Implement closed path for Curve3d

doc/classes/Curve3D.xml

@@ -204,6 +204,9 @@
 		<member name="bake_interval" type="float" setter="set_bake_interval" getter="get_bake_interval" default="0.2">
 			The distance in meters between two adjacent cached points. Changing it forces the cache to be recomputed the next time the [method get_baked_points] or [method get_baked_length] function is called. The smaller the distance, the more points in the cache and the more memory it will consume, so use with care.
 		</member>
+		<member name="closed" type="bool" setter="set_closed" getter="is_closed" default="false">
+			If [code]true[/code], and the curve has more than 2 control points, the last point and the first one will be connected in a loop.
+		</member>
 		<member name="point_count" type="int" setter="set_point_count" getter="get_point_count" default="0">
 			The number of points describing the curve.
 		</member>

editor/plugins/path_3d_editor_plugin.cpp

@@ -277,8 +277,15 @@ void Path3DGizmo::redraw() {
 	Ref<StandardMaterial3D> path_tilt_material = gizmo_plugin->get_material("path_tilt_material", this);
 	Ref<StandardMaterial3D> path_tilt_muted_material = gizmo_plugin->get_material("path_tilt_muted_material", this);
 	Ref<StandardMaterial3D> handles_material = gizmo_plugin->get_material("handles");
+	Ref<StandardMaterial3D> first_pt_handle_material = gizmo_plugin->get_material("first_pt_handle");
+	Ref<StandardMaterial3D> last_pt_handle_material = gizmo_plugin->get_material("last_pt_handle");
+	Ref<StandardMaterial3D> closed_pt_handle_material = gizmo_plugin->get_material("closed_pt_handle");
 	Ref<StandardMaterial3D> sec_handles_material = gizmo_plugin->get_material("sec_handles");
 
+	first_pt_handle_material->set_albedo(Color(0.2, 1.0, 0.0));
+	last_pt_handle_material->set_albedo(Color(1.0, 0.2, 0.0));
+	closed_pt_handle_material->set_albedo(Color(1.0, 0.8, 0.0));
+
 	Ref<Curve3D> c = path->get_curve();
 	if (c.is_null()) {
 		return;
@@ -369,7 +376,7 @@ void Path3DGizmo::redraw() {
 			info.point_idx = idx;
 
 			// Collect in-handles except for the first point.
-			if (idx > 0 && Path3DEditorPlugin::singleton->curve_edit_curve->is_pressed()) {
+			if (idx > (c->is_closed() ? -1 : 0) && Path3DEditorPlugin::singleton->curve_edit_curve->is_pressed()) {
 				const Vector3 in = c->get_point_in(idx);
 
 				info.type = HandleType::HANDLE_TYPE_IN;
@@ -383,7 +390,7 @@ void Path3DGizmo::redraw() {
 			}
 
 			// Collect out-handles except for the last point.
-			if (idx < c->get_point_count() - 1 && Path3DEditorPlugin::singleton->curve_edit_curve->is_pressed()) {
+			if (idx < (c->is_closed() ? c->get_point_count() : c->get_point_count() - 1) && Path3DEditorPlugin::singleton->curve_edit_curve->is_pressed()) {
 				const Vector3 out = c->get_point_out(idx);
 
 				info.type = HandleType::HANDLE_TYPE_OUT;
@@ -441,7 +448,42 @@ void Path3DGizmo::redraw() {
 		}
 
