Weird demos

[Veinen]

Thanks, I did not realize that it was checked only after the death animation ends although I should have been able to connect the dots since I knew of the map07 bug. I suppose the abruptness here made it look weirder.

[BiZ]

All Ghosts on Zone400 MAP15 (recorded with dsda-doom v0.19.2)

z415_allghosts.zip

[RjY]

On 8/8/2021 at 4:14 PM, Veinen said:

Thanks, I did not realize that it was checked only after the death animation ends although I should have been able to connect the dots since I knew of the map07 bug. I suppose the abruptness here made it look weirder.

 

FWIW, Compet-n apparently made a contest out of it: defeat 4 spiders on a modified E3M8, then 4 cyberdemons on the same map copied to E2M8. The best times relied on the effect to achieve faster exits.

[BaileyTW]

Guess I have a weird, to me, demo to add to this.

 

So I know about exiting after death. Stuff like sliding into line triggers for exiting, but what I have never seen, heard of, or experiences was exiting as you die without a death exit such as in E1M8.

 

Here's the zip for this: bailey_beyond_death.zip

 

Don't know if this is already known. I died right as I flipped the switch to exit on Doom 2's map 2. I did die, but didn't reset to the beginning of the map as usual. Instead I proceeded to map 3 with the usual 100 health 50 bullets you get after death.

[Shepardus]

2 hours ago, BaileyTW said:

Don't know if this is already known. I died right as I flipped the switch to exit on Doom 2's map 2. I did die, but didn't reset to the beginning of the map as usual. Instead I proceeded to map 3 with the usual 100 health 50 bullets you get after death.

Coincidentally, Zero-Master demonstrates this on the very same map in his Nightmare! TAS of Doom II.

[BaileyTW]

11 minutes ago, Shepardus said:

Coincidentally, Zero-Master demonstrates this on the very same map in his Nightmare! TAS of Doom II.

Wow, that's a very creative way to help with health management. Well in a TAS setting.

[Ancalagon]

https://www.doomworld.com/forum/post/1358416 back in 2015 on this same thread I posted a demo showing the same on this map.

[Coincident]

I was using a chaingun, and I grabbed a berserk pack.

While the chaingun was lowering, I pressed '3' once for a duration of 4 tics.
The SSG rises, and before I can shoot, it lowers again.

The regular shotgun rises.

 

Even after looking at the inputs frame by frame, I have no idea what can cause this.

I did not press the '3' key twice: I confirmed it both with my on screen keyboard overlay, and with the in-game inputs through DSDA Doom.

Also, I did not run out of bullets.
 

Is this some exotic weapon-swapping bug?

z300-weapon-swap-WTF.zip

-skipsec 250

[Sinshu]

The switching between SSG and shotgun seems to happen without releasing '3'. Besides, holding '3' keeps switching between SSG and shotgun. I didn't know that.

[Shepardus]

11 hours ago, Coincident said:

I was using a chaingun, and I grabbed a berserk pack.

While the chaingun was lowering, I pressed '3' once for a duration of 4 tics.
The SSG rises, and before I can shoot, it lowers again.

The regular shotgun rises.

 

Even after looking at the inputs frame by frame, I have no idea what can cause this.

I did not press the '3' key twice: I confirmed it both with my on screen keyboard overlay, and with the in-game inputs through DSDA Doom.

Also, I did not run out of bullets.
 

Is this some exotic weapon-swapping bug?

z300-weapon-swap-WTF.zip

-skipsec 250

This is due to what @Sinshu said, that holding 3 continuously swaps between SG and SSG without having to release the 3 key. Also, a new weapon switch can be queued up right when you start to raise your weapon. So what happened is that you started pressing 3 when the chaingun was almost all the way lowered, so part of the press queued the SSG, then the SSG raise began and the rest of the 3 press queued the SG.

[Teedre]

For a second I thought I did a void glide, but I somehow triggered the ghost effect while attempting Doom II Map 03 NM100s. I've now reached over 1000 attempts and currently burnt out from it for now. This is also my first time getting the glitch in the iwad. 

 

lv03nsghost.zip

[elmle]

xm31twtf.zip

-skipsec 85

 

While doing a tyson for H2HXMAS map 31 all of the ceilings seem to lower down to the floor and I have no Idea how from looking at doom builder, no zero tagged trigger lines or anything that could seemingly cause it.

