OK, I have a follow-up! I have tools that for "mapping" projections onto a virtual background. But now I've complicated my life by warping my background in the z-direction, AND have a desire to "fly around" my fake 3D city. Since my mapping never takes into account z, I can get it to look good from one angle, but not when I start to change the camera angle. I'm probably not making any sense here, but is there a way to add textures to this warped background that are scaled/position to fit in particular background, and maintain their relative position in the background image as the camera angle changes?
I've attached an image to show what I mean wrt adding an additional texture. I just need a nudge in the right direction…or confirmation that I'm in over my head without more gl knowledge.