feat(ecs): ECS 网络状态同步系统 | add ECS network state synchronization (#390)

## @esengine/ecs-framework

新增 @sync 装饰器和二进制编解码器，支持基于 Component 的网络状态同步：

- `sync` 装饰器标记需要同步的字段
- `ChangeTracker` 组件变更追踪
- 二进制编解码器 (BinaryWriter/BinaryReader)
- `encodeSnapshot`/`decodeSnapshot` 批量编解码
- `encodeSpawn`/`decodeSpawn` 实体生成编解码
- `encodeDespawn`/`processDespawn` 实体销毁编解码

将以下方法标记为 @internal，用户应通过 Core.update() 驱动更新：
- Scene.update()
- SceneManager.update()
- WorldManager.updateAll()

## @esengine/network

- 新增 ComponentSyncSystem 基于 @sync 自动同步组件状态
- 将 ecs-framework 从 devDependencies 移到 peerDependencies

## @esengine/server

新增 ECSRoom，带有 ECS World 支持的房间基类：

- 每个 ECSRoom 在 Core.worldManager 中创建独立的 World
- Core.update() 统一更新 Time 和所有 World
- onTick() 只处理状态同步逻辑
- 自动创建/销毁玩家实体
- 增量状态广播

packages/framework/core/src/ECS/Scene.ts

@@ -508,7 +508,9 @@ export class Scene implements IScene {
     }
 
     /**
-     * 更新场景
+     * @zh 更新场景
+     * @en Update scene
+     * @internal 由 SceneManager 或 World 调用，用户不应直接调用
      */
     public update() {
         this.epochManager.increment();

packages/framework/core/src/ECS/SceneManager.ts

@@ -240,18 +240,9 @@ export class SceneManager implements IService {
     }
 
     /**
-     * 更新场景
-     *
-     * 应该在每帧的游戏循环中调用。
-     * 会自动处理延迟场景切换。
-     *
-     * @example
-     * ```typescript
-     * function gameLoop(deltaTime: number) {
-     *     Core.update(deltaTime);
-     *     sceneManager.update();  // 每帧调用
-     * }
-     * ```
+     * @zh 更新场景
+     * @en Update scene
+     * @internal 由 Core.update() 调用，用户不应直接调用
      */
     public update(): void {
         // 处理延迟场景切换

packages/framework/core/src/ECS/Sync/ChangeTracker.ts

@@ -0,0 +1,125 @@
+/**
+ * @zh 组件变更追踪器
+ * @en Component change tracker
+ *
+ * @zh 用于追踪 @sync 标记字段的变更，支持增量同步
+ * @en Tracks changes to @sync marked fields for delta synchronization
+ */
+export class ChangeTracker {
+    /**
+     * @zh 脏字段索引集合
+     * @en Set of dirty field indices
+     */
+    private _dirtyFields: Set<number> = new Set();
+
+    /**
+     * @zh 是否有任何变更
+     * @en Whether there are any changes
+     */
+    private _hasChanges: boolean = false;
+
+    /**
+     * @zh 上次同步的时间戳
+     * @en Last sync timestamp
+     */
+    private _lastSyncTime: number = 0;
+
+    /**
+     * @zh 标记字段为脏
+     * @en Mark field as dirty
+     *
+     * @param fieldIndex - @zh 字段索引 @en Field index
+     */
+    public setDirty(fieldIndex: number): void {
+        this._dirtyFields.add(fieldIndex);
+        this._hasChanges = true;
+    }
+
+    /**
+     * @zh 检查是否有变更
+     * @en Check if there are any changes
+     */
+    public hasChanges(): boolean {
+        return this._hasChanges;
+    }
+
+    /**
+     * @zh 检查特定字段是否脏
+     * @en Check if a specific field is dirty
+     *
+     * @param fieldIndex - @zh 字段索引 @en Field index
+     */
+    public isDirty(fieldIndex: number): boolean {
+        return this._dirtyFields.has(fieldIndex);
+    }
+
+    /**
+     * @zh 获取所有脏字段索引
+     * @en Get all dirty field indices
+     */
+    public getDirtyFields(): number[] {
+        return Array.from(this._dirtyFields);
+    }
+
+    /**
+     * @zh 获取脏字段数量
+     * @en Get number of dirty fields
+     */
+    public getDirtyCount(): number {
+        return this._dirtyFields.size;
+    }
+
+    /**
+     * @zh 清除所有变更标记
+     * @en Clear all change marks
+     */
+    public clear(): void {
+        this._dirtyFields.clear();
+        this._hasChanges = false;
+        this._lastSyncTime = Date.now();
+    }
+
+    /**
+     * @zh 清除特定字段的变更标记
+     * @en Clear change mark for a specific field
+     *
+     * @param fieldIndex - @zh 字段索引 @en Field index
+     */
+    public clearField(fieldIndex: number): void {
+        this._dirtyFields.delete(fieldIndex);
+        if (this._dirtyFields.size === 0) {
+            this._hasChanges = false;
+        }
+    }
+
+    /**
+     * @zh 获取上次同步时间
+     * @en Get last sync time
+     */
+    public get lastSyncTime(): number {
+        return this._lastSyncTime;
+    }
+
+    /**
+     * @zh 标记所有字段为脏（用于首次同步）
+     * @en Mark all fields as dirty (for initial sync)
+     *
+     * @param fieldCount - @zh 字段数量 @en Field count
+     */
+    public markAllDirty(fieldCount: number): void {
+        for (let i = 0; i < fieldCount; i++) {
+            this._dirtyFields.add(i);
+        }
+        this._hasChanges = fieldCount > 0;
+    }
+
+    /**
+     * @zh 重置追踪器
+     * @en Reset tracker
+     */
+    public reset(): void {
+        this._dirtyFields.clear();
+        this._hasChanges = false;
+        this._lastSyncTime = 0;
+    }
+}

packages/framework/core/src/ECS/Sync/decorators.ts

@@ -0,0 +1,217 @@
+/**
+ * @zh 网络同步装饰器
+ * @en Network synchronization decorators
+ *
+ * @zh 提供 @sync 装饰器，用于标记需要网络同步的 Component 字段
+ * @en Provides @sync decorator to mark Component fields for network synchronization
+ */
+
+import type { SyncType, SyncFieldMetadata, SyncMetadata } from './types';
+import { SYNC_METADATA, CHANGE_TRACKER } from './types';
+import { ChangeTracker } from './ChangeTracker';
+
+/**
+ * @zh 获取或创建组件的同步元数据
+ * @en Get or create sync metadata for a component class
+ *
+ * @param target - @zh 组件类的原型 @en Component class prototype
+ * @returns @zh 同步元数据 @en Sync metadata
+ */
+function getOrCreateSyncMetadata(target: any): SyncMetadata {
+    const constructor = target.constructor;
+
+    // Check if has own metadata (not inherited)
+    const hasOwnMetadata = Object.prototype.hasOwnProperty.call(constructor, SYNC_METADATA);
+
+    if (hasOwnMetadata) {
+        return constructor[SYNC_METADATA];
+    }
+
+    // Check for inherited metadata
+    const inheritedMetadata: SyncMetadata | undefined = constructor[SYNC_METADATA];
+
+    // Create new metadata (copy from inherited if exists)
+    const metadata: SyncMetadata = {
+        typeId: constructor.name,
+        fields: inheritedMetadata ? [...inheritedMetadata.fields] : [],
+        fieldIndexMap: inheritedMetadata ? new Map(inheritedMetadata.fieldIndexMap) : new Map()
+    };
+
+    constructor[SYNC_METADATA] = metadata;
+    return metadata;
+}
+
+/**
+ * @zh 同步字段装饰器
+ * @en Sync field decorator
+ *
+ * @zh 标记 Component 字段为可网络同步。被标记的字段会自动追踪变更，
+ * 并在值修改时触发变更追踪器。
+ * @en Marks a Component field for network synchronization. Marked fields
+ * automatically track changes and trigger the change tracker on modification.
+ *
+ * @param type - @zh 字段的同步类型 @en Sync type of the field
+ *
+ * @example
+ * ```typescript
+ * import { Component, ECSComponent } from '@esengine/ecs-framework';
+ * import { sync } from '@esengine/ecs-framework';
+ *
+ * @ECSComponent('Player')
+ * class PlayerComponent extends Component {
+ *     @sync("string") name: string = "";
+ *     @sync("uint16") score: number = 0;
+ *     @sync("float32") x: number = 0;
+ *     @sync("float32") y: number = 0;
+ *
+ *     // 不带 @sync 的字段不会同步
+ *     // Fields without @sync will not be synchronized
+ *     localData: any;
+ * }
+ * ```
+ */
+export function sync(type: SyncType) {
+    return function (target: any, propertyKey: string) {
+        const metadata = getOrCreateSyncMetadata(target);
+
+        // Assign field index (auto-increment based on field count)
+        const fieldIndex = metadata.fields.length;
+
+        // Create field metadata
+        const fieldMeta: SyncFieldMetadata = {
+            index: fieldIndex,
+            name: propertyKey,
+            type: type
+        };
+
+        // Register field
+        metadata.fields.push(fieldMeta);
+        metadata.fieldIndexMap.set(propertyKey, fieldIndex);
+
+        // Store original property key for getter/setter
+        const privateKey = `_sync_${propertyKey}`;
+
+        // Define getter/setter to intercept value changes
+        Object.defineProperty(target, propertyKey, {
+            get() {
+                return this[privateKey];
+            },
+            set(value: any) {
+                const oldValue = this[privateKey];
+                if (oldValue !== value) {
+                    this[privateKey] = value;
+                    // Trigger change tracker if exists
+                    const tracker = this[CHANGE_TRACKER] as ChangeTracker | undefined;
+                    if (tracker) {
+                        tracker.setDirty(fieldIndex);
+                    }
+                }
+            },
+            enumerable: true,
+            configurable: true
+        });
+    };
+}
+
+/**
+ * @zh 获取组件类的同步元数据
+ * @en Get sync metadata for a component class
+ *
+ * @param componentClass - @zh 组件类或组件实例 @en Component class or instance
+ * @returns @zh 同步元数据，如果不存在则返回 null @en Sync metadata, or null if not exists
+ */
+export function getSyncMetadata(componentClass: any): SyncMetadata | null {
+    if (!componentClass) {
+        return null;
+    }
+
+    const constructor = typeof componentClass === 'function'
+        ? componentClass
+        : componentClass.constructor;
+
+    return constructor[SYNC_METADATA] || null;
+}
+
+/**
+ * @zh 检查组件是否有同步字段
+ * @en Check if a component has sync fields
+ *
+ * @param component - @zh 组件类或组件实例 @en Component class or instance
+ * @returns @zh 如果有同步字段返回 true @en Returns true if has sync fields
+ */
+export function hasSyncFields(component: any): boolean {
+    const metadata = getSyncMetadata(component);
+    return metadata !== null && metadata.fields.length > 0;
+}
+
+/**
+ * @zh 获取组件实例的变更追踪器
+ * @en Get change tracker of a component instance
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ * @returns @zh 变更追踪器，如果不存在则返回 null @en Change tracker, or null if not exists
+ */
+export function getChangeTracker(component: any): ChangeTracker | null {
+    if (!component) {
+        return null;
+    }
+    return component[CHANGE_TRACKER] || null;
+}
+
+/**
+ * @zh 为组件实例初始化变更追踪器
+ * @en Initialize change tracker for a component instance
+ *
+ * @zh 这个函数应该在组件首次添加到实体时调用。
+ * 它会创建变更追踪器并标记所有字段为脏（用于首次同步）。
+ * @en This function should be called when a component is first added to an entity.
+ * It creates the change tracker and marks all fields as dirty (for initial sync).
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ * @returns @zh 变更追踪器 @en Change tracker
+ */
+export function initChangeTracker(component: any): ChangeTracker {
+    const metadata = getSyncMetadata(component);
+    if (!metadata) {
+        throw new Error('Component does not have sync metadata. Use @sync decorator on fields.');
+    }
+
+    let tracker = component[CHANGE_TRACKER] as ChangeTracker | undefined;
+    if (!tracker) {
+        tracker = new ChangeTracker();
+        component[CHANGE_TRACKER] = tracker;
+    }
+
+    // Mark all fields as dirty for initial sync
+    tracker.markAllDirty(metadata.fields.length);
+
+    return tracker;
+}
+
+/**
+ * @zh 清除组件实例的变更标记
+ * @en Clear change marks for a component instance
+ *
+ * @zh 通常在同步完成后调用，清除所有脏标记
+ * @en Usually called after sync is complete, clears all dirty marks
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ */
+export function clearChanges(component: any): void {
+    const tracker = getChangeTracker(component);
+    if (tracker) {
+        tracker.clear();
+    }
+}
+
+/**
+ * @zh 检查组件是否有变更
+ * @en Check if a component has changes
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ * @returns @zh 如果有变更返回 true @en Returns true if has changes
+ */
+export function hasChanges(component: any): boolean {
+    const tracker = getChangeTracker(component);
+    return tracker ? tracker.hasChanges() : false;
+}

