[Brahma Engine] Perspective Correction (see description)

The author's explanation/demo: • Frame postprocessing i...
Testing Brahma Engine's perspective correction.
I downloaded Brahma Engine public demo from here: www.indiedb.co...
My stuff:
Main channel: / mrraveyard
Discord: / discord

[@MadsterV]

Very cool, would like to benchmark on old computers

[@Mankepanke]

It looks a bit cursed to me to see proper vertical look in these games, but at the same time it looks really really good!
I'm impressed!

[@retneychozken]

Now imagine it in reverse
What about... Quake without perspective correction?

[@Mankepanke]

@@retneychozken yeah, that's even more cursed!

[@usuarioextra9324]

@@retneychozken The engine's author is thinking about importing BSP files into Brahma, which means you'll be able to turn off perspective correction on them. If successful, I think it'll be very cool to see Quake maps inside a sector based engine. XD

[@retneychozken]

@@usuarioextra9324 Unreal

[@jaythecoderx4623]

that's very cool

[@jpc-273]

Is this just another source port or a modification of the Build Engine?

[@usuarioextra9324]

According to its author is a game engine inspired by Build but written from scratch in C++.

[@rol1939]

How do you fill the pixels that will be skipped over when drawing angled lines?

[@americanhuman1848]

probably just draws outside the screen bounds

[@punpcklbw]

There's a video on my channel that explains this type of projection in details (search for "frame postprocessing in Brahma Engine").

[@kerkieisreal]

what map is that at the end ?

[@punpcklbw]

Planisphere 2 by Perro Seco

[@doltBmB]

there's something messed up with the top of the skybox

[@cartoonhead9222]

The sky CYLINDER

[@usuarioextra9324]

The readme file says skyboxes are unfinished right now. The engine is buggy but looks promising.

[@Skyrilla]

That skybox tho.

[@spell105]

wow discovering projection matrices in 2024 that's sick

[@HyperMario64]

From reading the dev's notes, it doesn't seem to work that way at all. It's a custom software renderer, not triangle based. I mean, I'm not going to sit here and tell you that perspective division doesn't happen here: it has to somehow. But this thing doesn't seem to have any similarity with previous GPU-based or software renderers from the 90s. I'm kinda curious as to how it actually works.

[@spell105]

@@HyperMario64 It is definitely curious, but the math would work out the same way either way. Perspective geometry is simply what it is, no matter how you render it.
The rendering technique here is no doubt very interesting, I will grant it that.

[@adog3129]

nobody made you watch it. coding any rendering stuff is impressive even if it's not new

[@raveyardsextras4281]

The renderer is a column based renderer (walls/floors are strictly drawn in vertical rows of pixels). The only way to look up and down in this kind of system is to do Y shearing: zdoom.org/wiki/Y-shearing which is what you see in the beginning of the video
Afaik the perspective correction is a reprojection (done on CPU) sewn together from couple of renders with different Y shearing and FOV (to avoid wasteful rendering offscreen).

[@joeroeinski1107]

​@@raveyardsextras4281 So is it scaling the scanlines horizontally to achieve perspective? I notice on the sides that there is some artifacting on the side.