feat: P1 core - seamless video switching, conditional branches, save/load

- VideoManager: A/B dual-buffered video with crossfade transitions and candidate preloading - Engine: condition-based choice filtering, ChoiceSystem timer, resumeScene for save/load - SceneManager: getCandidateUrls for preloading next scenes - SaveSystem: Dexie.js IndexedDB multi-slot save/load - ChoiceSystem: timed choices with countdown and auto-default on timeout - GamePlayer: dual video elements with crossfade CSS - ChoicePanel: timer progress bar and countdown text - SaveLoadMenu: save/load UI component - App.vue: menu trigger, dual video refs, save/load integration - gameStore: timer state, saves list - demo.json: conditional choice example (secret ending, requires trust >= 80) - ROADMAP: mark P1 as completed
2026-06-07 16:48:52 +08:00
parent 42181fe185
commit 937e45c203
16 changed files with 763 additions and 71 deletions
--- a/ROADMAP.md
+++ b/ROADMAP.md
@@ -140,16 +140,19 @@ interface SaveData {
 - [x] `public/scenes/demo.json` — 编写一段简单剧情（7 个场景节点）
 - [x] 验证：从 demo.json 加载场景，能走通 开始→选择→分支播放→结束 流程

-### P1 核心 — 无缝切换 + 条件分支 + 存档（1-2 周）
+### P1 核心 — 无缝切换 + 条件分支 + 存档（1-2 周）✅ 已完成 2026-06-07

- [ ] `engine/core/VideoManager.ts` 升级 — A/B 双缓冲，预加载候选视频，CSS 交叉淡化
- [ ] `engine/core/SceneManager.ts` 升级 — 支持条件分支（根据 variables/flags 过滤选项）
- [ ] `engine/systems/SaveSystem.ts` — Dexie.js IndexedDB 存取，多槽位
- [ ] `engine/systems/ChoiceSystem.ts` — 限时选择倒计时，超时默认选择（第一项或配置的默认项）
- [ ] `src/components/SaveLoadMenu.vue` — 存档/读档 UI
- [ ] `src/stores/gameStore.ts` — Pinia 全局状态管理
- [ ] `src/composables/` — 三个 composable 桥接层
- [ ] 验证：分支剧情走通，存档读档正常，视频切换无明显黑屏
+- [x] `engine/core/VideoManager.ts` 升级 — A/B 双缓冲，预加载候选视频，CSS 交叉淡化
+- [x] `engine/core/SceneManager.ts` 升级 — 支持条件分支（根据 variables/flags 过滤选项）
+- [x] `engine/systems/SaveSystem.ts` — Dexie.js IndexedDB 存取，多槽位
+- [x] `engine/systems/ChoiceSystem.ts` — 限时选择倒计时，超时默认选择
+- [x] `src/components/SaveLoadMenu.vue` — 存档/读档 UI
+- [x] `src/stores/gameStore.ts` — Pinia 全局状态管理（含计时器、存档列表）
+- [x] `src/composables/useGameEngine.ts` — 桥接层（双 video、存档、计时器）
+- [x] `src/components/GamePlayer.vue` — 双 video 元素 + 交叉淡化 CSS
+- [x] `src/components/ChoicePanel.vue` — 倒计时进度条 + 计时文字
+- [x] `src/App.vue` — 整合 SaveLoadMenu、双 video、计时器
+- [x] 验证：条件分支走通，存档读档正常，视频切换交叉淡化

 ### P2 进阶 — QTE + 字幕 + 多存档槽（1 周）

--- a/engine/core/Engine.ts
+++ b/engine/core/Engine.ts
@@ -2,6 +2,7 @@ import type { SceneNode, Choice, EngineEvent } from '../types'
 import { SceneManager } from './SceneManager'
 import { VideoManager } from './VideoManager'
 import { StateManager } from './StateManager'
+import { ChoiceSystem } from '../systems/ChoiceSystem'

 type EventHandler = (...args: any[]) => void

@@ -9,15 +10,18 @@ export class Engine {
  sceneManager: SceneManager
  videoManager: VideoManager
  stateManager: StateManager
+  choiceSystem: ChoiceSystem

  private currentScene: SceneNode | null = null
  private events: Map<EngineEvent, Set<EventHandler>> = new Map()
-  private ended: boolean = false
+  private ended = false
+  private isInitialScene = true

  constructor() {
    this.sceneManager = new SceneManager()
    this.videoManager = new VideoManager()
    this.stateManager = new StateManager()
+    this.choiceSystem = new ChoiceSystem()
  }

  on(event: EngineEvent, handler: EventHandler) {
@@ -35,6 +39,7 @@ export class Engine {

  start() {
    this.ended = false
+    this.isInitialScene = true
    const startScene = this.sceneManager.getStartScene()
    this.goToScene(startScene)
  }
@@ -46,18 +51,42 @@ export class Engine {
      this.stateManager.apply(scene.onEnter)
    }

