AV-jumps

just a few questions, sorry to bother you.

How far can you get with a AV-jump, if you are running at max speed (non-strafe, just straight ahead!) on flat ground?

How high can you jump? I think I remember 32 units, is that correct?
Is the max height of the jump the same in prboom as in vanilla?

In Skulltag, ZDoom (?), GZDoom and stuff I know you can jump much higher. Why the hell would they add that? Totally ruins the planning of secrets and stuff that required AV-jumps when making maps.

I know I was wondering about some more stuff but I cant remember right now, I`ll get back to it.

The [G]ZDoom higher-jumping was fixed a long while ago, and has been in the official releases since at least 2.4.0, if not longer. Nobody "added" the extra height -- it was a side-effect of explosions' vertical thrust, I believe.

Also, the 'jump' height is much higher than 32 -- it's closer to the 70-mark or somewhere around there (at least according to something Phml posted once). I'm sure someone here has much more accurate metrics to share.

Adam Hegyi's post here gave several pieces of information, including the suggestion that 72 units was the height of an AV jump in Doom2.exe (and also in ports that don't make any changes that alter this).

Zdoom's different air control still makes AV jumps easier, even if there is no longer a difference in the height they propel you to. Try, for instance, Plutonia map18's AV jump to the exit. In Zdoom you just need to be pressed up against the wall, and the jump can't fail.

darkreaver said:

Is the max height of the jump the same in prboom as in vanilla?

It has to be - otherwise it wouldn't retain demo compatibility at all.

Aha, ok, I havent been keeping up with any of the ports, so pardon my ignorance :P

Hmmm, ok, so if you can be blown 72 units up, thats alot more than I thought.
I`m mapping in a BFG secret as we speak, so I wanted to ask here for some advice. I know I know I can test it myself, but while my playing skills are not that bad, I`m far from the best when it comes to tricks like this, and I want the secret to be very hard to reach.
I`m also having problems with pr-boom and vanilla, so I must do my testing with ZDoom/Skulltag/GZDoom and that fucks things up quite alot. I`m literally flying across the map when I`m trying it out hehe.

Ok, so what I need to know the most is how far I can jump (AV-jump) on flat ground. Both non-strafe running AND with strafe running. I believe there is a difference because of the speed of the player, right?

darkreaver said:

Hmmm, ok, so if you can be blown 72 units up, thats a lot more than I thought.

Just to clarify, that's the difference in height between the floor the player is starting on, and the one he arrives on. So part of it is just the normal step height that the player can make (24 units).

darkreaver said:

I`m also having problems with pr-boom and vanilla

Try prboom-plus, and report any problems to Andrey Budko (e.g. in the prboom-plus thread in the Source Ports forum or the prboom-plus sourceforge site. Most people seem to get it to run without many problems.

Yeah, I actually meant prboom+

It`s not a bug in prboom+, it has to do with my sound drivers, or whatever sound "code" prboom+ use. When in prboom+ I cant adjust the music volume, nor turn it off, and its sooo loud. Cant hear the in-game sounds at all almost. Not to mention it crashes on me 3 out of 4 times when I start it up.

Works like a charm in other ports though.

Well, I think I can get my hands on another laptop via a buddy this week, so I can probably run prboom+ and test on that one.

I think if you get blown up by an archvile your feet will reach a maximum height of 55 above the floor before gravity overcomes your upward momentum and you start to fall again.

(An archvile blast gives the player an upward momentum of 10 units per tic. Gravity is 1 unit per tic per tic. So on tic 1 you go up 10 units, tic 2 you go up 9, etc. So the total height will be the tenth triangular number i.e. 55. This is pretty easy to check in an engine that shows your Z-coordinate.)

When you're 55 units up and still moving horizontally you can still clear a step-up of 24 units so you end up with 79 units maximum.

So theoretically it should be a bit more than 72 unless there's something I have not taken into account. But there's only one tic when you can clear a height difference of 79 so it's probably really hard to do. (I didn't try.)

RjY said:

Gravity is 1 unit per tic per tic.

So you say gravity is 1225 units/second squared? That's a helluva lot more than in Quake's 800 units/second squared... yet I don't feel the difference, unless Quake uses another scale.

here is a demonstration of an 80unit climb (avj.wad map02). i'm guessing it is the middle step, right? another ~24unit bonus or something.

darkreaver said:

When in prboom+ I cant adjust the music volume, nor turn it off, and its sooo loud.

