Fix gizmos without visible geometry not being selectable

The issue was that Node3DEditorViewport was using the render server's BVH to filter out nodes,
which is not correct for gizmos that have no renderable components,
or have collision triangles that exceed the bounds of their renderable components.

editor/plugins/node_3d_editor_gizmos.cpp

@@ -81,6 +81,8 @@ void EditorNode3DGizmo::redraw() {
 		gizmo_plugin->redraw(this);
 	}
 
+	_update_bvh();
+
 	if (Node3DEditor::get_singleton()->is_current_selected_gizmo(this)) {
 		Node3DEditor::get_singleton()->update_transform_gizmo();
 	}
@@ -244,6 +246,32 @@ void EditorNode3DGizmo::add_mesh(const Ref<Mesh> &p_mesh, const Ref<Material> &p
 	instances.push_back(ins);
 }
 
+void EditorNode3DGizmo::_update_bvh() {
+	ERR_FAIL_NULL(spatial_node);
+
+	Transform3D transform = spatial_node->get_global_transform();
+
+	float effective_icon_size = selectable_icon_size > 0.0f ? selectable_icon_size : 0.0f;
+	Vector3 icon_size_vector3 = Vector3(effective_icon_size, effective_icon_size, effective_icon_size);
+	AABB aabb(spatial_node->get_position() - icon_size_vector3 * 100.0f, icon_size_vector3 * 200.0f);
+
+	for (const Vector3 &segment_end : collision_segments) {
+		aabb.expand_to(transform.xform(segment_end));
+	}
+
+	if (collision_mesh.is_valid()) {
+		for (const Face3 &face : collision_mesh->get_faces()) {
+			aabb.expand_to(transform.xform(face.vertex[0]));
+			aabb.expand_to(transform.xform(face.vertex[1]));
+			aabb.expand_to(transform.xform(face.vertex[2]));
+		}
+	}
+
+	Node3DEditor::get_singleton()->update_gizmo_bvh_node(
+			bvh_node_id,
+			aabb);
+}
+
 void EditorNode3DGizmo::add_lines(const Vector<Vector3> &p_lines, const Ref<Material> &p_material, bool p_billboard, const Color &p_modulate) {
 	add_vertices(p_lines, p_material, Mesh::PRIMITIVE_LINES, p_billboard, p_modulate);
 }
@@ -765,6 +793,10 @@ void EditorNode3DGizmo::create() {
 		instances.write[i].create_instance(spatial_node, hidden);
 	}
 
+	bvh_node_id = Node3DEditor::get_singleton()->insert_gizmo_bvh_node(
+			spatial_node,
+			AABB(spatial_node->get_position(), Vector3(0, 0, 0)));
+
 	transform();
 }
 
@@ -774,6 +806,8 @@ void EditorNode3DGizmo::transform() {
 	for (int i = 0; i < instances.size(); i++) {
 		RS::get_singleton()->instance_set_transform(instances[i].instance, spatial_node->get_global_transform() * instances[i].xform);
 	}
+
+	_update_bvh();
 }
 
 void EditorNode3DGizmo::free() {
@@ -790,6 +824,9 @@ void EditorNode3DGizmo::free() {
 
 	clear();
 
+	Node3DEditor::get_singleton()->remove_gizmo_bvh_node(bvh_node_id);
+	bvh_node_id = DynamicBVH::ID();
+
 	valid = false;
 }
 

editor/plugins/node_3d_editor_gizmos.h

@@ -31,6 +31,7 @@
 #ifndef NODE_3D_EDITOR_GIZMOS_H
 #define NODE_3D_EDITOR_GIZMOS_H
 
+#include "core/math/dynamic_bvh.h"
 #include "core/templates/hash_map.h"
 #include "core/templates/local_vector.h"
 #include "scene/3d/camera_3d.h"
@@ -72,8 +73,12 @@ class EditorNode3DGizmo : public Node3DGizmo {
 	Vector<Instance> instances;
 	Node3D *spatial_node = nullptr;
 
+	DynamicBVH::ID bvh_node_id;
+
 	void _set_node_3d(Node *p_node) { set_node_3d(Object::cast_to<Node3D>(p_node)); }
 
+	void _update_bvh();
+
 protected:
 	static void _bind_methods();
 

editor/plugins/node_3d_editor_plugin.cpp

@@ -800,7 +800,6 @@ ObjectID Node3DEditorViewport::_select_ray(const Point2 &p_pos) const {
 		RS::get_singleton()->sdfgi_set_debug_probe_select(pos, ray);
 	}
 
-	Vector<ObjectID> instances = RenderingServer::get_singleton()->instances_cull_ray(pos, pos + ray * camera->get_far(), get_tree()->get_root()->get_world_3d()->get_scenario());
 	HashSet<Ref<EditorNode3DGizmo>> found_gizmos;
 
 	Node *edited_scene = get_tree()->get_edited_scene_root();
@@ -808,9 +807,9 @@ ObjectID Node3DEditorViewport::_select_ray(const Point2 &p_pos) const {
 	Node *item = nullptr;
 	float closest_dist = 1e20;
 
-	for (int i = 0; i < instances.size(); i++) {
-		Node3D *spat = Object::cast_to<Node3D>(ObjectDB::get_instance(instances[i]));
+	Vector<Node3D *> nodes_with_gizmos = Node3DEditor::get_singleton()->gizmo_bvh_ray_query(pos, pos + ray * camera->get_far());
 
+	for (Node3D *spat : nodes_with_gizmos) {
 		if (!spat) {
 			continue;
 		}
@@ -863,12 +862,11 @@ void Node3DEditorViewport::_find_items_at_pos(const Point2 &p_pos, Vector<_RayRe
 	Vector3 ray = get_ray(p_pos);
 	Vector3 pos = get_ray_pos(p_pos);
 
