diff -r 94c92c923713 -r 40a1cf2f38f5 src/tools/drawtool.cpp
--- a/src/tools/drawtool.cpp	Sun Jul 25 13:49:37 2021 +0300
+++ b/src/tools/drawtool.cpp	Sun Jul 25 16:26:38 2021 +0300
@@ -1,9 +1,10 @@
 #include <QMessageBox>
 #include "drawtool.h"
 
-static const QBrush brush = {Qt::white};
-static const QPen pen = {Qt::black};
-static const QBrush polygonBrush = {QColor{64, 255, 128}};
+static const QBrush pointBrush = {Qt::white};
+static const QPen polygonPen = {QBrush{Qt::black}, 2.0, Qt::DashLine};
+static const QPen pointPen = {QBrush{Qt::black}, 2.0};
+static const QBrush polygonBrush = {QColor{64, 255, 128, 192}};
 
 DrawTool::DrawTool(QObject* parent) :
 	BaseTool{parent} {}
@@ -28,47 +29,58 @@
 		const auto isCloseToPos = [&](const glm::vec3& x){return geom::isclose(x, pos);};
 		if (any(this->polygon, isCloseToPos))
 		{
-			QMessageBox::information(nullptr, "test", "close the polygon");
+			this->closeShape();
 		}
 		else
 		{
 			this->polygon.push_back(pos);
-			auto& previewLayer = info.invoker->modifyPreviewLayer(Canvas::DrawToolPreview);
-			previewLayer.points.resize(this->polygon.size());
-			previewLayer.points.back() = {pos, brush, pen};
-			previewLayer.polygons.clear();
-			previewLayer.polygons.push_back({geom::NPolygon{this->polygon}, polygonBrush, pen});
 			if (this->polygon.size() == 4)
 			{
-				QMessageBox::information(nullptr, "test", "close the polygon");
+				this->closeShape();
 			}
 		}
 	}
+	this->previewPolygon = this->polygon;
 	return true;
 }
 
 bool DrawTool::mouseMove(const Canvas::MouseMoveInfo& info)
 {
-	if (this->polygon.size() < 4 and info.worldPosition.has_value())
+	if (info.worldPosition.has_value())
 	{
-		auto& previewLayer = info.invoker->modifyPreviewLayer(Canvas::DrawToolPreview);
-		previewLayer.points.resize(this->polygon.size() + 1);
-		previewLayer.points.back() = {info.worldPosition.value(), brush, pen};
-		if (previewLayer.polygons.size() > 0)
+		this->previewPoint = info.worldPosition.value();
+		if (this->polygon.size() < 4)
 		{
-			auto& polygon = previewLayer.polygons.back();
-			polygon.geometry.points.resize(this->polygon.size() + 1);
-			polygon.geometry.points.back() = info.worldPosition.value();
+			this->previewPolygon.resize(this->polygon.size() + 1);
+			this->previewPolygon.back() = this->previewPoint;
 		}
-		return true;
 	}
-	else
-	{
-		return false;
-	}
+	return false;
 }
 
 void DrawTool::reset()
 {
 	this->polygon.clear();
 }
+
+void DrawTool::overpaint(Canvas* canvas, QPainter* painter) const
+{
+	painter->setBrush(::polygonBrush);
+	painter->setPen(::polygonPen);
+	canvas->drawWorldPolygon(painter, this->previewPolygon);
+	painter->setBrush(::pointBrush);
+	painter->setPen(::pointPen);
+	for (const glm::vec3& point : this->polygon)
+	{
+		canvas->drawWorldPoint(painter, point);
+	}
+	if (this->polygon.size() < 4)
+	{
+		canvas->drawWorldPoint(painter, this->previewPoint);
+	}
+}
+
+void DrawTool::closeShape()
+{
+	QMessageBox::information(nullptr, "test", "close the polygon");
+}