[7DRL Prep] SDL audio working in browser (WASM) #247

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opened 2026-02-09 02:44:14 +00:00 by john · 1 comment

john commented

2026-02-09 02:44:14 +00:00

Owner

Goal

Get Sound and Music playback working in the Emscripten/WebAssembly build.

Current State

Desktop: SFML audio fully working (mcrfpy.Sound, mcrfpy.Music)
Web: All audio methods are no-ops in src/platform/SDL2Types.h:925-974
No SDL2_mixer in CMakeLists.txt for Emscripten builds
Audio assets ARE preloaded in .data file

Implementation Plan

Add -sUSE_SDL_MIXER=2 to Emscripten link flags
Replace audio stubs in SDL2Types.h with SDL2_mixer implementation
Implement SoundBuffer (Mix_Chunk), Sound (Mix_PlayChannel), Music (Mix_LoadMUS)
Initialize audio after user gesture ("Click to Run" overlay provides this)

Key Files

src/platform/SDL2Types.h:925-974 - Audio stub classes
src/PySound.h/cpp - Python Sound binding (no changes needed)
src/PyMusic.h/cpp - Python Music binding (no changes needed)
CMakeLists.txt:265-321 - Emscripten config

Browser Gotchas

Autoplay policy: audio context must start after user interaction
Main thread only: potential latency in Emscripten
OGG Vorbis decoding via Emscripten's built-in decoder

Detailed Report

.claude/reports/sdl_audio_wasm.md

7DRL Critical Path

20 days until 7DRL (Feb 28). Game needs sound for itch.io deployment.

## Goal Get Sound and Music playback working in the Emscripten/WebAssembly build. ## Current State - Desktop: SFML audio fully working (`mcrfpy.Sound`, `mcrfpy.Music`) - Web: All audio methods are no-ops in `src/platform/SDL2Types.h:925-974` - No SDL2_mixer in CMakeLists.txt for Emscripten builds - Audio assets ARE preloaded in .data file ## Implementation Plan 1. Add `-sUSE_SDL_MIXER=2` to Emscripten link flags 2. Replace audio stubs in SDL2Types.h with SDL2_mixer implementation 3. Implement SoundBuffer (Mix_Chunk), Sound (Mix_PlayChannel), Music (Mix_LoadMUS) 4. Initialize audio after user gesture ("Click to Run" overlay provides this) ## Key Files - `src/platform/SDL2Types.h:925-974` - Audio stub classes - `src/PySound.h/cpp` - Python Sound binding (no changes needed) - `src/PyMusic.h/cpp` - Python Music binding (no changes needed) - `CMakeLists.txt:265-321` - Emscripten config ## Browser Gotchas - Autoplay policy: audio context must start after user interaction - Main thread only: potential latency in Emscripten - OGG Vorbis decoding via Emscripten's built-in decoder ## Detailed Report `.claude/reports/sdl_audio_wasm.md` ## 7DRL Critical Path 20 days until 7DRL (Feb 28). Game needs sound for itch.io deployment.