I'm looking for a way to create a dynamic soft see-through hole effect for room walls. I know a few ways how to do it (for example multitexturing with second layer being the hole mask in screenspace), but all involve rendering walls with blending on which is too expensive for the mobile project I'm working on. Is there any way to do this without using blending on the whole geometry (the hole can appear in any place on any wall). Please see the attached image for a better illustration of the effect:
Also, I'm very open to any links to papers/tutorials that might not be solving the exact problem but doing something close that might get me on the right tracks. Thank you!