Add new property hint to determine if a scene graph node should focusable (#3508)

include/openspace/scene/scenegraphnode.h

@@ -181,6 +181,7 @@ private:
     properties::StringProperty _guiDisplayName;
     properties::StringProperty _guiDescription;
     properties::BoolProperty _useGuiOrdering;
+    properties::BoolProperty _guiFocusable;
     properties::FloatProperty _guiOrderingNumber;
 
     // Transformation defined by translation, rotation and scale

src/scene/scenegraphnode.cpp

@@ -193,6 +193,15 @@ namespace {
         openspace::properties::Property::Visibility::Hidden
     };
 
+    constexpr openspace::properties::Property::PropertyInfo GuiFocusableInfo = {
+        "IsFocusable",
+        "Focusable Hint",
+        "This value serves as a hint to determine if it makes sense to focus the camera "
+        "on this scene graph node. It only serves as a hint and does not actually "
+        "prevent the focussing. The default value is `true`.",
+        openspace::properties::Property::Visibility::Hidden
+    };
+
     constexpr openspace::properties::Property::PropertyInfo ShowDebugSphereInfo = {
         "ShowDebugSphere",
         "Show Debug Sphere",
@@ -330,6 +339,9 @@ namespace {
             // not display, for example, barycenters
             std::optional<bool> hidden;
 
+            // [[codegen::verbatim(GuiFocusableInfo.description)]]
+            std::optional<bool> focusable;
+
             // If this value is specified, the scene graph node will be ordered in
             // relation to its neighbors in the GUI based on this value, so that nodes
             // with a higher value appear later in the list. Scene graph nodes with the
@@ -396,6 +408,7 @@ ghoul::mm_unique_ptr<SceneGraphNode> SceneGraphNode::createFromDictionary(
         if (p.gui->orderingNumber.has_value()) {
             result->_guiOrderingNumber = *p.gui->orderingNumber;
         }
+        result->_guiFocusable = p.gui->focusable.value_or(result->_guiFocusable);
     }
 
     result->_boundingSphere = p.boundingSphere.value_or(result->_boundingSphere);
@@ -541,6 +554,7 @@ SceneGraphNode::SceneGraphNode()
     , _guiDisplayName(GuiNameInfo)
     , _guiDescription(GuiDescriptionInfo)
     , _useGuiOrdering(UseGuiOrderInfo, false)
+    , _guiFocusable(GuiFocusableInfo, true)
     , _guiOrderingNumber(GuiOrderInfo, 0.f)
     , _transform {
         ghoul::mm_unique_ptr<Translation>(
@@ -625,6 +639,7 @@ SceneGraphNode::SceneGraphNode()
     addProperty(_guiPath);
     addProperty(_guiOrderingNumber);
     addProperty(_useGuiOrdering);
+    addProperty(_guiFocusable);
 }
 
 SceneGraphNode::~SceneGraphNode() {}