pull script/event changes from `loek/collision-system`

1 files changed, 53 insertions, 7 deletions

diff --git a/src/crepe/api/Script.h b/src/crepe/api/Script.h
index c9eb211..373b253 100644
--- a/src/crepe/api/Script.h
+++ b/src/crepe/api/Script.h
@@ -18,8 +18,10 @@ class ComponentManager;
  * This class is used as a base class for user-defined scripts that can be added to game
  * objects using the \c BehaviorScript component.
  *
- * \note Additional *events* (like Unity's OnDisable and OnEnable) should be implemented as
+ * \info Additional *events* (like Unity's OnDisable and OnEnable) should be implemented as
  * member or lambda methods in derivative user script classes and registered in \c init().
+ *
+ * \see feature_script
  */
 class Script {
 protected:
@@ -88,18 +90,40 @@ protected:
 	void logf(Args &&... args);
 
 	/**
-	 * \brief Subscribe to an event
-	 *
+	 * \brief Subscribe to an event with an explicit channel
+	 * \see EventManager::subscribe
+	 */
+	template <typename EventType>
+	void subscribe(const EventHandler<EventType> & callback, event_channel_t channel);
+	/**
+	 * \brief Subscribe to an event on EventManager::CHANNEL_ALL
 	 * \see EventManager::subscribe
 	 */
 	template <typename EventType>
-	void subscribe(const EventHandler<EventType> & callback, event_channel_t channel = EventManager::CHANNEL_ALL);
+	void subscribe(const EventHandler<EventType> & callback);
 
 	//! \}
 
+private:
+	/**
+	 * \brief Internal subscribe function
+	 *
+	 * This function exists so certain template specializations of Script::subscribe can be
+	 * explicitly deleted, and does the following:
+	 * - Wrap the user-provided callback in a check that tests if the parent BehaviorScript
+	 *   component is still active
+	 * - Store the subscriber handle returned by the event manager so this listener is
+	 *   automatically unsubscribed at the end of this Script instance's life
+	 *
+	 * \tparam EventType concrete Event class
+	 * \param callback User-provided callback function
+	 * \param channel Event channel (may have been overridden by template specializations)
+	 */
+	template <typename EventType>
+	void subscribe_internal(const EventHandler<EventType> & callback, event_channel_t channel);
+
 protected:
-	// NOTE: Script must have a constructor without arguments so the game programmer doesn't need
-	// to manually add `using Script::Script` to their concrete script class.
+	// NOTE: This must be the only constructor on Script, see "Late references" below
 	Script() = default;
 	//! Only \c BehaviorScript instantiates Script
 	friend class BehaviorScript;
@@ -107,6 +131,7 @@ public:
 	// std::unique_ptr destroys script
 	virtual ~Script();
 
+private:
 	Script(const Script &) = delete;
 	Script(Script &&) = delete;
 	Script & operator=(const Script &) = delete;
@@ -119,10 +144,19 @@ private:
 	 * These references are set by BehaviorScript immediately after calling the constructor of
 	 * Script.
 	 *
+	 * \note Script must have a constructor without arguments so the game programmer doesn't need
+	 * to manually add `using Script::Script` to their concrete script class if they want to
+	 * implement a non-default constructor (e.g. for passing references to their own concrete
+	 * Script classes).
+	 *
+	 * \todo These should be converted to OptionalRef<> once `loek/util` is merged
+	 *
 	 * \{
 	 */
 	//! Game object ID of game object parent BehaviorScript is attached to
-	game_object_id_t game_object_id = -1;
+	const game_object_id_t * game_object_id_ref = nullptr;
+	//! Reference to parent component
+	bool * active_ref = nullptr;
 	//! Reference to component manager instance
 	ComponentManager * component_manager_ref = nullptr;
 	//! Reference to event manager instance
@@ -136,6 +170,18 @@ private:
 	std::vector<subscription_t> listeners;
 };
 
+/**
+ * \brief Subscribe to CollisionEvent for the current GameObject
+ *
+ * This is a template specialization for Script::subscribe which automatically sets the event
+ * channel so the callback handler is only called for CollisionEvent events that apply to the
+ * current GameObject the parent BehaviorScript is attached to.
+ */
+template <>
+void Script::subscribe(const EventHandler<CollisionEvent> & callback);
+template <>
+void Script::subscribe(const EventHandler<CollisionEvent> & callback, event_channel_t) = delete;
+
 } // namespace crepe
 
 #include "Script.hpp"