519 lines
15 KiB
Markdown
519 lines
15 KiB
Markdown
# 系统（System）详解指南
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系统是ECS架构中的"S"，负责处理拥有特定组件的实体。本指南详细介绍框架中的各种系统类型及其使用方法。
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## 系统基础概念
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### 什么是系统？
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系统是处理游戏逻辑的地方，它们：
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- 🎯 **专注单一职责** - 每个系统只处理一种类型的逻辑
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- 🔄 **自动执行** - 系统会在每帧自动被调用
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- 📊 **基于组件过滤** - 只处理包含特定组件的实体
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- ⚡ **高性能** - 利用ECS的数据局部性优势
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### 系统的工作原理
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```typescript
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// 系统的基本工作流程：
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// 1. 查询符合条件的实体
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// 2. 遍历这些实体
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// 3. 读取/修改实体的组件数据
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// 4. 执行游戏逻辑
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class MovementSystem extends EntitySystem {
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process(entities: Entity[]) {
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for (const entity of entities) {
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const position = entity.getComponent(PositionComponent);
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const velocity = entity.getComponent(VelocityComponent);
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// 更新位置 = 当前位置 + 速度 * 时间
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position.x += velocity.x * Time.deltaTime;
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position.y += velocity.y * Time.deltaTime;
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}
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}
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}
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```
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## 系统类型详解
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### 1. EntitySystem - 基础系统
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最常用的系统类型，每帧处理所有符合条件的实体。
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```typescript
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import { EntitySystem, Entity, Matcher } from '@esengine/ecs-framework';
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class HealthSystem extends EntitySystem {
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constructor() {
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// 使用Matcher指定需要的组件
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super(Matcher.empty().all(HealthComponent));
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}
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// 主要处理逻辑
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protected process(entities: Entity[]) {
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for (const entity of entities) {
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const health = entity.getComponent(HealthComponent);
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// 处理生命值逻辑
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if (health.currentHealth <= 0) {
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this.handleDeath(entity);
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} else if (health.currentHealth < health.maxHealth) {
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this.handleRegeneration(health);
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}
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}
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}
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private handleDeath(entity: Entity) {
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// 添加死亡标记
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entity.addComponent(new DeadComponent());
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// 触发死亡事件
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const eventBus = this.scene.entityManager.eventBus;
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eventBus.emit('entity:died', {
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entityId: entity.id,
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entityName: entity.name
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});
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}
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private handleRegeneration(health: HealthComponent) {
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// 缓慢恢复生命值
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health.currentHealth += health.regenRate * Time.deltaTime;
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health.currentHealth = Math.min(health.currentHealth, health.maxHealth);
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}
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}
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```
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**适用场景：**
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- 移动系统
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- 渲染系统
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- 碰撞检测系统
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- AI系统
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### 2. ProcessingSystem - 简化处理系统
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不需要处理具体实体，主要用于执行全局逻辑或不依赖特定实体的系统处理。
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```typescript
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import { ProcessingSystem, Matcher } from '@esengine/ecs-framework';
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class GameLogicSystem extends ProcessingSystem {
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constructor() {
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// ProcessingSystem可以不指定Matcher，或使用空Matcher
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super(Matcher.empty());
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}
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// 处理系统逻辑（每帧执行）
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public processSystem() {
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// 执行全局游戏逻辑
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this.updateGameState();
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this.checkWinConditions();
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this.updateUI();
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}
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private updateGameState() {
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// 更新游戏状态逻辑
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console.log("更新游戏状态");
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}
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private checkWinConditions() {
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// 检查胜利条件
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const players = this.scene.findEntitiesByTag(EntityTags.PLAYER);
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const enemies = this.scene.findEntitiesByTag(EntityTags.ENEMY);
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if (enemies.length === 0) {
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this.triggerVictory();
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} else if (players.length === 0) {
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this.triggerGameOver();
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}
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}
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private updateUI() {
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// 更新UI显示
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const gameTime = Time.totalTime;