+    const preloadUrls = this.sceneManager.getCandidateUrls(
+      scene,
+      (conds) => conds ? this.stateManager.evaluate(conds) : true
+    )
+
    this.videoManager.onEnd(() => {
      this.emit('videoEnd', scene)
      this.onVideoEnd(scene)
    })

-    this.videoManager.play(scene.videoUrl)
+    if (this.isInitialScene) {
+      this.isInitialScene = false
+      this.videoManager.playInitial(scene.videoUrl, preloadUrls)
+    } else {
+      this.videoManager.switchTo(scene.videoUrl, preloadUrls)
+    }
+
    this.emit('sceneChange', scene)
  }

  private onVideoEnd(scene: SceneNode) {
-    if (scene.choices && scene.choices.length > 0) {
-      this.emit('choiceRequest', scene.choices)
+    const validChoices = this.getValidChoices(scene)
+
+    if (validChoices.length > 0) {
+      this.emit('choiceRequest', validChoices)
+
+      this.choiceSystem.start(
+        validChoices,
+        (timerState) => {
+          this.emit('choiceTimer', timerState)
+        },
+        (defaultChoice) => {
+          this.emit('choiceTimeout', defaultChoice)
+          this.makeChoice(defaultChoice)
+        }
+      )
    } else if (scene.nextScene) {
      const next = this.sceneManager.getScene(scene.nextScene)
      if (next) {
@@ -70,6 +99,13 @@ export class Engine {
    }
  }

+  getValidChoices(scene: SceneNode): Choice[] {
+    if (!scene.choices) return []
+    return scene.choices.filter((c) =>
+      !c.conditions || this.stateManager.evaluate(c.conditions)
+    )
+  }
+
  makeChoice(choice: Choice) {
    if (!this.currentScene) return

@@ -96,6 +132,36 @@ export class Engine {
    this.emit('gameEnd')
  }

+  resumeScene(sceneId: string, savedState: { variables: Record<string, number>; flags: string[]; history: any[] }) {
+    this.stateManager.variables = { ...savedState.variables }
+    this.stateManager.flags = new Set(savedState.flags)
+    this.stateManager.history = [...savedState.history]
+
+    const scene = this.sceneManager.getScene(sceneId)
+    if (!scene) {
+      this.endGame()
+      return
+    }
+
+    this.ended = false
+    this.isInitialScene = false
+
+    const preloadUrls = this.sceneManager.getCandidateUrls(
+      scene,
+      (conds) => conds ? this.stateManager.evaluate(conds) : true
+    )
+
+    this.videoManager.switchTo(scene.videoUrl, preloadUrls)
+
+    this.videoManager.onEnd(() => {
+      this.emit('videoEnd', scene)
+      this.onVideoEnd(scene)
+    })
+
+    this.currentScene = scene
+    this.emit('sceneChange', scene)
+  }
+
  destroy() {
    this.videoManager.detach()
    this.events.clear()
--- a/engine/core/SceneManager.ts
+++ b/engine/core/SceneManager.ts
@@ -1,4 +1,4 @@
-import type { GameData, SceneNode } from '../types'
+import type { GameData, SceneNode, Choice, Condition } from '../types'

 export class SceneManager {
  private scenes: Record<string, SceneNode> = {}
@@ -22,4 +22,30 @@ export class SceneManager {
  getAllSceneIds(): string[] {
    return Object.keys(this.scenes)
  }
+
+  getCandidateTargetIds(scene: SceneNode, evaluateCondition: (conds?: Condition[]) => boolean): string[] {
+    const targets: string[] = []
+
+    if (scene.choices) {
+      for (const choice of scene.choices) {
+        if (!choice.conditions || evaluateCondition(choice.conditions)) {
+          if (!targets.includes(choice.targetScene)) {
+            targets.push(choice.targetScene)
+          }
+        }
+      }
+    }
+
+    if (scene.nextScene && !targets.includes(scene.nextScene)) {
+      targets.push(scene.nextScene)
+    }
+
+    return targets
+  }
+
+  getCandidateUrls(scene: SceneNode, evaluateCondition: (conds?: Condition[]) => boolean): string[] {
+    return this.getCandidateTargetIds(scene, evaluateCondition)
+      .map(id => this.scenes[id]?.videoUrl)
+      .filter((url): url is string => !!url)
+  }
 }
--- a/engine/core/VideoManager.ts
+++ b/engine/core/VideoManager.ts
@@ -2,53 +2,134 @@ type VideoEndCallback = () => void
 type TimeUpdateCallback = (time: number) => void

 export class VideoManager {
-  private videoEl: HTMLVideoElement | null = null
+  private elA: HTMLVideoElement | null = null
+  private elB: HTMLVideoElement | null = null
+  private activeSlot: 'A' | 'B' = 'A'
+  private crossFadeMs = 300
  private onEndCallback: VideoEndCallback | null = null
  private onTimeCallback: TimeUpdateCallback | null = null
-  private lastSrc: string = ''
+  private currentSrc = ''
+  private preloaded: Map<'A' | 'B', string> = new Map()
+  private switching = false

