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

src/game/Towers.cpp

@@ -213,7 +213,7 @@ void ArcherTower::tick(std::uint64_t delta, World* world) {
         std::uint8_t arrows = explosiveArrows ? 2 : getLevel().getLevel();
         for (MobPtr mob : world->getMobList()) {
             if (isMobInRange(mob)) {
-                world->OnArcherTowerShot(mob, this);
+                world->notifyListeners(&WorldListener::OnArcherTowerShot, mob, this);
                 m_Timer.applyCooldown();
                 arrowsShot++;
                 if (arrowsShot >= arrows)
@@ -229,7 +229,7 @@ void IceTower::tick(std::uint64_t delta, World* world) {
         for (MobPtr mob : world->getMobList()) {
             if (isMobInRange(mob)) {
                 mob->addEffect(EffectType::Slowness, 1, this);    // slowness for 1s every second
-                mob->damage(damage, this);
+                world->notifyListeners(&WorldListener::OnMobDamage, mob, damage, this);
                 m_Timer.applyCooldown();
             }
         }
@@ -252,7 +252,7 @@ void PoisonTower::tick(std::uint64_t delta, World* world) {
         for (MobPtr mob : world->getMobList()) {
             if (isMobInRange(mob)) {
                 if (getLevel().getPath() == TowerPath::Bottom) {
-                    mob->damage(getStats()->getDamage(), this);
+                    world->notifyListeners(&WorldListener::OnMobDamage, mob, getStats()->getDamage(), this);
                 } else {
                     float durationSec;
                     switch (getLevel().getLevel()) {

src/game/World.cpp

@@ -13,7 +13,7 @@ namespace td {
 namespace game {
 
 World::World(Game* game) : m_Game(game) {
-
+    bindListener(this);
 }
 
 TilePtr World::getTile(std::int32_t x, std::int32_t y) const {
@@ -400,30 +400,31 @@ TowerPtr World::getTowerById(TowerID towerID) {
 
 void World::OnArcherTowerShot(MobPtr target, ArcherTower* shooter) {
     bool explosiveArrows = shooter->getLevel().getPath() == TowerPath::Bottom;
+    notifyListeners(&WorldListener::OnArrowShot, target, shooter);
     if (explosiveArrows) {
-        OnArrowShot(target, shooter);
+        notifyListeners(&WorldListener::OnExplosion, utils::shape::Circle{ target->getCenterX(), target->getCenterY(), 1.0f }, 10.0f, shooter);
-        OnExplosion({ target->getCenterX(), target->getCenterY(), 1.0f }, 10.0f, shooter);
-    } else {
-        OnArrowShot(target, shooter);
     }
 }
 
 void World::OnArrowShot(MobPtr target, Tower* shooter) {
-    OnMobDamage(target, shooter->getStats()->getDamage(), shooter);
+    notifyListeners(&WorldListener::OnMobDamage, target, shooter->getStats()->getDamage(), shooter);
 }
 
 void World::OnExplosion(utils::shape::Circle explosion, float centerDamage, Tower* shooter) {
     for (MobPtr mob : m_Mobs) {
-        if (mob->collidesWith(explosion)) {
+        if (mob->isAlive() && mob->collidesWith(explosion)) {
             // linear distance damage reduction
             float explosionDamage = mob->distance(explosion) / explosion.getRadius() * centerDamage;
-            OnMobDamage(mob, explosionDamage, shooter);
+            notifyListeners(&WorldListener::OnMobDamage, mob, explosionDamage, shooter);
         }
     }
 }
 
-void World::OnMobDamage(MobPtr target, float damage, Tower* source){
+void World::OnMobDamage(MobPtr target, float damage, Tower* source) {
     target->damage(damage, source);
+    if (target->isDead()) {
+        notifyListeners(&WorldListener::OnMobDead, target);
+    }
 }
 
 Team& World::getRedTeam() {