diff -r a4055f67b9c7 -r cb81ecb5fb23 src/gl/partrenderer.h
--- a/src/gl/partrenderer.h	Thu Feb 13 15:25:01 2020 +0200
+++ b/src/gl/partrenderer.h	Wed Feb 26 02:21:07 2020 +0200
@@ -35,15 +35,20 @@
 	const ldraw::ColorTable& colorTable;
 	gl::Compiler* const compiler;
 	ldraw::Id highlighted = ldraw::NULL_ID;
+	std::optional<glm::vec3> cameraToGrid(const QPoint& point);
+	QPointF worldToCamera(const glm::vec3& point);
 private:
 	void setFragmentStyle(gl::FragmentStyle fragStyle);
 	void renderAllArrays();
 	void renderScene();
 	void updateViewMatrix();
+	void updateModelMatrix();
+	void setupBackgroundColor();
 	QPointF lastMousePosition;
 	gl::RenderPreferences renderPreferences;
 	glm::mat4 projectionMatrix;
 	glm::mat4 viewMatrix;
+	glm::mat3 viewportMatrix;
 	glm::quat modelQuaternion;
 	std::optional<GridProgram> gridProgram;
 	static constexpr double MIN_ZOOM = 0.0;