Don't serialize input arrangement for IAudioProcessor::getBusArrangement

src/common/logging/vst3.cpp

@@ -1720,7 +1720,7 @@ void Vst3Logger::log_response(
         if (response.result == Steinberg::kResultOk) {
             message << ", <SpeakerArrangement: 0b"
                     << std::bitset<sizeof(Steinberg::Vst::SpeakerArrangement)>(
-                           response.updated_arr)
+                           response.arr)
                     << ">";
         }
     });

src/common/serialization/vst3/plugin/audio-processor.h

@@ -97,22 +97,22 @@ class YaAudioProcessor : public Steinberg::Vst::IAudioProcessor {
 
     /**
      * The response code and written state for a call to
-     * `IAudioProcessor::getBusArrangement(dir, index, arr)`.
+     * `IAudioProcessor::getBusArrangement(dir, index, &arr)`.
      */
     struct GetBusArrangementResponse {
         UniversalTResult result;
-        Steinberg::Vst::SpeakerArrangement updated_arr;
+        Steinberg::Vst::SpeakerArrangement arr;
 
         template <typename S>
         void serialize(S& s) {
             s.object(result);
-            s.value8b(updated_arr);
+            s.value8b(arr);
         }
     };
 
     /**
      * Message to pass through a call to
-     * `IAudioProcessor::getBusArrangement(dir, index, arr)` to the Wine
+     * `IAudioProcessor::getBusArrangement(dir, index, &arr)` to the Wine
      * plugin host.
      */
     struct GetBusArrangement {
@@ -122,14 +122,12 @@ class YaAudioProcessor : public Steinberg::Vst::IAudioProcessor {
 
         Steinberg::Vst::BusDirection dir;
         int32 index;
-        Steinberg::Vst::SpeakerArrangement arr;
 
         template <typename S>
         void serialize(S& s) {
             s.value8b(instance_id);
             s.value4b(dir);
             s.value4b(index);
-            s.value8b(arr);
         }
     };
 

src/plugin/bridges/vst3-impls/plugin-proxy.cpp

@@ -110,13 +110,10 @@ tresult PLUGIN_API Vst3PluginProxyImpl::getBusArrangement(
     int32 index,
     Steinberg::Vst::SpeakerArrangement& arr) {
     const GetBusArrangementResponse response =
-        bridge.send_audio_processor_message(
+        bridge.send_audio_processor_message(YaAudioProcessor::GetBusArrangement{
-            YaAudioProcessor::GetBusArrangement{.instance_id = instance_id(),
+            .instance_id = instance_id(), .dir = dir, .index = index});
-                                                .dir = dir,
-                                                .index = index,
-                                                .arr = arr});
 
-    arr = response.updated_arr;
+    arr = response.arr;
 
     return response.result;
 }

src/wine-host/bridges/vst3.cpp

@@ -1128,13 +1128,14 @@ size_t Vst3Bridge::register_object_instance(
                     },
                     [&](YaAudioProcessor::GetBusArrangement& request)
                         -> YaAudioProcessor::GetBusArrangement::Response {
+                        Steinberg::Vst::SpeakerArrangement arr{};
                         const tresult result =
                             object_instances[request.instance_id]
                                 .audio_processor->getBusArrangement(
-                                    request.dir, request.index, request.arr);
+                                    request.dir, request.index, arr);
 
                         return YaAudioProcessor::GetBusArrangementResponse{
-                            .result = result, .updated_arr = request.arr};
+                            .result = result, .arr = arr};
                     },
                     [&](const YaAudioProcessor::CanProcessSampleSize& request)
                         -> YaAudioProcessor::CanProcessSampleSize::Response {