Old sliders required some of their associated cvars to be "extern" so
their current value could be read. That's no longer needed, so they are
"static" now.
"menuslider_s" types, used to create sliders in menus, now are directly
associated to a cvar. That makes possible for them to get their
currently selected value from the cvar, and express their min and max
values in terms of the real values of the cvar.
The rhythm at how they change can be overridden with s->slidestep.
The new sliders also present visually their current value to the user,
making them more useful than before.
"init_delay" was renamed to "updates_countdown", since it's now a "general
purpose" countdown, having also to count the inputs left for gyro calibration,
besides controller initialization.
Reason for the countdown is now explicit, not having to depend if
"gyro_calibration" was true or not to select what was the purpose of the
countdown.
Explanation comment added for gyro initialization on Linux & Mac.
REMINDER: see if SDL2 will keep the difference of gyro readings between Windows
and Linux/Mac for the Switch controllers.
For example, on Windows with AMDs drivers, GLES3 isn't supported,
so CreateSDLWindow() will fail. We should just try the regular GL3
renderer then instead of exiting with Com_Error()
Also make (Windows') Sys_Error() print to stdout (in addition to stderr),
so errors end up in stdout.txt as well (like all other messages).
SDL2 provides different gyro readings between Windows and Linux/Mac for
the Switch Pro Controller. To keep the natural sensitivity scale intact
(in-game turn = controller turn), the normalization factor is handled
differently by platform, at least for now.
Also, now giving info when there's no gyro sensor available/detected.
And green light for the DualShock 4, because why not :)
Cvar to choose between "yaw" (0) or "roll" (1) axis of the controller
to turn (change your yaw) in-game.
Cvars to change pitch and yaw gyro sensitivities.
Updated cvar documentation with new section "Game Controller".
SDL 2.0.16 and a controller with a gyroscope required to make it work.
Manual calibration of the gyro sensor is needed to avoid "drifting"; a menu
option to do it is included.
New cvar 'gyro_mode' for mode of operation, and to assign action to the new
"+gyroaction" button: disable or enable the gyro.
Several effects use dlights which are rendered for only one frame.
Muzzle flashes are an example. While this worked on 1997th computers,
todays hardware renders way too many frames for these dlights to be
visible at all. Work around that by enforcing a minimal display time
of 32 milliseconds for each dlight.
Fixes part of #815.
