feat: add world notifier

include/game/World.h

@@ -10,6 +10,8 @@
 #include "Mobs.h"
 #include "Team.h"
 
+#include "misc/ObjectNotifier.h"
+
 namespace td {
 namespace game {
 typedef std::pair<std::int16_t, std::int16_t> ChunkCoord;
@@ -123,10 +125,14 @@ public:
     virtual void OnArrowShot(MobPtr target, Tower* shooter){}
     virtual void OnExplosion(utils::shape::Circle explosion, float centerDamage, Tower* shooter){}
 
-    virtual void OnMobDamage(MobPtr target, float damage){}
+    virtual void OnMobDamage(MobPtr target, float damage, Tower* damager){}
+
+    virtual void OnMobDead(MobPtr mob){}
 };
 
-class World : public WorldListener{
+typedef utils::ObjectNotifier<WorldListener> WorldNotifier;
+
+class World : public WorldNotifier, public WorldListener{
 protected:
     TowerTileColorPalette m_TowerPlacePalette;
     Color m_WalkablePalette;

include/misc/ObjectNotifier.h

@@ -0,0 +1,36 @@
+#pragma once
+
+#include <algorithm>
+#include <functional>
+#include <vector>
+
+namespace td {
+namespace utils {
+
+template <typename Listener>
+class ObjectNotifier {
+protected:
+    std::vector<Listener*> m_Listeners;
+
+public:
+    void bindListener(Listener* listener) {
+        m_Listeners.push_back(listener);
+    }
+
+    void unbindListener(Listener* listener) {
+        auto iter = std::find(m_Listeners.begin(), m_Listeners.end(), listener);
+
+        if(iter == m_Listeners.end()) return;
+
+        m_Listeners.erase(iter);
+    }
+
+    template <typename Func, typename... Args>
+    void notifyListeners(Func function, Args... args) {
+        for (Listener* listener : m_Listeners)
+            std::bind(function, listener, args...)();
+    }
+};
+
+} // namespace utils
+} // namespace td