Ignore backfaces during Node3D selection

Author: vaner-org

core/math/triangle_mesh.cpp

@@ -290,7 +290,7 @@ bool TriangleMesh::intersect_segment(const Vector3 &p_begin, const Vector3 &p_en
 	return inters;
 }
 
-bool TriangleMesh::intersect_ray(const Vector3 &p_begin, const Vector3 &p_dir, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index, int32_t *r_face_index) const {
+bool TriangleMesh::intersect_ray(const Vector3 &p_begin, const Vector3 &p_dir, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index, int32_t *r_face_index, bool p_ignore_backfaces) const {
 	if (!valid) {
 		return false;
 	}
@@ -338,18 +338,23 @@ bool TriangleMesh::intersect_ray(const Vector3 &p_begin, const Vector3 &p_dir, V
 						Vector3 res;
 
 						if (f3.intersects_ray(p_begin, p_dir, &res)) {
-							real_t nd = n.dot(res);
-							if (nd < d) {
-								d = nd;
-								r_point = res;
-								r_normal = f3.get_plane().get_normal();
-								if (r_surf_index) {
-									*r_surf_index = s.surface_index;
+							Vector3 face_normal = f3.get_plane().get_normal();
+							if (p_ignore_backfaces && p_dir.dot(face_normal) >= 0) {
+								// Skip this triangle.
+							} else {
+								real_t nd = n.dot(res);
+								if (nd < d) {
+									d = nd;
+									r_point = res;
+									r_normal = face_normal;
+									if (r_surf_index) {
+										*r_surf_index = s.surface_index;
+									}
+									if (r_face_index) {
+										*r_face_index = b.face_index;
+									}
+									inters = true;
 								}
-								if (r_face_index) {
-									*r_face_index = b.face_index;
-								}
-								inters = true;
 							}
 						}
 

core/math/triangle_mesh.h

@@ -85,7 +85,7 @@ class TriangleMesh : public RefCounted {
 public:
 	bool is_valid() const;
 	bool intersect_segment(const Vector3 &p_begin, const Vector3 &p_end, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index = nullptr, int32_t *r_face_index = nullptr) const;
-	bool intersect_ray(const Vector3 &p_begin, const Vector3 &p_dir, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index = nullptr, int32_t *r_face_index = nullptr) const;
+	bool intersect_ray(const Vector3 &p_begin, const Vector3 &p_dir, Vector3 &r_point, Vector3 &r_normal, int32_t *r_surf_index = nullptr, int32_t *r_face_index = nullptr, bool p_ignore_backfaces = false) const;
 	bool inside_convex_shape(const Plane *p_planes, int p_plane_count, const Vector3 *p_points, int p_point_count, Vector3 p_scale = Vector3(1, 1, 1)) const;
 	Vector<Face3> get_faces() const;
 

doc/classes/EditorSettings.xml

@@ -357,6 +357,9 @@
 		<member name="editors/3d/grid_yz_plane" type="bool" setter="" getter="">
 			If [code]true[/code], renders the grid on the YZ plane in perspective view. This can be useful for 3D side-scrolling games.
 		</member>
+		<member name="editors/3d/ignore_backfaces_on_selection" type="bool" setter="" getter="">
+			If [code]true[/code], backfaces are ignored for 3D selection. This is useful for level editing, to select nodes inside enclosed geometry without accidentally selecting the ceiling or walls.
+		</member>
 		<member name="editors/3d/manipulator_gizmo_opacity" type="float" setter="" getter="">
 			Opacity of the default gizmo for moving, rotating, and scaling 3D nodes.
 		</member>

editor/run/game_view_plugin.cpp

@@ -78,6 +78,7 @@ void GameViewDebugger::_session_started(Ref<EditorDebuggerSession> p_session) {
 	settings["editors/3d/freelook/freelook_sensitivity"] = EDITOR_GET("editors/3d/freelook/freelook_sensitivity");
 	settings["editors/3d/navigation_feel/orbit_sensitivity"] = EDITOR_GET("editors/3d/navigation_feel/orbit_sensitivity");
 	settings["editors/3d/navigation_feel/translation_sensitivity"] = EDITOR_GET("editors/3d/navigation_feel/translation_sensitivity");
+	settings["editors/3d/ignore_backfaces_on_selection"] = EDITOR_GET("editors/3d/ignore_backfaces_on_selection");
 	settings["editors/3d/selection_box_color"] = EDITOR_GET("editors/3d/selection_box_color");
 	settings["editors/3d/freelook/freelook_base_speed"] = EDITOR_GET("editors/3d/freelook/freelook_base_speed");
 

editor/scene/3d/node_3d_editor_gizmos.cpp

@@ -762,9 +762,10 @@ bool EditorNode3DGizmo::intersect_ray(Camera3D *p_camera, const Point2 &p_point,
 		Vector3 ray_dir = ai.basis.xform(p_camera->project_ray_normal(p_point)).normalized();
 		Vector3 rpos, rnorm;
 