-	Vector<ObjectID> instances = RenderingServer::get_singleton()->instances_cull_ray(pos, pos + ray * camera->get_far(), get_tree()->get_root()->get_world_3d()->get_scenario());
-	HashSet<Node3D *> found_nodes;
+	Vector<Node3D *> nodes_with_gizmos = Node3DEditor::get_singleton()->gizmo_bvh_ray_query(pos, pos + ray * camera->get_far());
 
-	for (int i = 0; i < instances.size(); i++) {
-		Node3D *spat = Object::cast_to<Node3D>(ObjectDB::get_instance(instances[i]));
+	HashSet<Node3D *> found_nodes;
 
+	for (Node3D *spat : nodes_with_gizmos) {
 		if (!spat) {
 			continue;
 		}
@@ -1046,14 +1044,13 @@ void Node3DEditorViewport::_select_region() {
 		_clear_selected();
 	}
 
-	Vector<ObjectID> instances = RenderingServer::get_singleton()->instances_cull_convex(frustum, get_tree()->get_root()->get_world_3d()->get_scenario());
+	Vector<Node3D *> nodes_with_gizmos = Node3DEditor::get_singleton()->gizmo_bvh_frustum_query(frustum);
 	HashSet<Node3D *> found_nodes;
 	Vector<Node *> selected;
 
 	Node *edited_scene = get_tree()->get_edited_scene_root();
 
-	for (int i = 0; i < instances.size(); i++) {
-		Node3D *sp = Object::cast_to<Node3D>(ObjectDB::get_instance(instances[i]));
+	for (Node3D *sp : nodes_with_gizmos) {
 		if (!sp || _is_node_locked(sp)) {
 			continue;
 		}
@@ -9205,6 +9202,49 @@ void Node3DEditor::remove_gizmo_plugin(Ref<EditorNode3DGizmoPlugin> p_plugin) {
 	_update_gizmos_menu();
 }
 
+DynamicBVH::ID Node3DEditor::insert_gizmo_bvh_node(Node3D *p_node, const AABB &p_aabb) {
+	return gizmo_bvh.insert(p_aabb, p_node);
+}
+
+void Node3DEditor::update_gizmo_bvh_node(DynamicBVH::ID p_id, const AABB &p_aabb) {
+	gizmo_bvh.update(p_id, p_aabb);
+	gizmo_bvh.optimize_incremental(1);
+}
+
+void Node3DEditor::remove_gizmo_bvh_node(DynamicBVH::ID p_id) {
+	gizmo_bvh.remove(p_id);
+}
+
+Vector<Node3D *> Node3DEditor::gizmo_bvh_ray_query(const Vector3 &p_ray_start, const Vector3 &p_ray_end) {
+	struct Result {
+		Vector<Node3D *> nodes;
+		bool operator()(void *p_data) {
+			nodes.append((Node3D *)p_data);
+			return false;
+		}
+	} result;
+
+	gizmo_bvh.ray_query(p_ray_start, p_ray_end, result);
+
+	return result.nodes;
+}
+
+Vector<Node3D *> Node3DEditor::gizmo_bvh_frustum_query(const Vector<Plane> &p_frustum) {
+	Vector<Vector3> points = Geometry3D::compute_convex_mesh_points(&p_frustum[0], p_frustum.size());
+
+	struct Result {
+		Vector<Node3D *> nodes;
+		bool operator()(void *p_data) {
+			nodes.append((Node3D *)p_data);
+			return false;
+		}
+	} result;
+
+	gizmo_bvh.convex_query(p_frustum.ptr(), p_frustum.size(), points.ptr(), points.size(), result);
+
+	return result.nodes;
+}
+
 Node3DEditorPlugin::Node3DEditorPlugin() {
 	spatial_editor = memnew(Node3DEditor);
 	spatial_editor->set_v_size_flags(Control::SIZE_EXPAND_FILL);

editor/plugins/node_3d_editor_plugin.h

@@ -31,6 +31,7 @@
 #ifndef NODE_3D_EDITOR_PLUGIN_H
 #define NODE_3D_EDITOR_PLUGIN_H
 
+#include "core/math/dynamic_bvh.h"
 #include "editor/plugins/editor_plugin.h"
 #include "editor/plugins/node_3d_editor_gizmos.h"
 #include "editor/themes/editor_scale.h"
@@ -629,6 +630,8 @@ private:
 	int current_hover_gizmo_handle;
 	bool current_hover_gizmo_handle_secondary;
 
+	DynamicBVH gizmo_bvh;
+
 	real_t snap_translate_value;
 	real_t snap_rotate_value;
 	real_t snap_scale_value;
@@ -933,6 +936,12 @@ public:
 	void add_gizmo_plugin(Ref<EditorNode3DGizmoPlugin> p_plugin);
 	void remove_gizmo_plugin(Ref<EditorNode3DGizmoPlugin> p_plugin);
 
+	DynamicBVH::ID insert_gizmo_bvh_node(Node3D *p_node, const AABB &p_aabb);
+	void update_gizmo_bvh_node(DynamicBVH::ID p_id, const AABB &p_aabb);
+	void remove_gizmo_bvh_node(DynamicBVH::ID p_id);
+	Vector<Node3D *> gizmo_bvh_ray_query(const Vector3 &p_ray_start, const Vector3 &p_ray_end);
+	Vector<Node3D *> gizmo_bvh_frustum_query(const Vector<Plane> &p_frustum);
+
 	void edit(Node3D *p_spatial);
 	void clear();