86 lines
1.9 KiB
C++
86 lines
1.9 KiB
C++
/**
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* @file noise.cpp
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* @brief Perlin noise routines for procedural textures, etc
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*
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* $LicenseInfo:firstyear=2000&license=viewerlgpl$
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* Second Life Viewer Source Code
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* Copyright (C) 2010, Linden Research, Inc.
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation;
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* version 2.1 of the License only.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*
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* Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
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* $/LicenseInfo$
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*/
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#include "llviewerprecompiledheaders.h"
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#include "noise.h"
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#include "llrand.h"
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// static
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#define B 0x100
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S32 p[B + B + 2];
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F32 g3[B + B + 2][3];
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F32 g2[B + B + 2][2];
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F32 g1[B + B + 2];
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S32 gNoiseStart = 1;
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F32 noise2(F32 *vec)
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{
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U8 bx0, bx1, by0, by1;
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U32 b00, b10, b01, b11;
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F32 rx0, rx1, ry0, ry1, *q, sx, sy, a, b, u, v;
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S32 i, j;
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if (gNoiseStart) {
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gNoiseStart = 0;
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init();
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}
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fast_setup(*vec, bx0, bx1, rx0, rx1);
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fast_setup(*(vec + 1), by0, by1, ry0, ry1);
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i = *(p + bx0);
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j = *(p + bx1);
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b00 = *(p + i + by0);
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b10 = *(p + j + by0);
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b01 = *(p + i + by1);
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b11 = *(p + j + by1);
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sx = s_curve(rx0);
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sy = s_curve(ry0);
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q = *(g2 + b00);
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u = fast_at2(rx0, ry0, q);
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q = *(g2 + b10);
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v = fast_at2(rx1, ry0, q);
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a = lerp_m(sx, u, v);
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q = *(g2 + b01);
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u = fast_at2(rx0,ry1,q);
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q = *(g2 + b11);
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v = fast_at2(rx1,ry1,q);
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b = lerp_m(sx, u, v);
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return lerp_m(sy, a, b);
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}
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