Function ActivateMainAudioBuses

libraries/lib-vst3/VST3Wrapper.cpp:126–184

Activates main audio input/output buses and disables others (event, audio aux)

//Activates main audio input/output buses and disables others (event, audio aux)
bool ActivateMainAudioBuses(Steinberg::Vst::IComponent& component)
{
   using namespace Steinberg;

   constexpr int32 MaxChannelsPerAudioBus = 2;

   std::vector<Vst::SpeakerArrangement> defaultInputSpeakerArrangements;
   std::vector<Vst::SpeakerArrangement> defaultOutputSpeakerArrangements;

   const auto processor = FUnknownPtr<Vst::IAudioProcessor>(&component);

   for(int i = 0, count = component.getBusCount(Vst::kAudio, Vst::kInput); i < count; ++i)
   {
      Vst::BusInfo busInfo {};
      Vst::SpeakerArrangement arrangement {0ull};
      
      component.getBusInfo(Vst::kAudio, Vst::kInput, i, busInfo);

      Vst::SpeakerArrangement defaultArragement {};
      processor->getBusArrangement(Vst::kInput, i, defaultArragement);

      arrangement =
         busInfo.busType == Vst::kMain
            ? GetBusArragementForChannels(busInfo.channelCount, defaultArragement)
            : defaultArragement;
      
      component.activateBus(Vst::kAudio, Vst::kInput, i, busInfo.busType == Vst::kMain);
      defaultInputSpeakerArrangements.push_back(arrangement);
   }
   for(int i = 0, count = component.getBusCount(Vst::kAudio, Vst::kOutput); i < count; ++i)
   {
      Vst::BusInfo busInfo {};
      Vst::SpeakerArrangement arrangement {0ull};
      
      component.getBusInfo(Vst::kAudio, Vst::kOutput, i, busInfo);

      Vst::SpeakerArrangement defaultArragement {};
      processor->getBusArrangement(Vst::kOutput, i, defaultArragement);

      arrangement =
         busInfo.busType == Vst::kMain
            ? GetBusArragementForChannels(busInfo.channelCount, defaultArragement)
            : defaultArragement;

      component.activateBus(Vst::kAudio, Vst::kOutput, i, busInfo.busType == Vst::kMain);
      defaultOutputSpeakerArrangements.push_back(arrangement);
   }
   for(int i = 0, count = component.getBusCount(Vst::kEvent, Vst::kInput); i < count; ++i)
      component.activateBus(Vst::kEvent, Vst::kInput, i, 0);
   for(int i = 0, count = component.getBusCount(Vst::kEvent, Vst::kOutput); i < count; ++i)
      component.activateBus(Vst::kEvent, Vst::kOutput, i, 0);

   auto result = processor->setBusArrangements(
      defaultInputSpeakerArrangements.empty() ? nullptr : defaultInputSpeakerArrangements.data(), defaultInputSpeakerArrangements.size(),
      defaultOutputSpeakerArrangements.empty() ? nullptr : defaultOutputSpeakerArrangements.data(), defaultOutputSpeakerArrangements.size()
   );

   return result == kResultOk;