 		if (!Path3DEditorPlugin::singleton->curve_edit->is_pressed() && primary_handle_points.size()) {
-			add_handles(primary_handle_points, handles_material);
+			// Need to define indices separately.
+			// Point count.
+			const int pc = primary_handle_points.size();
+			Vector<int> idx;
+			idx.resize(pc);
+			int *idx_ptr = idx.ptrw();
+			for (int j = 0; j < pc; j++) {
+				idx_ptr[j] = j;
+			}
+
+			// Initialize arrays for first point.
+			PackedVector3Array first_pt_handle_point;
+			Vector<int> first_pt_id;
+			first_pt_handle_point.append(primary_handle_points[0]);
+			first_pt_id.append(idx[0]);
+
+			// Initialize arrays and add handle for last point if needed.
+			if (pc > 1) {
+				PackedVector3Array last_pt_handle_point;
+				Vector<int> last_pt_id;
+				last_pt_handle_point.append(primary_handle_points[pc - 1]);
+				last_pt_id.append(idx[pc - 1]);
+				primary_handle_points.remove_at(pc - 1);
+				idx.remove_at(pc - 1);
+				add_handles(last_pt_handle_point, c->is_closed() ? handles_material : last_pt_handle_material, last_pt_id);
+			}
+
+			// Add handle for first point.
+			primary_handle_points.remove_at(0);
+			idx.remove_at(0);
+			add_handles(first_pt_handle_point, c->is_closed() ? closed_pt_handle_material : first_pt_handle_material, first_pt_id);
+
+			// Add handles for remaining intermediate points.
+			if (!primary_handle_points.is_empty()) {
+				add_handles(primary_handle_points, handles_material, idx);
+			}
 		}
 		if (secondary_handle_points.size()) {
 			add_handles(secondary_handle_points, sec_handles_material, collected_secondary_handle_ids, false, true);
@@ -469,7 +511,7 @@ Path3DGizmo::Path3DGizmo(Path3D *p_path, float p_disk_size) {
 	Path3DEditorPlugin::singleton->curve_edit_curve->connect(SceneStringName(pressed), callable_mp(this, &Path3DGizmo::redraw));
 	Path3DEditorPlugin::singleton->curve_create->connect(SceneStringName(pressed), callable_mp(this, &Path3DGizmo::redraw));
 	Path3DEditorPlugin::singleton->curve_del->connect(SceneStringName(pressed), callable_mp(this, &Path3DGizmo::redraw));
-	Path3DEditorPlugin::singleton->curve_close->connect(SceneStringName(pressed), callable_mp(this, &Path3DGizmo::redraw));
+	Path3DEditorPlugin::singleton->curve_closed->connect(SceneStringName(pressed), callable_mp(this, &Path3DGizmo::redraw));
 }
 
 EditorPlugin::AfterGUIInput Path3DEditorPlugin::forward_3d_gui_input(Camera3D *p_camera, const Ref<InputEvent> &p_event) {
@@ -696,7 +738,7 @@ void Path3DEditorPlugin::_mode_changed(int p_mode) {
 	Node3DEditor::get_singleton()->clear_subgizmo_selection();
 }
 
-void Path3DEditorPlugin::_close_curve() {
+void Path3DEditorPlugin::_toggle_closed_curve() {
 	Ref<Curve3D> c = path->get_curve();
 	if (c.is_null()) {
 		return;
@@ -704,13 +746,10 @@ void Path3DEditorPlugin::_close_curve() {
 	if (c->get_point_count() < 2) {
 		return;
 	}
-	if (c->get_point_position(0) == c->get_point_position(c->get_point_count() - 1)) {
-		return;
-	}
 	EditorUndoRedoManager *ur = EditorUndoRedoManager::get_singleton();
-	ur->create_action(TTR("Close Curve"));
-	ur->add_do_method(c.ptr(), "add_point", c->get_point_position(0), c->get_point_in(0), c->get_point_out(0), -1);
-	ur->add_undo_method(c.ptr(), "remove_point", c->get_point_count());
+	ur->create_action(TTR("Toggle Open/Closed Curve"));
+	ur->add_do_method(c.ptr(), "set_closed", !c.ptr()->is_closed());
+	ur->add_undo_method(c.ptr(), "set_closed", c.ptr()->is_closed());
 	ur->commit_action();
 }
 
@@ -771,6 +810,7 @@ void Path3DEditorPlugin::_clear_curve_points() {
 		return;
 	}
 	Ref<Curve3D> curve = path->get_curve();
+	curve->set_closed(false);
 	curve->clear_points();
 }
 
