Everyone keeps asking for this and I had plans to support it initially. The main concern now will be to add that but not break any backwards compatibility.
If I can find some time here I’ll take a look at what the best options for this are. I was thinking sense it requires fragCoord data the best bet will be to have an RTT that captures once with the normal data then once with the color and transparency data. Then I could just return the two textures which could be bound to material and use all the same lighting processing as a normal BJS element.
Give me a little bit to figure out if it would be better to do it that way, or if it would be better to treat it like a volumetric particle.
Pretty sure I posted a PG not to long ago that shows how to capture the spriteMap as an RTT. If you can find that and anything I said made sense you might be able to come up with a solution before me.