This is a battery-saving measure. Whether a sensor should be suspended
is determined in the same way as whether key events and motion events
should be handled by the OS rather than consumed by Dolphin.
When Android presents an input event to an app, it wants the app to
return true or false depending on whether the app handled the event or
not. If the event wasn't handled by the app, it will be passed on to
the system, which may decide to take an action depending on what kind
of input event it is. For instance, if a B button press is passed on to
the system, it will be turned into a Back press. But if an R1 press is
passed on to the system, nothing in particular happens.
It's important that we get this return value right in Dolphin. For
instance, the user generally wouldn't want a B button press to open
the EmulationActivity menu, so B button presses usually shouldn't be
passed on to the system - but volume button presses usually should be
passed on to the system, since it would be hard to adjust the volume
otherwise. What ButtonManager did was to pass on input events that are
for a button which the user has not mapped, which I think makes sense.
But exactly how to implement that is more complicated in the new input
backend than in ButtonManager, because now we have a separation between
the input backend and the code that keeps track of the user's mappings.
What I'm going with in this commit is to treat an input as mapped if
it has been polled recently. In part I chose this because it seemed
like a simple way of implementing it that wouldn't cause too many
layering violations, but it also has two useful side effects:
1. If a controller is not being polled (e.g. GameCube controllers in
Wii games that don't use them), its mappings will not be considered.
2. Once sensor input is implemented in the Android input backend,
we will be able to use this "polled recently" tracking to power down
the sensors at times when the game is using a Wii Remote reporting
mode that doesn't include motion data. (Assuming that the sensor
inputs only are mapped to Wii Remote motion controls, that is.)
Android doesn't let us poll inputs whenever we want. Instead, we
listen to input events (activities will have to forward them to the
input backend), and store the received values in atomic variables
in the Input classes. This is similar in concept to how ButtonManager
worked, but without its homegrown second input mapping system.
ButtonManager is very different from how a normal input backend works,
and is making it hard for us to improve controller support on Android.
The following commits will add a new input backend in its place.
When that setting is enabled, m_xfb_entry is initially not present (during the phase where a shader compilation progress bar would be shown). The main path checks for m_xfb_entry, but the software renderer fallback path didn't.
Fixes another aspect of https://bugs.dolphin-emu.org/issues/13172.
Before, it used a fallback where it returned a default object, where the width and height were set to 0. Presenter::Initialize() used GetSurfaceInfo to set the backbuffer size, then used that size when initializing the on-screen UI (even for the software renderer, where the on-screen UI isn't currently present), which meant that ImGui got a window size of 0 and thus resulted in a failed assertion.
Although BindBackbuffer checks for size changes, it doesn't help because ImGui has already been initialized, and the size hasn't actually changed since initialization occured.
Fixes one aspect of https://bugs.dolphin-emu.org/issues/13172.
JosJuice