I don’t know if you’re familiar with MEL or expressions but here’s little sample
how I would do something like this.
Checkout the attached MA - file.
There’s lot of other ways also but I think this is one of the easiest.
Basically I’m using ramp ( I could use any 2D texture, inluding bitmaps ) to control
the visibility ( or any other attribute, for that matter ) of my cubes.
It’s all based on MEL - command colorAtPoint .
Checkout the documentation for more info about that.
To get to the bottom of this, open up Expression Editor and checkout the Expresssion1, I wrote.
Ramp1 is animated so you can see how it works. Change the ramp for U to V to diagonal and you’ll get the ideam I’m sure.
Hope this helps.