/indra/llmath/llperlin.cpp
C++ | 294 lines | 203 code | 59 blank | 32 comment | 13 complexity | 104c013c96edf81f6a0d872a106b618e MD5 | raw file
Possible License(s): LGPL-2.1
- /**
- * @file llperlin.cpp
- *
- * $LicenseInfo:firstyear=2001&license=viewerlgpl$
- * 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 "linden_common.h"
- #include "llmath.h"
- #include "llperlin.h"
- #define B 0x100
- #define BM 0xff
- #define N 0x1000
- #define NF32 (4096.f)
- #define NP 12 /* 2^N */
- #define NM 0xfff
- static S32 p[B + B + 2];
- static F32 g3[B + B + 2][3];
- static F32 g2[B + B + 2][2];
- static F32 g1[B + B + 2];
- bool LLPerlinNoise::sInitialized = 0;
- static void normalize2(F32 v[2])
- {
- F32 s = 1.f/(F32)sqrt(v[0] * v[0] + v[1] * v[1]);
- v[0] = v[0] * s;
- v[1] = v[1] * s;
- }
- static void normalize3(F32 v[3])
- {
- F32 s = 1.f/(F32)sqrt(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
- v[0] = v[0] * s;
- v[1] = v[1] * s;
- v[2] = v[2] * s;
- }
- static void fast_setup(F32 vec, U8 &b0, U8 &b1, F32 &r0, F32 &r1)
- {
- S32 t_S32;
- r1 = vec + NF32;
- t_S32 = lltrunc(r1);
- b0 = (U8)t_S32;
- b1 = b0 + 1;
- r0 = r1 - t_S32;
- r1 = r0 - 1.f;
- }
- void LLPerlinNoise::init(void)
- {
- int i, j, k;
- for (i = 0 ; i < B ; i++)
- {
- p[i] = i;
- g1[i] = (F32)((rand() % (B + B)) - B) / B;
- for (j = 0 ; j < 2 ; j++)
- g2[i][j] = (F32)((rand() % (B + B)) - B) / B;
- normalize2(g2[i]);
- for (j = 0 ; j < 3 ; j++)
- g3[i][j] = (F32)((rand() % (B + B)) - B) / B;
- normalize3(g3[i]);
- }
- while (--i)
- {
- k = p[i];
- p[i] = p[j = rand() % B];
- p[j] = k;
- }
- for (i = 0 ; i < B + 2 ; i++)
- {
- p[B + i] = p[i];
- g1[B + i] = g1[i];
- for (j = 0 ; j < 2 ; j++)
- g2[B + i][j] = g2[i][j];
- for (j = 0 ; j < 3 ; j++)
- g3[B + i][j] = g3[i][j];
- }
- sInitialized = true;
- }
- //============================================================================
- // Noise functions
- #define s_curve(t) ( t * t * (3.f - 2.f * t) )
- #define lerp_m(t, a, b) ( a + t * (b - a) )
- F32 LLPerlinNoise::noise1(F32 x)
- {
- int bx0, bx1;
- F32 rx0, rx1, sx, t, u, v;
- if (!sInitialized)
- init();
- t = x + N;
- bx0 = (lltrunc(t)) & BM;
- bx1 = (bx0+1) & BM;
- rx0 = t - lltrunc(t);
- rx1 = rx0 - 1.f;
- sx = s_curve(rx0);
- u = rx0 * g1[ p[ bx0 ] ];
- v = rx1 * g1[ p[ bx1 ] ];
- return lerp_m(sx, u, v);
- }
- static F32 fast_at2(F32 rx, F32 ry, F32 *q)
- {
- return rx * q[0] + ry * q[1];
- }
- F32 LLPerlinNoise::noise2(F32 x, F32 y)
- {
