/indra/newview/noise.cpp
C++ | 85 lines | 41 code | 18 blank | 26 comment | 1 complexity | 65c0331cc013d5fa6aa527ca44dec811 MD5 | raw file
Possible License(s): LGPL-2.1
- /**
- * @file noise.cpp
- * @brief Perlin noise routines for procedural textures, etc
- *
- * $LicenseInfo:firstyear=2000&license=viewerlgpl$
- * Second Life Viewer Source Code
- * Copyright (C) 2010, Linden Research, Inc.
- *
- * This library is free software; you can redistribute it and/or
- * modify it under the terms of the GNU Lesser General Public
- * License as published by the Free Software Foundation;
- * version 2.1 of the License only.
- *
- * This library is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * Lesser General Public License for more details.
- *
- * You should have received a copy of the GNU Lesser General Public
- * License along with this library; if not, write to the Free Software
- * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
- *
- * Linden Research, Inc., 945 Battery Street, San Francisco, CA 94111 USA
- * $/LicenseInfo$
- */
- #include "llviewerprecompiledheaders.h"
- #include "noise.h"
- #include "llrand.h"
- // static
- #define B 0x100
- S32 p[B + B + 2];
- F32 g3[B + B + 2][3];
- F32 g2[B + B + 2][2];
- F32 g1[B + B + 2];
- S32 gNoiseStart = 1;
- F32 noise2(F32 *vec)
- {
- U8 bx0, bx1, by0, by1;
- U32 b00, b10, b01, b11;
- F32 rx0, rx1, ry0, ry1, *q, sx, sy, a, b, u, v;
- S32 i, j;
- if (gNoiseStart) {
- gNoiseStart = 0;
- init();
- }
- fast_setup(*vec, bx0, bx1, rx0, rx1);
- fast_setup(*(vec + 1), by0, by1, ry0, ry1);
- i = *(p + bx0);
- j = *(p + bx1);
- b00 = *(p + i + by0);
- b10 = *(p + j + by0);
- b01 = *(p + i + by1);
- b11 = *(p + j + by1);
- sx = s_curve(rx0);
- sy = s_curve(ry0);
- q = *(g2 + b00);
- u = fast_at2(rx0, ry0, q);
- q = *(g2 + b10);
- v = fast_at2(rx1, ry0, q);
- a = lerp_m(sx, u, v);
- q = *(g2 + b01);
- u = fast_at2(rx0,ry1,q);
- q = *(g2 + b11);
- v = fast_at2(rx1,ry1,q);
- b = lerp_m(sx, u, v);
- return lerp_m(sy, a, b);
- }