Zauberwald/.planning/phases/04-polish-audio/04-01-SUMMARY.md

phase, plan, subsystem, tags, requires, provides, affects, tech-stack, key-files, key-decisions, patterns-established, requirements-completed, duration, completed

phase	plan	subsystem	tags	requires	provides	affects	tech-stack	key-files	key-decisions	patterns-established	requirements-completed	duration	completed
04-polish-audio	01	audio	web-audio-api web-speech-api audiocontext speech-synthesis mute-button	phase provides 03-gameplay-loop Settings store with audioEnabled, IndexedDB persistence	Web Audio API sound effects module (playCorrectSound, playRewardSound, playForestElementSound) Web Speech API text-to-speech module (speakText) Mute button UI with persisted toggle state AudioContext lazy initialization on first user interaction	04-02 04-03 04-04	added patterns Web Audio API Web Speech API lazy AudioContext initialization settings-gated audio playback	created modified src/audio/sounds.ts src/audio/speech.ts src/types.ts index.html src/styles/main.css src/main.ts src/api/gemini.ts src/storage/db.test.ts src/ui/parent.ts	speechEnabled defaults to false (opt-in feature, not opt-out) AudioContext created lazily on first click/keydown for autoplay policy compliance All sound functions use try/catch with silent fallback (never throw)	Audio gating: every sound/speech function checks Settings before playing Lazy AudioContext: initAudioOnInteraction() called from user event handlers	AUDI-01 AUDI-02 AUDI-03 AUDI-04 AUDI-05	4min	2026-03-29

Phase 04 Plan 01: Audio System Summary

Web Audio API procedural sounds (correct/reward/forest) and Web Speech API German TTS with mute button and Settings persistence

Performance

• Duration: 4 min
• Started: 2026-03-29T16:14:40Z
• Completed: 2026-03-29T16:18:48Z
• Tasks: 2
• Files modified: 9

Accomplishments

• Three procedural Web Audio API sounds: correct keystroke beep (800Hz), ascending reward melody (C5-E5-G5-C6), filtered white noise for forest elements
• German text-to-speech via Web Speech API with async voice loading and settings gate
• Mute button with fixed-position circular UI, toggle persistence in IndexedDB, and visual state feedback

Task Commits

Each task was committed atomically:

1. Task 1: Audio module + Speech module + Settings extension - c19b7fe (feat)
2. Task 2: Mute button in HTML + CSS + wiring in main.ts - 52596c5 (feat)

Files Created/Modified

• src/audio/sounds.ts - Web Audio API sound effects with AudioContext lazy init
• src/audio/speech.ts - Web Speech API speakText with German voice detection
• src/types.ts - Added speechEnabled to Settings interface
• index.html - Added mute-btn element outside all screen sections
• src/styles/main.css - Mute button fixed-position styles
• src/main.ts - Wired mute button toggle and AudioContext init on first interaction
• src/api/gemini.ts - Added speechEnabled default to getDefaultSettings
• src/storage/db.test.ts - Added speechEnabled to test Settings fixture
• src/ui/parent.ts - Added speechEnabled defaults in inline Settings initializers

Decisions Made

• speechEnabled defaults to false (opt-in) while audioEnabled defaults to true (opt-out) -- speech is more intrusive than sound effects
• AudioContext is created lazily on first user interaction (click or keydown) to comply with browser autoplay policies
• All audio functions wrap in try/catch and never throw to callers -- silent degradation preferred

Deviations from Plan

Auto-fixed Issues

1. [Rule 2 - Missing Critical] Added speechEnabled defaults to all Settings initializers

• Found during: Task 1 (Settings extension)
• Issue: Plan only mentioned adding speechEnabled to the types.ts interface, but several files create default Settings objects inline (gemini.ts, parent.ts, db.test.ts) that would fail type checking
• Fix: Added speechEnabled: false to all inline Settings object literals across the codebase
• Files modified: src/api/gemini.ts, src/storage/db.test.ts, src/ui/parent.ts
• Verification: npx tsc --noEmit passes
• Committed in: c19b7fe (Task 1 commit)

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Total deviations: 1 auto-fixed (1 missing critical) Impact on plan: Essential for type safety. No scope creep.

Issues Encountered

None

User Setup Required

None - no external service configuration required.

Next Phase Readiness

• Audio system ready to be wired into lesson/reward/forest screens (Plan 04-02+)
• Mute button functional and persisting state across reloads
• speakText ready for companion dialogue integration

Self-Check: PASSED

All created files exist, all commit hashes verified.

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Phase: 04-polish-audio Completed: 2026-03-29