Jump to content
Search In
  • More options...
Find results that contain...
Find results in...
bgraybr

Archvile targeting around corners?

Recommended Posts

Don't know if its my imagination or what, but sometimes when I'm fighting an Archvile, it starts to target me, and I quickly move out of its line of sight. The flames disappear, and I move back around the corner and as soon as I do so I get hit by the Archvile's attack. I moved out of its line of sight, so how could it possibly still have seen me? If it didn't how did it target me again so quickly?

...

Share this post


Link to post

What do you mean? if you get out of it's line of sight, and then get back into its line of sight, it can still hit you. You have to be out of it's sight long enough for it to complete it's sequence of attack, then when it's finished you can present yourself again without getting harmed, unless of course it attacks again.

Share this post


Link to post
40oz said:

What do you mean? if you get out of it's line of sight, and then get back into its line of sight, it can still hit you. You have to be out of it's sight long enough for it to complete it's sequence of attack, then when it's finished you can present yourself again without getting harmed, unless of course it attacks again.


I guess that explains it. For some reason I though that if I went out of the Archvile's line of sight it would immediately exit its attack sequence (because it has nothing to target) and go back to searching for a target.

Share this post


Link to post

Simply leaving an archvile's line of sight doesn't break its attack for good. To avoid getting damaged by an archvile you need to be out of its line of sight at a certain precise moment, three or four seconds after its attack begins. The plus side to this is that it's perfectly safe to be in an archvile's face, right up until that moment. Here, watch Xit Vono kill some archviles.

Share this post


Link to post

The archvile attack is a rather peculiar one, but once you know how it works, it's easy to understand. The archvile summons a column of fire. When you are in view of the archvile, the fire follows you. If you leave it's view, the fire remains where the archvile last saw you.

The damage effect originates from the fire location, but I'm not sure exactly how the damage is tied to it. The damage is triggered on one of the fire's frames, but I do not know which one because it seems to be hardcoded elsewhere in the engine (e.g. not dehackable). If the player returns back within the line of sight before said frame is reached and the explosion goes off, you can be hurt by the explosion as usual.

But other than that, if you stay out of sight, you're safe. Unless you got another archvile around the corner, and then you're fucked.

Edit: God damn, don't all post at once now!

Share this post


Link to post
EarthQuake said:

Edit: God damn, don't all post at once now!


Ugh yeah, this happens to me all the time.

EarthQuake said:

The damage effect originates from the fire location, but I'm not sure exactly how the damage is tied to it. The damage is triggered on one of the fire's frames, but I do not know which one because it seems to be hardcoded elsewhere in the engine (e.g. not dehackable). If the player returns back within the line of sight before said frame is reached and the explosion goes off, you can be hurt by the explosion as usual.


While we're posting too much information, I'm going to get even more anally precise about the archvile's attack, because, goddamit, I never go to bed until I've written at least a thousand words about things that don't matter. The archvile's attack has three, count 'em, three parts. First, there's the column of flames. This is a special thing that's summoned into the level and is set to remain in front of the player's face while the line-of-sight between player and archvile is intact. If you open your automap and type "IDDT" twice, let an archvile attack you, and then turn while standing in one place, you'll notice a green triangle that rotates around the player arrow - this is the archie's flame. If you leave the archie's line of sight before his attack finishes, then the flame thing will just stay where you left it and then despawn when the attack ends. This thing is just a graphical cue to the player to either get his ass behind some cover or fire a last, desperate salvo; it is not, in itself, damaging.

The second and third components come into play if the archie is able to see the player at the crucial moment, three or so seconds after the attack begins. Both are snippets of code that damage the player at the same instant, but in different ways. The first of these second and third components is a direct attack that damages the player for 20 health points, and launches the player vertically upward by a small amount - this is what makes vile-jumping possible. The second of these components, and thus the third, is a small explosion that originates very close to the player, but always between the player and the archvile. This tends to do about 63 health points worth of splash damage. Conventional wisdom has it that the column of flames emits this explosion, but this is demonstrably false, as this splash damage always pushes the player away from the archvile, no matter where the column of flames stood at the time of detonation. I have more evidence for my position which I shall save for an even more long-winded and unnecessary rebuttal.

Share this post


Link to post

As a rule of thumb, you're in danger only as long as the flame is burning.

Note that sometimes I was getting only 20 damage from the archvile, as if the explosion didn't lock. It was happening when he was on higher ground, and I was (partially) hidden beside his cliff.

Share this post


Link to post
Creaphis said:

The second of these components, and thus the third, is a small explosion that originates very close to the player, but always between the player and the archvile. This tends to do about 63 health points worth of splash damage. Conventional wisdom has it that the column of flames emits this explosion, but this is demonstrably false, as this splash damage always pushes the player away from the archvile, no matter where the column of flames stood at the time of detonation.

It's also interesting to note that since this damage is splash damage in ports that do not have fixed the bug with targets sometimes not being damaged properly (aka hitbox glitch) you can sometimes survive an arch-vile taking by taking only 20 damage.

Share this post


Link to post
40oz said:

if you get out of it's line of sight, and then get back into its line of sight, it can still hit you.

For a while I thought this was just urban legend because I kept getting back into its line of sight and not being hurt. Maybe I just don't know when the attack actually happens.

