)
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{
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a = a-b; a = a - c; a = a^(static_cast<unsigned int>(c) >> 13);
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b = b-c; b = b - a; b = b^(a << 8);
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c = c-a; c = c - b; c = c^(static_cast<unsigned int>(b) >> 13);
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a = a-b; a = a - c; a = a^(static_cast<unsigned int>(c) >> 12);
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b = b-c; b = b - a; b = b^(a << 16);
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c = c-a; c = c - b; c = c^(static_cast<unsigned int>(b) >> 5);
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a = a-b; a = a - c; a = a^(static_cast<unsigned int>(c) >> 3);
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b = b-c; b = b - a; b = b^(a << 10);
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c = c-a; c = c - b; c = c^(static_cast<unsigned int>(b) >> 15);
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return c;
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}
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