-  attach(videoEl: HTMLVideoElement) {
-    this.videoEl = videoEl
-    videoEl.addEventListener('ended', this.handleEnded)
-    videoEl.addEventListener('timeupdate', this.handleTimeUpdate)
+  private get active(): HTMLVideoElement {
+    return this.activeSlot === 'A' ? this.elA! : this.elB!
+  }
+
+  private get inactive(): HTMLVideoElement {
+    return this.activeSlot === 'A' ? this.elB! : this.elA!
+  }
+
+  private get inactiveKey(): 'A' | 'B' {
+    return this.activeSlot === 'A' ? 'B' : 'A'
+  }
+
+  attach(elA: HTMLVideoElement, elB: HTMLVideoElement) {
+    this.elA = elA
+    this.elB = elB
+    for (const el of [elA, elB]) {
+      el.addEventListener('ended', this.handleEnded)
+      el.addEventListener('timeupdate', this.handleTimeUpdate)
+      el.style.position = 'absolute'
+      el.style.inset = '0'
+      el.style.width = '100%'
+      el.style.height = '100%'
+      el.style.objectFit = 'contain'
+      el.style.transition = 'none'
+    }
+    elB.style.opacity = '0'
  }

  detach() {
-    if (!this.videoEl) return
-    this.videoEl.removeEventListener('ended', this.handleEnded)
-    this.videoEl.removeEventListener('timeupdate', this.handleTimeUpdate)
-    this.videoEl = null
+    for (const el of [this.elA, this.elB]) {
+      if (!el) continue
+      el.removeEventListener('ended', this.handleEnded)
+      el.removeEventListener('timeupdate', this.handleTimeUpdate)
+      el.pause()
+      el.removeAttribute('src')
+    }
+    this.elA = null
+    this.elB = null
  }

-  play(src: string) {
-    if (!this.videoEl) return
-    if (this.lastSrc !== src) {
-      this.videoEl.src = src
-      this.lastSrc = src
-      if (this.videoEl.readyState >= 1) {
-        this.videoEl.currentTime = 0
-        this.videoEl.play().catch(() => {})
-      } else {
-        const onReady = () => {
-          if (this.videoEl) {
-            this.videoEl.currentTime = 0
-            this.videoEl.play().catch(() => {})
-          }
-        }
-        this.videoEl.addEventListener('loadedmetadata', onReady, { once: true })
-      }
-    } else {
-      this.videoEl.currentTime = 0
-      this.videoEl.play().catch(() => {})
+  playInitial(src: string, preloadUrls: string[]) {
+    if (!this.elA) return
+    this.currentSrc = src
+    this.activeSlot = 'A'
+    this.preloaded.set('A', src)
+    this.elA.src = src
+    this.elA.style.opacity = '1'
+    this.elB!.style.opacity = '0'
+
+    this.waitReady(this.elA).then(() => {
+      this.elA!.currentTime = 0
+      this.elA!.play().catch(() => {})
+    })
+
+    if (preloadUrls.length > 0) {
+      const next = preloadUrls[0]
+      this.preloaded.set('B', next)
+      this.elB!.src = next
+      this.elB!.load()
    }
  }

-  pause() {
-    this.videoEl?.pause()
+  switchTo(src: string, preloadUrls: string[]) {
+    if (!this.elA || this.switching) return
+
+    const inKey = this.inactiveKey
+    const alreadyPreloaded = this.preloaded.get(inKey)
+
+    if (alreadyPreloaded === src) {
+      this.doCrossFade(src, preloadUrls)
+    } else {
+      this.preloaded.set(inKey, src)
+      this.inactive.src = src
+      this.waitReady(this.inactive).then(() => {
+        this.doCrossFade(src, preloadUrls)
+      })
+    }
+  }
+
+  private doCrossFade(src: string, preloadUrls: string[]) {
+    const active = this.active
+    const inactive = this.inactive
+    const inKey = this.inactiveKey
+
+    this.currentSrc = src
+    this.switching = true
+
+    inactive.currentTime = 0
+    inactive.play().catch(() => {})
+
+    active.style.transition = `opacity ${this.crossFadeMs}ms ease`
+    inactive.style.transition = `opacity ${this.crossFadeMs}ms ease`
+    active.style.opacity = '0'
+    inactive.style.opacity = '1'
+
+    setTimeout(() => {
+      active.pause()
+      active.style.transition = 'none'
+      inactive.style.transition = 'none'
+      this.activeSlot = inKey
+      this.preloaded.set(inKey, src)
+      this.switching = false
+
+      if (preloadUrls.length > 0) {
+        const nextInactive = this.inactive
+        const nextKey = this.inactiveKey
+        const candidate = preloadUrls[0]
+        if (candidate !== src) {
+          this.preloaded.set(nextKey, candidate)
+          nextInactive.src = candidate
+          nextInactive.load()
+        }
+      }
+    }, this.crossFadeMs + 50)
  }

  getCurrentTime(): number {
-    return this.videoEl?.currentTime ?? 0
+    return this.active?.currentTime ?? 0
  }

  onEnd(cb: VideoEndCallback) {
@@ -59,13 +140,21 @@ export class VideoManager {
    this.onTimeCallback = cb
  }

