Miscellaneous demos (part 1) [please post in part 3 instead]

I have found trick on "Phobia - The Age" and has finished the second level in "few" seconds. Sorry for the crappy demo, but there is no sense to make it clearly for (G)Zdoom.

map02 @ Phobia - The Age
Recorded with GZDoom 1.0.04

Share this post


Link to post

I probably spent a lot longer on this one than I should have done, but in the end I achieved my target time:

The Keep by Kurt Dillard, UV Pacifist in 0:07.

Share this post


Link to post

Not right now, thanks. :p

I forgot to mention that the wad is the same as the one used for this demo, so you can update that page with the author's name if you like. Both demos play back with either version of the wad (the one Jason Henry included had only a music change).

Share this post


Link to post

Hello all,

Here's a very miscellaneous demo -- map 32 of Sverre Andre Kvernmo's TEETH.WAD (from the Master levels), UV max in 1:06. This was really really hard. I think 1:05 is possible, but perhaps only with TAS?

BTW, also Reality, yay!!! :-)

Share this post


Link to post
Kristian Ronge said:

map 32 of Sverre Andre Kvernmo's TEETH.WAD (from the Master levels), UV max in 1:06.

Good stuff. BTW, what did you use to record it with? This demo desyncs without REJECT overflow emulation (as did Ledmeister's 1:07 demo), so I imagine you used a recent Prboom-plus or Chocolate-Doom - or Doom2.exe (despite what you put in the text-file).

Share this post


Link to post

Thanks for the kind words!

Grazza said:
BTW, what did you use to record it with? [...] I imagine you used a recent Prboom-plus or Chocolate-Doom - or Doom2.exe (despite what you put in the text-file).

I recorded it with PrBoom 2.2.4 (which is what I put in the text-file :-P). You're right... it de-synchs in all versions of PrBoom 2.2.6 I have. But it plays alright in doom2.exe. Wierd.

Share this post


Link to post

It seems you were quite lucky then!

The difference appears to be that Prboom 2.2.4 doesn't attempt to patch the REJECT (unlike later versions), which in the case of this demo appears by chance to keep it close enough to the Doom2.exe behaviour. Led's demo desyncs in 2.2.4, BTW, and there is no guarantee that other demos recorded in this way will work with Doom2.exe (I mention this in case you're thinking of going for 1:05).

Share this post


Link to post

Thanks for the heads up! Nifty detective work. I guess Sedlo's lucky bird landed on my shoulder temporarily there. Phew! :-)

1:05 would likely be a TAS project (at least for me), and to tell you the truth I've had quite enough of that map for now. Maybe some rainy day I'll have a look at it again?

Share this post


Link to post
Kristian Ronge said:

I recorded it with PrBoom 2.2.4 (which is what I put in the text-file :-P). You're right... it de-synchs in all versions of PrBoom 2.2.6 I have. But it plays alright in doom2.exe. Wierd.

What sense to record demos with old buggy version of prboom? I suggest to use last version of PrBoom+ or even PrBoom 2.4.1. Tons of compatibility bugs have been corrected in last versions PrBoom(+)

Share this post


Link to post

It makes no sense. Things are like that sometimes. :-) FYI, I still regularly use ZDoom 1.22, so that should tell you something about me...

Anyway, another Master levels run. This time UV speed on "Canyon" done in 0:11.
Featuring yet another one of those trick glides. I suspect it can be done quite a bit faster, actually (see the .txt for more details).

Share this post


Link to post

Another short demo on a map by AReyeP. The route is based on, and assisted by, monster cooperation.

"The Base" by AReyeP, UV Pacifist in 0:23.

All the monsters behaved perfectly until near the very end. The lost second due to that is annoying, but given that my next best was 0:27, I decided to call it a day at this.

Share this post


Link to post

I noticed something odd in my aforementioned 0:27 on "The Base", so I have included it in the zip (reuploaded) as an egg demo. Specifically, a baron scratches me but I take no damage (just after I teleport back with the red key). Perhaps it is a similar thing to Anima's GlitchRocket on Extremal E2M6, even though it is not an explosion in this case.

Share this post


Link to post
Grazza said:

a baron scratches me but I take no damage

This is what happens:

  1. Baron goes into its firing sequence; turns to face target (you, the player)
  2. Baron continues going through attack sequence; turns to face target again
  3. Lost soul behind baron hits it, doesn't cause it pain or interrupt its firing sequence, but does cause it to change target
  4. Baron reaches end of firing sequence; scratches target (the lost soul) but doesn't turn to face target again
That is, the baron hasn't attacked the player at all, it's attacked the lost soul behind it.

