370 lines
9.5 KiB
Markdown
370 lines
9.5 KiB
Markdown
# EntityManager 使用指南
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本文档详细介绍 EntityManager 的使用方法和最佳实践。
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## 目录
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1. [基础用法](#基础用法)
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2. [查询系统](#查询系统)
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3. [实体管理](#实体管理)
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4. [性能监控](#性能监控)
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5. [最佳实践](#最佳实践)
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## 基础用法
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### 创建 EntityManager
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```typescript
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import { EntityManager, Scene } from '@esengine/ecs-framework';
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// 创建场景和实体管理器
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const scene = new Scene();
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const entityManager = new EntityManager();
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// 批量创建实体（使用Scene方法）
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const enemies = scene.createEntities(50, "Enemy");
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// 为实体添加组件
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enemies.forEach((enemy, index) => {
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enemy.addComponent(new PositionComponent(
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Math.random() * 800,
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Math.random() * 600
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));
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enemy.addComponent(new HealthComponent(100));
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enemy.addComponent(new VelocityComponent(
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(Math.random() - 0.5) * 100,
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(Math.random() - 0.5) * 100
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));
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enemy.tag = 2; // 敌人标签
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});
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```
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## 查询系统
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### 基础查询
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```typescript
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// 按组件类型查询
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const healthEntities = entityManager.getEntitiesWithComponent(HealthComponent);
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// 按标签查询
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const enemies = entityManager.getEntitiesByTag(2);
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const players = entityManager.getEntitiesByTag(1);
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// 按名称查询
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const boss = entityManager.getEntityByName("BossEnemy");
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// 获取所有实体
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const allEntities = entityManager.getAllEntities();
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```
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### 流式查询 API
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```typescript
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// 复杂查询条件
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const movingEnemies = entityManager
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.query()
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.withAll(PositionComponent, VelocityComponent, HealthComponent)
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.withTag(2) // 敌人标签
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.execute();
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// 查询活跃的玩家
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const activePlayers = entityManager
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.query()
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.withAll(PositionComponent)
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.withTag(1) // 玩家标签
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.active() // 只查询活跃实体
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.execute();
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// 排除特定组件的实体
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const nonCombatEntities = entityManager
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.query()
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.withAll(PositionComponent)
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.without(WeaponComponent, HealthComponent)
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.execute();
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// 自定义条件查询
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const nearbyEnemies = entityManager
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.query()
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.withAll(PositionComponent)
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.withTag(2)
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.where(entity => {
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const pos = entity.getComponent(PositionComponent);
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return pos && Math.abs(pos.x - playerX) < 100;
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})
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.execute();
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```
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## 实体管理
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### 创建和销毁实体
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```typescript
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// 创建单个实体
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const player = entityManager.createEntity("Player");
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player.addComponent(new PositionComponent(400, 300));
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player.addComponent(new HealthComponent(100));
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player.tag = 1;
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// 销毁实体
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entityManager.destroyEntity(player);
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// 按名称销毁
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entityManager.destroyEntity("Enemy_1");
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// 按ID销毁
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entityManager.destroyEntity(123);
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```
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### 实体查找
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```typescript
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// 按ID查找
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const entity = entityManager.getEntity(123);
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// 按名称查找
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const player = entityManager.getEntityByName("Player");
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// 检查实体是否存在
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if (entity && !entity.isDestroyed) {
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// 实体有效
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}
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```
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## 性能监控
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### 基础统计
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```typescript
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// 获取实体数量
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console.log('总实体数:', entityManager.entityCount);
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console.log('活跃实体数:', entityManager.activeEntityCount);
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// 获取场景统计
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const sceneStats = scene.getStats();
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console.log('场景统计:', {
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实体数量: sceneStats.entityCount,
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系统数量: sceneStats.processorCount
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});
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// 获取查询系统统计
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const queryStats = scene.querySystem.getStats();
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console.log('查询统计:', queryStats);
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```
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## 最佳实践
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### 1. 高效查询
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```typescript
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// 好的做法：缓存查询结果
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class CombatSystem extends EntitySystem {
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private cachedEnemies: Entity[] = [];
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private lastUpdateFrame = 0;
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protected process(entities: Entity[]): void {
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// 每5帧更新一次缓存
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if (Time.frameCount - this.lastUpdateFrame > 5) {
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this.cachedEnemies = this.entityManager
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.query()
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.withAll(PositionComponent, HealthComponent)
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.withTag(2)
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.execute();
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this.lastUpdateFrame = Time.frameCount;
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}
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// 使用缓存的结果
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this.cachedEnemies.forEach(enemy => {
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// 处理敌人逻辑
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});
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}
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}
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```
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### 2. 批量操作
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```typescript
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// 好的做法：批量创建和配置
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function createBulletWave(count: number): Entity[] {
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// 使用Scene的批量创建
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const bullets = scene.createEntities(count, "Bullet");
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// 批量配置组件
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bullets.forEach((bullet, index) => {
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const angle = (index / count) * Math.PI * 2;
