BreakEscape/planning_notes/npc/SOUND_EFFECTS_IMPLEMENTATION.md

NPC Sound Effects Implementation

Status: ✅ Complete (2024-10-31)

Overview

Added audio feedback to the NPC bark notification system. All bark notifications now play a sound effect when they appear, providing audio cues for player attention.

Implementation

Files Modified

• js/core/game.js (+3 lines)
  • Added this.load.audio('message_received', ...) in preload function
  • Loads sound through Phaser's audio system
• js/systems/npc-barks.js (+65 lines, modified)
  • Replaced HTML5 Audio with Phaser sound manager
  • Added lazy loading fallback
  • Integrated sound playback into showBark() method

Sound Asset Used

• assets/sounds/message_received.mp3
  • Already existed in project
  • Used for phone message notifications
  • Now also used for NPC bark notifications
  • Loaded through Phaser's audio system (Web Audio API)

Features

1. Sound Preloading (Phaser)

// In game.js preload()
this.load.audio('message_received', 'assets/sounds/message_received.mp3');

// In npc-barks.js
loadBarkSound() {
  if (window.game && window.game.sound) {
    this.barkSound = window.game.sound.add('message_received');
    this.barkSound.setVolume(0.5); // 50% volume
  }
}

• Sound loaded once during Phaser's preload phase
• Managed by Phaser's Web Audio API system
• Automatically pooled for efficient playback
• Default volume: 50%

2. Sound Playback (Phaser)

playBarkSound() {
  if (!this.soundEnabled) return;
  
  // Lazy load if not available during init
  if (!this.barkSound && window.game && window.game.sound) {
    this.loadBarkSound();
  }
  
  if (!this.barkSound) return;
  
  this.barkSound.play(); // Phaser handles pooling
}

• Uses Phaser's .play() method (cleaner than HTML5 Audio)
• Phaser automatically handles sound pooling and memory management
• Lazy loading fallback if sound manager not ready during init
• No need to manually reset currentTime (Phaser handles this)

3. Sound Control

setSoundEnabled(enabled) {
  this.soundEnabled = enabled;
}

• Allows disabling sounds globally
• Useful for settings/preferences
• Default: enabled

4. showBark() Integration

showBark(payload = {}) {
  const playSound = payload.playSound !== false; // Default true
  
  if (playSound) {
    this.playBarkSound();
  }
  // ... rest of bark creation
}

• Sound enabled by default for all barks
• Can be disabled per-bark via playSound: false in payload
• Respects global soundEnabled setting

What Gets Sound?

✅ All Bark Notifications

1. Event-triggered barks

   • Door unlocks
   • Item pickups
   • Room discoveries
   • Lockpicking attempts
   • CEO office entry
   • Any other event-mapped reactions

2. Timed messages

   • Scheduled NPC messages
   • Delivered at specific game times
   • Automatically trigger barks with sound

3. Manual barks

   • Any npcManager.showBark() calls
   • Any barkSystem.showBark() calls

❌ No Sound

• Opening phone-chat minigame (no sound yet)
• Closing phone-chat minigame (no sound yet)
• Clicking barks (visual only)
• Choice selections in conversations (visual only)

Usage Examples

Default (Sound Enabled)

// Sound plays automatically
npcManager.showBark({
  npcId: 'helper_npc',
  npcName: 'Tech Support',
  text: 'Found something interesting!'
});

Disable Sound for Specific Bark

// Silent bark (no sound)
npcManager.showBark({
  npcId: 'helper_npc',
  npcName: 'Tech Support',
  text: 'This is a quiet message...',
  playSound: false
});

Disable All Sounds

// Turn off bark sounds globally
window.npcManager.barkSystem.setSoundEnabled(false);

// Turn them back on
window.npcManager.barkSystem.setSoundEnabled(true);

Testing

In-Game Testing

1. Refresh the game page to load updated code
2. Start CEO Exfiltration scenario
3. Test scenarios that trigger barks:
   • Pick up an item → Should hear sound
   • Walk through a door → Should hear sound
   • Unlock a door → Should hear sound
   • Enter CEO office → Should hear sound

Volume Testing

• Default volume: 50% (0.5)
• Can be adjusted by modifying this.barkSound.volume in loadBarkSound()
• Recommended range: 0.3 - 0.7 (30% - 70%)

Browser Compatibility

Phaser Audio System

• Chrome/Edge: ✅ Full Web Audio API support
• Firefox: ✅ Full Web Audio API support
• Safari: ✅ Full Web Audio API support
• Mobile browsers: ✅ Good support (Phaser handles fallbacks)

Autoplay Policy

Modern browsers restrict autoplay. Phaser handles this automatically:

• ✅ Works automatically: Phaser unlocks audio context on first user interaction
• ✅ No console warnings: Phaser manages audio context lifecycle
• ✅ Sounds triggered by user actions: Always work (clicking, walking)
• ✅ Better than HTML5 Audio: Phaser's Web Audio API is more reliable

Advantages Over HTML5 Audio

1. Unified audio management: All game audio through one system
2. Better performance: Web Audio API vs Audio Tag
3. Sound pooling: Multiple simultaneous sounds without creating new instances
4. No autoplay issues: Phaser handles audio context unlocking
5. Consistent volume control: Tied to game's master volume
6. Future-ready: Can add spatial audio, filters, analyzers, etc.

Future Enhancements

Potential Additions

1. Phone open/close sounds

   • Add phone_open.mp3 sound when opening phone-chat
   • Add phone_close.mp3 sound when closing phone-chat

2. Choice selection sound

   • Subtle click sound when selecting dialogue choices
   • Could use existing GASP_UI_Clicks_*.mp3 sounds

3. Typing indicator sound

   • Quiet keyboard sound during typing animation
   • Adds to realism of text messaging

4. Volume slider in settings

   • UI control for adjusting bark volume
   • Persist preference to localStorage

5. Different sounds per NPC type

   • Helper NPCs: friendly notification sound
   • Adversary NPCs: alert/warning sound
   • Neutral NPCs: standard notification

6. Sound variations

   • Randomly pick from multiple notification sounds
   • Prevents repetition fatigue
   • Could use GASP_UI_Notification_1.mp3 through _6.mp3

Implementation Stats

• Lines added: ~68 total
  • game.js: +3 lines (audio loading)
  • npc-barks.js: +65 lines (Phaser sound integration)
• Files modified: 2 (game.js, npc-barks.js)
• Breaking changes: None
• Default behavior: Sound enabled
• Asset used: Existing (message_received.mp3)
• Audio system: Phaser Web Audio API (consolidated)

Next Steps

Priority 3: NPC Avatars

• Create 3 default 32x32px pixel-art avatars
• Add avatar support to scenarios
• Display avatars in barks and conversations

Priority 2 Continued: More Events

• Implement objective_completed event
• Implement evidence_collected event
• Implement player_detected event

---

Status: ✅ Implementation complete, ready for testing Date: 2024-10-31