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console.log(`游戏时间: ${gameTime.toFixed(1)}秒`);
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}
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}
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private processIdle(entity: Entity, ai: AIComponent) {
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ai.idleTimer += Time.deltaTime;
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if (ai.idleTimer >= ai.idleTime) {
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ai.state = AIState.PATROL;
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ai.idleTimer = 0;
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}
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// 检查附近是否有玩家
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const nearbyPlayer = this.findNearbyPlayer(entity, ai.detectionRange);
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if (nearbyPlayer) {
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ai.state = AIState.CHASE;
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ai.target = nearbyPlayer;
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}
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}
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private processPatrol(entity: Entity, ai: AIComponent, position: PositionComponent) {
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// 简单的来回巡逻
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if (!ai.patrolTarget) {
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ai.patrolTarget = this.getNextPatrolPoint(ai);
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}
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const direction = ai.patrolTarget.subtract(position);
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const distance = direction.length();
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if (distance < 10) {
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ai.patrolTarget = this.getNextPatrolPoint(ai);
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} else {
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const normalized = direction.normalize();
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position.x += normalized.x * ai.moveSpeed * Time.deltaTime;
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position.y += normalized.y * ai.moveSpeed * Time.deltaTime;
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}
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}
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}
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```
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**适用场景：**
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- 全局游戏逻辑系统
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- 胜负判断系统
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- UI更新系统
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- 不依赖特定实体的处理
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### 3. IntervalSystem - 间隔执行系统
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不是每帧都执行，而是按指定间隔执行的系统，适合不需要高频更新的逻辑。
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```typescript
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import { IntervalSystem, Matcher } from '@esengine/ecs-framework';
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class SpawnSystem extends IntervalSystem {
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private spawnPoints: { x: number; y: number }[] = [
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{ x: 100, y: 100 },
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{ x: 700, y: 100 },
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{ x: 400, y: 500 }
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];
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// 每2秒执行一次
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constructor() {
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// IntervalSystem需要指定Matcher和间隔时间
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super(Matcher.empty().all(SpawnerComponent), 2.0);
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}
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// 间隔执行的逻辑（重写process方法）
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protected process(entities: Entity[]) {
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// entities就是匹配的生成器实体
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for (const spawner of entities) {
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const spawnerComp = spawner.getComponent(SpawnerComponent);
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if (this.shouldSpawn(spawnerComp)) {
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this.spawnEnemy(spawner, spawnerComp);
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}
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}
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}
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private shouldSpawn(spawner: SpawnerComponent): boolean {
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// 检查是否应该生成
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const currentEnemyCount = this.getCurrentEnemyCount();
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return currentEnemyCount < spawner.maxEnemies &&
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Math.random() < spawner.spawnChance;
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}
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private spawnEnemy(spawnerEntity: Entity, spawner: SpawnerComponent) {
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// 随机选择生成点
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const spawnPoint = this.spawnPoints[
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Math.floor(Math.random() * this.spawnPoints.length)
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];
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// 创建敌人实体
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const enemy = this.scene.createEntity("Enemy");
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enemy.addComponent(new PositionComponent(spawnPoint.x, spawnPoint.y));
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enemy.addComponent(new HealthComponent(50));
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enemy.addComponent(new AIComponent());
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enemy.addComponent(new VelocityComponent(0, 0));
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enemy.tag = EntityTags.ENEMY;
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// 更新生成器统计
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spawner.spawnedCount++;
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spawner.lastSpawnTime = Time.totalTime;
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// 发送生成事件
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const eventBus = this.scene.entityManager.eventBus;
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eventBus.emit('enemy:spawned', {
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enemyId: enemy.id,
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spawnPoint: spawnPoint,
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spawnerEntity: spawnerEntity.id
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});
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}
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}
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```
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**适用场景：**
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- 敌人生成系统
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- 自动保存系统
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- 资源回收系统
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- 定期数据同步
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### 4. PassiveSystem - 被动系统
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不主动遍历实体，而是响应事件的系统。
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```typescript
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import { PassiveSystem, Matcher, Core } from '@esengine/ecs-framework';
