nese/src/sdl_audio.c

#include <SDL2/SDL.h>

#include "audio.h"


typedef struct {
    SDL_AudioDeviceID id;
} sdl_audio_device;

static sdl_audio_device the_audio_device = {0};


int sdl_audio_init(nes_Audio_Stream* stream, int frequency) {
    int status = SDL_Init(SDL_INIT_AUDIO);

    if (0 == status) {
        sdl_audio_device* device = &the_audio_device;

        SDL_AudioSpec as = {
            .freq = frequency,
            .format = AUDIO_S16SYS,
            .channels = 1,
        };

        device->id = SDL_OpenAudioDevice(NULL, 0, &as, NULL, 0);
        if (0 == device->id) {
            printf("SDL: %s\n", SDL_GetError());
            status = -1;
        } else {
            stream->data = device;
            SDL_PauseAudioDevice(device->id, 0);
        }
    }

    return status;
}

void sdl_audio_done(nes_Audio_Stream* stream) {
    if (stream->data) {
        SDL_CloseAudioDevice(
                ((sdl_audio_device*)stream->data)->id
            );
        stream->data = NULL;
    }
}

int sdl_audio_push(nes_Audio_Stream* stream,
                   short* samples, int n_samples) {
    return SDL_QueueAudio(
            ((sdl_audio_device*)stream->data)->id,
            samples, n_samples * sizeof(short)
        );
}


nes_Audio_Stream sdl_audio = {
    .init = sdl_audio_init,
    .done = sdl_audio_done,
    .push = sdl_audio_push,
};