On Sat, Nov 12, 2016 at 9:41 AM, James Almer <jamr...@gmail.com> wrote:
> On 11/11/2016 10:39 PM, Michael Niedermayer wrote:
>> On Fri, Nov 11, 2016 at 05:49:00PM -0500, Vittorio Giovara wrote:
>> [...]
>>> +/**
>>> + * 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
>>> + * @{
>>> + * These fields represent the pose values that measure the rotation
>>> + * transformation (in degrees) to be applied to the projection.
>>> + * See this equirectangular projection as example:
>>> + *
>>> + * @code{.unparsed}
>>> + * Yaw
>>> + * -180 0 180
>>> + * 90 +-------------+-------------+ 180
>>> + * | | |
>>> + * P | | o> |
>>> + * i | ^ |
>>> + * t 0 +-------------X-------------+ 0 Roll
>>> + * c | | |
>>> + * h | | |
>>> + * | | |
>>> + * -90 +-------------+-------------+ -180
>>> + *
>>> + * X - the default camera center
>>> + * ^ - the default up vector
>>> + * > - the up vector for a rotation of 90 degrees
>>> + * o - the image center for yaw = 90, pitch = 45, roll = 0
>>> + * @endcode
>>> + *
>>> + * The order of transformation is always yaw, followed by pitch, and
>>> + * finally by roll.
>>> + */
>>
>>> + double yaw; ///< Clockwise rotation around the up vector [-180, 180].
>>> + double pitch; ///< Counter-clockwise rotation around the right vector
>>> [-90, 90].
>>> + double roll; ///< Counter-clockwise rotation around the forward
>>> vector [-180, 180].
>>
>> please use intXY (64 or 32 as preferred) so there are no platform
>> rounding dependancies
These are rotation angles which are inherently floating point, and
consistent with what other rotation-related APIs export (eg.
av_display_matrix_rotation_get()). Besides using intXX would lose
precision that the original specification offers.
--
Vittorio
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