Rectangle lights do not use Source Texture for Volumetric Scattering?


What I’m trying to achieve is basically a videoprojector through fog, and I’m struggling with the Volumetric Part - I don’t know if I’m misunderstanding what I thought was the expected behaviour, or just hitting a wall in the current state of things. I need your insights!

I’m using a Rectangle Light with a Source Texture to project the image (that part works perfectly, as the texture is projected to the floor).

Though, when I’m adding fog, the volumetric contribution of the Rectangle Light only seems to use the Light Color (and this does change if I set another color than the default white), rather than the image (as I was hoping).

Am I missing something, or is it meant this way?
Is the only current workaround this trick I saw by creating 3 other rectangle lights with R/G/B light colors, then using light functions + component masks on the original image to filter R/G/B channels and drive each of the three lights properly?
As seen here: TV Glow Effect in Unreal Engine 4.19 - YouTube

(I want to really see detail in volumetric rays, and not just an average flat color for the whole volume).

Thanks for your help!

It’d probably help if you posted a screenshot or two of the current scene area you are describing.