73 lines
1.5 KiB
C++
73 lines
1.5 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/Core/Error.hpp>
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#include <Nazara/Noise/Config.hpp>
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#include <Nazara/Noise/Perlin2D.hpp>
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#include <Nazara/Noise/Debug.hpp>
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NzPerlin2D::NzPerlin2D()
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{
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float grad2Temp[][2] = {
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{1.f,1.f},
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{-1.f,1.f},
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{1.f,-1.f},
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{-1.f,-1.f},
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{1.f,0.f},
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{-1.f,0.f},
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{0.f,1.f},
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{0.f,-1.f}
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};
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for(int i(0) ; i < 8 ; ++i)
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for(int j(0) ; j < 2 ; ++j)
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gradient2[i][j] = grad2Temp[i][j];
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}
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NzPerlin2D::NzPerlin2D(unsigned int seed) : NzPerlin2D()
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{
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this->SetNewSeed(seed);
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this->ShufflePermutationTable();
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}
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float NzPerlin2D::GetValue(float x, float y, float resolution)
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{
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x *= resolution;
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y *= resolution;
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x0 = fastfloor(x);
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y0 = fastfloor(y);
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ii = x0 & 255;
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jj = y0 & 255;
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gi0 = perm[ii + perm[jj]] & 7;
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gi1 = perm[ii + 1 + perm[jj]] & 7;
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gi2 = perm[ii + perm[jj + 1]] & 7;
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gi3 = perm[ii + 1 + perm[jj + 1]] & 7;
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temp.x = x-x0;
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temp.y = y-y0;
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Cx = temp.x * temp.x * temp.x * (temp.x * (temp.x * 6 - 15) + 10);
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Cy = temp.y * temp.y * temp.y * (temp.y * (temp.y * 6 - 15) + 10);
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s = gradient2[gi0][0]*temp.x + gradient2[gi0][1]*temp.y;
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temp.x = x-(x0+1);
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t = gradient2[gi1][0]*temp.x + gradient2[gi1][1]*temp.y;
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temp.y = y-(y0+1);
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v = gradient2[gi3][0]*temp.x + gradient2[gi3][1]*temp.y;
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temp.x = x-x0;
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u = gradient2[gi2][0]*temp.x + gradient2[gi2][1]*temp.y;
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Li1 = s + Cx*(t-s);
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Li2 = u + Cx*(v-u);
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return Li1 + Cy*(Li2-Li1);
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}
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