ditch multi-system idea

src/n64/core/Audio.cpp

@@ -0,0 +1,83 @@
+#include "Audio.hpp"
+#include <SDL2/SDL.h>
+#include "util.hpp"
+
+namespace natsukashii::core {
+#define AUDIO_SAMPLE_RATE 48000
+#define SYSTEM_SAMPLE_FORMAT AUDIO_F32SYS
+#define SYSTEM_SAMPLE_SIZE 4
+#define BYTES_PER_HALF_SECOND ((AUDIO_SAMPLE_RATE / 2) * SYSTEM_SAMPLE_SIZE)
+
+static SDL_AudioStream* audioStream = nullptr;
+SDL_mutex* audioStreamMutex;
+SDL_AudioSpec audioSpec;
+SDL_AudioSpec request;
+SDL_AudioDeviceID audioDev;
+
+#define LockAudioMutex() SDL_LockMutex(audioStreamMutex)
+#define UnlockAudioMutex() SDL_UnlockMutex(audioStreamMutex)
+
+void audioCallback(void* userdata, Uint8* stream, int length) {
+  int gotten = 0;
+  LockAudioMutex();
+  int available = SDL_AudioStreamAvailable(audioStream);
+
+  if (available > 0) {
+    gotten = SDL_AudioStreamGet(audioStream, stream, length);
+  }
+  UnlockAudioMutex();
+
+  int gotten_samples = (int)(gotten / sizeof(float));
+  auto* out = (float*)stream;
+  out += gotten_samples;
+
+  for (int i = gotten_samples; i < length / sizeof(float); i++) {
+    float sample = 0;
+    *out++ = sample;
+  }
+}
+
+void InitAudio() {
+  AdjustSampleRate(AUDIO_SAMPLE_RATE);
+  memset(&request, 0, sizeof(request));
+
+  request.freq = AUDIO_SAMPLE_RATE;
+  request.format = SYSTEM_SAMPLE_FORMAT;
+  request.channels = 2;
+  request.samples = 1024;
+  request.callback = audioCallback;
+  request.userdata = nullptr;
+
+  audioDev = SDL_OpenAudioDevice(nullptr, 0, &request, &audioSpec, 0);
+
+  if(!audioDev) {
+    util::panic("Failed to initialize SDL Audio: {}", SDL_GetError());
+  }
+
+  SDL_PauseAudioDevice(audioDev, false);
+
+  audioStreamMutex = SDL_CreateMutex();
+
+  if(!audioStreamMutex) {
+    util::panic("Unable to initialize audio mutex: {}", SDL_GetError());
+  }
+}
+
+void PushSample(s16 left, s16 right) {
+  s16 samples[2]{ left, right };
+
+  int availableBytes = SDL_AudioStreamAvailable(audioStream);
+  if(availableBytes < BYTES_PER_HALF_SECOND) {
+    SDL_AudioStreamPut(audioStream, samples, 2 * sizeof(16));
+  }
+}
+
+void AdjustSampleRate(int sampleRate) {
+  LockAudioMutex();
+  if(audioStream) SDL_FreeAudioStream(audioStream);
+
+  audioStream = SDL_NewAudioStream(AUDIO_S16SYS, 2, sampleRate, SYSTEM_SAMPLE_FORMAT, 2, AUDIO_SAMPLE_RATE);
+  UnlockAudioMutex();
+}
+
+}