diff options
| -rwxr-xr-x | render_sdl.c | 76 |
1 files changed, 69 insertions, 7 deletions
diff --git a/render_sdl.c b/render_sdl.c index c69d4d2..0f3fb76 100755 --- a/render_sdl.c +++ b/render_sdl.c @@ -57,12 +57,62 @@ struct audio_source { static audio_source *audio_sources[8]; static uint8_t num_audio_sources; -static void audio_callback(void * userdata, uint8_t *byte_stream, int len) +typedef void (*mix_func)(audio_source *audio, void *vstream, int len); + +static void mix_s16(audio_source *audio, void *vstream, int len) { - int16_t * stream = (int16_t *)byte_stream; int samples = len/(sizeof(int16_t)*2); + int16_t *stream = vstream; + int16_t *end = stream + 2*samples; + int16_t *src = audio->front; + if (audio->num_channels == 1) { + for (int16_t *cur = stream; cur < end;) + { + *(cur++) += *src; + *(cur++) += *(src++); + } + } else { + for (int16_t *cur = stream; cur < end;) + { + *(cur++) += *(src++); + *(cur++) += *(src++); + } + } +} + +static void mix_f32(audio_source *audio, void *vstream, int len) +{ + int samples = len/(sizeof(float)*2); + float *stream = vstream; + float *end = stream + 2*samples; + int16_t *src = audio->front; + if (audio->num_channels == 1) { + for (float *cur = stream; cur < end;) + { + *(cur++) += ((float)*src) / 0x7FFF; + *(cur++) += ((float)*(src++)) / 0x7FFF; + } + } else { + for (float *cur = stream; cur < end;) + { + *(cur++) += ((float)*(src++)) / 0x7FFF; + *(cur++) += ((float)*(src++)) / 0x7FFF; + } + } +} + +static void mix_null(audio_source *audio, void *vstream, int len) +{ +} + +static mix_func mix; + +static void audio_callback(void * userdata, uint8_t *byte_stream, int len) +{ + //int16_t * stream = (int16_t *)byte_stream; + //int samples = len/(sizeof(int16_t)*2); uint8_t num_populated; - memset(stream, 0, len); + memset(byte_stream, 0, len); SDL_LockMutex(audio_mutex); do { num_populated = 0; @@ -77,10 +127,11 @@ static void audio_callback(void * userdata, uint8_t *byte_stream, int len) } } while(!quitting && num_populated < num_audio_sources); if (!quitting) { - int16_t *end = stream + 2*samples; + //int16_t *end = stream + 2*samples; for (uint8_t i = 0; i < num_audio_sources; i++) { - int16_t *src = audio_sources[i]->front; + mix(audio_sources[i], byte_stream, len); + /*int16_t *src = audio_sources[i]->front; if (audio_sources[i]->num_channels == 1) { for (int16_t *cur = stream; cur < end;) { @@ -93,7 +144,7 @@ static void audio_callback(void * userdata, uint8_t *byte_stream, int len) *(cur++) += *(src++); *(cur++) += *(src++); } - } + }*/ audio_sources[i]->front_populated = 0; SDL_CondSignal(audio_sources[i]->cond); } @@ -556,7 +607,18 @@ void render_init(int width, int height, char * title, uint8_t fullscreen) } buffer_samples = actual.samples; sample_rate = actual.freq; - printf("Initialized audio at frequency %d with a %d sample buffer\n", actual.freq, actual.samples); + printf("Initialized audio at frequency %d with a %d sample buffer, ", actual.freq, actual.samples); + if (actual.format == AUDIO_S16SYS) { + puts("signed 16-bit int format"); + mix = mix_s16; + } else if (actual.format == AUDIO_F32SYS) { + puts("32-bit float format"); + mix = mix_f32; + } else { + printf("unsupported format %X\n", actual.format); + warning("Unsupported audio sample format: %X\n", actual.format); + mix = mix_null; + } SDL_PauseAudio(0); uint32_t db_size; |