Emscripten SDL2 Mobile Audio

mobile_audio.c

#include <SDL.h>
#include <emscripten/emscripten.h>

int eventFilter(void* userdata, SDL_Event* event){
int audio_started;
(void)(userdata);
switch(event->type){
      case SDL_FINGERDOWN:
      case SDL_MOUSEBUTTONDOWN:
      case SDL_KEYDOWN:
        audio_started = EM_ASM_INT_V({
          if(SDL2.audioContext && SDL2.audioContext.currentTime == 0){
            var buffer = SDL2.audioContext.createBuffer(1, 1, 22050);
            var source = SDL2.audioContext.createBufferSource();
            source.buffer = buffer;
            source.connect(SDL2.audioContext.destination);
            source.noteOn(0);
          } else if(SDL2.audioContext && SDL2.audioContext.currentTime != 0){
            return 1;
          }
          return 0;
        });
        if (audio_started){
          SDL_SetEventFilter(NULL, NULL);
          return 0;
        }
        break;
    }
    return 1;
}

void mobile_audio_start_on_user_input(){
  SDL_SetEventFilter(eventFilter, NULL);
}

mobile_audio.h

void mobile_audio_start_on_user_input();