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 "avstring.h"
  22 #include "mem.h"
  23 #include "spherical.h"
  24
  25 AVSphericalMapping *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
  37 void 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
  55 static 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
  61 const 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
  69 int 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 }