87 lines
2.3 KiB
C++
87 lines
2.3 KiB
C++
#include <Audio.hpp>
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#include <SDL_audio.h>
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#include <util.hpp>
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namespace n64 {
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#define AUDIO_SAMPLE_RATE 44100
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#define SYSTEM_SAMPLE_FORMAT AUDIO_F32SYS
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#define SYSTEM_SAMPLE_SIZE 4
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#define BYTES_PER_HALF_SECOND ((AUDIO_SAMPLE_RATE / 2) * SYSTEM_SAMPLE_SIZE)
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static SDL_AudioStream* audioStream = nullptr;
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SDL_mutex* audioStreamMutex;
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SDL_AudioSpec audioSpec;
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SDL_AudioSpec request;
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SDL_AudioDeviceID audioDev{};
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#define LockAudioMutex() SDL_LockMutex(audioStreamMutex)
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#define UnlockAudioMutex() SDL_UnlockMutex(audioStreamMutex)
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void audioCallback(void* userdata, Uint8* stream, int length) {
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int gotten = 0;
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LockAudioMutex();
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int available = SDL_AudioStreamAvailable(audioStream);
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if (available > 0) {
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gotten = SDL_AudioStreamGet(audioStream, stream, length);
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}
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UnlockAudioMutex();
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int gotten_samples = (int)(gotten / sizeof(float));
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auto* out = (float*)stream;
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out += gotten_samples;
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for (int i = gotten_samples; i < length / sizeof(float); i++) {
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float sample = 0;
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*out++ = sample;
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}
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}
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void InitAudio() {
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AdjustSampleRate(AUDIO_SAMPLE_RATE);
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memset(&request, 0, sizeof(request));
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request.freq = AUDIO_SAMPLE_RATE;
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request.format = SYSTEM_SAMPLE_FORMAT;
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request.channels = 2;
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request.samples = 1024;
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request.callback = audioCallback;
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request.userdata = nullptr;
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if(!audioDev) {
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audioDev = SDL_OpenAudioDevice(nullptr, 0, &request, &audioSpec, 0);
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}
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if(!audioDev) {
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util::panic("Failed to initialize SDL Audio: {}", SDL_GetError());
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}
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SDL_PauseAudioDevice(audioDev, false);
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audioStreamMutex = SDL_CreateMutex();
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if(!audioStreamMutex) {
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util::panic("Unable to initialize audio mutex: {}", SDL_GetError());
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}
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}
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void PushSample(float left, float volumeL, float right, float volumeR) {
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float adjustedL = left * volumeL;
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float adjustedR = right * volumeR;
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float samples[2]{ adjustedL, adjustedR };
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int availableBytes = SDL_AudioStreamAvailable(audioStream);
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if(availableBytes <= BYTES_PER_HALF_SECOND) {
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SDL_AudioStreamPut(audioStream, samples, 2 * sizeof(float));
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}
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}
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void AdjustSampleRate(int sampleRate) {
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LockAudioMutex();
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if(audioStream) SDL_FreeAudioStream(audioStream);
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audioStream = SDL_NewAudioStream(AUDIO_F32SYS, 2, sampleRate, SYSTEM_SAMPLE_FORMAT, 2, AUDIO_SAMPLE_RATE);
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UnlockAudioMutex();
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}
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} |