I don't know if this is actually what you'd call 'masking', but what I want to do is have every object on one layer display what's on another.
So, there would be one layer called 'Objects' with various rectangle sprites scattered around it, then another layer called 'Texture' which contains different moving shapes. Not sure how to phrase it, but I want everything on Objects to have the appearance of the Texture layer. The Texture layer is only visible where stuff is present on the Objects layer.
I guess you'd say I want Objects to 'mask' Texture?
What blend mode & other settings should I apply to each layer and what order should they be in?