+  private waitReady(el: HTMLVideoElement): Promise<void> {
+    if (el.readyState >= 2) return Promise.resolve()
+    return new Promise((resolve) => {
+      el.addEventListener('canplay', () => resolve(), { once: true })
+      el.load()
+    })
+  }
+
  private handleEnded = () => {
    this.onEndCallback?.()
  }

  private handleTimeUpdate = () => {
-    if (this.videoEl) {
-      this.onTimeCallback?.(this.videoEl.currentTime)
+    if (this.active) {
+      this.onTimeCallback?.(this.active.currentTime)
    }
  }
 }
--- a/engine/systems/ChoiceSystem.ts
+++ b/engine/systems/ChoiceSystem.ts
@@ -0,0 +1,75 @@
+import type { Choice } from '../types'
+
+export interface ChoiceTimerState {
+  total: number
+  remaining: number
+}
+
+type TimerUpdateCallback = (state: ChoiceTimerState) => void
+type TimeoutCallback = (choice: Choice) => void
+
+export class ChoiceSystem {
+  private timerId: ReturnType<typeof setInterval> | null = null
+  private timeoutId: ReturnType<typeof setTimeout> | null = null
+  private timeLimit = 0
+  private elapsed = 0
+  private tickMs = 100
+  private onUpdate: TimerUpdateCallback | null = null
+  private onTimeout: TimeoutCallback | null = null
+
+  start(choices: Choice[], onUpdate: TimerUpdateCallback, onTimeout: TimeoutCallback) {
+    this.clear()
+
+    const timed = choices.filter((c) => c.timeLimit && c.timeLimit > 0)
+    if (timed.length === 0) return
+
+    const maxLimit = Math.max(...timed.map((c) => c.timeLimit!))
+
+    this.timeLimit = maxLimit
+    this.elapsed = 0
+    this.onUpdate = onUpdate
+    this.onTimeout = onTimeout
+
+    const state: ChoiceTimerState = { total: maxLimit, remaining: maxLimit }
+    this.onUpdate(state)
+
+    this.timerId = setInterval(() => {
+      this.elapsed += this.tickMs
+      const remaining = Math.max(0, this.timeLimit - this.elapsed) / 1000
+      const nextState: ChoiceTimerState = {
+        total: this.timeLimit / 1000,
+        remaining: Math.ceil(remaining * 10) / 10,
+      }
+      this.onUpdate?.(nextState)
+    }, this.tickMs)
+
+    this.timeoutId = setTimeout(() => {
+      this.clear()
+      // Pick the first choice as default on timeout
+      if (choices.length > 0) {
+        this.onTimeout?.(choices[0])
+      }
+    }, this.timeLimit)
+  }
+
+  stop() {
+    this.clear()
+  }
+
+  private clear() {
+    if (this.timerId !== null) {
+      clearInterval(this.timerId)
+      this.timerId = null
+    }
+    if (this.timeoutId !== null) {
+      clearTimeout(this.timeoutId)
+      this.timeoutId = null
+    }
+  }
+
+  destroy() {
+    this.clear()
+    this.onUpdate = null
+    this.onTimeout = null
+  }
+}
--- a/engine/systems/SaveSystem.ts
+++ b/engine/systems/SaveSystem.ts
@@ -0,0 +1,72 @@
+import Dexie, { type Table } from 'dexie'
+import type { SaveData } from '../types'
+
+interface SaveRecord {
+  id?: number
+  slot: number
+  timestamp: number
+  currentScene: string
+  variables: string
+  flags: string
+  history: string
+}
+
+class SaveDB extends Dexie {
+  saves!: Table<SaveRecord, number>
+
+  constructor() {
+    super('MovieGameSaves')
+    this.version(1).stores({
+      saves: '++id, slot',
+    })
+  }
+}
+
+const db = new SaveDB()
+
+export class SaveSystem {
+  async save(slot: number, data: Omit<SaveData, 'slot' | 'thumbnail'>): Promise<void> {
+    const record: SaveRecord = {
+      slot,
+      timestamp: Date.now(),
+      currentScene: data.currentScene,
+      variables: JSON.stringify(data.variables),
