What maps have been designed with vanilla limitations/bugs in mind?

[unerxai]

I'm talking about stuff like infinitely tall actors, wallruning, etc. Are there any wads that have been designed with these in mind from a gameplay perspective? I'd like to know.

[The Nate]

Too many to count on both hands. An example would be one WAD exploiting the Lost Soul limit by having a couple Elementals in front of you, unable to attack you because there are already 21 Lost Souls present in the map. Then the Lost Souls are crushed and you're pretty much fucked from there.

[Dark Pulse]

Anything that exploits the ghost monsters bug counts for sure. There's quite a few of those as well.

[Capellan]

Literally thousands of WADs were designed with vanilla limitations "in mind" to the extent that the maps are designed to function while subject to those limits (most obviously, anything from before the advent of advanced ports).  A much smaller but still significant number actively make use of those limits in some specific manner.

 

Kamasutra comes to mind as something that deliberately used infinitely tall things (barrels, specifically) to make certain lines temporarily impassable.

 

Many older WADs used the "raise by shortest texture" bug without even knowing it.

 

STRAIN map07 that deliberately causes a spechits overflow to cause the level to end.  Why?  Only Adelusion knows.

 

Edited April 3, 2019 by Capellan

[Chainie]

The Sky May Be uses vanilla crashes for design purposes

[ZeMystic]

I believe Alien Vendetta uses the glitchy texture fill thing for missing wall textures to make it look like an acid pool that you can swim in on MAP01. With opengl it just looks like a missing texture.

[Maximum Matt]

On ‎4‎/‎3‎/‎2019 at 2:35 PM, Dark Pulse said:

Anything that exploits the ghost monsters bug counts for sure. There's quite a few of those as well.

Oh HELL no

[dugan]

Every level with an invisible bridge, including Plutonia map02.

[kb1]

One thing to understand is that map authors test and re-test their WADs, over and over, and tweak them until the gameplay is perfect. Every engine limitation takes part in presenting the map a certain way, and that presentation is what is tested against. That particular presentation is what influences the mapper to modify structure, add a monster here and there, add a power-up over there, etc.

 

So, technically, any WAD built where the tester used DOOM.EXE or DOOM2.EXE to test was built with that engine's quirks in mind. This is why, in my opinion, retaining or emulating those quirks is very important. Otherwise, it's kinda like a joke without a punch line. It's like a movie that's been cut to be played on network television, in a way that makes the plot not make sense. They sometimes cut scenes that are important to understanding the plot, drastically altering the meaning of the movie.

 

But, I think what you're looking for are WADs that are specifically built to directly take advantage of one or more of those quirks. It's kind hard to tell, as many of those quirks were not very well understood, before the source was released.

 

I am also interested to see a list of these WADs...if nothing else, to make sure I am rendering the maps as the author intended.

[Kira]

On 5/4/2019 at 7:44 AM, ZeMystic said:

I believe Alien Vendetta uses the glitchy texture fill thing for missing wall textures to make it look like an acid pool that you can swim in on MAP01. With opengl it just looks like a missing texture.

I used to annoy sourceport devs so much over this haha.

 

I'd say most pre-2000 or high profile wads with complevel 2/3/4 have vanilla bugs in mind. Complevel 9/11 wads tend to have infinitely tall actors in mind too, like a lot of the modern slaughter crop.

[Linguica]

Here is a brand new trick discovered last month that not only is intended as a vanilla trick, but it actually is broken in GZDoom instead 

 

[Spectre01]

Are there any maps specifically designed around getting shot through walls by a Mancubus?

[Kira]

9 hours ago, Spectre01 said:

Are there any maps specifically designed around getting shot through walls by a Mancubus?

Don't give me ideas.

What about a cramped room with a cyber in it. All you have is your pistol, and you have to trick a mancubus into shooting through the room's wall, to distract the cyber while you do your business inside said room.

[Graf Zahl]

On 4/3/2019 at 6:37 AM, Capellan said:

STRAIN map07 that deliberately causes a spechits overflow to cause the level to end.  Why?  Only Adelusion knows. 

