Added JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS option to workaround a Studio One bug

modules/juce_audio_plugin_client/AU/juce_AU_Wrapper.mm

@@ -1698,7 +1698,15 @@ private:
         if (isPositiveAndBelow (paramIndex, n))
         {
             const String& juceParamID = juceFilter->getParameterID (paramIndex);
-            return usingManagedParameter ? static_cast<AudioUnitParameterID> (juceParamID.hashCode())
+
+            AudioUnitParameterID paramHash = static_cast<AudioUnitParameterID> (juceParamID.hashCode());
+
+           #if JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
+            // studio one doesn't like negative parameters
+            paramHash &= ~(1 << (sizeof (AudioUnitParameterID) * 8 - 1));
+           #endif
+
+            return usingManagedParameter ? paramHash
                                          : static_cast<AudioUnitParameterID> (juceParamID.getIntValue());
         }
 

modules/juce_audio_plugin_client/VST3/juce_VST3_Wrapper.cpp

@@ -683,6 +683,13 @@ private:
         if (isPositiveAndBelow (paramIndex, n))
         {
             const String& juceParamID = pluginFilter->getParameterID (paramIndex);
+
+            Vst::ParamID paramHash = static_cast<Vst::ParamID> (juceParamID.hashCode());
+           #if JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
+            // studio one doesn't like negative parameters
+            paramHash &= ~(1 << (sizeof (Vst::ParamID) * 8 - 1));
+           #endif
+
             return managedParameter ? static_cast<Vst::ParamID> (juceParamID.hashCode())
                                     : static_cast<Vst::ParamID> (juceParamID.getIntValue());
         }

modules/juce_audio_plugin_client/juce_audio_plugin_client.h

@@ -64,6 +64,19 @@
  #define JUCE_FORCE_USE_LEGACY_PARAM_IDS 0
 #endif
 
+/** Config: JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
+
+    Enable this if you want JUCE to use parameter ids which are compatible
+    to Studio One. Studio One ignores any parameter ids which are negative.
+    Enabling this option will make JUCE generate only positive parameter ids.
+    Note that if you have already released a plug-in prio to JUCE 4.3.0 then
+    enabling this will change your parameter ids making your plug-in
+    incompatible to old automation data.
+ */
+#ifndef JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS
+ #define JUCE_USE_STUDIO_ONE_COMPATIBLE_PARAMETERS 1
+#endif
+
 namespace juce
 {
  #include "utility/juce_PluginHostType.h"