packages/framework/core/src/ECS/Sync/encoding/BinaryReader.ts

@@ -0,0 +1,285 @@
+/**
+ * @zh 二进制读取器
+ * @en Binary Reader
+ *
+ * @zh 提供高效的二进制数据读取功能
+ * @en Provides efficient binary data reading
+ */
+
+import { decodeVarint } from './varint';
+
+/**
+ * @zh 文本解码器（使用浏览器原生 API）
+ * @en Text decoder (using browser native API)
+ */
+const textDecoder = typeof TextDecoder !== 'undefined' ? new TextDecoder() : null;
+
+/**
+ * @zh 二进制读取器
+ * @en Binary reader for decoding data
+ */
+export class BinaryReader {
+    /**
+     * @zh 数据缓冲区
+     * @en Data buffer
+     */
+    private _buffer: Uint8Array;
+
+    /**
+     * @zh DataView 用于读取数值
+     * @en DataView for reading numbers
+     */
+    private _view: DataView;
+
+    /**
+     * @zh 当前读取位置
+     * @en Current read position
+     */
+    private _offset: number = 0;
+
+    /**
+     * @zh 创建二进制读取器
+     * @en Create binary reader
+     *
+     * @param buffer - @zh 要读取的数据 @en Data to read
+     */
+    constructor(buffer: Uint8Array) {
+        this._buffer = buffer;
+        this._view = new DataView(buffer.buffer, buffer.byteOffset, buffer.byteLength);
+    }
+
+    /**
+     * @zh 获取当前读取位置
+     * @en Get current read position
+     */
+    public get offset(): number {
+        return this._offset;
+    }
+
+    /**
+     * @zh 设置读取位置
+     * @en Set read position
+     */
+    public set offset(value: number) {
+        this._offset = value;
+    }
+
+    /**
+     * @zh 获取剩余可读字节数
+     * @en Get remaining readable bytes
+     */
+    public get remaining(): number {
+        return this._buffer.length - this._offset;
+    }
+
+    /**
+     * @zh 检查是否有更多数据可读
+     * @en Check if there's more data to read
+     */
+    public hasMore(): boolean {
+        return this._offset < this._buffer.length;
+    }
+
+    /**
+     * @zh 读取单个字节
+     * @en Read single byte
+     */
+    public readUint8(): number {
+        this.checkBounds(1);
+        return this._buffer[this._offset++]!;
+    }
+
+    /**
+     * @zh 读取有符号字节
+     * @en Read signed byte
+     */
+    public readInt8(): number {
+        this.checkBounds(1);
+        return this._view.getInt8(this._offset++);
+    }
+
+    /**
+     * @zh 读取布尔值
+     * @en Read boolean
+     */
+    public readBoolean(): boolean {
+        return this.readUint8() !== 0;
+    }
+
+    /**
+     * @zh 读取 16 位无符号整数（小端序）
+     * @en Read 16-bit unsigned integer (little-endian)
+     */
+    public readUint16(): number {
+        this.checkBounds(2);
+        const value = this._view.getUint16(this._offset, true);
+        this._offset += 2;
+        return value;
+    }
+
+    /**
+     * @zh 读取 16 位有符号整数（小端序）
+     * @en Read 16-bit signed integer (little-endian)
+     */
+    public readInt16(): number {
+        this.checkBounds(2);
+        const value = this._view.getInt16(this._offset, true);
+        this._offset += 2;
+        return value;
+    }
+
+    /**
+     * @zh 读取 32 位无符号整数（小端序）
+     * @en Read 32-bit unsigned integer (little-endian)
+     */
+    public readUint32(): number {
+        this.checkBounds(4);
+        const value = this._view.getUint32(this._offset, true);
+        this._offset += 4;
+        return value;
+    }
+
+    /**
+     * @zh 读取 32 位有符号整数（小端序）
+     * @en Read 32-bit signed integer (little-endian)
+     */
+    public readInt32(): number {
+        this.checkBounds(4);
+        const value = this._view.getInt32(this._offset, true);
+        this._offset += 4;
+        return value;
+    }
+
+    /**
+     * @zh 读取 32 位浮点数（小端序）
+     * @en Read 32-bit float (little-endian)
+     */
+    public readFloat32(): number {
+        this.checkBounds(4);
+        const value = this._view.getFloat32(this._offset, true);
+        this._offset += 4;
+        return value;
+    }
+
+    /**
+     * @zh 读取 64 位浮点数（小端序）
+     * @en Read 64-bit float (little-endian)
+     */
+    public readFloat64(): number {
+        this.checkBounds(8);
+        const value = this._view.getFloat64(this._offset, true);
+        this._offset += 8;
+        return value;
+    }
+
+    /**
+     * @zh 读取变长整数
+     * @en Read variable-length integer
+     */
+    public readVarint(): number {
+        const [value, newOffset] = decodeVarint(this._buffer, this._offset);
+        this._offset = newOffset;
+        return value;
+    }
+
+    /**
+     * @zh 读取字符串（UTF-8 编码，带长度前缀）
+     * @en Read string (UTF-8 encoded with length prefix)
+     */
+    public readString(): string {
+        const length = this.readVarint();
+        this.checkBounds(length);
+
+        const bytes = this._buffer.subarray(this._offset, this._offset + length);
+        this._offset += length;
+
+        if (textDecoder) {
+            return textDecoder.decode(bytes);
+        } else {
+            return this.utf8BytesToString(bytes);
+        }
+    }
+
+    /**
+     * @zh 读取原始字节
+     * @en Read raw bytes
+     *
+     * @param length - @zh 要读取的字节数 @en Number of bytes to read
+     */
+    public readBytes(length: number): Uint8Array {
+        this.checkBounds(length);
+        const bytes = this._buffer.slice(this._offset, this._offset + length);
+        this._offset += length;
+        return bytes;
+    }
+
+    /**
+     * @zh 查看下一个字节但不移动读取位置
+     * @en Peek next byte without advancing read position
+     */
+    public peekUint8(): number {
+        this.checkBounds(1);
+        return this._buffer[this._offset]!;
+    }
+
+    /**
+     * @zh 跳过指定字节数
+     * @en Skip specified number of bytes
+     */
+    public skip(count: number): void {
+        this.checkBounds(count);
+        this._offset += count;
+    }
+
+    /**
+     * @zh 检查边界
+     * @en Check bounds
+     */
+    private checkBounds(size: number): void {
+        if (this._offset + size > this._buffer.length) {
+            throw new Error(`BinaryReader: buffer overflow (offset=${this._offset}, size=${size}, bufferLength=${this._buffer.length})`);
+        }
+    }
+
+    /**
+     * @zh UTF-8 字节转字符串（后备方案）
+     * @en UTF-8 bytes to string (fallback)
+     */
+    private utf8BytesToString(bytes: Uint8Array): string {
+        let result = '';
+        let i = 0;
+
+        while (i < bytes.length) {
+            let charCode: number;
+            const byte1 = bytes[i++]!;
+
+            if (byte1 < 0x80) {
+                charCode = byte1;
+            } else if (byte1 < 0xE0) {
+                const byte2 = bytes[i++]!;
+                charCode = ((byte1 & 0x1F) << 6) | (byte2 & 0x3F);
+            } else if (byte1 < 0xF0) {
+                const byte2 = bytes[i++]!;
+                const byte3 = bytes[i++]!;
+                charCode = ((byte1 & 0x0F) << 12) | ((byte2 & 0x3F) << 6) | (byte3 & 0x3F);
+            } else {
+                const byte2 = bytes[i++]!;
+                const byte3 = bytes[i++]!;
+                const byte4 = bytes[i++]!;
+                charCode = ((byte1 & 0x07) << 18) | ((byte2 & 0x3F) << 12) |
+                    ((byte3 & 0x3F) << 6) | (byte4 & 0x3F);
+
+                // Convert to surrogate pair
+                if (charCode > 0xFFFF) {
+                    charCode -= 0x10000;
+                    result += String.fromCharCode(0xD800 + (charCode >> 10));
+                    charCode = 0xDC00 + (charCode & 0x3FF);
+                }
+            }
+
+            result += String.fromCharCode(charCode);
+        }
+
+        return result;
+    }
+}

