Extract explosion logic to ExplosionManager class

Refactored explosion particle system management from RockFactory to a dedicated ExplosionManager class for better code organization and reusability.

- Created ExplosionManager with particle system pooling
- Removed explosion-specific code from RockFactory
- Simplified collision handler in RockFactory

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude <noreply@anthropic.com>

src/explosionManager.ts

@@ -0,0 +1,147 @@
+import {
+    MeshBuilder,
+    ParticleHelper,
+    ParticleSystem,
+    ParticleSystemSet,
+    Scene,
+    Vector3
+} from "@babylonjs/core";
+
+/**
+ * Configuration for explosion effects
+ */
+export interface ExplosionConfig {
+    /** Size of the explosion pool */
+    poolSize?: number;
+    /** Duration of explosion in milliseconds */
+    duration?: number;
+    /** Rendering group ID for particles */
+    renderingGroupId?: number;
+}
+
+/**
+ * Manages explosion particle effects with pooling for performance
+ */
+export class ExplosionManager {
+    private explosionPool: ParticleSystemSet[] = [];
+    private scene: Scene;
+    private config: Required<ExplosionConfig>;
+
+    // Default configuration
+    private static readonly DEFAULT_CONFIG: Required<ExplosionConfig> = {
+        poolSize: 10,
+        duration: 2000,
+        renderingGroupId: 1
+    };
+
+    constructor(scene: Scene, config?: ExplosionConfig) {
+        this.scene = scene;
+        this.config = { ...ExplosionManager.DEFAULT_CONFIG, ...config };
+    }
+
+    /**
+     * Initialize the explosion pool by pre-creating particle systems
+     */
+    public async initialize(): Promise<void> {
+        console.log(`Pre-creating ${this.config.poolSize} explosion particle systems...`);
+
+        for (let i = 0; i < this.config.poolSize; i++) {
+            const set = await ParticleHelper.CreateAsync("explosion", this.scene);
+            set.systems.forEach((system) => {
+                system.renderingGroupId = this.config.renderingGroupId;
+            });
+            this.explosionPool.push(set);
+        }
+
+        console.log(`Created ${this.config.poolSize} explosion particle systems in pool`);
+    }
+
+    /**
+     * Get an explosion from the pool
+     */
+    private getExplosionFromPool(): ParticleSystemSet | null {
+        return this.explosionPool.pop() || null;
+    }
+
+    /**
+     * Return an explosion to the pool after use
+     */
+    private returnExplosionToPool(explosion: ParticleSystemSet): void {
+        explosion.dispose();
+        ParticleHelper.CreateAsync("explosion", this.scene).then((set) => {
+            set.systems.forEach((system) => {
+                system.renderingGroupId = this.config.renderingGroupId;
+            });
+            this.explosionPool.push(set);
+        });
+    }
+
+    /**
+     * Play an explosion at the specified position with optional scaling
+     */
+    public playExplosion(position: Vector3, scaling: Vector3 = Vector3.One()): void {
+        const explosion = this.getExplosionFromPool();
+
+        if (!explosion) {
+            // Pool is empty, create explosion on the fly
+            console.log("Explosion pool empty, creating new explosion on demand");
+            ParticleHelper.CreateAsync("explosion", this.scene).then((set) => {
+                const point = MeshBuilder.CreateSphere("explosionPoint", {
+                    diameter: 0.1
+                }, this.scene);
+                point.position = position.clone();
+                point.isVisible = false;
+
+                set.start(point);
+
+                setTimeout(() => {
+                    set.dispose();
+                    point.dispose();
+                }, this.config.duration);
+            });
+        } else {
+            // Use pooled explosion
+            const point = MeshBuilder.CreateSphere("explosionPoint", {
+                diameter: 10
+            }, this.scene);
+            point.position = position.clone();
+            point.isVisible = false;
+            point.scaling = scaling.multiplyByFloats(0.2, 0.3, 0.2);
+
+            console.log("Using pooled explosion with", explosion.systems.length, "systems at", position);
+
+            // Set emitter and start each system individually
+            explosion.systems.forEach((system: ParticleSystem, idx: number) => {
+                system.emitter = point;
+                system.start();
+                console.log(`  System ${idx}: emitter set to`, system.emitter, "activeCount=", system.getActiveCount());
+            });
+
+            // Stop and return to pool after duration
+            setTimeout(() => {
+                explosion.systems.forEach((system: ParticleSystem) => {
+                    system.stop();
+                });
+                this.returnExplosionToPool(explosion);
+                point.dispose();
+            }, this.config.duration);
+        }
+    }
+
+    /**
+     * Get the current number of available explosions in the pool
+     */
+    public getPoolSize(): number {
+        return this.explosionPool.length;
+    }
+
+    /**
+     * Dispose of all pooled explosions
+     */
+    public dispose(): void {
+        this.explosionPool.forEach(explosion => {
+            explosion.dispose();
+        });
+        this.explosionPool = [];
+    }
+}

