89 lines
2.1 KiB
C++
89 lines
2.1 KiB
C++
// Copyright (C) 2012 Rémi Bèges
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// This file is part of the "Nazara Engine".
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// For conditions of distribution and use, see copyright notice in Config.hpp
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//#include <Nazara/Noise/Error.hpp>
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//#include <Nazara/Noise/Config.hpp>
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//#include <Nazara/Noise/Debug.hpp>
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template <typename T>
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NzSimplex2D<T>::NzSimplex2D()
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{
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T unit = 1.0/sqrt(2);
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T grad2Temp[][2] = {{unit,unit},{-unit,unit},{unit,-unit},{-unit,-unit},
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{1,0},{-1,0},{0,1},{0,-1}};
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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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SkewCoeff2D = 0.5*(sqrt(3.0) - 1.0);
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UnskewCoeff2D = (3.0-sqrt(3.0))/6;
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}
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template <typename T>
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T NzSimplex2D<T>::GetValue(T x, T y, T res)
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{
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x /= res;
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y /= res;
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Origin.x = fastfloor(x + (x + y) * SkewCoeff2D);
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Origin.y = fastfloor(y + (x + y) * SkewCoeff2D);
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A.x = Origin.x - (Origin.x + Origin.y) * UnskewCoeff2D;
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A.y = Origin.y - (Origin.x + Origin.y) * UnskewCoeff2D;
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IsoOriginDist.x = x - A.x;
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IsoOriginDist.y = y - A.y;
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if(IsoOriginDist.x > IsoOriginDist.y)
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{
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off1.x = 1;
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off1.y = 0;
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}
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else
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{
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off1.x = 0;
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off1.y = 1;
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}
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d1.x = A.x - x;
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d1.y = A.y - y;
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d2.x = d1.x + off1.x - UnskewCoeff2D;
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d2.y = d1.y + off1.y - UnskewCoeff2D;
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d3.x = d1.x + 1.0 - 2 * UnskewCoeff2D;
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d3.y = d1.y + 1.0 - 2 * UnskewCoeff2D;
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ii = Origin.x & 255;
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jj = Origin.y & 255;
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gi0 = perm[ii + perm[jj]] % 8;
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gi1 = perm[ii + off1.x + perm[jj + off1.y]] % 8;
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gi2 = perm[ii + 1 + perm[jj + 1]] % 8;
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n1 = gradient2[gi0][0] * d1.x + gradient2[gi0][1] * d1.y;
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n2 = gradient2[gi1][0] * d2.x + gradient2[gi1][1] * d2.y;
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n3 = gradient2[gi2][0] * d3.x + gradient2[gi2][1] * d3.y;
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c1 = 0.5 - d1.x * d1.x - d1.y * d1.y;
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c2 = 0.5 - d2.x * d2.x - d2.y * d2.y;
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c3 = 0.5 - d3.x * d3.x - d3.y * d3.y;
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if(c1 < 0)
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c1 = 0;
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if(c2 < 0)
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c2 = 0;
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if(c3 < 0)
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c3 = 0;
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n1 = c1*c1*c1*n1;
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n2 = c2*c2*c2*n2;
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n3 = c3*c3*c3*n3;
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return (n1+n2+n3)*23.2;
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}
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