ZDoom

Thanks for the feedback. Moving to "General" now.

Adding orthogonal camera is mostly just a matter of changing the projection matrix, but I'm a bit with Graf on this one in the sense that I don't want to spend the time dealing with the places in the code where the projection does matter: BSP clipper, SSAO depth buffer lookup, the VR eye buffer setup code. I also wouldn't be surprised if there could be a problem with how portals are marked in the stencil buffer.

TL;DR: this will make it harder to maintain the renderer, requires actual work, and the only use case I can think of is people that's trying to convert Doom into a 2D game engine.

[quote="Major Cooke"]Rachael and quite a few others have said this is actually doable. There is some experimentation on the side ongoing currently, so I'd kindly like to ask if this can remain open until the theories have been denied at the very least.[/quote]


I think it can remain open, but considering that it has no business in the "Feature Suggestions" part of the forum, I think it should be moved to "General".
For me this is just more extraneous stuff that bears no relation to Doom so it may be better suited for an engine fork.

One idea for implementing this might be a vertex shader which, based on camera depth, will multiply a vertex's post-translated X/Y to always be at an angle from the camera's view rather than at its true location, which would give the illusion of a flat projection. This method would mitigate the problems with Z-fighting.

Rachael and quite a few others have said this is actually doable. There is some experimentation on the side ongoing currently, so I'd kindly like to ask if this can remain open until the theories have been denied at the very least.

Now for some use cases...
2D perspective games coming from the side make gratuitous use of orthogonal perspectives, aka parallel projections.

I'm making a 2D side-scroller game, and the way I'm mitigating as much 'perspective' as possible is by pulling a camera out and sinking in the FOV quite steeply. However, it's still not enough.

[url=https://upload.wikimedia.org/wikipedia/commons/4/47/FEZ_trial_gameplay_HD.webm]Fez is a game that utilizes orthogonal and it's quite impressive.[/url]