@@ -795,7 +835,7 @@ void Path3DEditorPlugin::_update_theme() {
 	curve_edit_tilt->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("CurveTilt")));
 	curve_create->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("CurveCreate")));
 	curve_del->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("CurveDelete")));
-	curve_close->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("CurveClose")));
+	curve_closed->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("CurveClose")));
 	curve_clear_points->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("Clear")));
 	create_curve_button->set_button_icon(topmenu_bar->get_editor_theme_icon(SNAME("Curve3D")));
 }
@@ -872,12 +912,12 @@ Path3DEditorPlugin::Path3DEditorPlugin() {
 	toolbar->add_child(curve_del);
 	curve_del->connect(SceneStringName(pressed), callable_mp(this, &Path3DEditorPlugin::_mode_changed).bind(MODE_DELETE));
 
-	curve_close = memnew(Button);
-	curve_close->set_theme_type_variation("FlatButton");
-	curve_close->set_focus_mode(Control::FOCUS_NONE);
-	curve_close->set_tooltip_text(TTR("Close Curve"));
-	toolbar->add_child(curve_close);
-	curve_close->connect(SceneStringName(pressed), callable_mp(this, &Path3DEditorPlugin::_close_curve));
+	curve_closed = memnew(Button);
+	curve_closed->set_theme_type_variation("FlatButton");
+	curve_closed->set_focus_mode(Control::FOCUS_NONE);
+	curve_closed->set_tooltip_text(TTR("Close Curve"));
+	toolbar->add_child(curve_closed);
+	curve_closed->connect(SceneStringName(pressed), callable_mp(this, &Path3DEditorPlugin::_toggle_closed_curve));
 
 	curve_clear_points = memnew(Button);
 	curve_clear_points->set_theme_type_variation("FlatButton");
@@ -943,6 +983,14 @@ void Path3DGizmoPlugin::redraw(EditorNode3DGizmo *p_gizmo) {
 	Ref<Curve3D> curve = path->get_curve();
 
 	Ref<StandardMaterial3D> handle_material = get_material("handles", p_gizmo);
+	Ref<StandardMaterial3D> first_pt_handle_material = get_material("first_pt_handle", p_gizmo);
+	Ref<StandardMaterial3D> last_pt_handle_material = get_material("last_pt_handle", p_gizmo);
+	Ref<StandardMaterial3D> closed_pt_handle_material = get_material("closed_pt_handle", p_gizmo);
+
+	first_pt_handle_material->set_albedo(Color(0.2, 1.0, 0.0));
+	last_pt_handle_material->set_albedo(Color(1.0, 0.2, 0.0));
+	closed_pt_handle_material->set_albedo(Color(1.0, 0.8, 0.0));
+
 	PackedVector3Array handles;
 
 	if (Path3DEditorPlugin::singleton->curve_edit->is_pressed()) {
@@ -955,7 +1003,37 @@ void Path3DGizmoPlugin::redraw(EditorNode3DGizmo *p_gizmo) {
 	}
 
 	if (handles.size()) {
-		p_gizmo->add_vertices(handles, handle_material, Mesh::PRIMITIVE_POINTS);
+		// Point count.
+		const int pc = handles.size();
+
+		// Initialize arrays for first point.
+		PackedVector3Array first_pt;
+		first_pt.append(handles[0]);
+
+		// Initialize arrays and add handle for last point if needed.
+		if (pc > 1) {
+			PackedVector3Array last_pt;
+			last_pt.append(handles[handles.size() - 1]);
+			handles.remove_at(handles.size() - 1);
+			if (curve->is_closed()) {
+				p_gizmo->add_vertices(last_pt, handle_material, Mesh::PRIMITIVE_POINTS);
+			} else {
+				p_gizmo->add_vertices(last_pt, last_pt_handle_material, Mesh::PRIMITIVE_POINTS);
+			}
+		}
+
+		// Add handle for first point.
+		handles.remove_at(0);
+		if (curve->is_closed()) {
+			p_gizmo->add_vertices(first_pt, closed_pt_handle_material, Mesh::PRIMITIVE_POINTS);
+		} else {
+			p_gizmo->add_vertices(first_pt, first_pt_handle_material, Mesh::PRIMITIVE_POINTS);
+		}
+
+		// Add handles for remaining intermediate points.
+		if (!handles.is_empty()) {
+			p_gizmo->add_vertices(handles, handle_material, Mesh::PRIMITIVE_POINTS);
+		}
 	}
 }
 
