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[ffmpeg] / libavutil / spherical.c
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 "mem.h"
22 #include "spherical.h"
23
24 AVSphericalMapping *av_spherical_alloc(size_t *size)
25 {
26     AVSphericalMapping *spherical = av_mallocz(sizeof(AVSphericalMapping));
27     if (!spherical)
28         return NULL;
29
30     if (size)
31         *size = sizeof(*spherical);
32
33     return spherical;
34 }
35
36 void av_spherical_tile_bounds(const AVSphericalMapping *map,
37                               size_t width, size_t height,
38                               size_t *left, size_t *top,
39                               size_t *right, size_t *bottom)
40 {
41     /* conversion from 0.32 coordinates to pixels */
42     uint64_t orig_width  = (uint64_t) width  * UINT32_MAX /
43                            (UINT32_MAX - map->bound_right  - map->bound_left);
44     uint64_t orig_height = (uint64_t) height * UINT32_MAX /
45                            (UINT32_MAX - map->bound_bottom - map->bound_top);
46
47     /* add a (UINT32_MAX - 1) to round up integer division */
48     *left   = (orig_width  * map->bound_left + UINT32_MAX - 1) / UINT32_MAX;
49     *top    = (orig_height * map->bound_top  + UINT32_MAX - 1) / UINT32_MAX;
50     *right  = orig_width  - width  - *left;
51     *bottom = orig_height - height - *top;
52 }
53
54 static const char *const spherical_projection_names[] = {
55     [AV_SPHERICAL_EQUIRECTANGULAR]      = "equirectangular",
56     [AV_SPHERICAL_CUBEMAP]              = "cubemap",
57     [AV_SPHERICAL_EQUIRECTANGULAR_TILE] = "tiled equirectangular",
58 };
59
60 const char *av_spherical_projection_name(enum AVSphericalProjection projection)
61 {
62     if ((unsigned)projection >= FF_ARRAY_ELEMS(spherical_projection_names))
63         return "unknown";
64
65     return spherical_projection_names[projection];
66 }
67
68 int av_spherical_from_name(const char *name)
69 {
70     int i;
71
72     for (i = 0; i < FF_ARRAY_ELEMS(spherical_projection_names); i++) {
73         size_t len = strlen(spherical_projection_names[i]);
74         if (!strncmp(spherical_projection_names[i], name, len))
75             return i;
76     }
77
78     return -1;
79 }