Add deadzone for joypad motion detection (#3)

Prior to this change, if there was both a keyboard and joypad connected
and the user was using the keyboard, but there was some stick drift with
the joypad, input detection would bounce between keyboard and joypad.

This change adds a minimum axis_value that an InputEventJoypadMotion
must have before being detecting the input type as a joypad.

The minimum axis_value is configurable via ProjectSettings.

Co-authored-by: John Pennycook <john.pennycook@gmail.com>

addons/input_prompts/input_prompt_manager.gd

@@ -44,6 +44,12 @@ var preferred_icons := InputPrompt.Icons.AUTOMATIC:
 			icons = value
 		emit_signal("icons_changed")
 
+## The deadzone value used to detect joypad activity. The default value is determined by the
+## "addons/input_prompts/joypad_detection_deadzone" setting in [ProjectSettings].
+var joypad_detection_deadzone := ProjectSettings.get_setting(
+	"addons/input_prompts/joypad_detection_deadzone", 0.5
+)
+
 
 ## Force all [InputPrompt] nodes to refresh their icons and events.
 ## Must be called if the [InputMap] is changed.
@@ -106,6 +112,10 @@ func _input(event: InputEvent):
 			icons = InputPrompt.Icons.KEYBOARD
 			emit_signal("icons_changed")
 	if event is InputEventJoypadButton or event is InputEventJoypadMotion:
+		# Do not detect Joypad unless value exceeds deadzone
+		if event is InputEventJoypadMotion and absf(event.axis_value) < joypad_detection_deadzone:
+			return
+
 		var device = event.device
 		var joy_name = Input.get_joy_name(device)
 		if joy_name.find("Xbox"):

addons/input_prompts/plugin.gd

@@ -10,6 +10,20 @@ func _enter_tree():
 	add_autoload_singleton("PromptManager", "res://addons/input_prompts/input_prompt_manager.gd")
 	add_inspector_plugin(inspector_plugin)
 
+	if Engine.is_editor_hint():
+		var deadzone_setting := "addons/input_prompts/joypad_detection_deadzone"
+		if not ProjectSettings.has_setting(deadzone_setting):
+			ProjectSettings.set_setting(deadzone_setting, 0.5)
+			ProjectSettings.set_initial_value(deadzone_setting, 0.5)
+			ProjectSettings.set_as_basic(deadzone_setting, true)
+			var property_info = {
+				"name": deadzone_setting,
+				"type": TYPE_FLOAT,
+				"hint": PROPERTY_HINT_RANGE,
+				"hint_string": "0,1"
+			}
+		ProjectSettings.save()
+
 
 func _exit_tree():
 	remove_inspector_plugin(inspector_plugin)