Share this post


Link to post
Jodwin said:

you can sometimes survive an arch-vile taking by taking only 20 damage.

start ksutra map02 with vanilla compat, open the exit room, go here. if you're pressed against that pillar, you will take 20% damage. if you step back a bit, it will be ~80%. you may experiment with the distance.

EarthQuake said:

a small explosion that originates very close to the player, but always between the player and the archvile

does this mean the splash damage won't be spawned when there's no space in front of the player in the archvile's direction? or is it spawned at wrong z-coordinate? how high does it have to be?

Share this post


Link to post

I'm pretty sure it's this frame that damages you. If you ever get a chance to see this in gameplay then you are taking damage. there is another frame that comes after it though that just finishes up the animation, it doesn't do anything.

Share this post


Link to post
Jodwin said:

It's also interesting to note that since this damage is splash damage in ports that do not have fixed the bug with targets sometimes not being damaged properly (aka hitbox glitch) you can sometimes survive an arch-vile taking by taking only 20 damage.


You actually don't need to rely on glitches like these to only take 20 damage from an archvile attack. You can consistently only take 20 damage if the topological conditions of the area are just right.

dew said:

does this mean the splash damage won't be spawned when there's no space in front of the player in the archvile's direction? or is it spawned at wrong z-coordinate? how high does it have to be?


...Unfortunately, I'm still not completely certain what those conditions have to be. I do know, however, that if the player is pressed against a chest-high obstacle that's between the player and the archvile, he'll almost always be protected from the splash damage. I actually exploited this in my latest equinox.wad speedrun, not because it sped things up at all, but because it's a cool stunt.

Share this post


Link to post

more testing: works anywhere, so it's not just a ksutra bug. also the lowest obstacle i managed to 'hide' behind was 20 units high, but this seems to differ depending on angles and positions and all. a smaller obstacle means a full archie hit, but 24 seemed safe every time i tried it. 24 is also the largest step a doomguy can take, that means you can hide behind big stairs!

i'm sorry if i am rediscovering the new world, but this weirded me out a bit.

Share this post


Link to post

This is pretty interesting to me too. I was thinking about how I would somehow attach this to my general tactics against fighting archviles, but then i realized that it's probably easier to find a corner to hide behind than it is to find a low wall to evade splash damage from.

Share this post


Link to post

Cue a gggmork/ToD map forcing you to abuse 20 damage AV blasts. ;)

Anyway, I tried getting the AV duds in a round room, and I managed to get them only when facing the south wall. Facing north, east, west, ne, se, sw or nw walls caused normal hits, regardless of position by the wall.

Share this post


Link to post
40oz said:

I'm pretty sure it's this frame that damages you. If you ever get a chance to see this in gameplay then you are taking damage. there is another frame that comes after it though that just finishes up the animation, it doesn't do anything.


I know that you can see this frame, and still not take the hit for a short time after that.

One of the ways I know it is safe to step out into line of sight again after an archvile flames you is by the sound. The crackling sound stops right at the moment of its attack, as near as I can tell, so once that stops, step out and shoot..

Share this post


Link to post
Jodwin said:

Cue a gggmork/ToD map forcing you to abuse 20 damage AV blasts. ;)

can there even be any doubt? :)

Share this post


Link to post
dew said:

i'm sorry if i am rediscovering the new world, but this weirded me out a bit.

I think the most critical point is that if the epicentre of the splash damage is in a sector where the reject is "safe", then there is no splash damage at all. This also applies for rocket and barrel explosions, but you normally only see that in a map with a faulty reject map (or a deliberately altered one). With AV blasts, it can happen more easily.

However, that may not be the end of the story, as there may well be more situations where the AV explosion is lost. See my dy06n007.lmp, for instance. Presumably there needs to be a line of sight between the epicentre and the object for damage to be taken.

Links to earlier discussion:
http://www.doomworld.com/vb/showthread.php?s=&postid=648760#post648760
http://www.doomworld.com/vb/showthread.php?s=&postid=665527#post665527

Share this post


Link to post

I have just had a quick look at this and maybe this can help explain some behaviour:
In order for the player to be damaged by the splash damage of the AV attack the player has to be able to see the splash damage (seems a bit odd this way round but that's just the way it is).
At the moment the AV attacks the AVs fire is moved 24 units away from the player (onto the line from the player to the AV) and becomes the center for the blast.
Doom then checks the line of sight:
First check is the reject (which can be modified to prevent the attack).
If that is OK the engine looks from the players eyes to the top and bottom of the splash damage thing (the AV fire) and if the line of sight is blocked no splash damage is applied.
It turns out that the height of the fire is only 16 units. So if you have a small post in front of you that's high enough it could be able to block the sight and prevent the attack. Also, when it moves the fire into position it does not appear to update it's z position (so it probably remains at the same z as the player).

In the original source there also seems to be a bug in P_RadiusAttack but it doesn't actually have any effect (the addition of MAXRADIUS).

Share this post


Link to post

so the splash damage is always spawned, but fizzles if line of sight is rejected. the LOS aspect would explain why there was so much difference in various scenarios i tested. this is very interesting, thank you for looking into the issue.

Share this post


Link to post
4mer said:

It turns out that the height of the fire is only 16 units. So if you have a small post in front of you that's high enough it could be able to block the sight and prevent the attack. Also, when it moves the fire into position it does not appear to update it's z position (so it probably remains at the same z as the player).


This is the part that confused me. Thanks a lot for looking this up.

Share this post


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