Rename ffmpeg-4.2-fit to ffmpeg-4-fit

trunk/3rdparty/ffmpeg-4-fit/libavutil/spherical.h

@@ -0,0 +1,232 @@
+/*
+ * Copyright (c) 2016 Vittorio Giovara <vittorio.giovara@gmail.com>
+ *
+ * This file is part of FFmpeg.
+ *
+ * FFmpeg is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 2.1 of the License, or (at your option) any later version.
+ *
+ * FFmpeg is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public
+ * License along with FFmpeg; if not, write to the Free Software
+ * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
+ */
+
+/**
+ * @file
+ * Spherical video
+ */
+
+#ifndef AVUTIL_SPHERICAL_H
+#define AVUTIL_SPHERICAL_H
+
+#include <stddef.h>
+#include <stdint.h>
+
+/**
+ * @addtogroup lavu_video
+ * @{
+ *
+ * @defgroup lavu_video_spherical Spherical video mapping
+ * @{
+ */
+
+/**
+ * @addtogroup lavu_video_spherical
+ * A spherical video file contains surfaces that need to be mapped onto a
+ * sphere. Depending on how the frame was converted, a different distortion
+ * transformation or surface recomposition function needs to be applied before
+ * the video should be mapped and displayed.
+ */
+
+/**
+ * Projection of the video surface(s) on a sphere.
+ */
+enum AVSphericalProjection {
+    /**
+     * Video represents a sphere mapped on a flat surface using
+     * equirectangular projection.
+     */
+    AV_SPHERICAL_EQUIRECTANGULAR,
+
+    /**
+     * Video frame is split into 6 faces of a cube, and arranged on a
+     * 3x2 layout. Faces are oriented upwards for the front, left, right,
+     * and back faces. The up face is oriented so the top of the face is
+     * forwards and the down face is oriented so the top of the face is
+     * to the back.
+     */
+    AV_SPHERICAL_CUBEMAP,
+
+    /**
+     * Video represents a portion of a sphere mapped on a flat surface
+     * using equirectangular projection. The @ref bounding fields indicate
+     * the position of the current video in a larger surface.
+     */
+    AV_SPHERICAL_EQUIRECTANGULAR_TILE,
+};
+
+/**
+ * This structure describes how to handle spherical videos, outlining
+ * information about projection, initial layout, and any other view modifier.
+ *
+ * @note The struct must be allocated with av_spherical_alloc() and
+ *       its size is not a part of the public ABI.
+ */
+typedef struct AVSphericalMapping {
+    /**
+     * Projection type.
+     */
+    enum AVSphericalProjection projection;
+
+    /**
+     * @name Initial orientation
+     * @{
+     * There fields describe additional rotations applied to the sphere after
+     * the video frame is mapped onto it. The sphere is rotated around the
+     * viewer, who remains stationary. The order of transformation is always
+     * yaw, followed by pitch, and finally by roll.
+     *
+     * The coordinate system matches the one defined in OpenGL, where the
+     * forward vector (z) is coming out of screen, and it is equivalent to
+     * a rotation matrix of R = r_y(yaw) * r_x(pitch) * r_z(roll).
+     *
+     * A positive yaw rotates the portion of the sphere in front of the viewer
+     * toward their right. A positive pitch rotates the portion of the sphere
+     * in front of the viewer upwards. A positive roll tilts the portion of
+     * the sphere in front of the viewer to the viewer's right.
+     *
+     * These values are exported as 16.16 fixed point.
+     *
+     * See this equirectangular projection as example:
+     *
+     * @code{.unparsed}
+     *                   Yaw
+     *     -180           0           180
+     *   90 +-------------+-------------+  180
+     *      |             |             |                  up
+     * P    |             |             |                 y|    forward
+     * i    |             ^             |                  |   /z
+     * t  0 +-------------X-------------+    0 Roll        |  /
+     * c    |             |             |                  | /
+     * h    |             |             |                 0|/_____right
+     *      |             |             |                        x
+     *  -90 +-------------+-------------+ -180
+     *
+     * X - the default camera center
+     * ^ - the default up vector
+     * @endcode
+     */
+    int32_t yaw;   ///< Rotation around the up vector [-180, 180].