packages/framework/core/src/ECS/Sync/encoding/BinaryWriter.ts

@@ -0,0 +1,257 @@
+/**
+ * @zh 二进制写入器
+ * @en Binary Writer
+ *
+ * @zh 提供高效的二进制数据写入功能，支持自动扩容
+ * @en Provides efficient binary data writing with auto-expansion
+ */
+
+import { encodeVarint, varintSize } from './varint';
+
+/**
+ * @zh 文本编码器（使用浏览器原生 API）
+ * @en Text encoder (using browser native API)
+ */
+const textEncoder = typeof TextEncoder !== 'undefined' ? new TextEncoder() : null;
+
+/**
+ * @zh 二进制写入器
+ * @en Binary writer for encoding data
+ */
+export class BinaryWriter {
+    /**
+     * @zh 内部缓冲区
+     * @en Internal buffer
+     */
+    private _buffer: Uint8Array;
+
+    /**
+     * @zh DataView 用于写入数值
+     * @en DataView for writing numbers
+     */
+    private _view: DataView;
+
+    /**
+     * @zh 当前写入位置
+     * @en Current write position
+     */
+    private _offset: number = 0;
+
+    /**
+     * @zh 创建二进制写入器
+     * @en Create binary writer
+     *
+     * @param initialCapacity - @zh 初始容量 @en Initial capacity
+     */
+    constructor(initialCapacity: number = 256) {
+        this._buffer = new Uint8Array(initialCapacity);
+        this._view = new DataView(this._buffer.buffer);
+    }
+
+    /**
+     * @zh 获取当前写入位置
+     * @en Get current write position
+     */
+    public get offset(): number {
+        return this._offset;
+    }
+
+    /**
+     * @zh 获取写入的数据
+     * @en Get written data
+     *
+     * @returns @zh 包含写入数据的 Uint8Array @en Uint8Array containing written data
+     */
+    public toUint8Array(): Uint8Array {
+        return this._buffer.slice(0, this._offset);
+    }
+
+    /**
+     * @zh 重置写入器（清空数据但保留缓冲区）
+     * @en Reset writer (clear data but keep buffer)
+     */
+    public reset(): void {
+        this._offset = 0;
+    }
+
+    /**
+     * @zh 确保有足够空间
+     * @en Ensure enough space
+     *
+     * @param size - @zh 需要的额外字节数 @en Extra bytes needed
+     */
+    private ensureCapacity(size: number): void {
+        const required = this._offset + size;
+        if (required > this._buffer.length) {
+            // Double the buffer size or use required size, whichever is larger
+            const newSize = Math.max(this._buffer.length * 2, required);
+            const newBuffer = new Uint8Array(newSize);
+            newBuffer.set(this._buffer);
+            this._buffer = newBuffer;
+            this._view = new DataView(this._buffer.buffer);
+        }
+    }
+
+    /**
+     * @zh 写入单个字节
+     * @en Write single byte
+     */
+    public writeUint8(value: number): void {
+        this.ensureCapacity(1);
+        this._buffer[this._offset++] = value;
+    }
+
+    /**
+     * @zh 写入有符号字节
+     * @en Write signed byte
+     */
+    public writeInt8(value: number): void {
+        this.ensureCapacity(1);
+        this._view.setInt8(this._offset++, value);
+    }
+
+    /**
+     * @zh 写入布尔值
+     * @en Write boolean
+     */
+    public writeBoolean(value: boolean): void {
+        this.writeUint8(value ? 1 : 0);
+    }
+
+    /**
+     * @zh 写入 16 位无符号整数（小端序）
+     * @en Write 16-bit unsigned integer (little-endian)
+     */
+    public writeUint16(value: number): void {
+        this.ensureCapacity(2);
+        this._view.setUint16(this._offset, value, true);
+        this._offset += 2;
+    }
+
+    /**
+     * @zh 写入 16 位有符号整数（小端序）
+     * @en Write 16-bit signed integer (little-endian)
+     */
+    public writeInt16(value: number): void {
+        this.ensureCapacity(2);
+        this._view.setInt16(this._offset, value, true);
+        this._offset += 2;
+    }
+
+    /**
+     * @zh 写入 32 位无符号整数（小端序）
+     * @en Write 32-bit unsigned integer (little-endian)
+     */
+    public writeUint32(value: number): void {
+        this.ensureCapacity(4);
+        this._view.setUint32(this._offset, value, true);
+        this._offset += 4;
+    }
+
+    /**
+     * @zh 写入 32 位有符号整数（小端序）
+     * @en Write 32-bit signed integer (little-endian)
+     */
+    public writeInt32(value: number): void {
+        this.ensureCapacity(4);
+        this._view.setInt32(this._offset, value, true);
+        this._offset += 4;
+    }
+
+    /**
+     * @zh 写入 32 位浮点数（小端序）
+     * @en Write 32-bit float (little-endian)
+     */
+    public writeFloat32(value: number): void {
+        this.ensureCapacity(4);
+        this._view.setFloat32(this._offset, value, true);
+        this._offset += 4;
+    }
+
+    /**
+     * @zh 写入 64 位浮点数（小端序）
+     * @en Write 64-bit float (little-endian)
+     */
+    public writeFloat64(value: number): void {
+        this.ensureCapacity(8);
+        this._view.setFloat64(this._offset, value, true);
+        this._offset += 8;
+    }
+
+    /**
+     * @zh 写入变长整数
+     * @en Write variable-length integer
+     */
+    public writeVarint(value: number): void {
+        this.ensureCapacity(varintSize(value));
+        this._offset = encodeVarint(value, this._buffer, this._offset);
+    }
+
+    /**
+     * @zh 写入字符串（UTF-8 编码，带长度前缀）
+     * @en Write string (UTF-8 encoded with length prefix)
+     */
+    public writeString(value: string): void {
+        if (textEncoder) {
+            const encoded = textEncoder.encode(value);
+            this.writeVarint(encoded.length);
+            this.ensureCapacity(encoded.length);
+            this._buffer.set(encoded, this._offset);
+            this._offset += encoded.length;
+        } else {
+            // Fallback for environments without TextEncoder
+            const bytes = this.stringToUtf8Bytes(value);
+            this.writeVarint(bytes.length);
+            this.ensureCapacity(bytes.length);
+            this._buffer.set(bytes, this._offset);
+            this._offset += bytes.length;
+        }
+    }
+
+    /**
+     * @zh 写入原始字节
+     * @en Write raw bytes
+     */
+    public writeBytes(data: Uint8Array): void {
+        this.ensureCapacity(data.length);
+        this._buffer.set(data, this._offset);
+        this._offset += data.length;
+    }
+
+    /**
+     * @zh 字符串转 UTF-8 字节（后备方案）
+     * @en String to UTF-8 bytes (fallback)
+     */
+    private stringToUtf8Bytes(str: string): Uint8Array {
+        const bytes: number[] = [];
+        for (let i = 0; i < str.length; i++) {
+            let charCode = str.charCodeAt(i);
+
+            // Handle surrogate pairs
+            if (charCode >= 0xD800 && charCode <= 0xDBFF && i + 1 < str.length) {
+                const next = str.charCodeAt(i + 1);
+                if (next >= 0xDC00 && next <= 0xDFFF) {
+                    charCode = 0x10000 + ((charCode - 0xD800) << 10) + (next - 0xDC00);
+                    i++;
+                }
+            }
+
+            if (charCode < 0x80) {
+                bytes.push(charCode);
+            } else if (charCode < 0x800) {
+                bytes.push(0xC0 | (charCode >> 6));
+                bytes.push(0x80 | (charCode & 0x3F));
+            } else if (charCode < 0x10000) {
+                bytes.push(0xE0 | (charCode >> 12));
+                bytes.push(0x80 | ((charCode >> 6) & 0x3F));
+                bytes.push(0x80 | (charCode & 0x3F));
+            } else {
+                bytes.push(0xF0 | (charCode >> 18));
+                bytes.push(0x80 | ((charCode >> 12) & 0x3F));
+                bytes.push(0x80 | ((charCode >> 6) & 0x3F));
+                bytes.push(0x80 | (charCode & 0x3F));
+            }
+        }
+        return new Uint8Array(bytes);
+    }
+}

packages/framework/core/src/ECS/Sync/encoding/Decoder.ts

@@ -0,0 +1,404 @@
+/**
+ * @zh 组件状态解码器
+ * @en Component state decoder
+ *
+ * @zh 从二进制格式解码并应用到 ECS Component
+ * @en Decodes binary format and applies to ECS Components
+ */
+
+import type { Entity } from '../../Entity';
+import type { Component } from '../../Component';
+import type { Scene } from '../../Scene';
+import type { SyncType, SyncMetadata } from '../types';
+import { SyncOperation, SYNC_METADATA } from '../types';
+import { BinaryReader } from './BinaryReader';
+
+/**
+ * @zh 组件类型注册表
+ * @en Component type registry
+ */
+const componentRegistry = new Map<string, new () => Component>();
+
+/**
+ * @zh 注册组件类型
+ * @en Register component type
+ *
+ * @param typeId - @zh 组件类型 ID @en Component type ID
+ * @param componentClass - @zh 组件类 @en Component class
+ */
+export function registerSyncComponent<T extends Component>(
+    typeId: string,
+    componentClass: new () => T
+): void {
+    componentRegistry.set(typeId, componentClass);
+}
+
+/**
+ * @zh 从 @ECSComponent 装饰器自动注册
+ * @en Auto-register from @ECSComponent decorator
+ *
+ * @param componentClass - @zh 组件类 @en Component class
+ */
+export function autoRegisterSyncComponent(componentClass: new () => Component): void {
+    const metadata: SyncMetadata | undefined = (componentClass as any)[SYNC_METADATA];
+    if (metadata) {
+        componentRegistry.set(metadata.typeId, componentClass);
+    }
+}
+
+/**
+ * @zh 解码字段值
+ * @en Decode field value
+ */
+function decodeFieldValue(reader: BinaryReader, type: SyncType): any {
+    switch (type) {
+        case 'boolean':
+            return reader.readBoolean();
+        case 'int8':
+            return reader.readInt8();
+        case 'uint8':
+            return reader.readUint8();
+        case 'int16':
+            return reader.readInt16();
+        case 'uint16':
+            return reader.readUint16();
+        case 'int32':
+            return reader.readInt32();
+        case 'uint32':
+            return reader.readUint32();
+        case 'float32':
+            return reader.readFloat32();
+        case 'float64':
+            return reader.readFloat64();
+        case 'string':
+            return reader.readString();
+    }
+}
+
+/**
+ * @zh 解码并应用组件数据
+ * @en Decode and apply component data
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ * @param metadata - @zh 组件同步元数据 @en Component sync metadata
+ * @param reader - @zh 二进制读取器 @en Binary reader
+ */
+export function decodeComponent(
+    component: Component,
+    metadata: SyncMetadata,
+    reader: BinaryReader
+): void {
+    const fieldCount = reader.readVarint();
+
+    for (let i = 0; i < fieldCount; i++) {
+        const fieldIndex = reader.readUint8();
+        const field = metadata.fields[fieldIndex];
+
+        if (field) {
+            const value = decodeFieldValue(reader, field.type);
+            // Directly set the private backing field to avoid triggering change tracking
+            (component as any)[`_sync_${field.name}`] = value;
+        } else {
+            // Unknown field, skip based on type info in metadata
+            console.warn(`Unknown sync field index: ${fieldIndex}`);
+        }
+    }
+}
+
+/**
+ * @zh 解码实体快照结果
+ * @en Decode entity snapshot result
+ */
+export interface DecodeEntityResult {
+    /**
+     * @zh 实体 ID
+     * @en Entity ID
+     */
+    entityId: number;
+
+    /**
+     * @zh 是否为新实体
+     * @en Whether it's a new entity
+     */
+    isNew: boolean;
+
+    /**
+     * @zh 解码的组件类型列表
+     * @en List of decoded component types
+     */
+    componentTypes: string[];
+}
+
+/**
+ * @zh 解码并应用实体数据
+ * @en Decode and apply entity data
+ *
+ * @param scene - @zh 场景 @en Scene
+ * @param reader - @zh 二进制读取器 @en Binary reader
+ * @param entityMap - @zh 实体 ID 映射（可选）@en Entity ID mapping (optional)
+ * @returns @zh 解码结果 @en Decode result
+ */
+export function decodeEntity(
+    scene: Scene,
+    reader: BinaryReader,
+    entityMap?: Map<number, Entity>
+): DecodeEntityResult {
+    const entityId = reader.readUint32();
+    const componentCount = reader.readVarint();
+    const componentTypes: string[] = [];
+
+    // Find or create entity
+    let entity: Entity | null | undefined = entityMap?.get(entityId);
+    let isNew = false;
+
+    if (!entity) {
+        entity = scene.findEntityById(entityId);
+    }
+
+    if (!entity) {
+        // Entity doesn't exist, create it
+        entity = scene.createEntity(`entity_${entityId}`);
+        isNew = true;
+        entityMap?.set(entityId, entity);
+    }
+
+    for (let i = 0; i < componentCount; i++) {
+        const typeId = reader.readString();
+        componentTypes.push(typeId);
+
+        // Find component class from registry
+        const componentClass = componentRegistry.get(typeId);
+        if (!componentClass) {
+            console.warn(`Unknown component type: ${typeId}`);
+            // Skip component data - we need to read it to advance the reader
+            const fieldCount = reader.readVarint();
+            for (let j = 0; j < fieldCount; j++) {
+                reader.readUint8(); // fieldIndex
+                // We can't skip properly without knowing the type, so this is a problem
+                // For now, log error and break
+                console.error(`Cannot skip unknown component type: ${typeId}`);
+                break;
+            }
+            continue;
+        }
+
+        const metadata: SyncMetadata | undefined = (componentClass as any)[SYNC_METADATA];
+        if (!metadata) {
+            console.warn(`Component ${typeId} has no sync metadata`);
+            continue;
+        }
+
+        // Find or add component
+        let component = entity.getComponent(componentClass);
+        if (!component) {
+            component = entity.addComponent(new componentClass());
+        }
+
+        // Decode component data
+        decodeComponent(component, metadata, reader);
+    }
+
+    return { entityId, isNew, componentTypes };
+}
+
+/**
+ * @zh 解码快照结果
+ * @en Decode snapshot result
+ */
+export interface DecodeSnapshotResult {
+    /**
+     * @zh 操作类型
+     * @en Operation type
+     */
+    operation: SyncOperation;
+
+    /**
+     * @zh 解码的实体列表
+     * @en List of decoded entities
+     */
+    entities: DecodeEntityResult[];
+}
+
+/**
+ * @zh 解码状态快照
+ * @en Decode state snapshot
+ *
+ * @param scene - @zh 场景 @en Scene
+ * @param data - @zh 二进制数据 @en Binary data
+ * @param entityMap - @zh 实体 ID 映射（可选）@en Entity ID mapping (optional)
+ * @returns @zh 解码结果 @en Decode result
+ */
+export function decodeSnapshot(
+    scene: Scene,
+    data: Uint8Array,
+    entityMap?: Map<number, Entity>
+): DecodeSnapshotResult {
+    const reader = new BinaryReader(data);
+    const operation = reader.readUint8() as SyncOperation;
+    const entityCount = reader.readVarint();
+    const entities: DecodeEntityResult[] = [];
+
+    const map = entityMap || new Map<number, Entity>();
+
+    for (let i = 0; i < entityCount; i++) {
+        const result = decodeEntity(scene, reader, map);
+        entities.push(result);
+    }
+
+    return { operation, entities };
+}
+
+/**
+ * @zh 解码生成消息结果
+ * @en Decode spawn message result
+ */
+export interface DecodeSpawnResult {
+    /**
+     * @zh 实体
+     * @en Entity
+     */
+    entity: Entity;
+
+    /**
+     * @zh 预制体类型
+     * @en Prefab type
+     */
+    prefabType: string;
+
+    /**
+     * @zh 解码的组件类型列表
+     * @en List of decoded component types
+     */
+    componentTypes: string[];
+}
+
+/**
+ * @zh 解码实体生成消息
+ * @en Decode entity spawn message
+ *
+ * @param scene - @zh 场景 @en Scene
+ * @param data - @zh 二进制数据 @en Binary data
+ * @param entityMap - @zh 实体 ID 映射（可选）@en Entity ID mapping (optional)
+ * @returns @zh 解码结果，如果不是 SPAWN 消息则返回 null @en Decode result, or null if not a SPAWN message
+ */
+export function decodeSpawn(
+    scene: Scene,
+    data: Uint8Array,
+    entityMap?: Map<number, Entity>
+): DecodeSpawnResult | null {
+    const reader = new BinaryReader(data);
+    const operation = reader.readUint8();
+
+    if (operation !== SyncOperation.SPAWN) {
+        return null;
+    }
+
+    const entityId = reader.readUint32();
+    const prefabType = reader.readString();
+    const componentCount = reader.readVarint();
+    const componentTypes: string[] = [];
+
+    // Create entity
+    const entity = scene.createEntity(`entity_${entityId}`);
+    entityMap?.set(entityId, entity);
+
+    for (let i = 0; i < componentCount; i++) {
+        const typeId = reader.readString();
+        componentTypes.push(typeId);
+
+        const componentClass = componentRegistry.get(typeId);
+        if (!componentClass) {
+            console.warn(`Unknown component type: ${typeId}`);
+            // Try to skip
+            const fieldCount = reader.readVarint();
+            for (let j = 0; j < fieldCount; j++) {
+                reader.readUint8();
+            }
+            continue;
+        }
+
+        const metadata: SyncMetadata | undefined = (componentClass as any)[SYNC_METADATA];
+        if (!metadata) {
+            continue;
+        }
+
+        const component = entity.addComponent(new componentClass());
+        decodeComponent(component, metadata, reader);
+    }
+
+    return { entity, prefabType, componentTypes };
+}
+
+/**
+ * @zh 解码销毁消息结果
+ * @en Decode despawn message result
+ */
+export interface DecodeDespawnResult {
+    /**
+     * @zh 销毁的实体 ID 列表
+     * @en List of despawned entity IDs
+     */
+    entityIds: number[];
+}
+
+/**
+ * @zh 解码实体销毁消息
+ * @en Decode entity despawn message
+ *
+ * @param data - @zh 二进制数据 @en Binary data
+ * @returns @zh 解码结果，如果不是 DESPAWN 消息则返回 null @en Decode result, or null if not a DESPAWN message
+ */
+export function decodeDespawn(data: Uint8Array): DecodeDespawnResult | null {
+    const reader = new BinaryReader(data);
+    const operation = reader.readUint8();
+
+    if (operation !== SyncOperation.DESPAWN) {
+        return null;
+    }
+
+    const entityIds: number[] = [];
+
+    // Check if it's a single entity or batch
+    if (reader.remaining === 4) {
+        // Single entity
+        entityIds.push(reader.readUint32());
+    } else {
+        // Batch
+        const count = reader.readVarint();
+        for (let i = 0; i < count; i++) {
+            entityIds.push(reader.readUint32());
+        }
+    }
+
+    return { entityIds };
+}
+
+/**
+ * @zh 处理销毁消息（从场景中移除实体）
+ * @en Process despawn message (remove entities from scene)
+ *
+ * @param scene - @zh 场景 @en Scene
+ * @param data - @zh 二进制数据 @en Binary data
+ * @param entityMap - @zh 实体 ID 映射（可选）@en Entity ID mapping (optional)
+ * @returns @zh 移除的实体 ID 列表 @en List of removed entity IDs
+ */
+export function processDespawn(
+    scene: Scene,
+    data: Uint8Array,
+    entityMap?: Map<number, Entity>
+): number[] {
+    const result = decodeDespawn(data);
+    if (!result) {
+        return [];
+    }
+
+    for (const entityId of result.entityIds) {
+        const entity = entityMap?.get(entityId) || scene.findEntityById(entityId);
+        if (entity) {
+            entity.destroy();
+            entityMap?.delete(entityId);
+        }
+    }
+
+    return result.entityIds;
+}