@@ -1072,5 +1150,8 @@ Path3DGizmoPlugin::Path3DGizmoPlugin(float p_disk_size) {
 	create_material("path_tilt_material", path_tilt_color);
 	create_material("path_tilt_muted_material", path_tilt_color * 0.7);
 	create_handle_material("handles", false, EditorNode::get_singleton()->get_editor_theme()->get_icon(SNAME("EditorPathSmoothHandle"), EditorStringName(EditorIcons)));
+	create_handle_material("first_pt_handle", false, EditorNode::get_singleton()->get_editor_theme()->get_icon(SNAME("EditorPathSmoothHandle"), EditorStringName(EditorIcons)));
+	create_handle_material("last_pt_handle", false, EditorNode::get_singleton()->get_editor_theme()->get_icon(SNAME("EditorPathSmoothHandle"), EditorStringName(EditorIcons)));
+	create_handle_material("closed_pt_handle", false, EditorNode::get_singleton()->get_editor_theme()->get_icon(SNAME("EditorPathSmoothHandle"), EditorStringName(EditorIcons)));
 	create_handle_material("sec_handles", false, EditorNode::get_singleton()->get_editor_theme()->get_icon(SNAME("EditorCurveHandle"), EditorStringName(EditorIcons)));
 }

editor/plugins/path_3d_editor_plugin.h

@@ -120,7 +120,7 @@ class Path3DEditorPlugin : public EditorPlugin {
 	Button *curve_edit_curve = nullptr;
 	Button *curve_edit_tilt = nullptr;
 	Button *curve_del = nullptr;
-	Button *curve_close = nullptr;
+	Button *curve_closed = nullptr;
 	Button *curve_clear_points = nullptr;
 	MenuButton *handle_menu = nullptr;
 
@@ -144,7 +144,7 @@ class Path3DEditorPlugin : public EditorPlugin {
 	void _update_toolbar();
 
 	void _mode_changed(int p_mode);
-	void _close_curve();
+	void _toggle_closed_curve();
 	void _handle_option_pressed(int p_option);
 	bool handle_clicked = false;
 	bool mirror_handle_angle = true;

scene/resources/curve.cpp

@@ -1454,6 +1454,9 @@ void Curve3D::_remove_point(int p_index) {
 
 void Curve3D::remove_point(int p_index) {
 	_remove_point(p_index);
+	if (closed && points.size() < 2) {
+		set_closed(false);
+	}
 	notify_property_list_changed();
 }
 
@@ -1470,15 +1473,25 @@ Vector3 Curve3D::sample(int p_index, real_t p_offset) const {
 	ERR_FAIL_COND_V(pc == 0, Vector3());
 
 	if (p_index >= pc - 1) {
-		return points[pc - 1].position;
+		if (!closed) {
+			return points[pc - 1].position;
+		} else {
+			p_index = pc - 1;
+		}
 	} else if (p_index < 0) {
 		return points[0].position;
 	}
 
 	Vector3 p0 = points[p_index].position;
 	Vector3 p1 = p0 + points[p_index].out;
-	Vector3 p3 = points[p_index + 1].position;
-	Vector3 p2 = p3 + points[p_index + 1].in;
+	Vector3 p3, p2;
+	if (!closed || p_index < pc - 1) {
+		p3 = points[p_index + 1].position;
+		p2 = p3 + points[p_index + 1].in;
+	} else {
+		p3 = points[0].position;
+		p2 = p3 + points[0].in;
+	}
 
 	return p0.bezier_interpolate(p1, p2, p3, p_offset);
 }
@@ -1596,13 +1609,16 @@ void Curve3D::_bake() const {
 	{
 		Vector<RBMap<real_t, Vector3>> midpoints = _tessellate_even_length(10, bake_interval);
 