- 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 (!sInitialized)
- init();
- fast_setup(x, bx0, bx1, rx0, rx1);
- fast_setup(y, 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);
- }
- static F32 fast_at3(F32 rx, F32 ry, F32 rz, F32 *q)
- {
- return rx * q[0] + ry * q[1] + rz * q[2];
- }
- F32 LLPerlinNoise::noise3(F32 x, F32 y, F32 z)
- {
- U8 bx0, bx1, by0, by1, bz0, bz1;
- S32 b00, b10, b01, b11;
- F32 rx0, rx1, ry0, ry1, rz0, rz1, *q, sy, sz, a, b, c, d, t, u, v;
- S32 i, j;
- if (!sInitialized)
- init();
- fast_setup(x, bx0,bx1, rx0,rx1);
- fast_setup(y, by0,by1, ry0,ry1);
- fast_setup(z, bz0,bz1, rz0,rz1);
- i = p[ bx0 ];
- j = p[ bx1 ];
- b00 = p[ i + by0 ];
- b10 = p[ j + by0 ];
- b01 = p[ i + by1 ];
- b11 = p[ j + by1 ];
- t = s_curve(rx0);
- sy = s_curve(ry0);
- sz = s_curve(rz0);
- q = g3[ b00 + bz0 ];
- u = fast_at3(rx0,ry0,rz0,q);
- q = g3[ b10 + bz0 ];
- v = fast_at3(rx1,ry0,rz0,q);
- a = lerp_m(t, u, v);
- q = g3[ b01 + bz0 ];
- u = fast_at3(rx0,ry1,rz0,q);
- q = g3[ b11 + bz0 ];
- v = fast_at3(rx1,ry1,rz0,q);
- b = lerp_m(t, u, v);
- c = lerp_m(sy, a, b);
- q = g3[ b00 + bz1 ];
- u = fast_at3(rx0,ry0,rz1,q);
- q = g3[ b10 + bz1 ];
- v = fast_at3(rx1,ry0,rz1,q);
- a = lerp_m(t, u, v);
- q = g3[ b01 + bz1 ];
- u = fast_at3(rx0,ry1,rz1,q);
- q = g3[ b11 + bz1 ];
- v = fast_at3(rx1,ry1,rz1,q);
- b = lerp_m(t, u, v);
- d = lerp_m(sy, a, b);
- return lerp_m(sz, c, d);
- }
- F32 LLPerlinNoise::turbulence2(F32 x, F32 y, F32 freq)
- {
- F32 t, lx, ly;
- for (t = 0.f ; freq >= 1.f ; freq *= 0.5f)
- {
- lx = freq * x;
- ly = freq * y;
- t += noise2(lx, ly)/freq;
- }
- return t;
- }
- F32 LLPerlinNoise::turbulence3(F32 x, F32 y, F32 z, F32 freq)
- {
- F32 t, lx, ly, lz;
- for (t = 0.f ; freq >= 1.f ; freq *= 0.5f)
- {
- lx = freq * x;
- ly = freq * y;
- lz = freq * z;
- t += noise3(lx,ly,lz)/freq;
- // t += fabs(noise3(lx,ly,lz)) / freq; // Like snow - bubbly at low frequencies
- // t += sqrt(fabs(noise3(lx,ly,lz))) / freq; // Better at low freq
- // t += (noise3(lx,ly,lz)*noise3(lx,ly,lz)) / freq;
- }
- return t;
- }
- F32 LLPerlinNoise::clouds3(F32 x, F32 y, F32 z, F32 freq)
- {
- F32 t, lx, ly, lz;
- for (t = 0.f ; freq >= 1.f ; freq *= 0.5f)
- {
- lx = freq * x;
- ly = freq * y;
- lz = freq * z;
- // t += noise3(lx,ly,lz)/freq;
- // t += fabs(noise3(lx,ly,lz)) / freq; // Like snow - bubbly at low frequencies
- // t += sqrt(fabs(noise3(lx,ly,lz))) / freq; // Better at low freq
- t += (noise3(lx,ly,lz)*noise3(lx,ly,lz)) / freq;
- }
- return t;
- }