packages/framework/core/src/ECS/Sync/encoding/Encoder.ts

@@ -0,0 +1,291 @@
+/**
+ * @zh 组件状态编码器
+ * @en Component state encoder
+ *
+ * @zh 将 ECS Component 的 @sync 字段编码为二进制格式
+ * @en Encodes @sync fields of ECS Components to binary format
+ */
+
+import type { Entity } from '../../Entity';
+import type { Component } from '../../Component';
+import type { SyncType, SyncMetadata } from '../types';
+import { SyncOperation, SYNC_METADATA, CHANGE_TRACKER } from '../types';
+import type { ChangeTracker } from '../ChangeTracker';
+import { BinaryWriter } from './BinaryWriter';
+
+/**
+ * @zh 编码单个字段值
+ * @en Encode a single field value
+ */
+function encodeFieldValue(writer: BinaryWriter, value: any, type: SyncType): void {
+    switch (type) {
+        case 'boolean':
+            writer.writeBoolean(value);
+            break;
+        case 'int8':
+            writer.writeInt8(value);
+            break;
+        case 'uint8':
+            writer.writeUint8(value);
+            break;
+        case 'int16':
+            writer.writeInt16(value);
+            break;
+        case 'uint16':
+            writer.writeUint16(value);
+            break;
+        case 'int32':
+            writer.writeInt32(value);
+            break;
+        case 'uint32':
+            writer.writeUint32(value);
+            break;
+        case 'float32':
+            writer.writeFloat32(value);
+            break;
+        case 'float64':
+            writer.writeFloat64(value);
+            break;
+        case 'string':
+            writer.writeString(value ?? '');
+            break;
+    }
+}
+
+/**
+ * @zh 编码组件的完整状态
+ * @en Encode full state of a component
+ *
+ * @zh 格式: [fieldCount: varint] ([fieldIndex: uint8] [value])...
+ * @en Format: [fieldCount: varint] ([fieldIndex: uint8] [value])...
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ * @param metadata - @zh 组件同步元数据 @en Component sync metadata
+ * @param writer - @zh 二进制写入器 @en Binary writer
+ */
+export function encodeComponentFull(
+    component: Component,
+    metadata: SyncMetadata,
+    writer: BinaryWriter
+): void {
+    const fields = metadata.fields;
+    writer.writeVarint(fields.length);
+
+    for (const field of fields) {
+        writer.writeUint8(field.index);
+        const value = (component as any)[field.name];
+        encodeFieldValue(writer, value, field.type);
+    }
+}
+
+/**
+ * @zh 编码组件的增量状态（只编码脏字段）
+ * @en Encode delta state of a component (only dirty fields)
+ *
+ * @zh 格式: [dirtyCount: varint] ([fieldIndex: uint8] [value])...
+ * @en Format: [dirtyCount: varint] ([fieldIndex: uint8] [value])...
+ *
+ * @param component - @zh 组件实例 @en Component instance
+ * @param metadata - @zh 组件同步元数据 @en Component sync metadata
+ * @param tracker - @zh 变更追踪器 @en Change tracker
+ * @param writer - @zh 二进制写入器 @en Binary writer
+ * @returns @zh 是否有数据编码 @en Whether any data was encoded
+ */
+export function encodeComponentDelta(
+    component: Component,
+    metadata: SyncMetadata,
+    tracker: ChangeTracker,
+    writer: BinaryWriter
+): boolean {
+    if (!tracker.hasChanges()) {
+        return false;
+    }
+
+    const dirtyFields = tracker.getDirtyFields();
+    writer.writeVarint(dirtyFields.length);
+
+    for (const fieldIndex of dirtyFields) {
+        const field = metadata.fields[fieldIndex];
+        if (field) {
+            writer.writeUint8(field.index);
+            const value = (component as any)[field.name];
+            encodeFieldValue(writer, value, field.type);
+        }
+    }
+
+    return dirtyFields.length > 0;
+}
+
+/**
+ * @zh 编码实体的所有同步组件
+ * @en Encode all sync components of an entity
+ *
+ * @zh 格式:
+ * [entityId: uint32]
+ * [componentCount: varint]
+ * ([typeIdLength: varint] [typeId: string] [componentData])...
+ *
+ * @en Format:
+ * [entityId: uint32]
+ * [componentCount: varint]
+ * ([typeIdLength: varint] [typeId: string] [componentData])...
+ *
+ * @param entity - @zh 实体 @en Entity
+ * @param writer - @zh 二进制写入器 @en Binary writer
+ * @param deltaOnly - @zh 只编码增量 @en Only encode delta
+ * @returns @zh 编码的组件数量 @en Number of components encoded
+ */
+export function encodeEntity(
+    entity: Entity,
+    writer: BinaryWriter,
+    deltaOnly: boolean = false
+): number {
+    writer.writeUint32(entity.id);
+
+    const components = entity.components;
+    const syncComponents: Array<{
+        component: Component;
+        metadata: SyncMetadata;
+        tracker: ChangeTracker | undefined;
+    }> = [];
+
+    // Collect components with sync metadata
+    for (const component of components) {
+        const constructor = component.constructor as any;
+        const metadata: SyncMetadata | undefined = constructor[SYNC_METADATA];
+        if (metadata && metadata.fields.length > 0) {
+            const tracker = (component as any)[CHANGE_TRACKER] as ChangeTracker | undefined;
+
+            // For delta encoding, only include components with changes
+            if (deltaOnly && tracker && !tracker.hasChanges()) {
+                continue;
+            }
+
+            syncComponents.push({ component, metadata, tracker });
+        }
+    }
+
+    writer.writeVarint(syncComponents.length);
+
+    for (const { component, metadata, tracker } of syncComponents) {
+        // Write component type ID
+        writer.writeString(metadata.typeId);
+
+        if (deltaOnly && tracker) {
+            encodeComponentDelta(component, metadata, tracker, writer);
+        } else {
+            encodeComponentFull(component, metadata, writer);
+        }
+    }
+
+    return syncComponents.length;
+}
+
+/**
+ * @zh 编码状态快照（多个实体）
+ * @en Encode state snapshot (multiple entities)
+ *
+ * @zh 格式:
+ * [operation: uint8] (FULL=0, DELTA=1, SPAWN=2, DESPAWN=3)
+ * [entityCount: varint]
+ * (entityData)...
+ *
+ * @en Format:
+ * [operation: uint8] (FULL=0, DELTA=1, SPAWN=2, DESPAWN=3)
+ * [entityCount: varint]
+ * (entityData)...
+ *
+ * @param entities - @zh 要编码的实体数组 @en Entities to encode
+ * @param operation - @zh 同步操作类型 @en Sync operation type
+ * @returns @zh 编码后的二进制数据 @en Encoded binary data
+ */
+export function encodeSnapshot(
+    entities: Entity[],
+    operation: SyncOperation = SyncOperation.FULL
+): Uint8Array {
+    const writer = new BinaryWriter(1024);
+
+    writer.writeUint8(operation);
+    writer.writeVarint(entities.length);
+
+    const deltaOnly = operation === SyncOperation.DELTA;
+
+    for (const entity of entities) {
+        encodeEntity(entity, writer, deltaOnly);
+    }
+
+    return writer.toUint8Array();
+}
+
+/**
+ * @zh 编码实体生成消息
+ * @en Encode entity spawn message
+ *
+ * @param entity - @zh 生成的实体 @en Spawned entity
+ * @param prefabType - @zh 预制体类型（可选）@en Prefab type (optional)
+ * @returns @zh 编码后的二进制数据 @en Encoded binary data
+ */
+export function encodeSpawn(entity: Entity, prefabType?: string): Uint8Array {
+    const writer = new BinaryWriter(256);
+
+    writer.writeUint8(SyncOperation.SPAWN);
+    writer.writeUint32(entity.id);
+    writer.writeString(prefabType || '');
+
+    // Encode all sync components for initial state
+    const components = entity.components;
+    const syncComponents: Array<{ component: Component; metadata: SyncMetadata }> = [];
+
+    for (const component of components) {
+        const constructor = component.constructor as any;
+        const metadata: SyncMetadata | undefined = constructor[SYNC_METADATA];
+        if (metadata && metadata.fields.length > 0) {
+            syncComponents.push({ component, metadata });
+        }
+    }
+
+    writer.writeVarint(syncComponents.length);
+
+    for (const { component, metadata } of syncComponents) {
+        writer.writeString(metadata.typeId);
+        encodeComponentFull(component, metadata, writer);
+    }
+
+    return writer.toUint8Array();
+}
+
+/**
+ * @zh 编码实体销毁消息
+ * @en Encode entity despawn message
+ *
+ * @param entityId - @zh 销毁的实体 ID @en Despawned entity ID
+ * @returns @zh 编码后的二进制数据 @en Encoded binary data
+ */
+export function encodeDespawn(entityId: number): Uint8Array {
+    const writer = new BinaryWriter(8);
+
+    writer.writeUint8(SyncOperation.DESPAWN);
+    writer.writeUint32(entityId);
+
+    return writer.toUint8Array();
+}
+
+/**
+ * @zh 编码批量实体销毁消息
+ * @en Encode batch entity despawn message
+ *
+ * @param entityIds - @zh 销毁的实体 ID 数组 @en Despawned entity IDs
+ * @returns @zh 编码后的二进制数据 @en Encoded binary data
+ */
+export function encodeDespawnBatch(entityIds: number[]): Uint8Array {
+    const writer = new BinaryWriter(8 + entityIds.length * 4);
+
+    writer.writeUint8(SyncOperation.DESPAWN);
+    writer.writeVarint(entityIds.length);
+
+    for (const id of entityIds) {
+        writer.writeUint32(id);
+    }
+
+    return writer.toUint8Array();
+}

