xref: /third_party/ffmpeg/libavutil/spherical.c (revision cabdff1a)
1/*
2 * Copyright (c) 2016 Vittorio Giovara <vittorio.giovara@gmail.com>
3 *
4 * This file is part of FFmpeg.
5 *
6 * FFmpeg is free software; you can redistribute it and/or
7 * modify it under the terms of the GNU Lesser General Public
8 * License as published by the Free Software Foundation; either
9 * version 2.1 of the License, or (at your option) any later version.
10 *
11 * FFmpeg is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
14 * Lesser General Public License for more details.
15 *
16 * You should have received a copy of the GNU Lesser General Public
17 * License along with FFmpeg; if not, write to the Free Software
18 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
19 */
20
21#include "avstring.h"
22#include "mem.h"
23#include "spherical.h"
24
25AVSphericalMapping *av_spherical_alloc(size_t *size)
26{
27    AVSphericalMapping *spherical = av_mallocz(sizeof(AVSphericalMapping));
28    if (!spherical)
29        return NULL;
30
31    if (size)
32        *size = sizeof(*spherical);
33
34    return spherical;
35}
36
37void av_spherical_tile_bounds(const AVSphericalMapping *map,
38                              size_t width, size_t height,
39                              size_t *left, size_t *top,
40                              size_t *right, size_t *bottom)
41{
42    /* conversion from 0.32 coordinates to pixels */
43    uint64_t orig_width  = (uint64_t) width  * UINT32_MAX /
44                           (UINT32_MAX - map->bound_right  - map->bound_left);
45    uint64_t orig_height = (uint64_t) height * UINT32_MAX /
46                           (UINT32_MAX - map->bound_bottom - map->bound_top);
47
48    /* add a (UINT32_MAX - 1) to round up integer division */
49    *left   = (orig_width  * map->bound_left + UINT32_MAX - 1) / UINT32_MAX;
50    *top    = (orig_height * map->bound_top  + UINT32_MAX - 1) / UINT32_MAX;
51    *right  = orig_width  - width  - *left;
52    *bottom = orig_height - height - *top;
53}
54
55static const char *const spherical_projection_names[] = {
56    [AV_SPHERICAL_EQUIRECTANGULAR]      = "equirectangular",
57    [AV_SPHERICAL_CUBEMAP]              = "cubemap",
58    [AV_SPHERICAL_EQUIRECTANGULAR_TILE] = "tiled equirectangular",
59};
60
61const char *av_spherical_projection_name(enum AVSphericalProjection projection)
62{
63    if ((unsigned)projection >= FF_ARRAY_ELEMS(spherical_projection_names))
64        return "unknown";
65
66    return spherical_projection_names[projection];
67}
68
69int av_spherical_from_name(const char *name)
70{
71    int i;
72
73    for (i = 0; i < FF_ARRAY_ELEMS(spherical_projection_names); i++) {
74        if (av_strstart(name, spherical_projection_names[i], NULL))
75            return i;
76    }
77
78    return -1;
79}
80