Adds a new FieldDescriptor struct

Use the field descriptor struct to add fields instead of the overloads
Adds a visibility function to control whether a field is visible in the inspector

EG:
ADD_FIELD("soundFile", TypeAssetLooseFilePath, Offset(mSoundFile, SoundAsset))
            .doc("Path to the sound file.")
            .elements(SFXPlayList::SFXPlaylistSettings::NUM_SLOTS)
            .onSet(&_setSoundFile);

the grammar can change to make these easier to work with, review changes carefully

Engine/source/gui/editor/guiInspector.cpp

@@ -785,6 +785,59 @@ void GuiInspector::refresh()
 
 //-----------------------------------------------------------------------------
 
+void GuiInspector::updateVisibility()
+{
+	const U32 numTargets = getNumInspectObjects();
+
+	for (U32 i = 0; i < numTargets; i++)
+	{
+
+		SimObject* target = getInspectObject(i);
+		if (!target) return;
+
+		for (GuiInspectorGroup* group : mGroups)
+		{
+			const AbstractClassRep::Field* g = target->findField(group->getGroupName().c_str());
+
+			// if group has its own visibility function let it control it.
+			bool group_visible = (!g || !g->visibilityFn) ? true : g->visibilityFn(target, "0");
+			if (!group_visible)
+			{
+				group->setVisible(group_visible);
+				return;
+			}
+
+			bool anyVisible = false;
+			for (GuiInspectorField* field : group->mChildren)
+			{
+				const AbstractClassRep::Field* f = field->getField();
+				StringTableEntry idx = field->getArrayIndex();
+				bool visible = (!f || !f->visibilityFn) ? true : f->visibilityFn(target, idx);
+
+				field->setVisible(visible);
+				if (visible)
+					anyVisible = true;
+			}
+
+			// Per-array-element rollout visibility
+			for (GuiInspectorGroup::ArrayElementEntry& elem : group->mArrayElements)
+			{
+				bool visible = false;
+				if (!elem.arrayField || !elem.arrayField->visibilityFn || elem.elementIndex == 0)
+					visible = true;
+
+				if (!visible)
+					visible = elem.arrayField->visibilityFn(target, String::ToString(elem.elementIndex));
+
+				elem.rollout->setVisible(visible);
+				if (visible) anyVisible = true;
+			}
+
+			group->setVisible(anyVisible);
+		}
+	}
+}
+
 void GuiInspector::sendInspectPreApply()
 {
    const U32 numObjects = getNumInspectObjects();

Engine/source/gui/editor/guiInspector.h

@@ -90,6 +90,8 @@ public:
          return NULL;
    }
 
+   void updateVisibility();
+
    S32 getComponentGroupTargetId() { return mComponentGroupTargetId; }
    void setComponentGroupTargetId(S32 compId) { mComponentGroupTargetId = compId; }
    

Engine/source/gui/editor/inspector/field.cpp

@@ -835,6 +835,8 @@ void GuiInspectorField::updateValue()
    }
    else
       setValue( getData() );
+
+   mInspector->updateVisibility();
 }
 
 //-----------------------------------------------------------------------------

Engine/source/gui/editor/inspector/field.h

@@ -164,6 +164,7 @@ class GuiInspectorField : public GuiControl
       
       ///
       StringTableEntry getArrayIndex() const { return mFieldArrayIndex; }
+      AbstractClassRep::Field* getField() const { return mField; }
 
       /// Called from within setData to allow child classes
       /// to perform their own verification.

Engine/source/gui/editor/inspector/group.cpp

@@ -79,6 +79,7 @@ GuiInspectorGroup::GuiInspectorGroup( const String& groupName,
 
    mChildren.clear();
    mMargin.set(0,0,4,0);
+   VECTOR_SET_ASSOCIATION(mArrayElements);
 }
 
 //-----------------------------------------------------------------------------
@@ -229,6 +230,7 @@ void GuiInspectorGroup::clearFields()
    // that we keep for our own convenience.
    mArrayCtrls.clear();
    mChildren.clear();
+   mArrayElements.clear();
 }
 
 //-----------------------------------------------------------------------------
@@ -336,7 +338,7 @@ bool GuiInspectorGroup::inspectGroup()
                   GuiControlProfile* elementRolloutProfile = dynamic_cast<GuiControlProfile*>(Sim::findObject("GuiInspectorRolloutProfile0"));
 
                   char buf[256];
-                  dSprintf(buf, 256, "  [%i]", i);
+                  dSprintf(buf, 256, "  [%i/%i]", i, field->elementCount);
 
                   elementRollout->setControlProfile(elementRolloutProfile);
                   elementRollout->setCaption(buf);
@@ -349,6 +351,8 @@ bool GuiInspectorGroup::inspectGroup()
                   elementRollout->instantCollapse();
 
                   arrayStack->addObject(elementRollout);
+
+                  mArrayElements.push_back({ elementRollout, (S32)i, field });
                }
 
                pArrayRollout = arrayRollout;

Engine/source/gui/editor/inspector/group.h

@@ -44,6 +44,13 @@ private:
    typedef GuiRolloutCtrl Parent;
 public:
    // Members
+   struct ArrayElementEntry
+   {
+      GuiRolloutCtrl*                  rollout;
+      S32                              elementIndex;
+      const AbstractClassRep::Field*   arrayField;  // the StartArrayFieldType field
+   };
+   Vector<ArrayElementEntry>           mArrayElements;
    SimObjectPtr<GuiInspector>          mParent;
    Vector<GuiInspectorField*>          mChildren;
    GuiStackControl*                    mStack;