packages/framework/core/src/ECS/Sync/encoding/index.ts

@@ -0,0 +1,52 @@
+/**
+ * @zh 二进制编解码模块
+ * @en Binary encoding/decoding module
+ *
+ * @zh 提供 ECS Component 状态的二进制序列化和反序列化功能
+ * @en Provides binary serialization and deserialization for ECS Component state
+ */
+
+// Variable-length integer encoding
+export {
+    varintSize,
+    encodeVarint,
+    decodeVarint,
+    zigzagEncode,
+    zigzagDecode,
+    encodeSignedVarint,
+    decodeSignedVarint
+} from './varint';
+
+// Binary writer/reader
+export { BinaryWriter } from './BinaryWriter';
+export { BinaryReader } from './BinaryReader';
+
+// Encoder
+export {
+    encodeComponentFull,
+    encodeComponentDelta,
+    encodeEntity,
+    encodeSnapshot,
+    encodeSpawn,
+    encodeDespawn,
+    encodeDespawnBatch
+} from './Encoder';
+
+// Decoder
+export {
+    registerSyncComponent,
+    autoRegisterSyncComponent,
+    decodeComponent,
+    decodeEntity,
+    decodeSnapshot,
+    decodeSpawn,
+    decodeDespawn,
+    processDespawn
+} from './Decoder';
+
+export type {
+    DecodeEntityResult,
+    DecodeSnapshotResult,
+    DecodeSpawnResult,
+    DecodeDespawnResult
+} from './Decoder';

packages/framework/core/src/ECS/Sync/encoding/varint.ts

@@ -0,0 +1,137 @@
+/**
+ * @zh 变长整数编解码
+ * @en Variable-length integer encoding/decoding
+ *
+ * @zh 使用 LEB128 编码方式，可变长度编码正整数。
+ * 小数值使用更少字节，大数值使用更多字节。
+ * @en Uses LEB128 encoding for variable-length integer encoding.
+ * Small values use fewer bytes, large values use more bytes.
+ *
+ * | 值范围 | 字节数 |
+ * |--------|--------|
+ * | 0-127 | 1 |
+ * | 128-16383 | 2 |
+ * | 16384-2097151 | 3 |
+ * | 2097152-268435455 | 4 |
+ * | 268435456+ | 5 |
+ */
+
+/**
+ * @zh 计算变长整数所需的字节数
+ * @en Calculate bytes needed for a varint
+ *
+ * @param value - @zh 整数值 @en Integer value
+ * @returns @zh 所需字节数 @en Bytes needed
+ */
+export function varintSize(value: number): number {
+    if (value < 0) {
+        throw new Error('Varint only supports non-negative integers');
+    }
+    if (value < 128) return 1;
+    if (value < 16384) return 2;
+    if (value < 2097152) return 3;
+    if (value < 268435456) return 4;
+    return 5;
+}
+
+/**
+ * @zh 编码变长整数到字节数组
+ * @en Encode varint to byte array
+ *
+ * @param value - @zh 要编码的整数 @en Integer to encode
+ * @param buffer - @zh 目标缓冲区 @en Target buffer
+ * @param offset - @zh 写入偏移 @en Write offset
+ * @returns @zh 写入后的新偏移 @en New offset after writing
+ */
+export function encodeVarint(value: number, buffer: Uint8Array, offset: number): number {
+    if (value < 0) {
+        throw new Error('Varint only supports non-negative integers');
+    }
+
+    while (value >= 0x80) {
+        buffer[offset++] = (value & 0x7F) | 0x80;
+        value >>>= 7;
+    }
+    buffer[offset++] = value;
+    return offset;
+}
+
+/**
+ * @zh 从字节数组解码变长整数
+ * @en Decode varint from byte array
+ *
+ * @param buffer - @zh 源缓冲区 @en Source buffer
+ * @param offset - @zh 读取偏移 @en Read offset
+ * @returns @zh [解码值, 新偏移] @en [decoded value, new offset]
+ */
+export function decodeVarint(buffer: Uint8Array, offset: number): [number, number] {
+    let result = 0;
+    let shift = 0;
+    let byte: number;
+
+    do {
+        if (offset >= buffer.length) {
+            throw new Error('Varint decode: buffer overflow');
+        }
+        byte = buffer[offset++]!;
+        result |= (byte & 0x7F) << shift;
+        shift += 7;
+    } while (byte >= 0x80);
+
+    return [result, offset];
+}
+
+/**
+ * @zh 编码有符号整数（ZigZag 编码）
+ * @en Encode signed integer (ZigZag encoding)
+ *
+ * @zh ZigZag 编码将有符号整数映射到无符号整数：
+ * 0 → 0, -1 → 1, 1 → 2, -2 → 3, 2 → 4, ...
+ * 这样小的负数也能用较少字节表示。
+ * @en ZigZag encoding maps signed integers to unsigned:
+ * 0 → 0, -1 → 1, 1 → 2, -2 → 3, 2 → 4, ...
+ * This allows small negative numbers to use fewer bytes.
+ *
+ * @param value - @zh 有符号整数 @en Signed integer
+ * @returns @zh ZigZag 编码后的值 @en ZigZag encoded value
+ */
+export function zigzagEncode(value: number): number {
+    return (value << 1) ^ (value >> 31);
+}
+
+/**
+ * @zh 解码有符号整数（ZigZag 解码）
+ * @en Decode signed integer (ZigZag decoding)
+ *
+ * @param value - @zh ZigZag 编码的值 @en ZigZag encoded value
+ * @returns @zh 原始有符号整数 @en Original signed integer
+ */
+export function zigzagDecode(value: number): number {
+    return (value >>> 1) ^ -(value & 1);
+}
+
+/**
+ * @zh 编码有符号变长整数
+ * @en Encode signed varint
+ *
+ * @param value - @zh 有符号整数 @en Signed integer
+ * @param buffer - @zh 目标缓冲区 @en Target buffer
+ * @param offset - @zh 写入偏移 @en Write offset
+ * @returns @zh 写入后的新偏移 @en New offset after writing
+ */
+export function encodeSignedVarint(value: number, buffer: Uint8Array, offset: number): number {
+    return encodeVarint(zigzagEncode(value), buffer, offset);
+}
+
+/**
+ * @zh 解码有符号变长整数
+ * @en Decode signed varint
+ *
+ * @param buffer - @zh 源缓冲区 @en Source buffer
+ * @param offset - @zh 读取偏移 @en Read offset
+ * @returns @zh [解码值, 新偏移] @en [decoded value, new offset]
+ */
+export function decodeSignedVarint(buffer: Uint8Array, offset: number): [number, number] {
+    const [encoded, newOffset] = decodeVarint(buffer, offset);
+    return [zigzagDecode(encoded), newOffset];
+}

packages/framework/core/src/ECS/Sync/index.ts

@@ -0,0 +1,55 @@
+/**
+ * @zh ECS 网络同步模块
+ * @en ECS Network Synchronization Module
+ *
+ * @zh 提供基于 ECS Component 的网络状态同步功能：
+ * - @sync 装饰器：标记需要同步的字段
+ * - ChangeTracker：追踪字段级变更
+ * - 二进制编解码器：高效的网络序列化
+ *
+ * @en Provides network state synchronization based on ECS Components:
+ * - @sync decorator: Mark fields for synchronization
+ * - ChangeTracker: Track field-level changes
+ * - Binary encoder/decoder: Efficient network serialization
+ *
+ * @example
+ * ```typescript
+ * import { Component, ECSComponent, sync } from '@esengine/ecs-framework';
+ *
+ * @ECSComponent('Player')
+ * class PlayerComponent extends Component {
+ *     @sync("string") name: string = "";
+ *     @sync("uint16") score: number = 0;
+ *     @sync("float32") x: number = 0;
+ *     @sync("float32") y: number = 0;
+ * }
+ * ```
+ */
+
+// Types
+export {
+    SyncType,
+    SyncFieldMetadata,
+    SyncMetadata,
+    SyncOperation,
+    TYPE_SIZES,
+    SYNC_METADATA,
+    CHANGE_TRACKER
+} from './types';
+
+// Change Tracker
+export { ChangeTracker } from './ChangeTracker';
+
+// Decorators
+export {
+    sync,
+    getSyncMetadata,
+    hasSyncFields,
+    getChangeTracker,
+    initChangeTracker,
+    clearChanges,
+    hasChanges
+} from './decorators';
+
+// Encoding
+export * from './encoding';