[4shockblast]

18 minutes ago, elmle said:

xm31twtf.zip

-skipsec 85

 

While doing a tyson for H2HXMAS map 31 all of the ceilings seem to lower down to the floor and I have no Idea how from looking at doom builder, no zero tagged trigger lines or anything that could seemingly cause it.

They are small, check lines 102 and 128. Basically, you avoid it by only going up and down those stairs directly forward and not jumping off the stairs sideways.

[elmle]

oh damn, how do you even cross lines that small if they are next to a wall...

[4shockblast]

1 minute ago, elmle said:

oh damn, how do you even cross lines that small if they are next to a wall...

I'm not actually sure about that either. Maybe has something to do with them being next to a corner? Or maybe just some quirk specific to this map.

[Hitherto]

Tries to download attachments in this topic cause this message for unlogged users:

 

"Sorry, there is a problem

This attachment is not available. It may have been removed or the person who shared it may not have permission to share it to this location.

Error code: 2C171/1"

 

[Niloquì]

mh1725weakrckt.zip

-skipsec 8

 

I fired a rocket at a chaingunner, but he didn't die despite being directly hit.

[taedev]

2 hours ago, Niloquì said:

mh1725weakrckt.zip

-skipsec 8

 

I fired a rocket at a chaingunner, but he didn't die despite being directly hit.

 

??

 

He did die. I switched to 3rd person cam to see it.

[Niloquì]

9 hours ago, taedev said:

He did die. I switched to 3rd person cam to see it.

There are 2 chaingunners there, the first one dies normally, but the second one doesn't. You don't need the 3rd person camera to see it because it happened right in front of me

 

imgur link

[taedev]

OK, thanks for the images. In the demo I downloaded, you killed the first chaingunner with a rocket, and then you're dead before you get a second shot off.

[Niloquì]

11 minutes ago, taedev said:

OK, thanks for the images. In the demo I downloaded, you killed the first chaingunner with a rocket, and then you're dead before you get a second shot off.

I was confused at first why the demo was desynced, but then I remembered this wad received an updated and map 25 was modified in the update. I played the demo without loading mayhem17_updatev1.wad and it happened what you described.

dsdarchive link to the wad + update

[taedev]

Oh. I ran Super Mayhem 17 a few weeks ago, and couldn't get the update to work, so I decided to just ignore it.

 

I can get what you described by dragging and dropping your demo and wad files into dsda-doom, but when I use a .bat file it desyncs.

[Zahid]

use oatb wad  

a manc shot first at imp second shot at me and third again at imp i never saw anything like it i.e manc target 3 different enemies with its tri shots

prboom+2.6 cl2 used

popi9.zip

[oecleus]

 

dbp-09_latetele_nohealth.zip <-- this is DBP6 ignore title

in DB6 every exit teleports you to a death room that kills you before sending you to the next level, which you then start with 100 hp. On the first level I skipped the line and didn't teleport away but still exited. Then on the end of next map it exits but doesn't start me with 100 health. I'm not sure how either happens.

Edited June 20, 2023 by oecleus

[Shepardus]

16 hours ago, oecleus said:

using https://dsdarchive.com/wads/dbp_09 and doom2

 

 

dbp-09_latetele_nohealth.zip

in DB9 every exit teleports you to a death room that kills you before sending you to the next level, which you then start with 100 hp. On the first level I skipped the line and didn't teleport away but still exited. Then on the end of next map it exits but doesn't start me with 100 health. I'm not sure how either happens.

This demo is for DBP06, not DBP09; had me confused for a moment until I looked at the footer.

 

The exit teleports you to an empty room and separately starts a crusher that crushes a pair of barrels that kill a voodoo doll and push it over the exit line. In the first map, you linedef skipped the teleporter but still activated the crusher. In the second map, the two barrels didn't detonate at the same time; one exploded a tic earlier than the other. The first one didn't do quite enough damage to kill you, but it still pushed you over the exit line before the second one was able to damage you. I didn't investigate whether this happens consistently or if there's more to it than that.

[oecleus]

On 6/19/2023 at 7:46 AM, Shepardus said:

This demo is for DBP06, not DBP09; had me confused for a moment until I looked at the footer.

