signal bus and entity invoking them

base/scripts/autoload/game_signal_bus.gd

@@ -0,0 +1,30 @@
+extends Node
+
+#region Entity
+
+## Invoked when entity is damaged or healed
+signal entity_hp_changed(context : Entity.HPChangedContext)
+
+## Invoked when entity is spawned
+signal entity_spawned(entity : Entity)
+
+## Invoked when entity is killed
+signal entity_killed(entity : Entity.KilledContext)
+
+#endregion
+
+#region Player interactions
+
+## Invoked when interactable detects mouse pointer over it
+signal interactable_hover_begin(interactable : InteractiveObject)
+
+## Invoked when interactable detects mouse pointer exit
+signal interactable_hover_end(interactable : InteractiveObject)
+
+## Invoked when interactable is interacted
+signal interactable_used(interactable : InteractiveObject)
+
+## Invoked by and ammo change
+signal ammo_updated(current_ammo : int, max_ammo : int)
+
+#endregion

base/scripts/autoload/game_signal_bus.gd.uid

@@ -0,0 +1 @@
+uid://5r53k5fk8ouy

base/scripts/entity.gd

@@ -8,6 +8,8 @@ class_name Entity
 ## Current amount of health points of an entity. Cannot be below 0 or [code]max_hp[/code]
 var hp : float = max_hp
 
+func _ready() -> void:
+	GameSignalBus.entity_spawned.emit(self)
 
 ## Emitted when damage is taken
 signal damage_taken(context : DamageTakenContext)
@@ -31,6 +33,7 @@ func deal_damage(amount : float, source : Entity):
 	delta_context.target = self
 	delta_context.delta = -amount
 	hp_changed.emit(delta_context)
+	GameSignalBus.entity_hp_changed.emit(delta_context)
 	
 	hp -= amount
 	if hp <= 0:
@@ -51,6 +54,7 @@ func heal(amount : float, source : Entity):
 	delta_context.target = self
 	delta_context.delta = amount
 	hp_changed.emit(delta_context)
+	GameSignalBus.entity_hp_changed.emit(delta_context)
 	
 	hp += amount
 	if hp > max_hp:
@@ -63,6 +67,7 @@ func kill(source : Entity):
 	context.source = source
 	context.target = self
 	killed.emit(context)
+	GameSignalBus.entity_killed.emit(context)
 	
 	deconstruct()