packages/framework/core/src/ECS/Sync/types.ts

@@ -0,0 +1,127 @@
+/**
+ * @zh 网络同步类型定义
+ * @en Network synchronization type definitions
+ */
+
+/**
+ * @zh 支持的同步数据类型
+ * @en Supported sync data types
+ */
+export type SyncType =
+    | 'boolean'
+    | 'int8'
+    | 'uint8'
+    | 'int16'
+    | 'uint16'
+    | 'int32'
+    | 'uint32'
+    | 'float32'
+    | 'float64'
+    | 'string';
+
+/**
+ * @zh 同步字段元数据
+ * @en Sync field metadata
+ */
+export interface SyncFieldMetadata {
+    /**
+     * @zh 字段索引（用于二进制编码）
+     * @en Field index (for binary encoding)
+     */
+    index: number;
+
+    /**
+     * @zh 字段名称
+     * @en Field name
+     */
+    name: string;
+
+    /**
+     * @zh 字段类型
+     * @en Field type
+     */
+    type: SyncType;
+}
+
+/**
+ * @zh 组件同步元数据
+ * @en Component sync metadata
+ */
+export interface SyncMetadata {
+    /**
+     * @zh 组件类型 ID
+     * @en Component type ID
+     */
+    typeId: string;
+
+    /**
+     * @zh 同步字段列表（按索引排序）
+     * @en Sync fields list (sorted by index)
+     */
+    fields: SyncFieldMetadata[];
+
+    /**
+     * @zh 字段名到索引的映射
+     * @en Field name to index mapping
+     */
+    fieldIndexMap: Map<string, number>;
+}
+
+/**
+ * @zh 同步操作类型
+ * @en Sync operation type
+ */
+export enum SyncOperation {
+    /**
+     * @zh 完整快照
+     * @en Full snapshot
+     */
+    FULL = 0,
+
+    /**
+     * @zh 增量更新
+     * @en Delta update
+     */
+    DELTA = 1,
+
+    /**
+     * @zh 实体生成
+     * @en Entity spawn
+     */
+    SPAWN = 2,
+
+    /**
+     * @zh 实体销毁
+     * @en Entity despawn
+     */
+    DESPAWN = 3,
+}
+
+/**
+ * @zh 各类型的字节大小
+ * @en Byte size for each type
+ */
+export const TYPE_SIZES: Record<SyncType, number> = {
+    boolean: 1,
+    int8: 1,
+    uint8: 1,
+    int16: 2,
+    uint16: 2,
+    int32: 4,
+    uint32: 4,
+    float32: 4,
+    float64: 8,
+    string: -1, // 动态长度 | dynamic length
+};
+
+/**
+ * @zh 同步元数据的 Symbol 键
+ * @en Symbol key for sync metadata
+ */
+export const SYNC_METADATA = Symbol('SyncMetadata');
+
+/**
+ * @zh 变更追踪器的 Symbol 键
+ * @en Symbol key for change tracker
+ */
+export const CHANGE_TRACKER = Symbol('ChangeTracker');

packages/framework/core/src/ECS/WorldManager.ts

@@ -317,9 +317,7 @@ export class WorldManager implements IService {
     /**
      * @zh 更新所有活跃的World
      * @en Update all active Worlds
-     *
-     * @zh 应该在每帧的游戏循环中调用
-     * @en Should be called in each frame of game loop
+     * @internal 由 Core.update() 调用，用户不应直接调用
      */
     public updateAll(): void {
         if (!this._isRunning) return;

packages/framework/core/src/ECS/index.ts

@@ -57,3 +57,6 @@ export { EpochManager } from './Core/EpochManager';
 // Compiled Query
 export { CompiledQuery } from './Core/Query/CompiledQuery';
 export type { InstanceTypes } from './Core/Query/CompiledQuery';
+
+// Network Synchronization
+export * from './Sync';

packages/framework/core/tests/ECS/Sync/ChangeTracker.test.ts

@@ -0,0 +1,172 @@
+import { ChangeTracker } from '../../../src/ECS/Sync/ChangeTracker';
+
+describe('ChangeTracker - 变更追踪器测试', () => {
+    let tracker: ChangeTracker;
+
+    beforeEach(() => {
+        tracker = new ChangeTracker();
+    });
+
+    describe('基本功能', () => {
+        test('初始状态应该没有变更', () => {
+            expect(tracker.hasChanges()).toBe(false);
+            expect(tracker.getDirtyCount()).toBe(0);
+            expect(tracker.getDirtyFields()).toEqual([]);
+        });
+
+        test('setDirty 应该标记字段为脏', () => {
+            tracker.setDirty(0);
+
+            expect(tracker.hasChanges()).toBe(true);
+            expect(tracker.isDirty(0)).toBe(true);
+            expect(tracker.getDirtyCount()).toBe(1);
+            expect(tracker.getDirtyFields()).toEqual([0]);
+        });
+
+        test('多次 setDirty 同一字段应该只记录一次', () => {
+            tracker.setDirty(0);
+            tracker.setDirty(0);
+            tracker.setDirty(0);
+
+            expect(tracker.getDirtyCount()).toBe(1);
+            expect(tracker.getDirtyFields()).toEqual([0]);
+        });
+
+        test('setDirty 不同字段应该都被记录', () => {
+            tracker.setDirty(0);
+            tracker.setDirty(1);
+            tracker.setDirty(2);
+
+            expect(tracker.getDirtyCount()).toBe(3);
+            expect(tracker.getDirtyFields().sort()).toEqual([0, 1, 2]);
+        });
+    });
+
+    describe('isDirty 方法', () => {
+        test('未标记的字段应该返回 false', () => {
+            expect(tracker.isDirty(0)).toBe(false);
+            expect(tracker.isDirty(5)).toBe(false);
+        });
+
+        test('已标记的字段应该返回 true', () => {
+            tracker.setDirty(3);
+
+            expect(tracker.isDirty(3)).toBe(true);
+            expect(tracker.isDirty(0)).toBe(false);
+        });
+    });
+
+    describe('clear 方法', () => {
+        test('clear 应该清除所有变更', () => {
+            tracker.setDirty(0);
+            tracker.setDirty(1);
+            tracker.setDirty(2);
+
+            expect(tracker.hasChanges()).toBe(true);
+
+            tracker.clear();
+
+            expect(tracker.hasChanges()).toBe(false);
+            expect(tracker.getDirtyCount()).toBe(0);
+            expect(tracker.getDirtyFields()).toEqual([]);
+        });
+
+        test('clear 应该更新 lastSyncTime', () => {
+            const before = tracker.lastSyncTime;
+            tracker.setDirty(0);
+            tracker.clear();
+
+            expect(tracker.lastSyncTime).toBeGreaterThan(0);
+        });
+    });
+
+    describe('clearField 方法', () => {
+        test('clearField 应该只清除指定字段', () => {
+            tracker.setDirty(0);
+            tracker.setDirty(1);
+            tracker.setDirty(2);
+
+            tracker.clearField(1);
+
+            expect(tracker.isDirty(0)).toBe(true);
+            expect(tracker.isDirty(1)).toBe(false);
+            expect(tracker.isDirty(2)).toBe(true);
+            expect(tracker.getDirtyCount()).toBe(2);
+        });
+
+        test('清除最后一个字段应该使 hasChanges 返回 false', () => {
+            tracker.setDirty(0);
+            expect(tracker.hasChanges()).toBe(true);
+
+            tracker.clearField(0);
+
+            expect(tracker.hasChanges()).toBe(false);
+        });
+    });
+
+    describe('markAllDirty 方法', () => {
+        test('markAllDirty 应该标记所有字段', () => {
+            tracker.markAllDirty(5);
+
+            expect(tracker.hasChanges()).toBe(true);
+            expect(tracker.getDirtyCount()).toBe(5);
+            expect(tracker.getDirtyFields().sort()).toEqual([0, 1, 2, 3, 4]);
+        });
+
+        test('markAllDirty(0) 应该没有变更', () => {
+            tracker.markAllDirty(0);
+
+            expect(tracker.hasChanges()).toBe(false);
+            expect(tracker.getDirtyCount()).toBe(0);
+        });
+
+        test('markAllDirty 用于首次同步', () => {
+            tracker.markAllDirty(3);
+
+            expect(tracker.isDirty(0)).toBe(true);
+            expect(tracker.isDirty(1)).toBe(true);
+            expect(tracker.isDirty(2)).toBe(true);
+            expect(tracker.isDirty(3)).toBe(false);
+        });
+    });
+
+    describe('reset 方法', () => {
+        test('reset 应该重置所有状态', () => {
+            tracker.setDirty(0);
+            tracker.setDirty(1);
+            tracker.clear();
+
+            tracker.reset();
+
+            expect(tracker.hasChanges()).toBe(false);
+            expect(tracker.getDirtyCount()).toBe(0);
+            expect(tracker.lastSyncTime).toBe(0);
+        });
+    });
+
+    describe('边界情况', () => {
+        test('大量字段标记应该正常工作', () => {
+            const fieldCount = 1000;
+
+            for (let i = 0; i < fieldCount; i++) {
+                tracker.setDirty(i);
+            }
+
+            expect(tracker.getDirtyCount()).toBe(fieldCount);
+            expect(tracker.hasChanges()).toBe(true);
+        });
+
+        test('交替设置和清除应该正常工作', () => {
+            tracker.setDirty(0);
+            tracker.setDirty(1);
+            tracker.clearField(0);
+            tracker.setDirty(2);
+            tracker.clearField(1);
+
+            expect(tracker.isDirty(0)).toBe(false);
+            expect(tracker.isDirty(1)).toBe(false);
+            expect(tracker.isDirty(2)).toBe(true);
+            expect(tracker.getDirtyCount()).toBe(1);
+        });
+    });
+});