The interesting part is that it doesn't turn round at the instant of attack (when it makes the scratch sound). It turns out that barons - and hellknights, they both call the same code pointer, A_BruisAttack - appear to be the only monsters which don't turn to face their target on the instant that they attack. The call to A_FaceTarget is omitted from A_BruisAttack in what I can only assume is an oversight by Doom's authors.

Incidentally, if you put the A_FaceTarget call into A_BruisAttack and play the demo, the baron happily spins round on the spot and smacks the lost soul behind it. The change doesn't affect demo sync, at least in this case.

Share this post


Link to post

Thanks for the analysis. My impression from watching with walkcam/slomo was that the LS attacked just after the baron's scratch, but I hadn't worked out the exact distances, etc.

Interesting: I've certainly seen Barons/Knights firing "out of their back", but never noticed them scratching in that way.

Share this post


Link to post
RjY said:

Incidentally, if you put the A_FaceTarget call into A_BruisAttack and play the demo, the baron happily spins round on the spot and smacks the lost soul behind it. The change doesn't affect demo sync, at least in this case.

It will affect sync only if attacked target is a spectre. Only in this case P_Random() is called.

Share this post


Link to post

Doom Advent Calendar 2005 stuff I've had sitting around for months:

dac11 in 2:15 (doom2 complevel, prboom 226)
dac12 in 3:40 (boom complevel, prboom 23x, plays in 226/241)
dac17 in 3:39 (doomu complevel, prboom 23x, plays in 226/241)

Note: the last two might count as tool-assisted as I made them with my hacked up version of PrBoom 2.3 that isn't available for download anywhere. I personally don't consider them cheated but it's not up to me to decide!

Share this post


Link to post

RjY said:
Note: the last two might count as tool-assisted as I made them with my hacked up version of PrBoom 2.3 that isn't available for download anywhere. I personally don't consider them cheated but it's not up to me to decide!

What does it do?

Share this post


Link to post

Hi, so I sat down and thought, "hey it's a high time to play some doom at last probably". And I did, at last. Played two Zdoom maps and after that came up with this 1994 map, which is quite good for its era methinks. After playing it through, my nightmare detector played an alarm, saying that this should be beatable in NM, and quite easily, in spite of all those monsters. And that turned out to be the case, since relatively quickly I came up with this demo, which I think I wasn't supposed to, keeping in mind this long no-dooming interval, rustiness and stuff.

Share this post


Link to post

Nice :)
Btw. I got a quicky demo for Europa 3 (eaeuro03.wad by Erik Alm) - UV Speed in 0:28, will be sent to Doug.

Share this post


Link to post

Everyone loves bug demos, don't they? Well here's one:

"The Base" by AReyeP, featuring an intercepts overflow. The demo is here.

The overflow occurs at 0:11.62, and causes a crash if the demo is played in Doom.exe (so Prboom-plus is the only current exe that will play this demo to the end). It would be interesting to know exactly what triggers the overflow here, and why it makes Doom.exe crash (or if this is system-dependent).

The zip also includes a demo showing what I was trying to do at the time, but so far I haven't even equalled my pacifist time with this method.

Share this post


Link to post
Grazza said:

The overflow occurs at 0:11.62, and causes a crash if the demo is played in Doom.exe (so Prboom-plus is the only current exe that will play this demo to the end). It would be interesting to know exactly what triggers the overflow here, and why it makes Doom.exe crash (or if this is system-dependent).

Because in vanilla it overwrites memory which contains not only simple variables, but also pointers (activeplats for example) It will cause a crash with a high probability. By the way, this overflow practically always leads to noclip effect because it overwrites blockmap width and height variables (see intercepts_overrun_t overrun array in void InterceptsOverrun(...) function)

Share this post


Link to post

Oh, so when people are playing with Doom(2).exe, the normal result is just an unexplained crash and, if one is recording, that no demo is recorded at all.

BTW, my "dream" idea in this is to find a way to trigger the overflow deliberately, and use it on E1M8 (you'd just run straight to the death room once the all-ghosts effect was triggered). It puts a bit of a dampener on things if more often than not the game will just crash instead.

Given that a crash is a standard result, I wonder if it would make sense to extend this limit in Doom-plus. OK, in principle it breaks demo compatibility, but I only know of one single demo where the overflow has been used in order to exit a level. I don't know; how does one weigh avoiding crashes vs a chance of an effect that is useful only in highly exceptional cases?

Share this post


Link to post

I'd say it should be fixed. It is a bug.
If someone wants it, they can play the real game.

let me put it this way, it is annoying to crash DOOM two hours into a demo. :)
but that is just my 2c

Share this post


Link to post
This topic is now closed to further replies.