Files
kaizen/src/backend/core/mmio/Audio.cpp
2024-05-13 20:55:55 +02:00

77 lines
2.1 KiB
C++

#include <Audio.hpp>
#include <log.hpp>
namespace n64 {
#define AUDIO_SAMPLE_RATE 44100
#define SYSTEM_SAMPLE_FORMAT AUDIO_F32SYS
#define SYSTEM_SAMPLE_SIZE 4
#define BYTES_PER_HALF_SECOND (((float)AUDIO_SAMPLE_RATE / 2) * SYSTEM_SAMPLE_SIZE)
void audioCallback(void* user, Uint8* stream, int length) {
auto audioDevice = (AudioDevice*)user;
int gotten = 0;
audioDevice->LockMutex();
int available = SDL_AudioStreamAvailable(audioDevice->GetStream());
if (available > 0) {
gotten = SDL_AudioStreamGet(audioDevice->GetStream(), stream, length);
}
audioDevice->UnlockMutex();
int gottenSamples = (int)(gotten / sizeof(float));
auto* out = (float*)stream;
out += gottenSamples;
for (int i = gottenSamples; i < length / sizeof(float); i++) {
float sample = 0;
*out++ = sample;
}
}
AudioDevice::AudioDevice() {
SDL_InitSubSystem(SDL_INIT_AUDIO);
AdjustSampleRate(AUDIO_SAMPLE_RATE);
request.freq = AUDIO_SAMPLE_RATE;
request.format = SYSTEM_SAMPLE_FORMAT;
request.channels = 2;
request.samples = 1024;
request.callback = audioCallback;
request.userdata = (void*)this;
if(!handle) {
handle = SDL_OpenAudioDevice(nullptr, 0, &request, &audioSpec, 0);
}
if(!handle) {
Util::panic("Failed to initialize SDL Audio: {}", SDL_GetError());
}
SDL_PauseAudioDevice(handle, false);
audioStreamMutex = SDL_CreateMutex();
if(!audioStreamMutex) {
Util::panic("Unable to initialize audio mutex: {}", SDL_GetError());
}
}
void AudioDevice::PushSample(float left, float volumeL, float right, float volumeR) {
float adjustedL = left * volumeL;
float adjustedR = right * volumeR;
float samples[2]{ adjustedL, adjustedR };
float availableBytes = SDL_AudioStreamAvailable(audioStream);
if(availableBytes <= BYTES_PER_HALF_SECOND) {
SDL_AudioStreamPut(audioStream, samples, 2 * sizeof(float));
}
}
void AudioDevice::AdjustSampleRate(int sampleRate) {
LockMutex();
if(audioStream) SDL_FreeAudioStream(audioStream);
audioStream = SDL_NewAudioStream(AUDIO_F32SYS, 2, sampleRate, SYSTEM_SAMPLE_FORMAT, 2, AUDIO_SAMPLE_RATE);
UnlockMutex();
}
}