I used to have that problem and ended up reducing the main midi volume at the mixer using the volume control (Start -> Accessories -> Entertainment -> Volume Control).

darkreaver said:

It`s not a bug in prboom+, it has to do with my sound drivers, or whatever sound "code" prboom+ use. When in prboom+ I cant adjust the music volume, nor turn it off, and its sooo loud. Cant hear the in-game sounds at all almost. Not to mention it crashes on me 3 out of 4 times when I start it up.

U can turn off music with "-nomusic"

@dew

yes :), the middle step is exactly the reason why you can manage this jump

for a single arch-vile jump the max height which you can climp is 72 units (in 8 units steps, so maybe 73 is also possible)

just try it out in map23 of avj.wad, there you have to jump 80 units high (with 2 Arch-Viles, it won't work with a single one)

Thanks for advice on the music, but nothing works. I can start with -nomusic, but the sounds in game are so low I cant even hear them (yes windows sound is on max).

I dont even have any sound mixer/control (except for main volume), so I think I`ll have to do some re-formatting :P

As for the AV-jumping: are there no numbers on how FAR one can jump?

RjY said:

An archvile blast gives the player an upward momentum of 10 units per tic.

What's interesting is that, as archvile attacks are the only things in Doom that give the player positive vertical momentum, the way that this momentum was implemented is quite singular. In my experience, archvile blasts don't merely increase the player's vertical momentum by 10 units/tic, but they change it to 10 units per tic. To illustrate the difference, here's an example: pretend that a player is falling at a rate of 30 units/tic when he gets hit by an archvile blast. If this blast added 10 units/tic to his vertical momentum, he would immediately continue falling at 20 units/tic. However, if the player's vertical momentum was changed to 10 units per tic, the player would move slightly upwards for a few tics before beginning to fall once again - and this is exactly what happens. This has important consequences. Having your vertical momentum "reset" in this way during a long fall makes it possible to travel a much larger horizontal distance in a given vertical distance - this crucial fact is what makes the archvile jump in this dv.wad MAP02 demo possible.

Another important consequence is that, when two archvile-blasts hit a player on the exact same tic, the player won't gain a vertical momentum of 20 units/tic, but still only 10. Therefore, if a double-vile-jump is being attempted, the player is best off if the attacks of the two archviles aren't simultaneous, but slightly out of phase. The ideal case is that the two attacks are 10 tics apart; then, once the first attack has lifted the player to 55 units above the ground, the second can reset the player's vertical momentum to 10 units/tic letting him gain another 55. I found that this staggering of archvile attacks was very important when working on the double jump in this dv.wad MAP04 demo.

I feel bad for always using my own demos as examples but they're what I think of first.

darkreaver said:

As for the AV-jumping: are there no numbers on how FAR one can jump?

Well, the math in this case isn't actually quite so simple. If we're talking about a level, ledge-to-ledge jump, then to find the maximum distance that can be jumped you could take the maximum distance the player can run in one tic, add that to the horizontal thrust caused by an archvile attack's splash damage, and multiply the result by 23, for the 23 tics of "hang time" that the player has after a vile jump. (The player isn't at his original height 23 tics after a vile jump, but 23 units below it - however, this is still high enough for the player to be able to "step up" onto the ledge he's jumping towards.) Something worth considering, though, is that it might be possible to jump even farther if the archvile blast hits the player a few tics after he's already run off the first ledge.

well, I could only tell you my experiences with the distance of AVJs is

you can jump over a gab of 640 units with SR50 ( I think 40 too ) like in avj.wad map04

with for example 3 AVs you can also overjump a distance of 1400 units ( map20 )

never tested such distance jumps without straferun

Shit, thats pretty far! Seems I have to redesign the secret a little bit :)

RjY said:

(An archvile blast gives the player an upward momentum of 10 units per tic. Gravity is 1 unit per tic per tic. So on tic 1 you go up 10 units, tic 2 you go up 9, etc. So the total height will be the tenth triangular number i.e. 55. This is pretty easy to check in an engine that shows your Z-coordinate.)

Isn't gravity doubled on the first tic, though? Or is that only when falling from a sector?

Creaphis: good point, an archvile blast does indeed set your momentum to +10 units, ignoring whatever it was before. My use of the word "gives" was unfortunately ambiguous, so thanks for clarifying things.

Gez: yes, that doubled gravity behaviour is observable during an archvile jump, just after you have reached the zenith. As I'm sure you know gravity is doubled when you are not touching the floor but your vertical momentum is zero.