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Dwango5 Map01 is not a safe map!

 
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Oxyde
Dominating!


Joined: 01 Feb 2012
Location: France (67) Host: Zero Dawn

PostPosted: Sat Jun 02, 2012 8:43 pm    Post subject: Dwango5 Map01 is not a safe map! Reply with quote

Because the title says so, and because this is a true fact.
See what I mean here: http://www.youtube.com/watch?v=gHLO1Xoki2M
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Sr69Mm-jC
Unstoppable!


Joined: 21 Jul 2011

PostPosted: Sat Jun 02, 2012 10:56 pm    Post subject: Reply with quote

There are 3 units of distance between those walls. Might be that the BFG shot sometimes travels through it.. Its speed isn't too high (25) and the radius is 13 but maybe it can travel through walls at such speed/radius. It happens with fast/small projectiles quite often. Or maybe the shot itself touches the player on the other side, idk.
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dewww
God like!


Joined: 29 Dec 2006

PostPosted: Sun Jun 03, 2012 1:59 am    Post subject: Reply with quote

yes, the shot clips through the wall, touches the player and damages him. this is vanilla behaviour connected to inter-tic movement and there's a long list of oddities resulting from it. monster projectiles can damage you through thin doors in a similar fashion, for example... and manco shots can potentially clip through whole solid structures!
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GreenchiL
Unstoppable!


Joined: 19 Aug 2011
Location: #FS #Ducks YouTube: Rosh Fragger

PostPosted: Sun Jun 03, 2012 5:43 am    Post subject: Reply with quote

Well, in such case, someone should fix the map.
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Oxyde
Dominating!


Joined: 01 Feb 2012
Location: France (67) Host: Zero Dawn

PostPosted: Sun Jun 03, 2012 10:30 am    Post subject: Reply with quote

I don't think "fixing" the map would help at all, it's not as if 90% of the frags in a game happen here! Razz

dew: Indeed I have experienced quite a few times already the problem of Manucbus' shots clipping through walls. About thing doors, didn't know that, I always thought the structure would require at least 1 pixels of height for the damage to connect, seem not!

Sr69: My bet would be the radius of the BFG ball that is big enough to actually hit the other side of the wall.
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dewww
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Joined: 29 Dec 2006

PostPosted: Sun Jun 03, 2012 1:20 pm    Post subject: Reply with quote

i'm not familiar with doom's source code, so what i say is acquired through less precise channels like ingame observation, reading the doom wiki or being told by a knowledgeable coder, so don't take my word as the final authority, but here's what happens...

it's not about the radius of the bfg ball, it's about its speed. consider the location of the projectile in the last tic before it hits the wall. this distance from the wall can (and most likely will) be smaller than the exact distance the projectile travels between each two tics. this means the next tic its location will bleed into the wall by some depth. the doom engine will do a collision check and remove the projectile from existence - but as far as i know it will check that it's touching the player on the other side first and only "invalidate" the wall breach further down the collision algorithm (still within the same tic, mind you). this is why you get hit by projectiles through thin walls and doors.

this behaviour extends to player and monster actors too, actually. this speedrun abuses the fact that the door is thin and locked with a key only from one side. also monsters constantly "press the use button", so they activate everything they can. the archvile is fast enough to bleed into the door far enough to use it from the other side before the collision detection returns it back from its quantum trip. :)

now to take that one step further, when you get the right location and speed, you can actually "tunnel" through the wall, because your next valid location is on the other side already and the engine won't detect a collision with the wall. i assume this is what happens with manco shots when they clip through walls as their radius is tiny and their speed is high. doomguy is pretty fast himself, but his quantum tunneling abilities are hampered by his fatness - he's a square 32 units wide. still, if we're talking about a simple fence (just an impassible linedef with no width), even he can do the trick. it happens here at 25s or here at 28s.

doom is weird, you know.
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EarthQuake
Wicked Sick!


Joined: 02 Apr 2004
Location: Athens, Ohio. Dieblieber gonna getcha!

PostPosted: Sun Jun 03, 2012 11:15 pm    Post subject: Reply with quote

Can verify what dew said. This is pretty much what is happening here. I've seen it in other maps, but had no idea it happened in dwango5 map01. Embarassed

I can even verify doomguy being able to skip through linedefs. I made a wad demonstrating this some time ago, but it's gone now. The thread is still intact though, showing how this discovery unfolded for me. I also had a similar explanation as dew in another thread, when someone was reporting noclipping through walls when player widths were decreased with DeHackEd.

It's all the same engine behavior, and it's not really possible to fix any of it without completely rewriting collision checking (and perhaps much, much more). The map itself can be fixed... but who seriously cares about such a minor thing in such a well-established map?

Props if you can achieve more than one or two frags with it. That's probably all it's good for.
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Cybershark
Spamming!


Joined: 05 Jan 2005
Location: off the grid, but still fighting for the users!

PostPosted: Tue Jun 05, 2012 12:18 am    Post subject: Reply with quote

Shouldn't be news to anyone that this map is full of fail Smile
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dewww
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Joined: 29 Dec 2006

PostPosted: Tue Jun 05, 2012 6:45 pm    Post subject: Reply with quote

oh, shut up! we LOVE doom bugs and finding ways how to exploit them! :P
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[LA]FLunky
Dominating!


Joined: 13 Feb 2011

PostPosted: Wed Jun 06, 2012 8:23 am    Post subject: Reply with quote

Just play your games xDD

Maybe we should make some new servers

Capture the Bug
Bugoperative
Bug-Match
Bug on Bug
Find the Bug
Bugs Bunny
etc..
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