+		const int num_intervals = closed ? points.size() : points.size() - 1;
+
 #ifdef TOOLS_ENABLED
-		points_in_cache.resize(points.size());
+		points_in_cache.resize(closed ? (points.size() + 1) : points.size());
 		points_in_cache.set(0, 0);
 #endif
 
+		// Point Count: Begins at 1 to account for the last point.
 		int pc = 1;
-		for (int i = 0; i < points.size() - 1; i++) {
+		for (int i = 0; i < num_intervals; i++) {
 			pc++;
 			pc += midpoints[i].size();
 #ifdef TOOLS_ENABLED
@@ -1625,18 +1641,29 @@ void Curve3D::_bake() const {
 		btw[0] = points[0].tilt;
 		int pidx = 0;
 
-		for (int i = 0; i < points.size() - 1; i++) {
+		for (int i = 0; i < num_intervals; i++) {
 			for (const KeyValue<real_t, Vector3> &E : midpoints[i]) {
 				pidx++;
 				bpw[pidx] = E.value;
-				bfw[pidx] = _calculate_tangent(points[i].position, points[i].position + points[i].out, points[i + 1].position + points[i + 1].in, points[i + 1].position, E.key);
-				btw[pidx] = Math::lerp(points[i].tilt, points[i + 1].tilt, E.key);
+				if (!closed || i < num_intervals - 1) {
+					bfw[pidx] = _calculate_tangent(points[i].position, points[i].position + points[i].out, points[i + 1].position + points[i + 1].in, points[i + 1].position, E.key);
+					btw[pidx] = Math::lerp(points[i].tilt, points[i + 1].tilt, E.key);
+				} else {
+					bfw[pidx] = _calculate_tangent(points[i].position, points[i].position + points[i].out, points[0].position + points[0].in, points[0].position, E.key);
+					btw[pidx] = Math::lerp(points[i].tilt, points[0].tilt, E.key);
+				}
 			}
 
 			pidx++;
-			bpw[pidx] = points[i + 1].position;
-			bfw[pidx] = _calculate_tangent(points[i].position, points[i].position + points[i].out, points[i + 1].position + points[i + 1].in, points[i + 1].position, 1.0);
-			btw[pidx] = points[i + 1].tilt;
+			if (!closed || i < num_intervals - 1) {
+				bpw[pidx] = points[i + 1].position;
+				bfw[pidx] = _calculate_tangent(points[i].position, points[i].position + points[i].out, points[i + 1].position + points[i + 1].in, points[i + 1].position, 1.0);
+				btw[pidx] = points[i + 1].tilt;
+			} else {
+				bpw[pidx] = points[0].position;
+				bfw[pidx] = _calculate_tangent(points[i].position, points[i].position + points[i].out, points[0].position + points[0].in, points[0].position, 1.0);
+				btw[pidx] = points[0].tilt;
+			}
 		}
 
 		// Recalculate the baked distances.
@@ -2075,6 +2102,20 @@ real_t Curve3D::get_closest_offset(const Vector3 &p_to_point) const {
 	return nearest;
 }
 
+void Curve3D::set_closed(bool p_closed) {
+	if (closed == p_closed) {
+		return;
+	}
+
+	closed = p_closed;
+	mark_dirty();
+	notify_property_list_changed();
+}
+
+bool Curve3D::is_closed() const {
+	return closed;
+}
+
 void Curve3D::set_bake_interval(real_t p_tolerance) {
 	bake_interval = p_tolerance;
 	mark_dirty();
@@ -2153,11 +2194,17 @@ PackedVector3Array Curve3D::tessellate(int p_max_stages, real_t p_tolerance) con
 	}
 	Vector<RBMap<real_t, Vector3>> midpoints;
 
