When multiple controller or other Input devices are mapped to the same InputMap action, the action is "eaten" or not consistently triggered

[golddotasksquestions]

Tested versions

Godot 3.5.3 stable, 4.2.1 stable, 4.3. Dev1

System information

Win 10, Nvidea RTX 1080, GLES3, Forward+

Issue description

In situations where two or more controllers or other input devices have the same event mapped to an InputMap action I would expect all input presses and releases to be registered.

This however is not the case in any Godot version I have tested.

This is especially problematic for couch coop games when many players should be allowed to perform the same action. With Godot's current implementation the Godot dev cannot decide which input to give priority or which input to neglect, or to execute on all of the registered input presses or releases, because not all of the Input presses and releases are registered and triggered.

Example:

Given two joypads are mapped to the same action (let's call the action "joy_a") and both press the mapped input (let's say button A on two Xbox controller for example), then one of the joypads released the button and then the other ...

func _process(delta):
	if Input.is_action_just_pressed("joy_a"):
		print("joy_a is just pressed")
	if Input.is_action_just_released("joy_a"):
		print("joy_a is just released")

I would expect this to print:

joy_a is just pressed
joy_a is just pressed
joy_a is just released
joy_a is just released

So all of the joypad "presses" and "releases" I would expect to register and print.
I tested this in Godot 3.5.3, 4.2.1 and 4.3.dev1, none of those produce this result:

Godot 3.5.3:

joy_a is just pressed
joy_a is just released

Godot 4.2.1:

joy_a is just pressed
joy_a is just released
joy_a is just released

Godot 4.3 dev1:

joy_a is just pressed
joy_a is just released

I also tested all of this with a single Input (All Devices) mapping, and with two mappings (for both Device 0, Device 1), same result. To be clear, I would expected the result to be the same. I just wanted to be sure this is not correlated.

It first glance it seems like Godot 3.5.3 and Godot 4.3. Dev1 behave the same. But they do not. If you press and hold A on joypad_0, then repeatedly quickly press A on the other joypad_1 (while still holding A on joypad__0), in Godot 3.5.3, the first "press" is from the joypad_0, the first "release" is from joypad_1, and then it's only joypad_1 printing "press" and "release":

Godot 3.5.3:

joy_a is just pressed (joypad_0)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)

Note: When finally releasing A on joypad_0, (which was held all while pressing A joypad_1 repeatedly), it won't print "released"!

In Godot 4.2.1:

joy_a is just pressed (joypad_0)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just released (joypad_0)

In contrast to Godot 3.5.3, joypad_0 will print "release" once it is finally released! But the first joypad_1 "pressed" is not printed.

In Godot 4.3 Dev1:

joy_a is just pressed (joypad_0)
joy_a is just released (joypad_0)

Godot 4.3 Dev1 is totally different once again, not printing either "pressed" nor "released" of joypad_1, regardless how often you press A on joypad_1, while Button A of joypad_0 is held.

To reiterate, what I would expect is all joypad presses and released to register and print. So in the above example of A on joypad_0 being held while A on joypad_1 is repeadedly pressed, I would expect this to print:

joy_a is just pressed (joypad_0)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just pressed (joypad_ 1)
joy_a is just released (joypad_ 1)
joy_a is just released (joypad_0)

However none of the Godot versions I tested behaved as expected.

Steps to reproduce

1. Connect two joypad controllers.
2. In the InputMap Project Settings map Joy button A (All Devices or both devices separately, does not matter) to the same input action called "joy_a"
3. run the code example below:

func _process(delta):
	if Input.is_action_just_pressed("joy_a"):
		print("joy_a is just pressed")
	if Input.is_action_just_released("joy_a"):
		print("joy_a is just released")

Minimal reproduction project (MRP)

Godot 4.3. Dev1:
multiple_devices_same_input_action_bug.zip

Unsure if this is a related issue: #86272

[golddotasksquestions]

Btw, I currently work around this issue by creating individual actions for each controller which connects. Imho this should not be necessary, and is a rather advanced solutions as it requires a fair bit of custom code and good understanding of InputMap and InputEvent classes. This is also not a solution for coop games which are not controlled by controllers.

[groud]

My opinion on the matter is that the behavior of is_action_just_pressed() and is_action_just_released() should be consistent with the result of is_action_pressed(). Basically, when is_action_just_pressed() is true, then is_action_pressed() should return true and when is_action_just_released() is true, then is_action_pressed() should return false. This proposal of having is_action_just_pressed/released() triggered for every event would make managing actions a lot more complex and inconsistent.

As an example, with this solution, you could have is_action_pressed() being false just after is_action_just_released() if not all devices (keyboard and controllers) were not all released.

Btw, I currently work around this issue by creating individual actions for each controller which connects. Imho this should not be necessary, and is a rather advanced solutions as it requires a fair bit of custom code and good understanding of InputMap and InputEvent classes. This is also not a solution for coop games which are not controlled by controllers.

Having one action for each controller is not necessary (if you want one player to use whatever device they plugged in), but for each player, it is. And it has always been the case as far as I can tell. Each action has only one boolean status (and its associated strength), so is_action_pressed has never been able to handle several players at once anyway. The usual strategy is to have several actions, with similar names, one per player. (I wish this could be improved somehow, but that deserves a proposal)

[golddotasksquestions]

I disagree strongly. This is not consistent behavior at all.

is_action_pressed() should return true for as long as any of the Input devices presses this action.

Instead of eating inputs, if you want to differentiate, I think it would be much more sensible to add device as an argument to is_action_pressed() or is_action_released() , with the default being All Devices.