Add an editor setting for the 3D selection box color

A restart is required to apply the setting change.

(cherry picked from commit 8221037be0b22219d942ea746784592732e7b14e)

editor/editor_settings.cpp

@@ -501,6 +501,10 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	_initial_set("editors/3d/primary_grid_color", Color(0.56, 0.56, 0.56, 0.5));
 	_initial_set("editors/3d/secondary_grid_color", Color(0.38, 0.38, 0.38, 0.5));
 
+	// Use a similar color to the 2D editor selection.
+	_initial_set("editors/3d/selection_box_color", Color(1.0, 0.5, 0));
+	hints["editors/3d/selection_box_color"] = PropertyInfo(Variant::COLOR, "editors/3d/selection_box_color", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_DEFAULT | PROPERTY_USAGE_RESTART_IF_CHANGED);
+
 	// If a line is a multiple of this, it uses the primary grid color.
 	// Use a power of 2 value by default as it's more common to use powers of 2 in level design.
 	_initial_set("editors/3d/primary_grid_steps", 8);

editor/plugins/spatial_editor_plugin.cpp

@@ -4534,8 +4534,8 @@ void SpatialEditor::_generate_selection_boxes() {
 
 	Ref<SpatialMaterial> mat = memnew(SpatialMaterial);
 	mat->set_flag(SpatialMaterial::FLAG_UNSHADED, true);
-	// Use a similar color to the 2D editor selection.
-	mat->set_albedo(Color(1, 0.5, 0));
+	const Color selection_box_color = EDITOR_GET("editors/3d/selection_box_color");
+	mat->set_albedo(selection_box_color);
 	mat->set_feature(SpatialMaterial::FEATURE_TRANSPARENT, true);
 	st->set_material(mat);
 	selection_box = st->commit();
@@ -4543,7 +4543,7 @@ void SpatialEditor::_generate_selection_boxes() {
 	Ref<SpatialMaterial> mat_xray = memnew(SpatialMaterial);
 	mat_xray->set_flag(SpatialMaterial::FLAG_UNSHADED, true);
 	mat_xray->set_flag(SpatialMaterial::FLAG_DISABLE_DEPTH_TEST, true);
-	mat_xray->set_albedo(Color(1, 0.5, 0, 0.15));
+	mat_xray->set_albedo(selection_box_color * Color(1, 1, 1, 0.15));
 	mat_xray->set_feature(SpatialMaterial::FEATURE_TRANSPARENT, true);
 	st_xray->set_material(mat_xray);
 	selection_box_xray = st_xray->commit();