61 lines
1.5 KiB
C++
61 lines
1.5 KiB
C++
#include "zx_speaker.h"
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#include <SDL2/SDL.h>
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#include "z80.h"
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#include <vector>
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namespace speaker
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{
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#define SAMPLING_FREQ 44100
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#define AUDIO_BUFFER_SIZE 2048
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SDL_AudioDeviceID sdlAudioDevice;
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uint8_t sound_buffer[AUDIO_BUFFER_SIZE];
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uint16_t sound_pos=0;
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uint16_t t_sound=0;
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std::vector<uint8_t(*)()> sources;
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float cycles_per_sample;
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void init()
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{
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SDL_AudioSpec audioSpec{SAMPLING_FREQ, AUDIO_U8, 1, 0, AUDIO_BUFFER_SIZE>>2, 0, 0, NULL, NULL};
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sdlAudioDevice = SDL_OpenAudioDevice(NULL, 0, &audioSpec, NULL, 0);
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cycles_per_sample = z80::getClock() / SAMPLING_FREQ;
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enable();
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}
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void enable()
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{
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SDL_PauseAudioDevice(sdlAudioDevice, 0);
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}
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void disable()
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{
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SDL_PauseAudioDevice(sdlAudioDevice, 1);
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}
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void register_source(uint8_t(*callback)())
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{
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sources.push_back(callback);
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}
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void update(const uint8_t dt)
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{
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t_sound += dt;
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if (t_sound>=cycles_per_sample) {
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t_sound-=cycles_per_sample;
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uint32_t sample = 0;
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for (auto callback : sources) sample += callback();
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sample /= sources.size();
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sound_buffer[(sound_pos++)&(AUDIO_BUFFER_SIZE-1)] = sample;
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}
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if (sound_pos>=1000) {
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SDL_QueueAudio(sdlAudioDevice, sound_buffer, sound_pos);
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sound_pos = 0;
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while (SDL_GetQueuedAudioSize(sdlAudioDevice) > 4096 ) {}
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}
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}
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}
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