libsdloutput.h

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#pragma once
 
#ifndef pianod2_libsdloutput_h
#define pianod2_libsdloutput_h
 
#include <mutex>
#include <condition_variable>
 
#pragma GCC diagnostic push
#pragma GCC diagnostic ignored "-Wdocumentation"
#include <SDL/SDL.h>
#include <SDL/SDL_version.h>
#include <SDL/SDL_audio.h>
#pragma GCC diagnostic pop
 
#include "audio/audiooutput.h"
 
namespace Audio {
    class LibsdlOutput : public Output {
    private:
#if SDL_VERSION >= 2
        SDL_AudioDeviceID device_id;
#endif
        static std::mutex sdl_mutex;
        std::mutex data_mutex;
        std::condition_variable notifier;
 
        using BufferIndex = uint32_t;
 
        uint8_t *audio_cirque = nullptr;
        const BufferIndex block_samples = 0x400;
        const BufferIndex block_count = 0x10;
        const BufferIndex cirque_samples = block_samples * block_count;
        const BufferIndex cirque_size;
        volatile BufferIndex cirque_write = 0; // Only written by play().
        volatile BufferIndex cirque_read = 0; // Only writte by fetch().
    public:
        LibsdlOutput (const AudioSettings &settings,
                      const AudioFormat &format);
        virtual ~LibsdlOutput () override;
        void fetch (Uint8 *buffer, int length);
        virtual bool play (void *buffer, unsigned numberOfBytes) override;
    };
}
 
#endif