 

 

That one's a clear mapping bug, nothing else. There's one line that's accidentally flagged as impassible but thanks to the spechit overflow that flag was rendered ineffective so nobody noticed the bug.

 

9 hours ago, Spectre01 said:

Are there any maps specifically designed around getting shot through walls by a Mancubus?

 

That's very unlikely because the mechanics behind this bug require some mathematic understanding to exploit effectively. There's far easier ways to place a monster so that it can ambush a player without being seen.

 

One thing here should not be forgotten: Exploiting genuine bugs is a very different thing than exploiting a limitation. Infinitely tall actors are an engine limitation with known properties and behavior. So you get some well-defined and usable behavior when depending on it.

 

The Mancubus shooting through walls is a bug, caused by a missing range check in the movement code. So it only gets triggered in certain situations that are not intuitively understandable on a logical level. But in order to exploit it you have to understand it.

Chances are also that most vanilla maps may depend on one or the other limitation but rarely depend on engine bugs, unless those bugs can be triggered 100% reliably, like the AV-ghost bug.

 

Similarly, some of the known render hacks often cause glitchy maps, because the mappers have some knowledge how they need to tweak the visuals, but have no idea how the render hack will affect the gameplay physics. This is especially critical for source ports which never use the nodes that come with the map but always discard them and use their own ones. (No, not GZDoom. It will always preserve the original nodes for gameplay position determination.)

 

[4shockblast]

13 hours ago, Spectre01 said:

Are there any maps specifically designed around getting shot through walls by a Mancubus?

Yeah, I've made a map like that.

[kb1]

19 hours ago, Graf Zahl said:

One thing here should not be forgotten: Exploiting genuine bugs is a very different thing than exploiting a limitation. Infinitely tall actors are an engine limitation with known properties and behavior. So you get some well-defined and usable behavior when depending on it.

 

The Mancubus shooting through walls is a bug, caused by a missing range check in the movement code. So it only gets triggered in certain situations that are not intuitively understandable on a logical level. But in order to exploit it you have to understand it.

Chances are also that most vanilla maps may depend on one or the other limitation but rarely depend on engine bugs, unless those bugs can be triggered 100% reliably, like the AV-ghost bug.

My guess is that mappers stumbled upon some of these bugs honestly. They made a map that just happens to do this interesting thing. From that point, maybe they tried to understand and replicate the "thing".

 

I don't have any examples. But there were a lot of original Doom bugs, and a lot of mappers using barely functional map editors for quite some time. It's reasonable to assume that, every now and then, a map tends to do this weird thing somewhat reliably, and the mapper took advantage of it, without really understanding why.

 

The programmer in me cringes, but the gamer in me appreciates a cool map, regardless of how it got that way.

[Koko Ricky]

The hanging crate in Suspended in Dusk glitches out in GzDoom. I think you can only properly view it in software rendering.

[Graf Zahl]

It doesn't really work that well in software rendering as well,  the illusion already breaks when you can look up and down. That mod contains several non-standard render hacks that cause problems with hardware renderers.

[Mordeth]

17 minutes ago, Graf Zahl said:

(...) the illusion already breaks when you can look up and down.

 

Yes, those maps were designed to look flawless for vanilla which didn't have the ability to look up/down. So, fitting right in this topic.

[Koko Ricky]

How was the crate trick done? I imagine you might have to self reference both sectors and lines, use dummy sectors, something like that?

[Graf Zahl]

It was an elaborate open sector and missing texture setup. The main problem is not that it doesn't work in GL - the renderer can handle the trick if one specific hack feature of the renderer gets disabled - the main problem is that the trick itself isn't fully stable even in the software renderer if you look at it too closely - when you can look down you can get close enough to see it fall apart.  And basically the same happens with the GL renderer but thanks to having full 3D freelook it's a lot easier to see it break down.

 

It only looks like it's working in vanilla because you cannot look up and down, this is somewhat similar to the fake floor in Requiem's MAP31 which also breaks apart in the software renderer if you can look down and get too close.