Add snapping to the transform gizmo

Author: aaronfranke

editor/viewport/editor_main_screen_nd.cpp

@@ -119,6 +119,8 @@ void EditorMainScreenND::_on_transform_settings_menu_id_pressed(const int p_id)
 			_nd_editor_config_file->set_value("transform", "keep_mode", (int)keep_mode);
 		}
 		_nd_editor_config_file->save(_nd_editor_config_file_path);
+	} else if (p_id == TRANSFORM_SETTING_CONFIGURE_SNAP) {
+		_snap_settings_dialog->popup_centered(Size2(400, 450) * EDSCALE);
 	}
 }
 
@@ -261,6 +263,9 @@ void EditorMainScreenND::_notification(int p_what) {
 		} break;
 #if GODOT_MODULE || (GODOT_VERSION_MAJOR > 4 || (GODOT_VERSION_MAJOR == 4 && GODOT_VERSION_MINOR >= 4))
 		case NOTIFICATION_EXIT_TREE: {
+			if (_snap_settings_inspector != nullptr) {
+				_snap_settings_inspector->edit(nullptr);
+			}
 			if (_camera_settings_inspector != nullptr) {
 				_camera_settings_inspector->edit(nullptr);
 			}
@@ -398,6 +403,7 @@ void EditorMainScreenND::setup(EditorUndoRedoManager *p_undo_redo_manager) {
 	// All viewports share one gizmo and origin marker.
 	_transform_gizmo_nd = memnew(EditorTransformGizmoND);
 	add_child(_transform_gizmo_nd);
+	_transform_gizmo_nd->setup(this, p_undo_redo_manager);
 
 	_origin_marker = memnew(MarkerND);
 	_origin_marker->set_name(StringName("OriginMarkerND"));
@@ -428,8 +434,29 @@ void EditorMainScreenND::setup(EditorUndoRedoManager *p_undo_redo_manager) {
 	transform_settings_menu_popup->add_radio_check_item(TTR("Keep Conformal (uniform scale)"), TRANSFORM_SETTING_KEEP_CONFORMAL);
 	transform_settings_menu_popup->add_radio_check_item(TTR("Keep Orthonormal (no scale)"), TRANSFORM_SETTING_KEEP_ORTHONORMAL);
 	transform_settings_menu_popup->set_item_checked((int)EditorTransformGizmoND::KeepMode::FREEFORM, true);
+	transform_settings_menu_popup->add_separator();
+	transform_settings_menu_popup->add_item(TTR("Configure Snap..."), TRANSFORM_SETTING_CONFIGURE_SNAP);
 	transform_settings_menu_popup->connect(StringName("id_pressed"), callable_mp(this, &EditorMainScreenND::_on_transform_settings_menu_id_pressed));
 
+#if GODOT_MODULE || (GODOT_VERSION_MAJOR > 4 || (GODOT_VERSION_MAJOR == 4 && GODOT_VERSION_MINOR >= 4))
+	// Set up the snap settings dialog as long as this is Godot >= 4.4.
+	EditorTransformSnapSettingsND *snap_settings = _transform_gizmo_nd->get_snap_settings();
+	snap_settings->setup(_nd_editor_config_file, _nd_editor_config_file_path);
+	_snap_settings_dialog = memnew(ConfirmationDialog);
+	_snap_settings_dialog->set_name(StringName("SnapSettingsDialog"));
+	_snap_settings_dialog->set_title(TTR("Transform Gizmo Snap Settings"));
+	_snap_settings_inspector = memnew(EditorInspector);
+	_snap_settings_inspector->set_name(StringName("SnapSettingsInspector"));
+	_snap_settings_inspector->set_anchors_and_offsets_preset(Control::PRESET_FULL_RECT);
+	_snap_settings_inspector->set_custom_minimum_size(Size2(400, 200) * EDSCALE);
+	_snap_settings_inspector->edit(snap_settings);
+	_snap_settings_dialog->add_child(_snap_settings_inspector);
+	add_child(_snap_settings_dialog);
+#else
+	transform_settings_menu_popup->set_item_disabled(TRANSFORM_SETTING_CONFIGURE_SNAP, true);
+	transform_settings_menu_popup->set_item_tooltip(TRANSFORM_SETTING_CONFIGURE_SNAP, TTR("Snap settings requires compiling with a minimum Godot version of 4.4, but this was compiled for Godot " + itos(GODOT_VERSION_MAJOR) + "." + itos(GODOT_VERSION_MINOR) + "."));
+#endif
+
 	// Set up the Layout menu in the toolbar.
 	_layout_menu = memnew(MenuButton);
 	_layout_menu->set_flat(false);
@@ -503,9 +530,6 @@ void EditorMainScreenND::setup(EditorUndoRedoManager *p_undo_redo_manager) {
 
 	EditorInterface::get_singleton()->get_selection()->connect(StringName("selection_changed"), callable_mp(this, &EditorMainScreenND::_on_selection_changed));
 
