1/*
2 * This implementation of the noise functions was ported from the Java
3 * implementation by Jerry Huxtable (http://www.jhlabs.com) under
4 * Apache License 2.0 (see http://jhlabs.com/ip/filters/download.html)
5 *
6 * Original header:
7 *
8 * Copyright 2006 Jerry Huxtable
9 *
10 * Licensed under the Apache License, Version 2.0 (the "License");
11 * you may not use this file except in compliance with the License.
12 * You may obtain a copy of the License at
13 *
14 * http://www.apache.org/licenses/LICENSE-2.0
15 *
16 * Unless required by applicable law or agreed to in writing, software
17 * distributed under the License is distributed on an "AS IS" BASIS,
18 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
19 * See the License for the specific language governing permissions and
20 * limitations under the License.
21 */
22
23#include "rsNoise.h"
24
25#include <math.h>
26#include <stdlib.h>
27#include <time.h>
28
29namespace android {
30namespace renderscript {
31
32#define B 0x100
33#define BM 0xff
34#define N 0x1000
35
36static int p[B + B + 2];
37static float g3[B + B + 2][3];
38static float g2[B + B + 2][2];
39static float g1[B + B + 2];
40static bool noise_start = true;
41
42#define lerpf(start, stop, amount) start + (stop - start) * amount
43
44static inline float noise_sCurve(float t)
45{
46    return t * t * (3.0f - 2.0f * t);
47}
48
49inline void SC_normalizef2(float v[])
50{
51    float s = (float)sqrtf(v[0] * v[0] + v[1] * v[1]);
52    v[0] = v[0] / s;
53    v[1] = v[1] / s;
54}
55
56inline void SC_normalizef3(float v[])
57{
58    float s = (float)sqrtf(v[0] * v[0] + v[1] * v[1] + v[2] * v[2]);
59    v[0] = v[0] / s;
60    v[1] = v[1] / s;
61    v[2] = v[2] / s;
62}
63
64static void noise_init()
65{
66    int i, j, k;
67
68    for (i = 0; i < B; i++) {
69        p[i] = i;
70
71        g1[i] = (float)((rand() % (B + B)) - B) / B;
72
73        for (j = 0; j < 2; j++)
74            g2[i][j] = (float)((rand() % (B + B)) - B) / B;
75        SC_normalizef2(g2[i]);
76
77        for (j = 0; j < 3; j++)
78            g3[i][j] = (float)((rand() % (B + B)) - B) / B;
79        SC_normalizef3(g3[i]);
80    }
81
82    for (i = B-1; i >= 0; i--) {
83        k = p[i];
84        p[i] = p[j = rand() % B];
85        p[j] = k;
86    }
87
88    for (i = 0; i < B + 2; i++) {
89        p[B + i] = p[i];
90        g1[B + i] = g1[i];
91        for (j = 0; j < 2; j++)
92            g2[B + i][j] = g2[i][j];
93        for (j = 0; j < 3; j++)
94            g3[B + i][j] = g3[i][j];
95    }
96}
97
98float SC_noisef(float x)
99{
100    srand(time(NULL));
101    int bx0, bx1;
102    float rx0, rx1, sx, t, u, v;
103
104    if (noise_start) {
105        noise_start = false;
106        noise_init();
107    }
108
109    t = x + N;
110    bx0 = ((int)t) & BM;
111    bx1 = (bx0+1) & BM;
112    rx0 = t - (int)t;
113    rx1 = rx0 - 1.0f;
114
115    sx = noise_sCurve(rx0);
116
117    u = rx0 * g1[p[bx0]];
118    v = rx1 * g1[p[bx1]];
119    return 2.3f * lerpf(u, v, sx);
120}
121
122float SC_noisef2(float x, float y)
123{
124    srand(time(NULL));
125    int bx0, bx1, by0, by1, b00, b10, b01, b11;
126    float rx0, rx1, ry0, ry1, sx, sy, a, b, t, u, v;
