Stores general information about mouse events.
The mouse button mask identifier, one of or a bitwise combination of the MouseButton button masks.
When received in Node._input() or Node._unhandled_input(), returns the mouse's position in the root Viewport using the coordinate system of the root Viewport.
When received in Control._gui_input(), returns the mouse's position in the CanvasLayer that the Control is in using the coordinate system of the CanvasLayer.
When received in Node._input() or Node._unhandled_input(), returns the mouse's position in the Viewport this Node is in using the coordinate system of this Viewport.
When received in Control._gui_input(), returns the mouse's position in the Control using the local coordinate system of the Control.