1/*
2 * This file is part of FFmpeg.
3 *
4 * FFmpeg is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU Lesser General Public
6 * License as published by the Free Software Foundation; either
7 * version 2.1 of the License, or (at your option) any later version.
8 *
9 * FFmpeg is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12 * Lesser General Public License for more details.
13 *
14 * You should have received a copy of the GNU Lesser General Public
15 * License along with FFmpeg; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
17 */
18
19#include <stdint.h>
20#include "libavutil/avassert.h"
21#include "avfilter.h"
22#include "generate_wave_table.h"
23
24void ff_generate_wave_table(enum WaveType wave_type,
25                            enum AVSampleFormat sample_fmt,
26                            void *table, int table_size,
27                            double min, double max, double phase)
28{
29    uint32_t i, phase_offset = phase / M_PI / 2 * table_size + 0.5;
30
31    for (i = 0; i < table_size; i++) {
32        uint32_t point = (i + phase_offset) % table_size;
33        double d;
34
35        switch (wave_type) {
36        case WAVE_SIN:
37            d = (sin((double)point / table_size * 2 * M_PI) + 1) / 2;
38            break;
39        case WAVE_TRI:
40            d = (double)point * 2 / table_size;
41            switch (4 * point / table_size) {
42            case 0: d = d + 0.5; break;
43            case 1:
44            case 2: d = 1.5 - d; break;
45            case 3: d = d - 1.5; break;
46            }
47            break;
48        default:
49            av_assert0(0);
50        }
51
52        d  = d * (max - min) + min;
53        switch (sample_fmt) {
54        case AV_SAMPLE_FMT_FLT: {
55            float *fp = (float *)table;
56            *fp++ = (float)d;
57            table = fp;
58            continue; }
59        case AV_SAMPLE_FMT_DBL: {
60            double *dp = (double *)table;
61            *dp++ = d;
62            table = dp;
63            continue; }
64        }
65
66        d += d < 0 ? -0.5 : 0.5;
67        switch (sample_fmt) {
68        case AV_SAMPLE_FMT_S16: {
69            int16_t *sp = table;
70            *sp++ = (int16_t)d;
71            table = sp;
72            continue; }
73        case AV_SAMPLE_FMT_S32: {
74            int32_t *ip = table;
75            *ip++ = (int32_t)d;
76            table = ip;
77            continue; }
78        default:
79            av_assert0(0);
80        }
81    }
82}
83
84
85