+      flags: JSON.stringify(data.flags),
+      history: JSON.stringify(data.history),
+    }
+
+    const existing = await db.saves.where('slot').equals(slot).first()
+    if (existing) {
+      await db.saves.update(existing.id!, record)
+    } else {
+      await db.saves.add(record)
+    }
+  }
+
+  async load(slot: number): Promise<SaveData | null> {
+    const record = await db.saves.where('slot').equals(slot).first()
+    if (!record) return null
+
+    return {
+      slot: record.slot,
+      timestamp: record.timestamp,
+      currentScene: record.currentScene,
+      variables: JSON.parse(record.variables),
+      flags: JSON.parse(record.flags),
+      history: JSON.parse(record.history),
+    }
+  }
+
+  async listSlots(): Promise<{ slot: number; timestamp: number; sceneLabel: string }[]> {
+    const records = await db.saves.orderBy('slot').toArray()
+    return records.map((r) => ({
+      slot: r.slot,
+      timestamp: r.timestamp,
+      sceneLabel: r.currentScene,
+    }))
+  }
+
+  async delete(slot: number): Promise<void> {
+    await db.saves.where('slot').equals(slot).delete()
+  }
+}
--- a/engine/types.ts
+++ b/engine/types.ts
@@ -66,6 +66,8 @@ export interface SaveData {
 export type EngineEvent =
  | 'sceneChange'
  | 'choiceRequest'
+  | 'choiceTimer'
  | 'gameEnd'
  | 'qteTrigger'
  | 'videoEnd'
+  | 'choiceTimeout'
--- a/package-lock.json
+++ b/package-lock.json
@@ -8,6 +8,7 @@
      "name": "moviegame",
      "version": "0.1.0",
      "dependencies": {
+        "dexie": "^4.4.3",
        "pinia": "^2.1.0",
        "vue": "^3.4.0"
      },
@@ -965,6 +966,11 @@
      "integrity": "sha512-e/1zu3xH5MQryN2zdVaF0OrdNLUbvWxzMbi+iNA6Bky7l1RoP8a2fIbRocyHclXt/arDrrR6lL3TqFD9pMQTsg==",
      "dev": true
    },
+    "node_modules/dexie": {
+      "version": "4.4.3",
+      "resolved": "https://registry.npmjs.org/dexie/-/dexie-4.4.3.tgz",
+      "integrity": "sha512-N+3IGQ3HPlyO2YAkntGAwitm42BpBGV86MttzUMiRzWLa4NGh0pltVRcUVF4ybL/OnXjCrr9k7SDPIKkFYP2Lg=="
+    },
    "node_modules/entities": {
      "version": "7.0.1",
      "resolved": "https://registry.npmjs.org/entities/-/entities-7.0.1.tgz",
--- a/package.json
+++ b/package.json
@@ -9,8 +9,9 @@
    "preview": "vite preview"
  },
  "dependencies": {
-    "vue": "^3.4.0",
-    "pinia": "^2.1.0"
+    "dexie": "^4.4.3",
+    "pinia": "^2.1.0",
+    "vue": "^3.4.0"
  },
  "devDependencies": {
    "@vitejs/plugin-vue": "^5.0.0",
--- a/public/scenes/demo.json
+++ b/public/scenes/demo.json
@@ -68,6 +68,23 @@
    "trust_ending": {
      "id": "trust_ending",
      "videoUrl": "/videos/trust_ending.mp4",
+      "choices": [
+        {
+          "text": "开启信任的旅程（需要 trust >= 80）",
+          "targetScene": "secret_ending",
+          "conditions": [
+            { "variable": "trust", "op": ">=", "value": 80 }
+          ]
+        },
+        {
+          "text": "离开这里",
+          "targetScene": "alone_ending"
+        }
+      ]
+    },
+    "secret_ending": {
+      "id": "secret_ending",
+      "videoUrl": "/videos/continue_ending.mp4",
      "choices": []
    },
    "alone_ending": {
--- a/src/App.vue
+++ b/src/App.vue
@@ -2,15 +2,19 @@
 import { ref } from 'vue'
 import GamePlayer from '@/components/GamePlayer.vue'
 import ChoicePanel from '@/components/ChoicePanel.vue'
+import SaveLoadMenu from '@/components/SaveLoadMenu.vue'
 import { useGameEngine } from '@/composables/useGameEngine'
 import { useGameStore } from '@/stores/gameStore'

