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Impossible hit

Posted: Fri Apr 18, 2014 5:36 am
by shadowcrust
Opponent is a Slug Assault and it has 3 shields. Firing Burst Laser Mk II and a Heavy Laser, its cockpit turns red. So far, so good, but: the first or the second shot of the BL II salvo missed (indicated by a white MISS message), and the cockpit turned red before the Heavy Laser even arrived (it was fired a bit later). No other weapons were fired, drone control is not installed.

Happened in sector 7 in the Slug Home World, using the Kestrel. FTL AE 1.5.10 (Humble Bundle for Linux) on Hard, AE content enabled.

Re: Impossible hit

Posted: Fri Apr 18, 2014 6:56 am
by shadowcrust
Come to think of it, it also happened at least once the other way around in v1.5.4, where suddenly my life support turned red, although the opponent only had laser weapons and my shields were still up. It was also with the Kestrel, but I can't remember other details of that occurrence.

Re: Impossible hit

Posted: Sat Apr 26, 2014 11:14 pm
by shadowcrust
Image

There are three shield layers on the Torus, and the enemy got a Burst Laser Mk II and an attack drone, adding up to 4 shots at one time if synchronised. Note that there are two points of damage displayed at the same time, one in the engine room, one in the cockpit.

If you watch closely, these "impossible hits" or phantom hits happen fairly often, I've seen it once more in the same fight.

I don't remember seeing that in FTL Classic, this bug was probably introduced with AE.

Re: Impossible hit

Posted: Sun Apr 27, 2014 1:17 am
by 5thHorseman
Weird. I don't think I've ever seen this though I'll keep an eye out for it.

Re: Impossible hit

Posted: Sun Apr 27, 2014 8:07 am
by Matthew
@shadowcrust:

What sort of system are you running on? Could you try installing something like fraps and seeing what FPS you're getting? It shouldn't make a difference, but I could have messed up something and it does :-P

Re: Impossible hit

Posted: Sun Apr 27, 2014 11:35 am
by Levgre
Well the Combat Drone has a cycle in which sometimes it does 1 shot very quickly after another, before a shield may even be back. And I think when it does it, it usually/always is around the location shown in the picture.

Just a possibility.

Re: Impossible hit

Posted: Sun Apr 27, 2014 12:28 pm
by shadowcrust
Matthew wrote:@shadowcrust:

What sort of system are you running on? Could you try installing something like fraps and seeing what FPS you're getting? It shouldn't make a difference, but I could have messed up something and it does :-P


I'm using a Debian variant, fraps is not working, sorry, and recordmydesktop kills my machine and my game profile :-( The machine is a Thinkpad X61, so fairly outdated, I'm very happy the game even runs (although rather slowly, compared to newer machines, I've done head-to-head comparisons with colleagues, I need about 2-3 times for a sector than they do, and the movement is visibly slower)*.

I've played most of FTL Classic on a (faster) Windows PC, so it could also be that the bug was present already in FTL Classic, but only for Linux and/or very slow machines?

Levgre wrote:Well the Combat Drone has a cycle in which sometimes it does 1 shot very quickly after another, before a shield may even be back. And I think when it does it, it usually/always is around the location shown in the picture.

Just a possibility.


I agree that it is a possibility, and I've seen drones shooting in a very small interval, but I'm almost certain this didn't happen here, as I've not seen the drone shooting twice very fast (but I could have overlooked it), and if you look at the damage indicators on the Torus, the shots hit almost at the same time, which even for superfast drone intervals would be too fast, I think. And the phantom hits not only occur in the presence of drones, although unfortunately I don't have screenshots from these events. Maybe indeed a rather obscure bug.

*This is probably/certainly a fringe case, but the game even runs on 1024x768, you just have to move the window around a bit - I use that when I'm abroad, where I don't have an external monitor with me :-)

Re: Impossible hit

Posted: Sun Apr 27, 2014 3:12 pm
by Matthew
Hmm. If the game is noticeably slower, then it's probably quite an abnormal frame rate. That could explain it, as that used to cause problems in earlier version of FTL. I'll have to go test my collision code again to see if it would make a difference. It's admittedly been about 2 years since I've needed to deal with it, so I may have forgotten something.

That old Thinkpad is similar to the one I did some of the very earliest Linux / old machine testing on. Good to hear that it's at least mostly playable for you :)

Re: Impossible hit

Posted: Mon Apr 28, 2014 11:55 am
by shadowcrust
I'm happy to hear the old Thinkpads are still appreciated by other people as well! - The game on the X61 is much slower when connected to an external monitor with high resolution, almost unbearably so with 1600x1200 (only played once), but pretty ok with 1280x1024 and probably even better with 1024x768, although one needs to pause frequently to see the other side of the screen (unless one is really daring, might qualify for a challenge run ;-) ).

Re: Impossible hit

Posted: Mon Apr 28, 2014 1:00 pm
by FDru
shadowcrust wrote:I agree that it is a possibility, and I've seen drones shooting in a very small interval, but I'm almost certain this didn't happen here, as I've not seen the drone shooting twice very fast (but I could have overlooked it), and if you look at the damage indicators on the Torus, the shots hit almost at the same time, which even for superfast drone intervals would be too fast, I think. And the phantom hits not only occur in the presence of drones, although unfortunately I don't have screenshots from these events. Maybe indeed a rather obscure bug.

You're thinking about this the wrong way. The damage could easily appear at the exact same time if the drone hits first to take off the first shield layer, then the burst hits twice and the 3rd burst and 2nd drone hit land simultaneously. Like this:

Drone hit - - - - - - - -Drone hit
Burst hit - Burst hit - Burst hit