:wrench: Update only when visible

godot/slides/203/RenderingEngine.tscn

@@ -24,6 +24,5 @@ texture = SubResource("ViewportTexture_yehud")
 [node name="SubViewport" type="SubViewport" parent="."]
 transparent_bg = true
 size = Vector2i(732, 872)
-render_target_update_mode = 4
 
 [node name="3DRoot" parent="SubViewport" instance=ExtResource("4_yehud")]