Can’t be done, can it?
Yes but not from material settings, you do it in the compositor. Put the Halos on their own render layer then multiply whatever image or texture that you want to use by that render layer’s alpha channel via a Mix node.
But then it will be 2d-ish.
Thanks for answering my question though. At least I know what won’t work.
Well, uv texture it around a cone then use the spot’s alpha to set the cone’s alpha. The results you get from the compositor are directly related to what you do in the 3D window. I’m not exactly sure what it is that you’re expecting but it’s very possible and not difficult at all.
I’ve started setting it up. I’ve discovered a new problem - how do you animate noise in Blender? I don’t see anything like a seed value ( I’m working with clouds).
Figured out how to make the noise move.