How to extract a projected texture?


I’m working on a shot that is a background replacement and set extension.

I’m camera projecting a matte painting onto some geometry, but I’m also wanting to add some additional shading and highlight detail via 3D, to make the projected street have a bit of reflectivity to pic up some glinty highlights from the light.

I would like to use the actual texture that I’m projecting as part of my shader tree (I’m using Redshift) so I can limit what parts are receiving the shading and what parts are not.

How would I go about “extracting” this projected texture for use in my Redshift shader tree on a Plane that is using a different UV space (Not projected UVs).

Does that make sense?