packages/framework/core/tests/ECS/Sync/decorators.test.ts

@@ -0,0 +1,327 @@
+import { Component } from '../../../src/ECS/Component';
+import { ECSComponent } from '../../../src/ECS/Decorators';
+import { Scene } from '../../../src/ECS/Scene';
+import {
+    sync,
+    getSyncMetadata,
+    hasSyncFields,
+    getChangeTracker,
+    initChangeTracker,
+    clearChanges,
+    hasChanges
+} from '../../../src/ECS/Sync/decorators';
+import { SYNC_METADATA, CHANGE_TRACKER } from '../../../src/ECS/Sync/types';
+
+@ECSComponent('SyncTest_PlayerComponent')
+class PlayerComponent extends Component {
+    @sync("string") name: string = "";
+    @sync("uint16") score: number = 0;
+    @sync("float32") x: number = 0;
+    @sync("float32") y: number = 0;
+
+    localData: string = "not synced";
+}
+
+@ECSComponent('SyncTest_SimpleComponent')
+class SimpleComponent extends Component {
+    @sync("boolean") active: boolean = true;
+    @sync("int32") value: number = 100;
+}
+
+@ECSComponent('SyncTest_NoSyncComponent')
+class NoSyncComponent extends Component {
+    localValue: number = 0;
+}
+
+@ECSComponent('SyncTest_AllTypesComponent')
+class AllTypesComponent extends Component {
+    @sync("boolean") boolField: boolean = false;
+    @sync("int8") int8Field: number = 0;
+    @sync("uint8") uint8Field: number = 0;
+    @sync("int16") int16Field: number = 0;
+    @sync("uint16") uint16Field: number = 0;
+    @sync("int32") int32Field: number = 0;
+    @sync("uint32") uint32Field: number = 0;
+    @sync("float32") float32Field: number = 0;
+    @sync("float64") float64Field: number = 0;
+    @sync("string") stringField: string = "";
+}
+
+describe('@sync 装饰器测试', () => {
+    describe('getSyncMetadata', () => {
+        test('应该返回带 @sync 字段的组件元数据', () => {
+            const metadata = getSyncMetadata(PlayerComponent);
+
+            expect(metadata).not.toBeNull();
+            expect(metadata!.typeId).toBe('PlayerComponent');
+            expect(metadata!.fields.length).toBe(4);
+        });
+
+        test('应该正确记录字段信息', () => {
+            const metadata = getSyncMetadata(PlayerComponent);
+
+            const nameField = metadata!.fields.find(f => f.name === 'name');
+            expect(nameField).toBeDefined();
+            expect(nameField!.type).toBe('string');
+            expect(nameField!.index).toBe(0);
+
+            const scoreField = metadata!.fields.find(f => f.name === 'score');
+            expect(scoreField).toBeDefined();
+            expect(scoreField!.type).toBe('uint16');
+
+            const xField = metadata!.fields.find(f => f.name === 'x');
+            expect(xField).toBeDefined();
+            expect(xField!.type).toBe('float32');
+        });
+
+        test('没有 @sync 字段的组件应该返回 null', () => {
+            const metadata = getSyncMetadata(NoSyncComponent);
+
+            expect(metadata).toBeNull();
+        });
+
+        test('可以从实例获取元数据', () => {
+            const component = new PlayerComponent();
+            const metadata = getSyncMetadata(component);
+
+            expect(metadata).not.toBeNull();
+            expect(metadata!.fields.length).toBe(4);
+        });
+
+        test('fieldIndexMap 应该正确映射字段名到索引', () => {
+            const metadata = getSyncMetadata(PlayerComponent);
+
+            expect(metadata!.fieldIndexMap.get('name')).toBe(0);
+            expect(metadata!.fieldIndexMap.get('score')).toBe(1);
+            expect(metadata!.fieldIndexMap.get('x')).toBe(2);
+            expect(metadata!.fieldIndexMap.get('y')).toBe(3);
+        });
+    });
+
+    describe('hasSyncFields', () => {
+        test('有 @sync 字段应该返回 true', () => {
+            expect(hasSyncFields(PlayerComponent)).toBe(true);
+            expect(hasSyncFields(new PlayerComponent())).toBe(true);
+        });
+
+        test('没有 @sync 字段应该返回 false', () => {
+            expect(hasSyncFields(NoSyncComponent)).toBe(false);
+            expect(hasSyncFields(new NoSyncComponent())).toBe(false);
+        });
+    });
+
+    describe('支持所有同步类型', () => {
+        test('AllTypesComponent 应该有所有类型的字段', () => {
+            const metadata = getSyncMetadata(AllTypesComponent);
+
+            expect(metadata).not.toBeNull();
+            expect(metadata!.fields.length).toBe(10);
+
+            const types = metadata!.fields.map(f => f.type);
+            expect(types).toContain('boolean');
+            expect(types).toContain('int8');
+            expect(types).toContain('uint8');
+            expect(types).toContain('int16');
+            expect(types).toContain('uint16');
+            expect(types).toContain('int32');
+            expect(types).toContain('uint32');
+            expect(types).toContain('float32');
+            expect(types).toContain('float64');
+            expect(types).toContain('string');
+        });
+    });
+
+    describe('字段值拦截', () => {
+        test('修改 @sync 字段应该触发变更追踪', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            const tracker = getChangeTracker(component);
+            expect(tracker).not.toBeNull();
+            tracker!.clear();
+
+            component.name = "TestPlayer";
+
+            expect(tracker!.hasChanges()).toBe(true);
+            expect(tracker!.isDirty(0)).toBe(true);
+        });
+
+        test('设置相同值不应该触发变更', () => {
+            const component = new PlayerComponent();
+            component.name = "Test";
+            initChangeTracker(component);
+
+            const tracker = getChangeTracker(component);
+            tracker!.clear();
+
+            component.name = "Test";
+
+            expect(tracker!.hasChanges()).toBe(false);
+        });
+
+        test('修改非 @sync 字段不应该触发变更', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            const tracker = getChangeTracker(component);
+            tracker!.clear();
+
+            component.localData = "new value";
+
+            expect(tracker!.hasChanges()).toBe(false);
+        });
+
+        test('多个字段变更应该都被追踪', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            const tracker = getChangeTracker(component);
+            tracker!.clear();
+
+            component.name = "NewName";
+            component.score = 100;
+            component.x = 1.5;
+
+            expect(tracker!.getDirtyCount()).toBe(3);
+            expect(tracker!.isDirty(0)).toBe(true);
+            expect(tracker!.isDirty(1)).toBe(true);
+            expect(tracker!.isDirty(2)).toBe(true);
+            expect(tracker!.isDirty(3)).toBe(false);
+        });
+    });
+
+    describe('initChangeTracker', () => {
+        test('应该创建变更追踪器', () => {
+            const component = new PlayerComponent();
+
+            expect(getChangeTracker(component)).toBeNull();
+
+            initChangeTracker(component);
+
+            expect(getChangeTracker(component)).not.toBeNull();
+        });
+
+        test('应该标记所有字段为脏（用于首次同步）', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            const tracker = getChangeTracker(component);
+            expect(tracker!.hasChanges()).toBe(true);
+            expect(tracker!.getDirtyCount()).toBe(4);
+        });
+
+        test('对没有 @sync 字段的组件应该抛出错误', () => {
+            const component = new NoSyncComponent();
+
+            expect(() => {
+                initChangeTracker(component);
+            }).toThrow();
+        });
+
+        test('重复初始化应该重新标记所有字段', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            const tracker = getChangeTracker(component);
+            tracker!.clear();
+
+            expect(tracker!.hasChanges()).toBe(false);
+
+            initChangeTracker(component);
+
+            expect(tracker!.hasChanges()).toBe(true);
+            expect(tracker!.getDirtyCount()).toBe(4);
+        });
+    });
+
+    describe('clearChanges', () => {
+        test('应该清除所有变更标记', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            expect(hasChanges(component)).toBe(true);
+
+            clearChanges(component);
+
+            expect(hasChanges(component)).toBe(false);
+        });
+
+        test('对没有追踪器的组件应该安全执行', () => {
+            const component = new PlayerComponent();
+
+            expect(() => {
+                clearChanges(component);
+            }).not.toThrow();
+        });
+    });
+
+    describe('hasChanges', () => {
+        test('初始化后应该有变更', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+
+            expect(hasChanges(component)).toBe(true);
+        });
+
+        test('清除后应该没有变更', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+            clearChanges(component);
+
+            expect(hasChanges(component)).toBe(false);
+        });
+
+        test('修改字段后应该有变更', () => {
+            const component = new PlayerComponent();
+            initChangeTracker(component);
+            clearChanges(component);
+
+            component.score = 999;
+
+            expect(hasChanges(component)).toBe(true);
+        });
+
+        test('没有追踪器应该返回 false', () => {
+            const component = new PlayerComponent();
+
+            expect(hasChanges(component)).toBe(false);
+        });
+    });
+
+    describe('与实体集成', () => {
+        let scene: Scene;
+
+        beforeEach(() => {
+            scene = new Scene();
+        });
+
+        test('添加到实体的组件应该能正常工作', () => {
+            const entity = scene.createEntity('TestEntity');
+            const component = new PlayerComponent();
+
+            entity.addComponent(component);
+            initChangeTracker(component);
+
+            component.name = "EntityPlayer";
+            component.x = 100;
+
+            const tracker = getChangeTracker(component);
+            expect(tracker!.hasChanges()).toBe(true);
+        });
+
+        test('从实体获取的组件应该保持追踪状态', () => {
+            const entity = scene.createEntity('TestEntity');
+            const component = new PlayerComponent();
+
+            entity.addComponent(component);
+            initChangeTracker(component);
+            clearChanges(component);
+
+            const retrieved = entity.getComponent(PlayerComponent);
+            retrieved!.score = 50;
+
+            expect(hasChanges(component)).toBe(true);
+            expect(hasChanges(retrieved!)).toBe(true);
+        });
+    });
+});

