Can't break the secret glass window in Griffin Chapel

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Expand view Topic review: Can't break the secret glass window in Griffin Chapel

Re: Can't break the secret glass window in Griffin Chapel

by VoidMage » Fri Jun 19, 2015 4:54 am

NeuralStunner wrote:They work fine, but with two oddities:
...
2. The second line is only breakable once placing the gem onto the pedestal. Until then, attacks pass through it (as per the Impassable flag).
Actually, for that map this part looks like a design choice (at least as far as I recall the map, would need to recheck).

Re: Can't break the secret glass window in Griffin Chapel

by NeuralStunner » Thu Jun 18, 2015 5:09 pm

They work fine, but with two oddities:
  1. The first line is erroneously flagged Repeatable. Shooting throguh it will continuously produce glass shards and sound.
  2. The second line is only breakable once placing the gem onto the pedestal. Until then, attacks pass through it (as per the Impassable flag).
I've found a way to fix the first but not the second (short of making it a dropping sector, but only if I don't have to rebuild nodes for vanilla).

Re: Can't break the secret glass window in Griffin Chapel

by Graf Zahl » Thu Jun 18, 2015 4:39 pm

NeuralStunner wrote:
I wrote:The sector past the window in Map30 doesn't allow enough room for most missiles to completely enter it. Sure enough, by making the sector deeper, I can get the window to break easily.
As mentioned earlier, the windows in "Bright Crucible" demonstrate that this knid of window can work.

It's too long since I played vanilla Hexen, but according to my (spotty) memory, these lines did NOT work properly.

Re: Can't break the secret glass window in Griffin Chapel

by Graf Zahl » Thu Jun 18, 2015 4:37 pm

VoidMage wrote:OK, in such case, while I probably won't understand the answer, would you mind telling how should that window have been implemented in the map (compared to the way it is) if vanilla had a consistent implementation ?
The only proper option would have been to implement consistent trigger semantics. What was missing here is a trigger type that gets triggered by both crossing projectiles and hitscans.
Strife had such semantics so it was certainly doable.

Re: Can't break the secret glass window in Griffin Chapel

by NeuralStunner » Thu Jun 18, 2015 3:39 pm

I wrote:The sector past the window in Map30 doesn't allow enough room for most missiles to completely enter it. Sure enough, by making the sector deeper, I can get the window to break easily.
As mentioned earlier, the windows in "Bright Crucible" demonstrate that this knid of window can work.

Though really it'd be better to use a dropping sector like Map01's windows.

Re: Can't break the secret glass window in Griffin Chapel

by VoidMage » Thu Jun 18, 2015 3:19 pm

OK, in such case, while I probably won't understand the answer, would you mind telling how should that window have been implemented in the map (compared to the way it is) if vanilla had a consistent implementation ?

Re: Can't break the secret glass window in Griffin Chapel

by Graf Zahl » Thu Jun 18, 2015 1:22 pm

The original implementation was clearly broken. You can see that in its inconsistency.
The entire Doom movement code suffers from ugly side effects of some supposedly 'purely informative' functions doing some actions and collecting data - but that data collection again depending on order of checking and not something getting in the way that may cause an early-out of the checks.

The impact trigger at play here is such a thing.

Re: Can't break the secret glass window in Griffin Chapel

by VoidMage » Thu Jun 18, 2015 1:12 pm

Well, I don't know.
For some reason, the original implementation sounds a bit like splash damage...
So, perhaps it wasn't a side effect...

Re: Can't break the secret glass window in Griffin Chapel

by NeuralStunner » Thu Jun 18, 2015 12:12 pm

So it's a case of an IWad developer exploiting a weird engine glitch? They should've known better. :twisted:

Glad it could be fixed. Though I'm still going to keep the map fix I made, since it makes the window produce glass shards as well.

Re: Can't break the secret glass window in Griffin Chapel

by Graf Zahl » Thu Jun 18, 2015 2:22 am

After some debugging I found the cause.

The semantics for 'impact' lines are quite messy. They normally only get triggered when either a hitscan crosses the line or a projectile actually hits it.
But there was a side effect in the original code that also triggers impact and push lines if they get touched by a projectile that at the same time hits another wall.
ZDoom fixes this bug and as a result this setup which explicitly abuses it does not work as intended.

This requires setting a compatibility option for this map.

Re: Can't break the secret glass window in Griffin Chapel

by hfc2x » Wed Jun 17, 2015 10:17 pm

Graf Zahl wrote:This may just be a case where ZDoom's stricter collision detection is making things harder. But that window definitely is too small to be hit consistently. I'd classify it as a map bug as things stand.
I think the map issue is to be considered, but the culprit is definitely ZDoom's collision detection. Just tested this map in Vanilla with all ranged weapons, and unless DosBox is cheating on me, the results were the following:

Cleric:
-Serpent Staff works 95% of the time (due to weird projectile trajectory)
-Firestorm works 100%
-Wraithverge doesn't even try

Mage:
-Sapphire Wand works 100%
-Frost Shards works 100%
-Arc Of Death doesn't even try
-Bloodscourge doesn't work because its projectiles are too fat

Fighter:
-Hammer Of Retribution works 100%
-Quietus doesn't seem to work

Meanwhile on ZDoom 2.7.1 and the latest development build, I couldn't get any of these weapons to break the window. Only melee weapons + Wings Of Wrath could.

Re: Can't break the secret glass window in Griffin Chapel

by VoidMage » Mon Jun 15, 2015 7:39 pm

Gez wrote:
VoidMage wrote:
Graf Zahl wrote:This may just be a case where ZDoom's stricter collision detection is making things harder.
Out of curiosity, what parts of GZDoom work significantly diferently than ZDoom with 'vid_renderer = 0' ?
"ZDoom's stricter collision detection" is stricter than vanilla Hexen, not stricter than GZDoom.
OK, that was the part I was asking about (though the other answer was useful too, in a different context).
Arctangent wrote:
VoidMage wrote:On a vanilla map that worked in vanilla ?
Aren't those the reference ?
Using this logic, overlapping shotgunners with barrels so they can't move or do much of everything is not an error and is completely normal.
No, your logic is broken.
You're comparing a case where something got accidentally broken in vanilla by its devs to a case where something that was working-as-intended (as opposed to working-by-engine-glitch like wallrunning or whatever) in vanilla but doesn't anymore in a source port.

Re: Can't break the secret glass window in Griffin Chapel

by Gez » Mon Jun 15, 2015 4:45 pm

VoidMage wrote:
Graf Zahl wrote:This may just be a case where ZDoom's stricter collision detection is making things harder.
Out of curiosity, what parts of GZDoom work significantly diferently than ZDoom with 'vid_renderer = 0' ?
"ZDoom's stricter collision detection" is stricter than vanilla Hexen, not stricter than GZDoom.

Re: Can't break the secret glass window in Griffin Chapel

by Graf Zahl » Mon Jun 15, 2015 3:06 pm

VoidMage wrote:
Graf Zahl wrote:This may just be a case where ZDoom's stricter collision detection is making things harder.
Out of curiosity, what parts of GZDoom work significantly diferently than ZDoom with 'vid_renderer = 0' ?
None. The playsim code is 99.9% identical, the only notable difference some calls into the dynamic lights code and some handling for reflective floors.

Re: Can't break the secret glass window in Griffin Chapel

by Arctangent » Mon Jun 15, 2015 2:53 pm

VoidMage wrote:On a vanilla map that worked in vanilla ?
Aren't those the reference ?
Using this logic, overlapping shotgunners with barrels so they can't move or do much of everything is not an error and is completely normal.

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