Input handling in Godot 4.0 using GDExtension

This is a READ-ONLY snapshot of the Godot Community Forums when TwistedTwigleg was the owner, which is hosted for archival reasons only. The current Godot Community Forums can be found here.

Some links may point to external websites, including the current Godot Community Forums. These websites are not associated with TwistedTwigleg.

Input handling in Godot 4.0 using GDExtension

chanfort

I am upgrading some input handling code from Godot 3.5 to 4.0 and noticed that some parts are not working as expected. So was wondering to check if this might be a bug or intended behaviour which I am not aware of.

Here is the C++ code which I am using in 3.5 to separate generic input events into key, mouse button and mouse motion events.

void _input(Variant event) {
	Ref<InputEvent> input_event = event;

	if (input_event != nullptr) {
		Ref<InputEventKey> input_event_key = event;

		if (input_event_key != nullptr) {
			if (input_event_key->is_pressed()) {
				// Handle keyboard key press
			} else {
				// Handle keyboard key release
			}
		}

		Ref<InputEventMouseButton> input_mouse_button = event;

		if (input_mouse_button != nullptr) {
			int button_index = input_mouse_button->get_button_index();

			if (input_mouse_button->is_pressed()) {
				// Handle left and right mouse button press, and mouse wheel scrolls
				
			} else {
				// Handle left and right mouse button release
			}
		}

		Ref<InputEventMouseMotion> input_mouse_motion = event;

		if (input_mouse_motion != nullptr) {
			// Handle mouse motion
		}
	}
}

This was working well in 3.5. However, when running this in 4.0 all nullptr checks return false and it never goes into if statements. I also tried casting with these ones but it also does not allow me to separate between key, mouse button and mouse motion events. I.e. using static_cast I am never getting nullptr while using dynamic_cast and cast_to always comes as nullptr.

So was wondering if this is intended or it might be a bug? If it's intended then was wondering how could I distinguish between key, mouse button and mouse motion events?

chanfort

So after some investigation I find out how to handle this separation by using combo of static_cast and is_class. I guess that is a bit more similar to what GDScript is using with is keyword in official docs (i.e. https://docs.godotengine.org/en/stable/tutorials/inputs/input_examples.html). Anyways, here is the code which works in Godot 4 just in case others are strugling with input.

void _input(InputEvent *input_event) {
	bool is_input_event_key = input_event->is_class("InputEventKey");

	if (is_input_event_key) {
		InputEventKey *input_event_key = static_cast<InputEventKey *>(input_event);
		if (input_event_key->is_pressed()) {
			// Handle keyboard key press
		} else {
			// Handle keyboard key release
		}
	}

	bool is_input_event_mouse_button = input_event->is_class("InputEventMouseButton");

	if (is_input_event_mouse_button) {
		InputEventMouseButton *input_event_mouse_button = static_cast<InputEventMouseButton *>(input_event);

		if (input_event_mouse_button->is_pressed()) {
			// Handle left and right mouse button press, and mouse wheel scrolls
			
		} else {
			// Handle left and right mouse button release
		}
	}

	bool is_input_event_mouse_motion = input_event->is_class("InputEventMouseMotion");

	if (is_input_event_mouse_motion) {
		InputEventMouseMotion *input_event_mouse_motion = static_cast<InputEventMouseMotion *>(input_event);
		// Handle mouse motion
	}
}