-	midpoints.resize(points.size() - 1);
+	const int num_intervals = closed ? points.size() : points.size() - 1;
+	midpoints.resize(num_intervals);
 
+	// Point Count: Begins at 1 to account for the last point.
 	int pc = 1;
-	for (int i = 0; i < points.size() - 1; i++) {
-		_bake_segment3d(midpoints.write[i], 0, 1, points[i].position, points[i].out, points[i + 1].position, points[i + 1].in, 0, p_max_stages, p_tolerance);
+	for (int i = 0; i < num_intervals; i++) {
+		if (!closed || i < num_intervals - 1) {
+			_bake_segment3d(midpoints.write[i], 0, 1, points[i].position, points[i].out, points[i + 1].position, points[i + 1].in, 0, p_max_stages, p_tolerance);
+		} else {
+			_bake_segment3d(midpoints.write[i], 0, 1, points[i].position, points[i].out, points[0].position, points[0].in, 0, p_max_stages, p_tolerance);
+		}
 		pc++;
 		pc += midpoints[i].size();
 	}
@@ -2167,14 +2214,18 @@ PackedVector3Array Curve3D::tessellate(int p_max_stages, real_t p_tolerance) con
 	bpw[0] = points[0].position;
 	int pidx = 0;
 
-	for (int i = 0; i < points.size() - 1; i++) {
+	for (int i = 0; i < num_intervals; i++) {
 		for (const KeyValue<real_t, Vector3> &E : midpoints[i]) {
 			pidx++;
 			bpw[pidx] = E.value;
 		}
 
 		pidx++;
-		bpw[pidx] = points[i + 1].position;
+		if (!closed || i < num_intervals - 1) {
+			bpw[pidx] = points[i + 1].position;
+		} else {
+			bpw[pidx] = points[0].position;
+		}
 	}
 
 	return tess;
@@ -2184,10 +2235,15 @@ Vector<RBMap<real_t, Vector3>> Curve3D::_tessellate_even_length(int p_max_stages
 	Vector<RBMap<real_t, Vector3>> midpoints;
 	ERR_FAIL_COND_V_MSG(points.size() < 2, midpoints, "Curve must have at least 2 control point");
 
-	midpoints.resize(points.size() - 1);
+	const int num_intervals = closed ? points.size() : points.size() - 1;
+	midpoints.resize(num_intervals);
 
-	for (int i = 0; i < points.size() - 1; i++) {
-		_bake_segment3d_even_length(midpoints.write[i], 0, 1, points[i].position, points[i].out, points[i + 1].position, points[i + 1].in, 0, p_max_stages, p_length);
+	for (int i = 0; i < num_intervals; i++) {
+		if (!closed || i < num_intervals - 1) {
+			_bake_segment3d_even_length(midpoints.write[i], 0, 1, points[i].position, points[i].out, points[i + 1].position, points[i + 1].in, 0, p_max_stages, p_length);
+		} else {
+			_bake_segment3d_even_length(midpoints.write[i], 0, 1, points[i].position, points[i].out, points[0].position, points[0].in, 0, p_max_stages, p_length);
+		}
 	}
 	return midpoints;
 }
@@ -2200,8 +2256,10 @@ PackedVector3Array Curve3D::tessellate_even_length(int p_max_stages, real_t p_le
 		return tess;
 	}
 
+	const int num_intervals = closed ? points.size() : points.size() - 1;
+	// Point Count: Begins at 1 to account for the last point.
 	int pc = 1;
-	for (int i = 0; i < points.size() - 1; i++) {
+	for (int i = 0; i < num_intervals; i++) {
 		pc++;
 		pc += midpoints[i].size();
 	}
@@ -2211,14 +2269,18 @@ PackedVector3Array Curve3D::tessellate_even_length(int p_max_stages, real_t p_le
 	bpw[0] = points[0].position;
 	int pidx = 0;
 