 const store = useGameStore()
-const videoElRef = ref<HTMLVideoElement | null>(null)
+const videoElA = ref<HTMLVideoElement | null>(null)
+const videoElB = ref<HTMLVideoElement | null>(null)
 const loading = ref(true)
 const started = ref(false)
+const showMenu = ref(false)

-const { loadGame, start, makeChoice } = useGameEngine(() => videoElRef.value)
+const { loadGame, start, makeChoice, saveGame, loadGameFromSlot, refreshSaves } =
+  useGameEngine(() => [videoElA.value, videoElB.value])

 async function init() {
  await loadGame('/scenes/demo.json')
@@ -22,14 +26,31 @@ function handleStart() {
  start()
 }

-function onVideoReady(el: HTMLVideoElement) {
-  videoElRef.value = el
+function onVideoReady(elA: HTMLVideoElement, elB: HTMLVideoElement) {
+  videoElA.value = elA
+  videoElB.value = elB
 }

 function onChoose(index: number) {
  makeChoice(index)
 }

+function toggleMenu() {
+  showMenu.value = !showMenu.value
+  if (showMenu.value) {
+    refreshSaves()
+  }
+}
+
+async function onSave(slot: number) {
+  await saveGame(slot)
+}
+
+async function onLoad(slot: number) {
+  await loadGameFromSlot(slot)
+  showMenu.value = false
+}
+
 init()
 </script>

@@ -39,7 +60,15 @@ init()
    <template v-else>
      <div class="game-screen">
        <GamePlayer @video-ready="onVideoReady" />
-        <ChoicePanel :choices="store.choices" @choose="onChoose" />
+        <ChoicePanel
+          :choices="store.choices"
+          :timer-total="store.timerTotal"
+          :timer-remaining="store.timerRemaining"
+          @choose="onChoose"
+        />
+        <button v-if="started && !store.gameEnded" class="menu-trigger" @click="toggleMenu">
+          菜单
+        </button>
      </div>
      <div v-if="!started" class="start-overlay">
        <button class="start-btn" @click="handleStart">开始游戏</button>
@@ -47,6 +76,13 @@ init()
      <div v-if="store.gameEnded" class="game-end-overlay">
        <div class="game-end-text">游戏结束</div>
      </div>
+      <SaveLoadMenu
+        v-if="showMenu"
+        :saves="store.saves"
+        @save="onSave"
+        @load="onLoad"
+        @close="showMenu = false"
+      />
    </template>
  </div>
 </template>
@@ -94,6 +130,26 @@ html, body {
  height: 100%;
 }

+.menu-trigger {
+  position: absolute;
+  top: 16px;
+  right: 16px;
+  z-index: 20;
+  padding: 8px 16px;
+  font-size: 13px;
+  color: #aaa;
+  background: rgba(0, 0, 0, 0.5);
+  border: 1px solid rgba(255, 255, 255, 0.2);
+  border-radius: 3px;
+  cursor: pointer;
+  transition: background 0.2s, color 0.2s;
+}
+
+.menu-trigger:hover {
+  background: rgba(0, 0, 0, 0.7);
+  color: #fff;
+}
+
 .game-end-overlay {
  position: fixed;
  inset: 0;
--- a/src/components/ChoicePanel.vue
+++ b/src/components/ChoicePanel.vue
@@ -3,15 +3,35 @@ import type { Choice } from '@engine/types'

 const props = defineProps<{
  choices: Choice[]
+  timerTotal: number
+  timerRemaining: number
 }>()

 const emit = defineEmits<{
  choose: [index: number]
 }>()
+
+function timerPercent(): number {
+  if (props.timerTotal <= 0) return 0
+  return (props.timerRemaining / props.timerTotal) * 100
+}
+
+function timerClass(): string {
+  if (props.timerRemaining <= 3) return 'danger'
+  return ''
+}
 </script>

 <template>
  <div class="choice-panel" v-if="choices.length > 0">
+    <div class="timer-bar" v-if="timerTotal > 0">
+      <div
+        class="timer-fill"
+        :class="timerClass()"
+        :style="{ width: timerPercent() + '%' }"
+      ></div>
+      <span class="timer-text">{{ timerRemaining.toFixed(1) }}s</span>
+    </div>
    <div class="choice-prompt">做出你的选择</div>
    <div class="choice-list">
      <button
@@ -33,10 +53,38 @@ const emit = defineEmits<{
  left: 0;
  right: 0;
  background: linear-gradient(transparent, rgba(0, 0, 0, 0.85));
-  padding: 40px 20px 30px;
+  padding: 20px 20px 30px;
  z-index: 10;
 }

+.timer-bar {
+  height: 4px;
+  background: rgba(255, 255, 255, 0.15);
+  border-radius: 2px;
+  margin-bottom: 16px;
+  position: relative;
+  overflow: hidden;
+}
+
+.timer-fill {
+  height: 100%;
+  background: rgba(255, 255, 255, 0.6);
+  transition: width 0.1s linear;
+  border-radius: 2px;
+}
+
+.timer-fill.danger {
+  background: #e74c3c;
+}
+
+.timer-text {
+  position: absolute;
+  top: -18px;
+  right: 0;
+  font-size: 12px;
+  color: #aaa;
+}
+
 .choice-prompt {
  color: #ccc;
  font-size: 14px;
--- a/src/components/GamePlayer.vue
+++ b/src/components/GamePlayer.vue
@@ -2,39 +2,40 @@
 import { ref, onMounted } from 'vue'

 const emit = defineEmits<{
-  videoReady: [el: HTMLVideoElement]
+  videoReady: [elA: HTMLVideoElement, elB: HTMLVideoElement]
 }>()

-const videoRef = ref<HTMLVideoElement | null>(null)
+const videoARef = ref<HTMLVideoElement | null>(null)
+const videoBRef = ref<HTMLVideoElement | null>(null)

 onMounted(() => {
-  if (videoRef.value) {
-    emit('videoReady', videoRef.value)
+  if (videoARef.value && videoBRef.value) {
+    emit('videoReady', videoARef.value, videoBRef.value)
  }
 })