packages/framework/core/tests/ECS/Sync/encoding.test.ts

@@ -0,0 +1,538 @@
+import { BinaryWriter } from '../../../src/ECS/Sync/encoding/BinaryWriter';
+import { BinaryReader } from '../../../src/ECS/Sync/encoding/BinaryReader';
+import { Component } from '../../../src/ECS/Component';
+import { ECSComponent } from '../../../src/ECS/Decorators';
+import { Scene } from '../../../src/ECS/Scene';
+import { sync, initChangeTracker, clearChanges } from '../../../src/ECS/Sync/decorators';
+import {
+    encodeSnapshot,
+    encodeSpawn,
+    encodeDespawn,
+    encodeDespawnBatch
+} from '../../../src/ECS/Sync/encoding/Encoder';
+import {
+    decodeSnapshot,
+    decodeSpawn,
+    processDespawn,
+    registerSyncComponent
+} from '../../../src/ECS/Sync/encoding/Decoder';
+import { SyncOperation } from '../../../src/ECS/Sync/types';
+
+@ECSComponent('EncodingTest_PlayerComponent')
+class PlayerComponent extends Component {
+    @sync("string") name: string = "";
+    @sync("uint16") score: number = 0;
+    @sync("float32") x: number = 0;
+    @sync("float32") y: number = 0;
+}
+
+@ECSComponent('EncodingTest_AllTypesComponent')
+class AllTypesComponent extends Component {
+    @sync("boolean") boolField: boolean = false;
+    @sync("int8") int8Field: number = 0;
+    @sync("uint8") uint8Field: number = 0;
+    @sync("int16") int16Field: number = 0;
+    @sync("uint16") uint16Field: number = 0;
+    @sync("int32") int32Field: number = 0;
+    @sync("uint32") uint32Field: number = 0;
+    @sync("float32") float32Field: number = 0;
+    @sync("float64") float64Field: number = 0;
+    @sync("string") stringField: string = "";
+}
+
+describe('BinaryWriter/BinaryReader - 二进制读写器测试', () => {
+    describe('基本数值类型', () => {
+        test('writeUint8/readUint8', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint8(0);
+            writer.writeUint8(127);
+            writer.writeUint8(255);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readUint8()).toBe(0);
+            expect(reader.readUint8()).toBe(127);
+            expect(reader.readUint8()).toBe(255);
+        });
+
+        test('writeInt8/readInt8', () => {
+            const writer = new BinaryWriter();
+            writer.writeInt8(-128);
+            writer.writeInt8(0);
+            writer.writeInt8(127);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readInt8()).toBe(-128);
+            expect(reader.readInt8()).toBe(0);
+            expect(reader.readInt8()).toBe(127);
+        });
+
+        test('writeBoolean/readBoolean', () => {
+            const writer = new BinaryWriter();
+            writer.writeBoolean(true);
+            writer.writeBoolean(false);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readBoolean()).toBe(true);
+            expect(reader.readBoolean()).toBe(false);
+        });
+
+        test('writeUint16/readUint16', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint16(0);
+            writer.writeUint16(32767);
+            writer.writeUint16(65535);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readUint16()).toBe(0);
+            expect(reader.readUint16()).toBe(32767);
+            expect(reader.readUint16()).toBe(65535);
+        });
+
+        test('writeInt16/readInt16', () => {
+            const writer = new BinaryWriter();
+            writer.writeInt16(-32768);
+            writer.writeInt16(0);
+            writer.writeInt16(32767);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readInt16()).toBe(-32768);
+            expect(reader.readInt16()).toBe(0);
+            expect(reader.readInt16()).toBe(32767);
+        });
+
+        test('writeUint32/readUint32', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint32(0);
+            writer.writeUint32(2147483647);
+            writer.writeUint32(4294967295);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readUint32()).toBe(0);
+            expect(reader.readUint32()).toBe(2147483647);
+            expect(reader.readUint32()).toBe(4294967295);
+        });
+
+        test('writeInt32/readInt32', () => {
+            const writer = new BinaryWriter();
+            writer.writeInt32(-2147483648);
+            writer.writeInt32(0);
+            writer.writeInt32(2147483647);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readInt32()).toBe(-2147483648);
+            expect(reader.readInt32()).toBe(0);
+            expect(reader.readInt32()).toBe(2147483647);
+        });
+
+        test('writeFloat32/readFloat32', () => {
+            const writer = new BinaryWriter();
+            writer.writeFloat32(0);
+            writer.writeFloat32(3.14);
+            writer.writeFloat32(-100.5);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readFloat32()).toBe(0);
+            expect(reader.readFloat32()).toBeCloseTo(3.14, 5);
+            expect(reader.readFloat32()).toBeCloseTo(-100.5, 5);
+        });
+
+        test('writeFloat64/readFloat64', () => {
+            const writer = new BinaryWriter();
+            writer.writeFloat64(0);
+            writer.writeFloat64(Math.PI);
+            writer.writeFloat64(-1e100);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readFloat64()).toBe(0);
+            expect(reader.readFloat64()).toBe(Math.PI);
+            expect(reader.readFloat64()).toBe(-1e100);
+        });
+    });
+
+    describe('变长整数 (Varint)', () => {
+        test('小值 (1字节)', () => {
+            const writer = new BinaryWriter();
+            writer.writeVarint(0);
+            writer.writeVarint(127);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readVarint()).toBe(0);
+            expect(reader.readVarint()).toBe(127);
+        });
+
+        test('中等值 (2字节)', () => {
+            const writer = new BinaryWriter();
+            writer.writeVarint(128);
+            writer.writeVarint(16383);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readVarint()).toBe(128);
+            expect(reader.readVarint()).toBe(16383);
+        });
+
+        test('大值 (多字节)', () => {
+            const writer = new BinaryWriter();
+            writer.writeVarint(16384);
+            writer.writeVarint(1000000);
+            writer.writeVarint(2147483647);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readVarint()).toBe(16384);
+            expect(reader.readVarint()).toBe(1000000);
+            expect(reader.readVarint()).toBe(2147483647);
+        });
+    });
+
+    describe('字符串', () => {
+        test('空字符串', () => {
+            const writer = new BinaryWriter();
+            writer.writeString("");
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readString()).toBe("");
+        });
+
+        test('ASCII 字符串', () => {
+            const writer = new BinaryWriter();
+            writer.writeString("Hello, World!");
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readString()).toBe("Hello, World!");
+        });
+
+        test('Unicode 字符串', () => {
+            const writer = new BinaryWriter();
+            writer.writeString("你好世界");
+            writer.writeString("日本語テスト");
+            writer.writeString("emoji: 🎮🎯");
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readString()).toBe("你好世界");
+            expect(reader.readString()).toBe("日本語テスト");
+            expect(reader.readString()).toBe("emoji: 🎮🎯");
+        });
+
+        test('混合字符串', () => {
+            const writer = new BinaryWriter();
+            writer.writeString("Player_玩家_プレイヤー");
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.readString()).toBe("Player_玩家_プレイヤー");
+        });
+    });
+
+    describe('字节数组', () => {
+        test('writeBytes/readBytes', () => {
+            const writer = new BinaryWriter();
+            const data = new Uint8Array([1, 2, 3, 4, 5]);
+            writer.writeBytes(data);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            const result = reader.readBytes(5);
+            expect(Array.from(result)).toEqual([1, 2, 3, 4, 5]);
+        });
+    });
+
+    describe('BinaryReader 辅助方法', () => {
+        test('remaining 应该返回剩余字节数', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint32(100);
+            writer.writeUint32(200);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.remaining).toBe(8);
+
+            reader.readUint32();
+            expect(reader.remaining).toBe(4);
+        });
+
+        test('hasMore 应该正确判断', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint8(1);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.hasMore()).toBe(true);
+
+            reader.readUint8();
+            expect(reader.hasMore()).toBe(false);
+        });
+
+        test('peekUint8 不应该移动读取位置', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint8(42);
+            writer.writeUint8(99);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            expect(reader.peekUint8()).toBe(42);
+            expect(reader.peekUint8()).toBe(42);
+            expect(reader.offset).toBe(0);
+        });
+
+        test('skip 应该跳过指定字节', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint8(1);
+            writer.writeUint8(2);
+            writer.writeUint8(3);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            reader.skip(2);
+            expect(reader.readUint8()).toBe(3);
+        });
+
+        test('读取超出范围应该抛出错误', () => {
+            const reader = new BinaryReader(new Uint8Array([1, 2]));
+
+            expect(() => reader.readUint32()).toThrow();
+        });
+    });
+
+    describe('BinaryWriter 自动扩容', () => {
+        test('应该自动扩容', () => {
+            const writer = new BinaryWriter(4);
+
+            for (let i = 0; i < 100; i++) {
+                writer.writeUint32(i);
+            }
+
+            expect(writer.offset).toBe(400);
+
+            const reader = new BinaryReader(writer.toUint8Array());
+            for (let i = 0; i < 100; i++) {
+                expect(reader.readUint32()).toBe(i);
+            }
+        });
+
+        test('reset 应该清空数据但保留缓冲区', () => {
+            const writer = new BinaryWriter();
+            writer.writeUint32(100);
+            writer.writeUint32(200);
+
+            expect(writer.offset).toBe(8);
+
+            writer.reset();
+
+            expect(writer.offset).toBe(0);
+            expect(writer.toUint8Array().length).toBe(0);
+        });
+    });
+});
+
+describe('Encoder/Decoder - 实体编解码测试', () => {
+    let scene: Scene;
+
+    beforeAll(() => {
+        registerSyncComponent('PlayerComponent', PlayerComponent);
+        registerSyncComponent('AllTypesComponent', AllTypesComponent);
+    });
+
+    beforeEach(() => {
+        scene = new Scene();
+    });
+
+    describe('encodeSnapshot/decodeSnapshot', () => {
+        test('应该编码和解码单个实体', () => {
+            const entity = scene.createEntity('Player1');
+            const comp = entity.addComponent(new PlayerComponent());
+            comp.name = "TestPlayer";
+            comp.score = 100;
+            comp.x = 10.5;
+            comp.y = 20.5;
+            initChangeTracker(comp);
+
+            const data = encodeSnapshot([entity], SyncOperation.FULL);
+
+            const targetScene = new Scene();
+            const result = decodeSnapshot(targetScene, data);
+
+            expect(result.operation).toBe(SyncOperation.FULL);
+            expect(result.entities.length).toBe(1);
+            expect(result.entities[0].isNew).toBe(true);
+
+            const decodedEntity = targetScene.entities.buffer[0];
+            expect(decodedEntity).toBeDefined();
+
+            const decodedComp = decodedEntity!.getComponent(PlayerComponent);
+            expect(decodedComp).not.toBeNull();
+            expect(decodedComp!.name).toBe("TestPlayer");
+            expect(decodedComp!.score).toBe(100);
+            expect(decodedComp!.x).toBeCloseTo(10.5, 5);
+            expect(decodedComp!.y).toBeCloseTo(20.5, 5);
+        });
+
+        test('应该编码和解码多个实体', () => {
+            const entity1 = scene.createEntity('Player1');
+            const comp1 = entity1.addComponent(new PlayerComponent());
+            comp1.name = "Player1";
+            comp1.score = 50;
+            initChangeTracker(comp1);
+
+            const entity2 = scene.createEntity('Player2');
+            const comp2 = entity2.addComponent(new PlayerComponent());
+            comp2.name = "Player2";
+            comp2.score = 100;
+            initChangeTracker(comp2);
+
+            const data = encodeSnapshot([entity1, entity2], SyncOperation.FULL);
+
+            const targetScene = new Scene();
+            const result = decodeSnapshot(targetScene, data);
+
+            expect(result.entities.length).toBe(2);
+        });
+
+        test('DELTA 操作应该只编码变更的字段', () => {
+            const entity = scene.createEntity('Player1');
+            const comp = entity.addComponent(new PlayerComponent());
+            comp.name = "TestPlayer";
+            comp.score = 0;
+            initChangeTracker(comp);
+            clearChanges(comp);
+
+            comp.score = 200;
+
+            const deltaData = encodeSnapshot([entity], SyncOperation.DELTA);
+
+            expect(deltaData[0]).toBe(SyncOperation.DELTA);
+            expect(deltaData.length).toBeLessThan(50);
+        });
+    });
+
+    describe('encodeSpawn/decodeSpawn', () => {
+        test('应该编码和解码实体生成', () => {
+            const entity = scene.createEntity('SpawnedEntity');
+            const comp = entity.addComponent(new PlayerComponent());
+            comp.name = "SpawnedPlayer";
+            comp.score = 50;
+            comp.x = 100;
+            comp.y = 200;
+            initChangeTracker(comp);
+
+            const data = encodeSpawn(entity, 'Player');
+
+            const targetScene = new Scene();
+            const result = decodeSpawn(targetScene, data);
+
+            expect(result).not.toBeNull();
+            expect(result!.prefabType).toBe('Player');
+            expect(result!.componentTypes).toContain('PlayerComponent');
+
+            const decodedComp = result!.entity.getComponent(PlayerComponent);
+            expect(decodedComp!.name).toBe("SpawnedPlayer");
+            expect(decodedComp!.score).toBe(50);
+        });
+
+        test('没有 prefabType 应该也能工作', () => {
+            const entity = scene.createEntity('Entity');
+            const comp = entity.addComponent(new PlayerComponent());
+            initChangeTracker(comp);
+
+            const data = encodeSpawn(entity);
+
+            const targetScene = new Scene();
+            const result = decodeSpawn(targetScene, data);
+
+            expect(result!.prefabType).toBe('');
+        });
+    });
+
+    describe('encodeDespawn/processDespawn', () => {
+        test('应该编码和处理单个实体销毁', () => {
+            const targetScene = new Scene();
+            const entity = targetScene.createEntity('ToBeDestroyed');
+            const entityId = entity.id;
+
+            const data = encodeDespawn(entityId);
+
+            expect(data[0]).toBe(SyncOperation.DESPAWN);
+
+            const removedIds = processDespawn(targetScene, data);
+
+            expect(removedIds).toContain(entityId);
+        });
+
+        test('应该编码和处理批量实体销毁', () => {
+            const targetScene = new Scene();
+            const entity1 = targetScene.createEntity('Entity1');
+            const entity2 = targetScene.createEntity('Entity2');
+            const entity3 = targetScene.createEntity('Entity3');
+
+            const data = encodeDespawnBatch([entity1.id, entity2.id, entity3.id]);
+
+            expect(data[0]).toBe(SyncOperation.DESPAWN);
+
+            const removedIds = processDespawn(targetScene, data);
+
+            expect(removedIds.length).toBe(3);
+            expect(removedIds).toContain(entity1.id);
+            expect(removedIds).toContain(entity2.id);
+            expect(removedIds).toContain(entity3.id);
+        });
+    });
+
+    describe('所有同步类型编解码', () => {
+        beforeAll(() => {
+            registerSyncComponent('AllTypesComponent', AllTypesComponent);
+        });
+
+        test('应该正确编解码所有类型', () => {
+            const entity = scene.createEntity('AllTypes');
+            const comp = entity.addComponent(new AllTypesComponent());
+            comp.boolField = true;
+            comp.int8Field = -100;
+            comp.uint8Field = 200;
+            comp.int16Field = -30000;
+            comp.uint16Field = 60000;
+            comp.int32Field = -2000000000;
+            comp.uint32Field = 4000000000;
+            comp.float32Field = 3.14159;
+            comp.float64Field = Math.PI;
+            comp.stringField = "测试字符串";
+            initChangeTracker(comp);
+
+            const data = encodeSnapshot([entity], SyncOperation.FULL);
+
+            const targetScene = new Scene();
+            decodeSnapshot(targetScene, data);
+
+            const decodedEntity = targetScene.entities.buffer[0];
+            const decodedComp = decodedEntity!.getComponent(AllTypesComponent);
+
+            expect(decodedComp!.boolField).toBe(true);
+            expect(decodedComp!.int8Field).toBe(-100);
+            expect(decodedComp!.uint8Field).toBe(200);
+            expect(decodedComp!.int16Field).toBe(-30000);
+            expect(decodedComp!.uint16Field).toBe(60000);
+            expect(decodedComp!.int32Field).toBe(-2000000000);
+            expect(decodedComp!.uint32Field).toBe(4000000000);
+            expect(decodedComp!.float32Field).toBeCloseTo(3.14159, 4);
+            expect(decodedComp!.float64Field).toBe(Math.PI);
+            expect(decodedComp!.stringField).toBe("测试字符串");
+        });
+    });
+
+    describe('边界情况', () => {
+        test('空实体列表应该能编码', () => {
+            const data = encodeSnapshot([], SyncOperation.FULL);
+
+            const targetScene = new Scene();
+            const result = decodeSnapshot(targetScene, data);
+
+            expect(result.entities.length).toBe(0);
+        });
+
+        test('entityMap 应该正确跟踪实体', () => {
+            const entity = scene.createEntity('Tracked');
+            const comp = entity.addComponent(new PlayerComponent());
+            comp.name = "TrackedPlayer";
+            initChangeTracker(comp);
+
+            const data = encodeSnapshot([entity], SyncOperation.FULL);
+
+            const targetScene = new Scene();
+            const entityMap = new Map();
+            decodeSnapshot(targetScene, data, entityMap);
+
+            expect(entityMap.size).toBe(1);
+        });
+    });
+});