src/rockFactory.ts

@@ -19,6 +19,7 @@ import {Debug} from "@babylonjs/core/Legacy/legacy";
 import {createSphereLightmap} from "./sphereLightmap";
 import { GameConfig } from "./gameConfig";
 import { MaterialFactory } from "./materialFactory";
+import { ExplosionManager } from "./explosionManager";
 let _particleData: any = null;
 
 export class Rock {
@@ -38,20 +39,17 @@ export class RockFactory {
     private static _rockMesh: AbstractMesh;
     private static _rockMaterial: PBRMaterial;
     private static _originalMaterial: PBRMaterial = null;
-    private static _explosionPool: ParticleSystemSet[] = [];
+    private static _explosionManager: ExplosionManager;
-    private static _poolSize: number = 10;
     private static _viewer: PhysicsViewer = null;
+
     public static async init() {
-        // Pre-create explosion particle systems for pooling
+        // Initialize explosion manager
-        console.log("Pre-creating explosion particle systems...");
+        this._explosionManager = new ExplosionManager(DefaultScene.MainScene, {
-        for (let i = 0; i < this._poolSize; i++) {
+            poolSize: 10,
-            const set = await ParticleHelper.CreateAsync("explosion", DefaultScene.MainScene);
+            duration: 2000,
-            set.systems.forEach((system) => {
+            renderingGroupId: 1
-                system.renderingGroupId =1;
+        });
-            })
+        await this._explosionManager.initialize();
-            this._explosionPool.push(set);
-        }
-        console.log(`Created ${this._poolSize} explosion particle systems in pool`);
 
         if (!this._rockMesh) {
             await this.loadMesh();
@@ -85,16 +83,6 @@ export class RockFactory {
             importMesh.meshes[0].dispose();
         }
     }
-    private static getExplosionFromPool(): ParticleSystemSet | null {
-        return this._explosionPool.pop() || null;
-    }
-
-    private static returnExplosionToPool(explosion: ParticleSystemSet) {
-        explosion.dispose();
-        ParticleHelper.CreateAsync("explosion", DefaultScene.MainScene).then((set) => {
-            this._explosionPool.push(set);
-        })
-    }
 
     public static async createRock(i: number, position: Vector3, size: Vector3,
                                    score: Observable<ScoreEvent>): Promise<Rock> {
@@ -145,46 +133,8 @@ export class RockFactory {
                         eventData.collidedAgainst.transformNode.dispose();
                         eventData.collidedAgainst.dispose();
 
-                        // Get explosion from pool (or create new if pool empty)
+                        // Play explosion using ExplosionManager
-                        let explosion = RockFactory.getExplosionFromPool();
+                        RockFactory._explosionManager.playExplosion(position, scaling);
-
-                        if (!explosion) {
-                            console.log("Pool empty, creating new explosion");
-                            ParticleHelper.CreateAsync("explosion", DefaultScene.MainScene).then((set) => {
-                                const point = MeshBuilder.CreateSphere("point", {diameter: 0.1}, DefaultScene.MainScene);
-                                point.position = position.clone();
-                                point.isVisible = false;
-
-                                set.start(point);
-
-                                setTimeout(() => {
-                                    set.dispose();
-                                    point.dispose();
-                                }, 2000);
-                            });
-                        } else {
-                            // Use pooled explosion
-                            const point = MeshBuilder.CreateSphere("point", {diameter: 10}, DefaultScene.MainScene);
-                            point.position = position.clone();
-                            point.isVisible = false;
-                            point.scaling = scaling.multiplyByFloats(.2,.3,.2);
-                            console.log("Using pooled explosion with", explosion.systems.length, "systems at", position);
-
-                            // Set emitter and start each system individually
-                            explosion.systems.forEach((system: ParticleSystem, idx: number) => {
-                                system.emitter = point;  // Set emitter to the collision point
-                                system.start();  // Start this specific system
-                                console.log(`  System ${idx}: emitter set to`, system.emitter, "activeCount=", system.getActiveCount());
-                            });
-
-                            setTimeout(() => {
-                                explosion.systems.forEach((system: ParticleSystem) => {
-                                    system.stop();
-                                });
-                                RockFactory.returnExplosionToPool(explosion);
-                                point.dispose();
-                            }, 2000);
-                        }
                     }
                 }
             });