127    float *q;
128    int i, j;
129
130    if (noise_start) {
131        noise_start = false;
132        noise_init();
133    }
134
135    t = x + N;
136    bx0 = ((int)t) & BM;
137    bx1 = (bx0+1) & BM;
138    rx0 = t - (int)t;
139    rx1 = rx0 - 1.0f;
140
141    t = y + N;
142    by0 = ((int)t) & BM;
143    by1 = (by0+1) & BM;
144    ry0 = t - (int)t;
145    ry1 = ry0 - 1.0f;
146
147    i = p[bx0];
148    j = p[bx1];
149
150    b00 = p[i + by0];
151    b10 = p[j + by0];
152    b01 = p[i + by1];
153    b11 = p[j + by1];
154
155    sx = noise_sCurve(rx0);
156    sy = noise_sCurve(ry0);
157
158    q = g2[b00]; u = rx0 * q[0] + ry0 * q[1];
159    q = g2[b10]; v = rx1 * q[0] + ry0 * q[1];
160    a = lerpf(u, v, sx);
161
162    q = g2[b01]; u = rx0 * q[0] + ry1 * q[1];
163    q = g2[b11]; v = rx1 * q[0] + ry1 * q[1];
164    b = lerpf(u, v, sx);
165
166    return 1.5f*lerpf(a, b, sy);
167}
168
169float SC_noisef3(float x, float y, float z)
170{
171    srand(time(NULL));
172    int bx0, bx1, by0, by1, bz0, bz1, b00, b10, b01, b11;
173    float rx0, rx1, ry0, ry1, rz0, rz1, sy, sz, a, b, c, d, t, u, v;
174    float *q;
175    int i, j;
176
177    if (noise_start) {
178        noise_start = false;
179        noise_init();
180    }
181
182    t = x + N;
183    bx0 = ((int)t) & BM;
184    bx1 = (bx0+1) & BM;
185    rx0 = t - (int)t;
186    rx1 = rx0 - 1.0f;
187
188    t = y + N;
189    by0 = ((int)t) & BM;
190    by1 = (by0+1) & BM;
191    ry0 = t - (int)t;
192    ry1 = ry0 - 1.0f;
193
194    t = z + N;
195    bz0 = ((int)t) & BM;
196    bz1 = (bz0+1) & BM;
197    rz0 = t - (int)t;
198    rz1 = rz0 - 1.0f;
199
200    i = p[bx0];
201    j = p[bx1];
202
203    b00 = p[i + by0];
204    b10 = p[j + by0];
205    b01 = p[i + by1];
206    b11 = p[j + by1];
207
208    t  = noise_sCurve(rx0);
209    sy = noise_sCurve(ry0);
210    sz = noise_sCurve(rz0);
211
212    q = g3[b00 + bz0]; u = rx0 * q[0] + ry0 * q[1] + rz0 * q[2];
213    q = g3[b10 + bz0]; v = rx1 * q[0] + ry0 * q[1] + rz0 * q[2];
214    a = lerpf(u, v, t);
215
216    q = g3[b01 + bz0]; u = rx0 * q[0] + ry1 * q[1] + rz0 * q[2];
217    q = g3[b11 + bz0]; v = rx1 * q[0] + ry1 * q[1] + rz0 * q[2];
218    b = lerpf(u, v, t);
219
220    c = lerpf(a, b, sy);
221
222    q = g3[b00 + bz1]; u = rx0 * q[0] + ry0 * q[1] + rz1 * q[2];
223    q = g3[b10 + bz1]; v = rx1 * q[0] + ry0 * q[1] + rz1 * q[2];
224    a = lerpf(u, v, t);
225
226    q = g3[b01 + bz1]; u = rx0 * q[0] + ry1 * q[1] + rz1 * q[2];
227    q = g3[b11 + bz1]; v = rx1 * q[0] + ry1 * q[1] + rz1 * q[2];
228    b = lerpf(u, v, t);
229
230    d = lerpf(a, b, sy);
231
232    return 1.5f*lerpf(c, d, sz);
233}
234
235float SC_turbulencef2(float x, float y, float octaves)
236{
237    srand(time(NULL));
238    float t = 0.0f;
239
240    for (float f = 1.0f; f <= octaves; f *= 2)
241        t += fabs(SC_noisef2(f * x, f * y)) / f;
242    return t;
243}
244
245float SC_turbulencef3(float x, float y, float z, float octaves)
246{
247    srand(time(NULL));
248    float t = 0.0f;
249
250    for (float f = 1.0f; f <= octaves; f *= 2)
251        t += fabs(SC_noisef3(f * x, f * y, f * z)) / f;
252    return t;
253}
254
255}
256}