@@ 25,13 25,22 @@ public class MinimumTranslationVectorTes
 	private MinimumTranslationVector mtv = new MinimumTranslationVector();
 	private Vector2 centroid = new Vector2();
 
+	public MinimumTranslationVectorTest() {
+		GeometryUtils.polygonCentroid(polygon.getVertices(), 0, polygon.getVertices().length, centroid);
+		polygon.setOrigin(centroid.x, centroid.y);
+	}
+
 	@Override
 	public void show() {
 		Gdx.input.setInputProcessor(new InputAdapter() {
 			@Override
 			public boolean scrolled(int amount) {
-				((OrthographicCamera) viewport.getCamera()).zoom += amount / 25f;
-				viewport.apply();
+				if(UIUtils.ctrl())
+					polygon.setRotation(polygon.getRotation() + amount * 5);
+				else {
+					((OrthographicCamera) viewport.getCamera()).zoom += amount / 25f;
+					viewport.apply();
+				}
 				return true;
 			}
 

          
@@ 43,7 52,7 @@ public class MinimumTranslationVectorTes
 					viewport.apply();
 				} else {
 					viewport.unproject(centroid.set(screenX, screenY));
-					polygon.setPosition(centroid.x, centroid.y);
+					polygon.setPosition(centroid.x - polygon.getOriginX() * polygon.getScaleX(), centroid.y - polygon.getOriginY() * polygon.getScaleY());
 				}
 				return true;
 			}