I have 2D sidescroller where the background (Behind everything) needs to be rendered orthographically. The rest of the scene is rendered with a perspective camera that has an overlay of another perspective camera. The issue is, there is custom fog in the scene that needs the same background that the orthographic camera is rendering to render correctly but the fog itself cannot be rendered orthographically. So no matter how many cameras or overlay cameras I use, the fog will always be rendered incorrectly as the background must be rendered orthographically but the fog relies on this background and needs it rendered prospectively. The perspective cameras have a literal void behind them without the orthographic cameras background, so the perspective camera and more importantly the fog itself sees nothing behind it which causes it to render incorrectly, I need to make the fog think there is something there even though the perspective camera which renders the fog has masks which make it so there is just a void behind.
What I am trying to figure out is if there is a way to render a background prospectively that then is overwritten by the orthographic camera even though the orthographic camera sees the lowest priority in rendering. So, even though that perspective camera would have a higher priority, keep the background as a lower priority in rendering, that way, the fog can be rendered as if the background is indeed there prospectively and then the orthographic camera can render the background orthographically just right in front of the perspective background.
So somehow → render background prospectively for the first time, → render orthographically the same background which overlaps it completely, → render my perspective camera and its overlay which will render over that background with whatever objects are in scene, fog is then rendered but instead of seeing void since that is what has been written, it sees a perspective background.
The main issue is there is no way for me to do this without putting the background on the perspective cameras which will just overwrite the orthographic cameras background anyway. I was trying to use RenderObjects to accomplish this.