text: #ifndef UTIL_SOUND_MIXER_H
  #define UTIL_SOUND_MIXER_H
  
  #include <SDL_sound.h>
  #include <SDL_mixer.h>
  #include "sound_device.h"
  
  namespace Audio {
    class Mixer {
      public:
        Mixer();
        ~Mixer();
  
        Audio::SoundDevice device;
  
        int setVolume(int channel, int volume);
        int setVolumeMusic();
        int getVolume(int channel);
        int getVolumeMusic();
  
        void playSample(const size_t & sampleId);
  
        void pause(int channel);
        void pauseMusic();
      private:
        inline bool checkDeviceOK() { return (device.getStatus() == 
          Audio::SoundDevice::OPEN); }
    };
  }
  
  #endif
  