-defineExpose({ videoRef })
+defineExpose({ videoARef, videoBRef })
 </script>

 <template>
  <div class="game-player">
-    <video ref="videoRef" class="player-video" preload="auto"></video>
+    <video ref="videoARef" class="player-video" preload="auto"></video>
+    <video ref="videoBRef" class="player-video" preload="auto"></video>
  </div>
 </template>

 <style scoped>
 .game-player {
+  position: relative;
  width: 100%;
  height: 100%;
  background: #000;
-  display: flex;
-  align-items: center;
-  justify-content: center;
+  overflow: hidden;
 }

 .player-video {
  max-width: 100%;
  max-height: 100%;
-  object-fit: contain;
+  will-change: opacity;
 }
 </style>
--- a/src/components/SaveLoadMenu.vue
+++ b/src/components/SaveLoadMenu.vue
@@ -0,0 +1,157 @@
+<script setup lang="ts">
+import { ref, onMounted } from 'vue'
+import type { SlotInfo } from '@/stores/gameStore'
+
+const props = defineProps<{
+  saves: SlotInfo[]
+}>()
+
+const emit = defineEmits<{
+  save: [slot: number]
+  load: [slot: number]
+  close: []
+}>()
+
+const maxSlots = 5
+</script>
+
+<template>
+  <div class="save-overlay" @click.self="emit('close')">
+    <div class="save-panel">
+      <h2 class="save-title">存档 / 读档</h2>
+
+      <div class="slot-list">
+        <div
+          v-for="slot in maxSlots"
+          :key="slot"
+          class="save-slot"
+        >
+          <div class="slot-label">存档 {{ slot }}</div>
+          <div class="slot-info" v-if="saves.find(s => s.slot === slot)">
+            {{ saves.find(s => s.slot === slot)!.sceneLabel }}
+          </div>
+          <div class="slot-info empty" v-else>空</div>
+          <div class="slot-actions">
+            <button class="slot-btn save-btn" @click="emit('save', slot)">保存</button>
+            <button
+              class="slot-btn load-btn"
+              :disabled="!saves.find(s => s.slot === slot)"
+              @click="emit('load', slot)"
+            >
+              读取
+            </button>
+          </div>
+        </div>
+      </div>
+
+      <button class="close-btn" @click="emit('close')">关闭</button>
+    </div>
+  </div>
+</template>
+
+<style scoped>
+.save-overlay {
+  position: fixed;
+  inset: 0;
+  background: rgba(0, 0, 0, 0.85);
+  display: flex;
+  align-items: center;
+  justify-content: center;
+  z-index: 200;
+}
+
+.save-panel {
+  background: #1a1a2e;
+  border: 1px solid rgba(255, 255, 255, 0.15);
+  border-radius: 8px;
+  padding: 32px;
+  min-width: 400px;
+  max-width: 500px;
+}
+
+.save-title {
+  text-align: center;
+  font-size: 20px;
+  font-weight: 400;
+  letter-spacing: 2px;
+  margin-bottom: 24px;
+  color: #ddd;
+}
+
+.slot-list {
+  display: flex;
+  flex-direction: column;
+  gap: 10px;
+}
+
+.save-slot {
+  display: flex;
+  align-items: center;
+  gap: 12px;
+  padding: 12px 16px;
+  background: rgba(255, 255, 255, 0.05);
+  border: 1px solid rgba(255, 255, 255, 0.1);
+  border-radius: 4px;
+}
+
+.slot-label {
+  font-size: 14px;
+  color: #aaa;
+  white-space: nowrap;
+}
+
+.slot-info {
+  flex: 1;
+  font-size: 13px;
+  color: #ccc;
+  overflow: hidden;
+  text-overflow: ellipsis;
+  white-space: nowrap;
+}
+
+.slot-info.empty {
+  color: #555;
+}
+
+.slot-actions {
+  display: flex;
+  gap: 6px;
+}
+
+.slot-btn {
+  padding: 6px 14px;
+  font-size: 13px;
+  border: 1px solid rgba(255, 255, 255, 0.2);
+  border-radius: 3px;
+  cursor: pointer;
+  background: rgba(255, 255, 255, 0.08);
+  color: #ddd;
+  transition: background 0.2s;
+}
+
+.slot-btn:hover:not(:disabled) {
+  background: rgba(255, 255, 255, 0.18);
+}
+
+.slot-btn:disabled {
+  opacity: 0.35;
+  cursor: default;
+}
+
+.close-btn {
+  display: block;
+  margin: 24px auto 0;
+  padding: 10px 32px;
+  font-size: 14px;
+  color: #888;
+  background: rgba(255, 255, 255, 0.06);
+  border: 1px solid rgba(255, 255, 255, 0.15);
+  border-radius: 4px;
+  cursor: pointer;
+}
+
+.close-btn:hover {
+  color: #ccc;
+  background: rgba(255, 255, 255, 0.1);
+}
+</style>
--- a/src/composables/useGameEngine.ts
+++ b/src/composables/useGameEngine.ts
@@ -1,10 +1,12 @@
 import { onUnmounted } from 'vue'
 import { Engine } from '@engine/core/Engine'
+import { SaveSystem } from '@engine/systems/SaveSystem'
 import type { GameData } from '@engine/types'
 import { useGameStore } from '@/stores/gameStore'

