ZDoom/Prboom player speeds

[Bishop]

Don't know if anyone mentioned this before... Is it just me or does the player seem to move a bit faster in Zdoom than PrBoom/Vanilla? (doesn't matter if I'm strafe running or not) Or could it be another factor? I'm interested in knowing is all.

[Graf Zahl]

This has been reported before but I have never been able to confirm it. Maybe it's some kind of voodoo, maybe something system dependent. I have no idea.

The acceleration values are the same in both ports though.

[Spleen]

Is air control the same in both ports?

[Quasar]

Spleen said:

Is air control the same in both ports?

I know that's not the case for certain.

As for player movement speed, I seem to remember something in Randy's changelog years ago that mentioned "made the movefactor compatible with Heretic and Hexen," which people remarked at the time that this changed the physics in DOOM ever so slightly.

I have never been able to find what this difference amounts to by examining the source, though part of the reason I have that difficulty is because BOOM and MBF really mauled that code to the point that it's almost unrecognizable if compared against the vanilla codebase.

[Graf Zahl]

That concerned friction for Heretic's ice sector. There was some slight adjustment to the friction calculation at that point in time but it shouldn't have any impact on normal movement because the friction setting code is never called for that.

[Bishop]

If no one knows for sure, it's not that big a deal. Just wondering because when I'm testing levels. Espeically playability between different ports.

[Quasar]

Graf Zahl said:

That concerned friction for Heretic's ice sector. There was some slight adjustment to the friction calculation at that point in time but it shouldn't have any impact on normal movement because the friction setting code is never called for that.

Thanks for clearing that up. Any clue what the proper movefactor for Raven-style friction is? Is it as simple as changing the number or is there more to it than that?

I've had trouble getting it right in EE, and I still don't think it's correct. It seems harder to change directions than it should be.

[trrobin]

Yes! I've been thinking this for years now.
It's not just the movement either, but the shooting too.
Basically the whole game seems somehow minutely faster in Zdoom.

There is definitely something to this.

[Maes]

Well, either way, it should be easy to hack in a "tic-o-meter" to the player and see what is the effective moving speed in different ports, as I had done in this thread.

[Phml]

If no one knows for sure, it's not that big a deal.

You'd be surprised. ZDoom ports handle small height changes very smoothly, whereas on PrBoom it feels like the player is slipping on ice.

[Vermil]

Phml said:

You'd be surprised. ZDoom ports handle small height changes very smoothly, whereas on PrBoom it feels like the player is slipping on ice.

That ZDoom might feel smoother when moving up/down small height changes might well just be the movement of the camera (which is seperate from the player movement).

[DaniJ]

Indeed. Interpolating actual player z like that wouldn't be useful and would in fact result in all manner of gameplay quirks due to the playsim assuming that a player on the ground has a z height equal to that of the ground plane.

[Phml]

It may be so, I would be foolish to claim I understand anything about the technicalities, but I know it makes areas that are perfectly playable in ZDoom into an annoying mess in PrBoom.

[DooMAD]

The perception of a difference in speed could be attributed to the uncapped fps in ZDoom. Something feels different and the player assumes it's the speed they're moving, when actually it's just displayed to the screen more smoothly.

[__Lagger__]

Sorry to bump this old thread, but I experience exactly this in a jumpmaze that I've made. It has jumps of 187 units and they seem hard in PRBoom. In ZDoom however you can make this jump easily even with SR40.

[TimeOfDeath]

__Lagger__ said:

Sorry to bump this old thread, but I experience exactly this in a jumpmaze that I've made. It has jumps of 187 units and they seem hard in PRBoom. In ZDoom however you can make this jump easily even with SR40.

Could you record a zdoom demo of this plz? 192to180.wad

I've tried with zdoom 2.4.1 and 2.6.0 with the default aircontrol & gravity settings and can only make the jumps with sr50.

[__Lagger__]

Looks like things got a bit more complicated. I tried ZDoom 2.6.0, but it seems like the running speed is fixed there. However, I do have a demo on version 2.2.0 where I first jump with sr40 over a 192 gap, then I teleport back and jump using sr50. As you can see the angle is different and so is the player speed. The sr40 jump needs the right angle and can be a bit tricky. The sr50 jump is really easy.

Then there are 2 more demo's recorded in... Zandronum 1.0-alpha-120602-1356. Showing a sr40 jump over a 186 gap. Isn't 178 supposed to be the maximum? This jump was harder than the sr40 jump over the 192 gap in ZDoom 2.2.0.

Demo files here.

[TimeOfDeath]

You're right about zdoom 2.2.0, I wonder what's going on there. I use to play with 2.2.0 for quite a while and didn't notice that before. :)

I know Skulltag/Zandronum has extra air control compared to ZDoom, so I assume that's why you get more distance there.

[abyrvalg]

i wonder what was the cause of that behaviour. Tried 2.2.0 and 2.1.7, clearing a distance of 192 units with sr40 is easy there, as well as at least 206 units with sr50. Noticed that a long time ago, didn't know they fixed that later. Perhaps i should dl a new version.

[RjY]

Sounds like the gravity doubling when momz==0. I think that was taken out and re-added later.

[Vermil]

Maybe I'm missing something, but I thought it was well known that ZDoom changed this relative to Vanilla Doom.

I recall a point of contention where the final jump at the end of PL2 Map29 was possible with a normal jump in ZDoom, but required straferunning in other more faithful ports.

[RjY]

Vermil: I think it's this

r1452 | graf | 2009-02-28 21:38:20 +0000 (Sat, 28 Feb 2009) | 13 lines

[...]
- Fixed: Gravity application was not correct. For actors with no vertical 
  momentum the initial pull is supposed to be twice as strong as when 
  vertical movement already takes place.
[...]

r1543 | rheit | 2009-04-14 02:20:44 +0100 (Tue, 14 Apr 2009) | 2 lines

- Changed gravity doubling so that it only happens when you run off a ledge.

and given the dates I imagine this thread zdoom physics question was where it came from...

[Vermil]

Thanks for the info RjY.

So, the gravity issue has been completely fixed?

[Graf Zahl]

Some more info can be found here (mostly on the reason for the second change):

http://forum.zdoom.org/viewtopic.php?f=3&t=21310