Are Doom graphics based on Projective geometry?

[doomlayman]

I never learned a lot of math in my youth so please don't make fun of me.

 

If I am not mistaken, Projective geometry is often used to make two dimensional graphics appear somewhat illusionary as three dimensional graphics, then termed as 2.5 dimensional graphics.

 

Given that all or most of the original Doom graphics are termed 2.5 dimensional as they somewhat give an illusion of three dimensional graphics, would it be then correct to say that Doom graphics are based solely or primarily upon Projective geometry?

Edited December 1, 2023 by doomlayman

[Edward850]

This question seems to be based entirely on buzzwords. I don't know about anyone else but from my position I feel as though I don't even understand the question, and I know how the renderer works. I get the impression you are trying to come up with any reason to call Doom flat (which it isn't) and have picked a bunch of fancy words to try and reason that description.

If you want a technical insight as to what's going on, this pretty much covers it: https://fabiensanglard.net/doomIphone/doomClassicRenderer.php

Edited December 1, 2023 by Edward850

[LoatharMDPhD]

What's the phrase? "Carmack's Reverse"?

Edited December 1, 2023 by LoatharMDPhD

[Edward850]

Just now, LoatharMDPhD said:

What's the phrase? "Carmack's Reverse"??

That's from Doom 3, and it's a Depth Fail algorithm used for calculating shadow volumes. https://en.wikipedia.org/wiki/Shadow_volume#Depth_fail
It's called a reverse because it's the reverse of an existing Depth Pass algorithm, which had limitations.

[LoatharMDPhD]

// then for a doom 2 perspective.. i guess its just... trigonometry then... that right ?

[TheMagicMushroomMan]

12 minutes ago, LoatharMDPhD said:

// then for a doom 2 perspective.. i guess its just... trigonometry then... that right ?

I always heard it was algebra.

[LoatharMDPhD]

lets get into a speculative fight over 30 year old maths!!! unleash the beast...

[OniriA]

1 + 1 = 3

Edited December 1, 2023 by OniriA

[Shepardus]

All 3D rendering involves projecting geometry onto a 2D surface (i.e. the screen); that has nothing to do with whether Doom is 3D or 2.5D or one-and-a-half-D or whatever. If you're asking whether studying the specific branch of mathematics branch of mathematics known as "projective geometry" would help you understand the Doom renderer, well, probably not. Better to just read the article that Edward850 linked.

[doomlayman]

46 minutes ago, Shepardus said:

All 3D rendering involves projecting geometry onto a 2D surface (i.e. the screen); that has nothing to do with whether Doom is 3D or 2.5D or one-and-a-half-D or whatever. If you're asking whether studying the specific branch of mathematics branch of mathematics known as "projective geometry" would help you understand the Doom renderer, well, probably not. Better to just read the article that Edward850 linked.

 

Nice explanation, thanks.

[Lucius Wooding]

It's based on rays of light bouncing around inside your eye, triggering your optic nerve.

[LoatharMDPhD]

2 hours ago, OniriA said:

1 + 1 = 3

// Well.. Kind of... yeah

 

 

[LoatharMDPhD]

2 hours ago, doomlayman said:

I never learned a lot of math in my youth so please don't make fun of me.

 

If I am not mistaken, Projective geometry is often used to make two dimensional graphics appear somewhat illusionary as three dimensional graphics, then termed as 2.5 dimensional graphics.

 

Given that all or most of the original Doom graphics are termed 2.5 dimensional as they somewhat give an illusion of three dimensional graphics, would it be then correct to say that Doom graphics are based solely or primarily upon Projective geometry?

 

[Soundblock]

No

[Amaruψ]

Carmack divided by 0 and the output was video games.