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bullet.addComponent(new PositionComponent(400, 300));
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bullet.addComponent(new VelocityComponent(
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Math.cos(angle) * 200,
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Math.sin(angle) * 200
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));
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bullet.addComponent(new BulletComponent());
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bullet.tag = 3; // 子弹标签
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});
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return bullets;
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}
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```
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### 3. 内存管理
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```typescript
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// 好的做法：及时清理无用实体
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class CleanupSystem extends EntitySystem {
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protected process(entities: Entity[]): void {
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// 清理超出边界的子弹
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const bullets = this.entityManager.getEntitiesByTag(3);
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bullets.forEach(bullet => {
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const pos = bullet.getComponent(PositionComponent);
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if (pos && (pos.x < -100 || pos.x > 900 || pos.y < -100 || pos.y > 700)) {
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this.entityManager.destroyEntity(bullet);
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}
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});
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// 清理死亡的敌人
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const deadEnemies = this.entityManager
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.query()
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.withAll(HealthComponent)
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.withTag(2)
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.where(entity => {
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const health = entity.getComponent(HealthComponent);
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return health && health.currentHealth <= 0;
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})
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.execute();
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deadEnemies.forEach(enemy => {
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this.entityManager.destroyEntity(enemy);
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});
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}
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}
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```
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### 4. 查询优化
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```typescript
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// 好的做法：使用合适的查询方法
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class GameSystem extends EntitySystem {
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findTargetsInRange(attacker: Entity, range: number): Entity[] {
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const attackerPos = attacker.getComponent(PositionComponent);
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if (!attackerPos) return [];
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// 先按标签快速筛选，再按距离过滤
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return this.entityManager
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.getEntitiesByTag(2) // 敌人标签
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.filter(enemy => {
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const enemyPos = enemy.getComponent(PositionComponent);
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if (!enemyPos) return false;
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const distance = Math.sqrt(
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Math.pow(attackerPos.x - enemyPos.x, 2) +
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Math.pow(attackerPos.y - enemyPos.y, 2)
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);
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return distance <= range;
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});
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}
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}
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```
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## 完整示例
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```typescript
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import {
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EntityManager,
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Scene,
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Entity,
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Component,
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EntitySystem,
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Matcher
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} from '@esengine/ecs-framework';
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// 组件定义
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class PositionComponent extends Component {
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constructor(public x: number = 0, public y: number = 0) {
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super();
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}
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}
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class HealthComponent extends Component {
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constructor(
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public maxHealth: number = 100,
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public currentHealth: number = 100
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) {
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super();
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}
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}
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// 游戏管理器
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class GameManager {
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private scene: Scene;
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private entityManager: EntityManager;
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constructor() {
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this.scene = new Scene();
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this.entityManager = new EntityManager();
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this.setupGame();
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}
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private setupGame(): void {
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// 创建玩家
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const player = this.entityManager.createEntity("Player");
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player.addComponent(new PositionComponent(400, 300));
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player.addComponent(new HealthComponent(100));
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player.tag = 1;
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// 创建敌人
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const enemies = this.scene.createEntities(10, "Enemy");
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enemies.forEach(enemy => {
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enemy.addComponent(new PositionComponent(
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Math.random() * 800,
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Math.random() * 600
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));
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enemy.addComponent(new HealthComponent(50));
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enemy.tag = 2;
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});
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// 添加系统
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this.scene.addEntityProcessor(new HealthSystem());
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}
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public update(): void {
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this.scene.update();
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// 输出统计信息
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console.log('实体数量:', this.entityManager.entityCount);
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console.log('活跃实体数:', this.entityManager.activeEntityCount);
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}
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}
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// 生命值系统
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class HealthSystem extends EntitySystem {
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constructor() {
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super(Matcher.empty().all(HealthComponent));
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}
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protected process(entities: Entity[]): void {
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const healthEntities = this.scene.querySystem.queryAll(HealthComponent);
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healthEntities.entities.forEach(entity => {
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const health = entity.getComponent(HealthComponent);
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if (health && health.currentHealth <= 0) {
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console.log(`实体 ${entity.name} 死亡`);
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entity.destroy();
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}
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});
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}
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}
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// 启动游戏
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const game = new GameManager();
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setInterval(() => game.update(), 16); // 60 FPS
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```
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## 总结
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EntityManager 提供了强大的实体管理功能：
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- **创建管理**：`createEntity()`, `destroyEntity()`
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- **查询功能**：`getEntitiesWithComponent()`, `getEntitiesByTag()`, `query()`
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- **实体查找**：`getEntity()`, `getEntityByName()`
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- **统计信息**：`entityCount`, `activeEntityCount`
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通过合理使用这些API，可以构建高性能的游戏系统。记住要及时清理无用实体，缓存频繁查询的结果，并使用合适的查询方法来优化性能。 |