-	// Set up things with the arguments (not constructor things).
-	_transform_gizmo_nd->setup(this, p_undo_redo_manager);
-
 	_apply_nd_editor_settings();
 }
 

editor/viewport/editor_main_screen_nd.h

@@ -56,6 +56,7 @@ class EditorMainScreenND : public Control {
 		TRANSFORM_SETTING_KEEP_CONFORMAL, // 2
 		TRANSFORM_SETTING_KEEP_ORTHONORMAL, // 3
 		TRANSFORM_SETTING_KEEP_MAX, // 4
+		TRANSFORM_SETTING_CONFIGURE_SNAP = TRANSFORM_SETTING_KEEP_MAX, // Still 4
 	};
 
 	enum LayoutItem {
@@ -80,6 +81,8 @@ class EditorMainScreenND : public Control {
 	MenuButton *_layout_menu = nullptr;
 	MenuButton *_view_menu = nullptr;
 	PopupMenu *_rendering_engine_menu_popup = nullptr;
+	ConfirmationDialog *_snap_settings_dialog = nullptr;
+	EditorInspector *_snap_settings_inspector = nullptr;
 	ConfirmationDialog *_camera_settings_dialog = nullptr;
 	EditorInspector *_camera_settings_inspector = nullptr;
 	EditorCameraSettingsND *_camera_settings = nullptr;

editor/viewport/editor_transform_gizmo_nd.cpp

@@ -295,6 +295,7 @@ void EditorTransformGizmoND::_update_gizmo_transform() {
 		set_visible(false);
 	} else {
 		set_visible(true);
+		sum_transform->set_dimension(sum_transform->get_dimension()); // Make sure the matrix is square.
 		sum_transform = sum_transform->divide_scalar(double(transform_count));
 		if (_is_use_local_rotation) {
 			// Scale/shear/skew can mess with the rotation gizmo, so get rid of it.
@@ -583,7 +584,7 @@ void EditorTransformGizmoND::_end_transformation() {
 	}
 	// Create an undo/redo action for the transformation.
 	const String action = _get_transform_part_simple_action_name(_current_transformation);
-	_undo_redo->create_action(action + String(" 4D nodes with gizmo"));
+	_undo_redo->create_action(action + String(" ND nodes with gizmo"));
 	const int size = _selected_top_nodes.size();
 	for (int i = 0; i < size; i++) {
 		NodeND *node_nd = Object::cast_to<NodeND>(_selected_top_nodes[i]);
@@ -660,7 +661,12 @@ void EditorTransformGizmoND::_process_transform(const VectorN &p_local_ray_origi
 	// The above position changes happen relative to the visual gizmo mesh holder, but
 	// we want them relative to the gizmo itself. Scale/rotation should not be adjusted.
 	transform_change->set_origin(_old_mesh_holder_transform->xform(transform_change->get_origin()));
-	Ref<TransformND> new_transform = _old_gizmo_transform->compose_square(transform_change);
+	transform_change->set_dimension(transform_change->get_dimension()); // Make sure the matrix is square.
+	Ref<TransformND> new_transform = _snap_settings->snap_transform_change(_old_gizmo_transform, transform_change);
+	// Special case: Only in move mode, ignore any snapping that happened to the basis.
+	if (_current_transformation == TRANSFORM_MOVE_AXIS || _current_transformation == TRANSFORM_MOVE_PLANE) {
+		new_transform->set_basis(_old_gizmo_transform->get_basis());
+	}
 	set_transform(new_transform);
 	// We want the global diff so we can apply it from the left on the global transform of all selected nodes.
 	// Without this, the transforms would be relative to each node (ex: moving on X moves on each node's X axis).
@@ -669,6 +675,11 @@ void EditorTransformGizmoND::_process_transform(const VectorN &p_local_ray_origi
 		NodeND *node_nd = Object::cast_to<NodeND>(_selected_top_nodes[i]);
 		if (node_nd != nullptr) {
 			node_nd->set_global_transform(transform_change->compose_square(_selected_top_node_old_transforms[i]));
+			if (_snap_settings->get_snap_final_values()) {
+				node_nd->set_transform(_snap_settings->snap_single_transform(node_nd->get_transform()));
+			}
+			// Note: The keep mode takes priority over snapping, so we apply it after snapping.
+			// In most cases these won't conflict, but in an edge case where they do, keep mode wins.
 			switch (_keep_mode) {
 				case KeepMode::FREEFORM: {
 					// Do nothing.
@@ -832,10 +843,10 @@ bool EditorTransformGizmoND::gizmo_mouse_input(const Ref<InputEventMouse> &p_mou
 	const Ref<TransformND> global_to_local = _old_gizmo_transform->compose_square(_old_mesh_holder_transform)->inverse();
 	const VectorN local_ray_origin = global_to_local->xform(ray_origin);
 	const VectorN local_ray_direction = global_to_local->xform_basis(ray_direction);
-	return gizmo_mouse_raycast(p_mouse_event, local_ray_origin, local_ray_direction);
+	return _gizmo_mouse_raycast(p_mouse_event, p_camera, local_ray_origin, local_ray_direction);
 }
 
