irei1as I tested this in basic lighting too and it seems to work fine - though as you say BL is pretty redundant these days.
I did notice screen-wrapping as well when adding it to a static object and moving it to the edge of the screen - but only on the "Y axis" (?), so 0 0 0 in worldspace. Horizontal seems okay for some reason ...
Not sure what to do about that though - though thankfully it's not going to affect what I want it for too much as it might help the player see invisible enemies when they approach.
One more thing I'd like to do, is to add a colour shade/tint/darken to it but don't know. I noticed you commented about modifying colour_exit:
//here you can modify colourexit if needed
I tried adding an rgba to colour_exit before the return and got the colouring - but lost all the transparency and wobble
Any hints for how I should be doing this?