This abstracts away the details of particular input devices for netplay,
and adds support for mice and (similar) lightguns. Unfortunately, in
practice, no core handles mice or lightguns in a savestate-safe way, so
they need to be used in stateless mode to be reliable, but they do work.
(1) All mode change code unified, so server mode changes and client mode
changes and announcements go through the same functions
(2) New messages which are translateable and work with multiple input
devices
The new input handling makes adding and removing players more
complicated, since data can be present that's not expected from the
connected clients list, or absent that's expected in the list but
actually shouldn't be there.
== DETAILS
This should fix#6025.
After confirming that dummying out the init block of the HID subsystem
driver eliminated the crash, I narrowed it down to the event loop.
And that's when I noticed that, when the thread consumes the event,
it doesn't free it.
Oops.
Updated the event loop to free the event after it has been processed.
== TESTING
Local build, was able to load multiple ROMs in succession where prior
I was getting the system memory errors.
I've #if 0'd out a call to HIDRead that is still getting deadlocked,
because it slows down the startup/shutdown process.
== DETAILS
The joypad driver was only copying the first 16 bits when executing
get_buttons(). The touchpad button is bit 19, so as a result
RETRO_DEVICE_ID_POINTER_PRESSED would never fire.
We fix this for now by copying 32 bits.
== TESTING
Will need someone to verify. I don't have a core handy that leverages
the pointer device state functionality.