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class ScoreSystem extends PassiveSystem {
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private score: number = 0;
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private multiplier: number = 1;
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private combo: number = 0;
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constructor() {
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// PassiveSystem也需要Matcher，即使不使用
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super(Matcher.empty());
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}
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initialize() {
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super.initialize();
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// 监听游戏事件（使用EntityManager的事件系统）
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const eventBus = this.scene.entityManager.eventBus;
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eventBus.on('enemy:killed', this.onEnemyKilled, { context: this });
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eventBus.on('item:collected', this.onItemCollected, { context: this });
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eventBus.on('combo:broken', this.onComboBroken, { context: this });
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}
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// PassiveSystem被移除时清理
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destroy() {
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// 事件监听会在系统销毁时自动清理
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// 如需手动清理，可以保存listenerId并调用eventBus.off()
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}
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private onEnemyKilled(data: { enemyType: string; position: { x: number; y: number } }) {
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// 根据敌人类型给分
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let baseScore = this.getScoreForEnemyType(data.enemyType);
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// 连击奖励
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this.combo++;
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if (this.combo > 3) {
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this.multiplier = Math.min(this.combo * 0.1, 3.0); // 最多3倍
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}
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const finalScore = Math.floor(baseScore * this.multiplier);
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this.addScore(finalScore);
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// 显示分数奖励
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this.showScorePopup(data.position, finalScore);
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}
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private addScore(points: number) {
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this.score += points;
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// 发送分数更新事件
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const eventBus = this.scene.entityManager.eventBus;
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eventBus.emit('score:updated', {
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score: this.score,
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points: points,
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multiplier: this.multiplier,
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combo: this.combo
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});
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}
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}
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```
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**适用场景：**
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- 分数统计系统
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- 音效播放系统
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- UI更新系统
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- 成就系统
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## 系统管理和注册
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### 在场景中添加系统
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```typescript
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import { Scene, Core } from '@esengine/ecs-framework';
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const scene = new Scene();
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// 添加各种系统（使用addEntityProcessor方法）
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scene.addEntityProcessor(new MovementSystem());
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scene.addEntityProcessor(new GameLogicSystem());
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scene.addEntityProcessor(new SpawnSystem());
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scene.addEntityProcessor(new ScoreSystem());
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// 设置系统的执行优先级
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const movementSystem = scene.getEntityProcessor(MovementSystem);
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if (movementSystem) {
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movementSystem.updateOrder = 10; // 数值越小越先执行
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}
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const renderSystem = scene.getEntityProcessor(RenderSystem);
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if (renderSystem) {
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renderSystem.updateOrder = 100; // 渲染系统最后执行
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}
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// 设置为当前场景
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Core.scene = scene;
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```
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### 系统的启用和禁用
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```typescript
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// 暂时禁用某个系统
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const gameLogicSystem = scene.getEntityProcessor(GameLogicSystem);
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if (gameLogicSystem) {
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gameLogicSystem.enabled = false;
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}
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// 重新启用
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if (gameLogicSystem) {
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gameLogicSystem.enabled = true;
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}
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// 移除系统
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scene.removeEntityProcessor(gameLogicSystem);
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```
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## 系统设计最佳实践
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### 1. 单一职责原则
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```typescript
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// ✅ 好的设计：每个系统只负责一件事
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class MovementSystem extends EntitySystem {
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// 只负责移动
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}
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class CollisionSystem extends EntitySystem {
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// 只负责碰撞检测
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}
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class RenderSystem extends EntitySystem {
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// 只负责渲染
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}
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// ❌ 不好的设计：一个系统做太多事情
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class GameplaySystem extends EntitySystem {
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// 既处理移动，又处理碰撞，还处理渲染...