-bool EditorTransformGizmoND::gizmo_mouse_raycast(const Ref<InputEventMouse> &p_mouse_event, const VectorN &p_local_ray_origin, const VectorN &p_local_ray_direction) {
+bool EditorTransformGizmoND::_gizmo_mouse_raycast(const Ref<InputEventMouse> &p_mouse_event, const CameraND *p_camera, const VectorN &p_local_ray_origin, const VectorN &p_local_ray_direction) {
 	Ref<InputEventMouseButton> mouse_button = p_mouse_event;
 	if (mouse_button.is_valid()) {
 		if (mouse_button->get_button_index() != MOUSE_BUTTON_LEFT) {
@@ -850,6 +861,8 @@ bool EditorTransformGizmoND::gizmo_mouse_raycast(const Ref<InputEventMouse> &p_m
 				_primary_axis = new_primary_axis;
 				_secondary_axis = new_secondary_axis;
 				_begin_transformation(p_local_ray_origin, p_local_ray_direction);
+				const double dist = VectorND::distance_to(_old_gizmo_transform->get_origin(), p_camera->get_global_position());
+				_snap_settings->set_camera_distance(dist);
 			}
 		} else if (!mouse_button->is_pressed() && _current_transformation != TRANSFORM_NONE) {
 			// If we are transforming something and the user releases the click, end the transformation.
@@ -901,6 +914,7 @@ void EditorTransformGizmoND::setup(EditorMainScreenND *p_editor_main_screen, Edi
 	_mesh_holder = memnew(NodeND);
 	_mesh_holder->set_name(StringName("GizmoMeshHolderND"));
 	add_child(_mesh_holder);
+	_snap_settings = memnew(EditorTransformSnapSettingsND);
 	RenderingServerND::get_singleton()->connect(StringName("pre_render"), callable_mp(this, &EditorTransformGizmoND::_on_rendering_server_pre_render));
 	EditorInterface::get_singleton()->get_inspector()->connect(StringName("property_edited"), callable_mp(this, &EditorTransformGizmoND::_on_editor_inspector_property_edited));
 
@@ -909,3 +923,9 @@ void EditorTransformGizmoND::setup(EditorMainScreenND *p_editor_main_screen, Edi
 	_undo_redo = p_undo_redo_manager;
 	p_undo_redo_manager->connect(StringName("version_changed"), callable_mp(this, &EditorTransformGizmoND::_on_undo_redo_version_changed));
 }
+
+EditorTransformGizmoND::~EditorTransformGizmoND() {
+	if (_snap_settings != nullptr) {
+		memdelete(_snap_settings);
+	}
+}

editor/viewport/editor_transform_gizmo_nd.h

@@ -2,6 +2,8 @@
 
 #include "editor_viewport_nd_defines.h"
 
+#include "editor_transform_snap_settings_nd.h"
+
 #include "../../math/rect_nd.h"
 #include "../../model/mesh_instance_nd.h"
 
@@ -47,6 +49,7 @@ class EditorTransformGizmoND : public NodeND {
 	Vector<NodeND *> _mesh_keep_conformal;
 	Vector<MeshInstanceND *> _meshes[TRANSFORM_MAX];
 	EditorMainScreenND *_editor_main_screen = nullptr;
+	EditorTransformSnapSettingsND *_snap_settings = nullptr;
 	EditorUndoRedoManager *_undo_redo = nullptr;
 
 	KeepMode _keep_mode = KeepMode::FREEFORM;
@@ -77,6 +80,7 @@ class EditorTransformGizmoND : public NodeND {
 	void _regenerate_gizmo_meshes();
 
 	// Misc internal functions.
+	bool _gizmo_mouse_raycast(const Ref<InputEventMouse> &p_mouse_event, const CameraND *p_camera, const VectorN &p_ray_origin, const VectorN &p_ray_direction);
 	void _on_rendering_server_pre_render(CameraND *p_camera, Viewport *p_viewport, RenderingEngineND *p_rendering_engine);
 	void _on_editor_inspector_property_edited(const String &p_prop);
 	void _on_undo_redo_version_changed();
@@ -102,16 +106,17 @@ class EditorTransformGizmoND : public NodeND {
 	static void _bind_methods() {}
 
 public:
+	EditorTransformSnapSettingsND *get_snap_settings() const { return _snap_settings; }
 	void selected_nodes_changed(const TypedArray<Node> &p_top_nodes);
 	void set_axis_colors(const PackedColorArray &p_axis_colors);
 	void set_keep_mode(const KeepMode p_mode);
 	void set_gizmo_mode(const GizmoMode p_mode);
 	void set_gizmo_dimension(const int p_dimension);
 	bool gizmo_mouse_input(const Ref<InputEventMouse> &p_mouse_event, const CameraND *p_camera);
-	bool gizmo_mouse_raycast(const Ref<InputEventMouse> &p_mouse_event, const VectorN &p_ray_origin, const VectorN &p_ray_direction);
 
 	bool get_use_local_rotation() const;
 	void set_use_local_rotation(const bool p_use_local_transform);
 
 	void setup(EditorMainScreenND *p_editor_main_screen, EditorUndoRedoManager *p_undo_redo_manager);
+	~EditorTransformGizmoND();
 };