Returns the current resolution the canvas is rendering at. The resolution is dependent on the render mode the canvas was configured with.

For <node3d:canvas>.setRenderWorld and <node3d:canvas>.setRenderWorldOverlay, the resolution will be the values specified in those commands.

For <node3d:canvas>.setRenderScreenOrtho and <node3d:canvas>.setRenderScreenPerspective, the resolution will be the current size of the window the canvas is parented to.