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/**
* @file noise.h
* @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
* $/LicenseInfo$
*/
#ifndef LL_NOISE_H
#define LL_NOISE_H
#include "llmath.h"
F32 turbulence2(F32 *v, F32 freq);
F32 turbulence3(float *v, float freq);
F32 clouds3(float *v, float freq);
F32 noise2(float *vec);
F32 noise3(float *vec);
inline F32 bias(F32 a, F32 b)
{
return (F32)pow(a, (F32)(log(b) / log(0.5f)));
}
inline F32 gain(F32 a, F32 b)
{
F32 p = (F32) (log(1.f - b) / log(0.5f));
if (a < .001f)
return 0.f;
else if (a > .999f)
return 1.f;
if (a < 0.5f)
return (F32)(pow(2 * a, p) / 2.f);
else
return (F32)(1.f - pow(2 * (1.f - a), p) / 2.f);
}
inline F32 turbulence2(F32 *v, F32 freq)
{
F32 t, vec[2];
for (t = 0.f ; freq >= 1.f ; freq *= 0.5f) {
vec[0] = freq * v[0];
vec[1] = freq * v[1];
t += noise2(vec)/freq;
}
return t;
}
inline F32 turbulence3(F32 *v, F32 freq)
{
F32 t, vec[3];
for (t = 0.f ; freq >= 1.f ; freq *= 0.5f) {
vec[0] = freq * v[0];
vec[1] = freq * v[1];
vec[2] = freq * v[2];
t += noise3(vec)/freq;
// t += fabs(noise3(vec)) / freq; // Like snow - bubbly at low frequencies
// t += sqrt(fabs(noise3(vec))) / freq; // Better at low freq
// t += (noise3(vec)*noise3(vec)) / freq;
}
return t;
}
inline F32 clouds3(F32 *v, F32 freq)
{
F32 t, vec[3];
for (t = 0.f ; freq >= 1.f ; freq *= 0.5f) {
vec[0] = freq * v[0];
vec[1] = freq * v[1];
vec[2] = freq * v[2];
//t += noise3(vec)/freq;
// t += fabs(noise3(vec)) / freq; // Like snow - bubbly at low frequencies
// t += sqrt(fabs(noise3(vec))) / freq; // Better at low freq
t += (noise3(vec)*noise3(vec)) / freq;
}
return t;
}
/* noise functions over 1, 2, and 3 dimensions */
#define B 0x100
#define BM 0xff
#define N 0x1000
#define NF32 (4096.f)
#define NP 12 /* 2^N */
#define NM 0xfff
extern S32 p[B + B + 2];
extern F32 g3[B + B + 2][3];
extern F32 g2[B + B + 2][2];
extern F32 g1[B + B + 2];
extern S32 gNoiseStart;
static void init(void);
#define s_curve(t) ( t * t * (3.f - 2.f * t) )
#define lerp_m(t, a, b) ( a + t * (b - a) )
#define setup_noise(i,b0,b1,r0,r1)\
t = vec[i] + N;\
b0 = (lltrunc(t)) & BM;\
b1 = (b0+1) & BM;\
r0 = t - lltrunc(t);\
r1 = r0 - 1.f;
inline 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;
}
inline F32 noise1(const F32 arg)
{
int bx0, bx1;
F32 rx0, rx1, sx, t, u, v, vec[1];
vec[0] = arg;
if (gNoiseStart) {
gNoiseStart = 0;
init();
}
setup_noise(0, bx0,bx1, rx0,rx1);
sx = s_curve(rx0);
u = rx0 * g1[ p[ bx0 ] ];
v = rx1 * g1[ p[ bx1 ] ];
return lerp_m(sx, u, v);
}
inline F32 fast_at2(F32 rx, F32 ry, F32 *q)
{
return rx * (*q) + ry * (*(q + 1));
}
inline F32 fast_at3(F32 rx, F32 ry, F32 rz, F32 *q)
{
return rx * (*q) + ry * (*(q + 1)) + rz * (*(q + 2));
}
inline F32 noise3(F32 *vec)
{
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 (gNoiseStart) {
gNoiseStart = 0;
init();
}
fast_setup(*vec, bx0,bx1, rx0,rx1);
fast_setup(*(vec + 1), by0,by1, ry0,ry1);
fast_setup(*(vec + 2), 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 noise3(F32 *vec)
{
int bx0, bx1, by0, by1, bz0, bz1, 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 (gNoiseStart) {
gNoiseStart = 0;
init();
}
setup_noise(0, bx0,bx1, rx0,rx1);
setup_noise(1, by0,by1, ry0,ry1);
setup_noise(2, 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);
#define at3(rx,ry,rz) ( rx * q[0] + ry * q[1] + rz * q[2] )
q = g3[ b00 + bz0 ] ; u = at3(rx0,ry0,rz0);
q = g3[ b10 + bz0 ] ; v = at3(rx1,ry0,rz0);
a = lerp_m(t, u, v);
q = g3[ b01 + bz0 ] ; u = at3(rx0,ry1,rz0);
q = g3[ b11 + bz0 ] ; v = at3(rx1,ry1,rz0);
b = lerp_m(t, u, v);
c = lerp_m(sy, a, b);
q = g3[ b00 + bz1 ] ; u = at3(rx0,ry0,rz1);
q = g3[ b10 + bz1 ] ; v = at3(rx1,ry0,rz1);
a = lerp_m(t, u, v);
q = g3[ b01 + bz1 ] ; u = at3(rx0,ry1,rz1);
q = g3[ b11 + bz1 ] ; v = at3(rx1,ry1,rz1);
b = lerp_m(t, u, v);
d = lerp_m(sy, a, b);
return lerp_m(sz, c, d);
}
*/
static void normalize2(F32 v[2])
{
F32 s;
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;
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 init(void)
{
// we want repeatable noise (e.g. for stable terrain texturing), so seed with known value
srand(42);
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];
}
// reintroduce entropy
srand(time(NULL)); // Flawfinder: ignore
}
#undef B
#undef BM
#undef N
#undef NF32
#undef NP
#undef NM
#endif // LL_NOISE_
|
