noise.h
上传用户:king477883
上传日期:2021-03-01
资源大小:9553k
文件大小:7k
- /**
- * @file noise.h
- * @brief Perlin noise routines for procedural textures, etc
- *
- * $LicenseInfo:firstyear=2000&license=viewergpl$
- *
- * Copyright (c) 2000-2010, Linden Research, Inc.
- *
- * Second Life Viewer Source Code
- * The source code in this file ("Source Code") is provided by Linden Lab
- * to you under the terms of the GNU General Public License, version 2.0
- * ("GPL"), unless you have obtained a separate licensing agreement
- * ("Other License"), formally executed by you and Linden Lab. Terms of
- * the GPL can be found in doc/GPL-license.txt in this distribution, or
- * online at http://secondlifegrid.net/programs/open_source/licensing/gplv2
- *
- * There are special exceptions to the terms and conditions of the GPL as
- * it is applied to this Source Code. View the full text of the exception
- * in the file doc/FLOSS-exception.txt in this software distribution, or
- * online at
- * http://secondlifegrid.net/programs/open_source/licensing/flossexception
- *
- * By copying, modifying or distributing this software, you acknowledge
- * that you have read and understood your obligations described above,
- * and agree to abide by those obligations.
- *
- * ALL LINDEN LAB SOURCE CODE IS PROVIDED "AS IS." LINDEN LAB MAKES NO
- * WARRANTIES, EXPRESS, IMPLIED OR OTHERWISE, REGARDING ITS ACCURACY,
- * COMPLETENESS OR PERFORMANCE.
- * $/LicenseInfo$
- */
- #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)
- {
- 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];
- }
- }
- #undef B
- #undef BM
- #undef N
- #undef NF32
- #undef NP
- #undef NM
- #endif // LL_NOISE_