Creates and returns a Geometry Mask. This mask can be used by any Game Object, including this one.
To create the mask you need to pass in a reference to a Graphics Game Object.
If you do not provide a graphics object, and this Game Object is an instance of a Graphics object, then it will use itself to create the mask.
This means you can call this method to create a Geometry Mask from any Graphics Game Object.
A Graphics Game Object. The geometry within it will be used as the mask.
This Geometry Mask that was created.