+    int32_t pitch; ///< Rotation around the right vector [-90, 90].
+    int32_t roll;  ///< Rotation around the forward vector [-180, 180].
+    /**
+     * @}
+     */
+
+    /**
+     * @name Bounding rectangle
+     * @anchor bounding
+     * @{
+     * These fields indicate the location of the current tile, and where
+     * it should be mapped relative to the original surface. They are
+     * exported as 0.32 fixed point, and can be converted to classic
+     * pixel values with av_spherical_bounds().
+     *
+     * @code{.unparsed}
+     *      +----------------+----------+
+     *      |                |bound_top |
+     *      |            +--------+     |
+     *      | bound_left |tile    |     |
+     *      +<---------->|        |<--->+bound_right
+     *      |            +--------+     |
+     *      |                |          |
+     *      |    bound_bottom|          |
+     *      +----------------+----------+
+     * @endcode
+     *
+     * If needed, the original video surface dimensions can be derived
+     * by adding the current stream or frame size to the related bounds,
+     * like in the following example:
+     *
+     * @code{c}
+     *     original_width  = tile->width  + bound_left + bound_right;
+     *     original_height = tile->height + bound_top  + bound_bottom;
+     * @endcode
+     *
+     * @note These values are valid only for the tiled equirectangular
+     *       projection type (@ref AV_SPHERICAL_EQUIRECTANGULAR_TILE),
+     *       and should be ignored in all other cases.
+     */
+    uint32_t bound_left;   ///< Distance from the left edge
+    uint32_t bound_top;    ///< Distance from the top edge
+    uint32_t bound_right;  ///< Distance from the right edge
+    uint32_t bound_bottom; ///< Distance from the bottom edge
+    /**
+     * @}
+     */
+
+    /**
+     * Number of pixels to pad from the edge of each cube face.
+     *
+     * @note This value is valid for only for the cubemap projection type
+     *       (@ref AV_SPHERICAL_CUBEMAP), and should be ignored in all other
+     *       cases.
+     */
+    uint32_t padding;
+} AVSphericalMapping;
+
+/**
+ * Allocate a AVSphericalVideo structure and initialize its fields to default
+ * values.
+ *
+ * @return the newly allocated struct or NULL on failure
+ */
+AVSphericalMapping *av_spherical_alloc(size_t *size);
+
+/**
+ * Convert the @ref bounding fields from an AVSphericalVideo
+ * from 0.32 fixed point to pixels.
+ *
+ * @param map    The AVSphericalVideo map to read bound values from.
+ * @param width  Width of the current frame or stream.
+ * @param height Height of the current frame or stream.
+ * @param left   Pixels from the left edge.
+ * @param top    Pixels from the top edge.
+ * @param right  Pixels from the right edge.
+ * @param bottom Pixels from the bottom edge.
+ */
+void av_spherical_tile_bounds(const AVSphericalMapping *map,
+                              size_t width, size_t height,
+                              size_t *left, size_t *top,
+                              size_t *right, size_t *bottom);
+
+/**
+ * Provide a human-readable name of a given AVSphericalProjection.
+ *
+ * @param projection The input AVSphericalProjection.
+ *
+ * @return The name of the AVSphericalProjection, or "unknown".
+ */
+const char *av_spherical_projection_name(enum AVSphericalProjection projection);
+
+/**
+ * Get the AVSphericalProjection form a human-readable name.
+ *
+ * @param name The input string.
+ *
+ * @return The AVSphericalProjection value, or -1 if not found.
+ */
+int av_spherical_from_name(const char *name);
+/**
+ * @}
+ * @}
+ */
+
+#endif /* AVUTIL_SPHERICAL_H */