+		bool ignore_backfaces = EDITOR_GET("editors/3d/ignore_backfaces_on_selection");
 		for (Ref<TriangleMesh> collision_mesh : collision_meshes) {
 			if (collision_mesh.is_valid()) {
-				if (collision_mesh->intersect_ray(ray_from, ray_dir, rpos, rnorm)) {
+				if (collision_mesh->intersect_ray(ray_from, ray_dir, rpos, rnorm, nullptr, nullptr, ignore_backfaces)) {
 					r_pos = gt.xform(rpos);
 					r_normal = gt.basis.xform(rnorm).normalized();
 					return true;

editor/settings/editor_settings.cpp

@@ -858,6 +858,7 @@ void EditorSettings::_load_defaults(Ref<ConfigFile> p_extra_config) {
 	EDITOR_SETTING_BASIC(Variant::COLOR, PROPERTY_HINT_NONE, "editors/3d/primary_grid_color", Color(0.56, 0.56, 0.56, 0.5), "")
 	EDITOR_SETTING_BASIC(Variant::COLOR, PROPERTY_HINT_NONE, "editors/3d/secondary_grid_color", Color(0.38, 0.38, 0.38, 0.5), "")
 
+	EDITOR_SETTING_USAGE(Variant::BOOL, PROPERTY_HINT_NONE, "editors/3d/ignore_backfaces_on_selection", true, "", PROPERTY_USAGE_DEFAULT)
 	// Use a similar color to the 2D editor selection.
 	EDITOR_SETTING_USAGE(Variant::COLOR, PROPERTY_HINT_NONE, "editors/3d/selection_box_color", Color(1.0, 0.5, 0), "", PROPERTY_USAGE_DEFAULT)
 	EDITOR_SETTING_USAGE(Variant::COLOR, PROPERTY_HINT_NONE, "editors/3d/active_selection_box_color", Color(1.5, 0.75, 0, 1.0), "", PROPERTY_USAGE_DEFAULT)

scene/debugger/scene_debugger.cpp

@@ -1537,6 +1537,7 @@ void RuntimeNodeSelect::_setup(const Dictionary &p_settings) {
 	/// 3D Selection Box Generation
 	// Copied from the Node3DEditor implementation.
 
+	ignore_backfaces_on_selection = p_settings.get("editors/3d/ignore_backfaces_on_selection", true);
 	sbox_3d_color = p_settings.get("editors/3d/selection_box_color", Color());
 
 	// Use two AABBs to create the illusion of a slightly thicker line.
@@ -2562,7 +2563,7 @@ void RuntimeNodeSelect::_find_3d_items_at_pos(const Point2 &p_pos, Vector<Select
 				Transform3D gt = geo_instance->get_global_transform();
 				Transform3D ai = gt.affine_inverse();
 				Vector3 point, normal;
-				if (mesh_collision->intersect_ray(ai.xform(pos), ai.basis.xform(ray).normalized(), point, normal)) {
+				if (mesh_collision->intersect_ray(ai.xform(pos), ai.basis.xform(ray).normalized(), point, normal, nullptr, nullptr, ignore_backfaces_on_selection)) {
 					SelectResult res;
 					res.item = Object::cast_to<Node>(obj);
 					res.order = -pos.distance_to(gt.xform(point));

scene/debugger/scene_debugger.h

@@ -361,6 +361,7 @@ class RuntimeNodeSelect : public Object {
 	};
 	HashMap<ObjectID, Ref<SelectionBox3D>> selected_3d_nodes;
 
+	bool ignore_backfaces_on_selection = true;
 	Color sbox_3d_color;
 	Ref<ArrayMesh> sbox_3d_mesh;
 	Ref<ArrayMesh> sbox_3d_mesh_xray;