This change introduces the standard gamepad layout. This changes adds
these APIs:
* func HasGamepadStandardLayoutMapping
* func IsGamepadStandardButtonPressed
* func GamepadStandardAxisValue
* type StandardGamepadButton
* type StandardGamepadAxis
The standard gamepad layout is based on the web standard. See
https://www.w3.org/TR/gamepad/#remapping.
On desktops, the SDL's gamecontrllerdb.txt is used. If the gamepad is
listed in the text file, the mapping works. GLFW's mapping featrue is
not used.
On browsers, the property of a gamepad 'mapping' is used. When the
mapping value is 'standard', the gamepad is recognized to have the
standard mapping.
On mobiles, the implementation is still WIP.
Updates #1557
Callbacks created by NewCallbackCDecl were never released and then
they are leaked, especially when the window size was changed by
SetWindowSize on Windows.
This change defines new callback ID types with uintptr, and reuse
the callbacks.
Closes#1672
Before the initialization finishes, AdjustPosition could return Inf
values and in this case AdjustPosition's returning values don't make
sense. Let's return NaN in this case.
Closes#1545
Apparently, there are some special devices that are recognized as
joysticks by GLFW, even though they are not. Such devices can have
too many 'buttons'. Skip them as a tentative solution.
Updates #1173
Gamepad GUID is a SDL specific notion and, strictly speaking,
they are not GUID (UUID) since they don't follow UUID's
specifications.
Renaming the function makes the situation clearer.
Updates #1048
