With multitouch, register to receive XI_Motion (which desctivates MotionNotify),
so that we can distinguish real mouse motions from synthetic one.
(bug 4690)
Touch device types include SDL_TOUCH_DEVICE_DIRECT (a touch screen with window-relative coordinates for touches), SDL_TOUCH_DEVICE_INDIRECT_ABSOLUTE (a trackpad-style device with absolute device coordinates), and SDL_TOUCH_DEVICE_INDIRECT_RELATIVE (a trackpad-style device with screen cursor-relative coordinates).
Phone screens are an example of a direct device type. Mac trackpads are the indirect-absolute touch device type. The Apple TV remote is an indirect-relative touch device type.
"Applications (such as SDL's testgesture) do "event.tfinger.x * window_width"
to find window coord. Currently the X11 XInput2 backend expects application
to do "event.tfinger.x * (window_width-1)" instead.
X11 XInput2 touch events are normalized so x is 1.0 at "width - 1" but other
SDL backends appear to have x be 1.0 at "width". Same issue for touch event
y with regards to height."
Fixes Bugzilla #4183.
Trent Gamblin
The documentation for SDL_TouchFingerEvent says that the x and y coordinates are normalised between 0-1. I've found that to be true on Windows, Android and iOS but on X11 they are in pixel coordinates. This patch fixes the issue. This was the cleanest way I could do it with what was available without changing things around a lot but you may know a better way.
The internal function SDL_EGL_LoadLibrary() did not delete and remove a mostly
uninitialized data structure if loading the library first failed. A later try to
use EGL then skipped initialization and assumed it was previously successful
because the data structure now already existed. This led to at least one crash
in the internal function SDL_EGL_ChooseConfig() because a NULL pointer was
dereferenced to make a call to eglBindAPI().