-	for (int i = 0; i < points.size() - 1; i++) {
+	for (int i = 0; i < num_intervals; i++) {
 		for (const KeyValue<real_t, Vector3> &E : midpoints[i]) {
 			pidx++;
 			bpw[pidx] = E.value;
 		}
 
 		pidx++;
-		bpw[pidx] = points[i + 1].position;
+		if (!closed || i < num_intervals - 1) {
+			bpw[pidx] = points[i + 1].position;
+		} else {
+			bpw[pidx] = points[0].position;
+		}
 	}
 
 	return tess;
@@ -2274,13 +2336,13 @@ void Curve3D::_get_property_list(List<PropertyInfo> *p_list) const {
 		pi.usage &= ~PROPERTY_USAGE_STORAGE;
 		p_list->push_back(pi);
 
-		if (i != 0) {
+		if (closed || i != 0) {
 			pi = PropertyInfo(Variant::VECTOR3, vformat("point_%d/in", i));
 			pi.usage &= ~PROPERTY_USAGE_STORAGE;
 			p_list->push_back(pi);
 		}
 
-		if (i != points.size() - 1) {
+		if (closed || i != points.size() - 1) {
 			pi = PropertyInfo(Variant::VECTOR3, vformat("point_%d/out", i));
 			pi.usage &= ~PROPERTY_USAGE_STORAGE;
 			p_list->push_back(pi);
@@ -2308,6 +2370,8 @@ void Curve3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("clear_points"), &Curve3D::clear_points);
 	ClassDB::bind_method(D_METHOD("sample", "idx", "t"), &Curve3D::sample);
 	ClassDB::bind_method(D_METHOD("samplef", "fofs"), &Curve3D::samplef);
+	ClassDB::bind_method(D_METHOD("set_closed", "closed"), &Curve3D::set_closed);
+	ClassDB::bind_method(D_METHOD("is_closed"), &Curve3D::is_closed);
 	//ClassDB::bind_method(D_METHOD("bake","subdivs"),&Curve3D::bake,DEFVAL(10));
 	ClassDB::bind_method(D_METHOD("set_bake_interval", "distance"), &Curve3D::set_bake_interval);
 	ClassDB::bind_method(D_METHOD("get_bake_interval"), &Curve3D::get_bake_interval);
@@ -2329,6 +2393,8 @@ void Curve3D::_bind_methods() {
 	ClassDB::bind_method(D_METHOD("_get_data"), &Curve3D::_get_data);
 	ClassDB::bind_method(D_METHOD("_set_data", "data"), &Curve3D::_set_data);
 
+	ADD_PROPERTY(PropertyInfo(Variant::BOOL, "closed"), "set_closed", "is_closed");
+
 	ADD_PROPERTY(PropertyInfo(Variant::FLOAT, "bake_interval", PROPERTY_HINT_RANGE, "0.01,512,0.01"), "set_bake_interval", "get_bake_interval");
 	ADD_PROPERTY(PropertyInfo(Variant::INT, "_data", PROPERTY_HINT_NONE, "", PROPERTY_USAGE_NO_EDITOR | PROPERTY_USAGE_INTERNAL), "_set_data", "_get_data");
 	ADD_ARRAY_COUNT("Points", "point_count", "set_point_count", "get_point_count", "point_");

scene/resources/curve.h

@@ -264,6 +264,8 @@ class Curve3D : public Resource {
 	mutable Vector<size_t> points_in_cache;
 #endif
 
+	bool closed = false;
+
 	mutable bool baked_cache_dirty = false;
 	mutable PackedVector3Array baked_point_cache;
 	mutable Vector<real_t> baked_tilt_cache;
@@ -330,6 +332,8 @@ public:
 	Vector3 sample(int p_index, real_t p_offset) const;
 	Vector3 samplef(real_t p_findex) const;
 
+	void set_closed(bool p_closed);
+	bool is_closed() const;
 	void set_bake_interval(real_t p_tolerance);
 	real_t get_bake_interval() const;
 	void set_up_vector_enabled(bool p_enable);