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}
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```
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### 2. 合理的系统执行顺序
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```typescript
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// 设置合理的执行顺序
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scene.addEntityProcessor(new InputSystem()).updateOrder = 0; // 输入最先
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scene.addEntityProcessor(new GameLogicSystem()).updateOrder = 10; // 游戏逻辑
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scene.addEntityProcessor(new MovementSystem()).updateOrder = 20; // 移动计算
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scene.addEntityProcessor(new CollisionSystem()).updateOrder = 30; // 碰撞检测
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scene.addEntityProcessor(new HealthSystem()).updateOrder = 40; // 生命值处理
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scene.addEntityProcessor(new RenderSystem()).updateOrder = 100; // 渲染最后
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```
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### 3. 系统间通信
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```typescript
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// 使用事件进行系统间通信
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class CollisionSystem extends EntitySystem {
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process(entities: Entity[]) {
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// ... 碰撞检测逻辑
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if (collision) {
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// 发送碰撞事件，让其他系统响应
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const eventBus = this.scene.entityManager.eventBus;
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eventBus.emit('collision:detected', {
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entity1: collider1,
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entity2: collider2,
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collisionPoint: point
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});
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}
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}
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}
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class HealthSystem extends PassiveSystem {
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onAddedToScene() {
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// 监听碰撞事件
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const eventBus = this.scene.entityManager.eventBus;
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eventBus.on('collision:detected', this.onCollision, { context: this });
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}
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private onCollision(data: CollisionEventData) {
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// 处理碰撞伤害
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if (data.entity1.hasComponent(HealthComponent)) {
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const health = data.entity1.getComponent(HealthComponent);
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health.takeDamage(10);
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}
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}
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}
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```
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### 4. 性能优化
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```typescript
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class OptimizedMovementSystem extends EntitySystem {
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private lastUpdateTime: number = 0;
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private readonly UPDATE_INTERVAL = 16; // 60FPS
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process(entities: Entity[]) {
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const currentTime = Time.totalTime;
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// 限制更新频率
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if (currentTime - this.lastUpdateTime < this.UPDATE_INTERVAL) {
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return;
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}
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// 批量处理
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this.processBatch(entities);
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this.lastUpdateTime = currentTime;
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}
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private processBatch(entities: Entity[]) {
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// 使用for循环而不是forEach，性能更好
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for (let i = 0; i < entities.length; i++) {
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const entity = entities[i];
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// 处理逻辑...
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}
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}
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}
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```
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## 常见问题
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### Q: 系统的执行顺序重要吗？
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A: 非常重要！合理的执行顺序可以避免逻辑错误：
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```typescript
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// 正确顺序：
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// 1. 输入系统（收集玩家输入）
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// 2. AI系统（敌人决策）
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// 3. 移动系统（更新位置）
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// 4. 碰撞系统（检测碰撞）
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// 5. 渲染系统（显示画面）
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```
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### Q: 什么时候使用哪种系统类型？
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A:
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- **EntitySystem** - 大部分游戏逻辑（移动、AI、碰撞等）
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- **ProcessingSystem** - 复杂的单实体处理（复杂AI、粒子系统）
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- **IntervalSystem** - 不需要每帧执行的逻辑（生成器、自动保存）
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- **PassiveSystem** - 事件响应系统（分数、音效、UI更新）
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### Q: 系统可以访问其他系统吗？
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A: 不建议直接访问。推荐使用事件系统进行系统间通信，保持松耦合。
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### Q: 如何调试系统性能？
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A: 使用框架内置的性能监控：
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```typescript
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const monitor = PerformanceMonitor.instance;
|
||
monitor.startFrame('MovementSystem');
|
||
// 系统逻辑...
|
||
monitor.endFrame('MovementSystem');
|
||
|
||
// 查看性能报告
|
||
console.log(monitor.getReport());
|
||
```
|
||
|
||
通过合理使用这些系统类型，你可以构建出高性能、易维护的游戏逻辑！ |