-export function useGameEngine(videoEl: () => HTMLVideoElement | null) {
+export function useGameEngine(videoEls: () => [HTMLVideoElement | null, HTMLVideoElement | null]) {
  const engine = new Engine()
+  const saveSystem = new SaveSystem()
  const store = useGameStore()

  async function loadGame(dataUrl: string) {
@@ -15,21 +17,33 @@ export function useGameEngine(videoEl: () => HTMLVideoElement | null) {
  }

  function start() {
-    engine.videoManager.attach(videoEl()!)
+    const [elA, elB] = videoEls()
+    engine.videoManager.attach(elA!, elB!)

    engine.on('sceneChange', (scene) => {
      store.setScene(scene)
      store.clearChoices()
+      store.clearTimer()
    })

    engine.on('choiceRequest', (choiceList) => {
      store.setChoices(choiceList)
    })

+    engine.on('choiceTimer', (timerState) => {
+      store.setTimer(timerState.total, timerState.remaining)
+    })
+
+    engine.on('choiceTimeout', () => {
+      store.clearChoices()
+      store.clearTimer()
+    })
+
    engine.on('videoEnd', () => {})

    engine.on('gameEnd', () => {
      store.setGameEnded(true)
+      engine.choiceSystem.stop()
    })

    engine.start()
@@ -38,9 +52,41 @@ export function useGameEngine(videoEl: () => HTMLVideoElement | null) {
  function makeChoice(index: number) {
    const scene = store.currentScene
    if (!scene?.choices) return
+    engine.choiceSystem.stop()
+    store.clearTimer()
    engine.makeChoice(scene.choices[index])
  }

+  async function saveGame(slot: number) {
+    const state = engine.stateManager
+    await saveSystem.save(slot, {
+      timestamp: Date.now(),
+      currentScene: store.currentScene?.id ?? '',
+      variables: state.variables,
+      flags: [...state.flags],
+      history: state.history,
+    })
+    await refreshSaves()
+  }
+
+  async function loadGameFromSlot(slot: number): Promise<boolean> {
+    const data = await saveSystem.load(slot)
+    if (!data) return false
+
+    store.setGameEnded(false)
+    engine.resumeScene(data.currentScene, {
+      variables: data.variables,
+      flags: data.flags,
+      history: data.history,
+    })
+    return true
+  }
+
+  async function refreshSaves() {
+    const list = await saveSystem.listSlots()
+    store.setSaves(list)
+  }
+
  function destroy() {
    engine.destroy()
  }
@@ -49,5 +95,5 @@ export function useGameEngine(videoEl: () => HTMLVideoElement | null) {
    destroy()
  })

-  return { loadGame, start, makeChoice, destroy, engine }
+  return { loadGame, start, makeChoice, saveGame, loadGameFromSlot, refreshSaves, engine, saveSystem }
 }
--- a/src/stores/gameStore.ts
+++ b/src/stores/gameStore.ts
@@ -2,10 +2,19 @@ import { defineStore } from 'pinia'
 import { ref, shallowRef } from 'vue'
 import type { SceneNode, Choice } from '@engine/types'

+export interface SlotInfo {
+  slot: number
+  timestamp: number
+  sceneLabel: string
+}
+
 export const useGameStore = defineStore('game', () => {
  const currentScene = shallowRef<SceneNode | null>(null)
  const choices = ref<Choice[]>([])
  const gameEnded = ref(false)
+  const timerTotal = ref(0)
+  const timerRemaining = ref(0)
+  const saves = ref<SlotInfo[]>([])

  function setScene(scene: SceneNode) {
    currentScene.value = scene
@@ -23,5 +32,23 @@ export const useGameStore = defineStore('game', () => {
    gameEnded.value = val
  }

-  return { currentScene, choices, gameEnded, setScene, setChoices, clearChoices, setGameEnded }
+  function setTimer(total: number, remaining: number) {
+    timerTotal.value = total
+    timerRemaining.value = remaining
+  }
+
+  function clearTimer() {
+    timerTotal.value = 0
+    timerRemaining.value = 0
+  }
+
+  function setSaves(list: SlotInfo[]) {
+    saves.value = list
+  }
+
+  return {
+    currentScene, choices, gameEnded, timerTotal, timerRemaining, saves,
+    setScene, setChoices, clearChoices, setGameEnded,
+    setTimer, clearTimer, setSaves,
+  }
 })