 

The exit teleports you to an empty room and separately starts a crusher that crushes a pair of barrels that kill a voodoo doll and push it over the exit line. In the first map, you linedef skipped the teleporter but still activated the crusher. In the second map, the two barrels didn't detonate at the same time; one exploded a tic earlier than the other. The first one didn't do quite enough damage to kill you, but it still pushed you over the exit line before the second one was able to damage you. I didn't investigate whether this happens consistently or if there's more to it than that.

 

My bad for the wrong title, you're right. Thank you for your explanation. How did you figure out about one barrel exploding a tic before the other? Did you just watch the demo back in super slow motion or something? Or did you use some sort of tool that lists the events in the demo? Thanks again.

[Shepardus]

1 hour ago, oecleus said:

 

My bad for the wrong title, you're right. Thank you for your explanation. How did you figure out about one barrel exploding a tic before the other? Did you just watch the demo back in super slow motion or something? Or did you use some sort of tool that lists the events in the demo? Thanks again.

I played back the demo in dsda-doom with the third-person camera next to the crusher + barrels setup, and when it got close to the time I entered build mode and advanced tic by tic.

[Andrea Rovenski]

ghost monster in cl9????

 

d5da4b.wad map63 uv -fast

d5da4b63fwtfghost.zip 

video: https://youtu.be/YTUeiNRPOAw

[RjY]

9 hours ago, Andrea Rovenski said:

ghost monster in cl9????

 

Oh this is a good one. Thank you very much for saving the demo.

The ghost revenant started as thing 365. But it is not technically a ghost in the usual sense. A ghost has positive health and the flags of a normal monster, but zero height, so you cannot hit it except by splash damage (or being at exactly the right height to shoot its feet, but I digress). This revenant, on the other hand, is still technically a corpse. It has -31 health and the corpse flag. It can go over dropoffs, but is neither solid nor shootable -- you could not have damaged it no matter how many rockets you fired.

On tic 8123 (3:52+03) a charging lost soul slams into an archvile (thing 406). Naturally, the archvile takes damage. But this time, the collision wakes it up. (On the second attempt, funnily enough, it already hit it once before.) An awakened, chasing archvile, before it does anything else, checks around itself for corpses to resurrect. This one finds two dead revenants on the other side of the wall next to it. However, neither have enough room to be resurrected, so they are left alone. The archvile gets on with the business of incinerating the hapless lost soul.

It is important to emphasise that the revenant is not revived by the usual mechanisms of an archvile resurrection. The archvile's corpse search finds the dead revenant, and runs a test to see if there is room for it, if it were resurrected. This fails, but since it uses the usual movement and position checking code, it changes the value of a variable that is still in use by the currently-in-progress moving actor (that is, the lost soul) to refer instead to the revenant.

 

So instead of the lost soul being returned to spawn state having hit something, it is the revenant corpse. It gets up instantly, without a resurrection animation or most of the properties a live monster is expected to have being reset. Technically still dead, non-solid, and totally indestructible.

 

[ For source divers: in PIT_CheckThing, P_DamageMobj has called P_CheckPosition re-entrantly, causing tmthing to change to point to the revenant. The abridged call chain goes something like P_CheckPosition(lostsoul) -> PIT_CheckThing -> P_DamageMobj -> P_SetMobjState -> A_VileCheck -> PIT_VileCheck -> P_CheckPosition(revenant). "This is the strife we get into for using global variables", as cph observed. ]

[besus]

I did some digging and came to the same conclusions as RjY several hours ago and just found a way to reproduce it semi-consistently.

bghost.zip

In this test map there's just a bunch of crushers that crushes the rev once you flip the switch (cl9,11,21) or run across the 2 black triangles (cl2). This bug seems to work the same on most/all cls, this is just the different crusher line actions. Everything happens as explained above, except that the archvile is what is causing checkposition to fail and assigns the revenant to tmthing (the global variable thats been causing trouble). I also found that since the corpse can be 1/4 original height or 0 height when crushed, you can have 2 different versions if you either time the crusher to kill but not crush the corpse or let it crush the corpse.
The 1/4 tall version gets instantly turned back into an immobile crushed corpse under crusher while the 0 tall version is just invincible.

1/4 tall cannot pass through walls and blocking lines while 0 tall just passes through everything.

Also both cannot be hit from -32 lower floor with projectiles, unlike the usual ghost monster.

Edit: I just checked, p_damagemobj guards against damaging the monster in any way, so a corpse imp can actually survive an archvile blast which looks rather hilarious

 

Edited February 3 by besus