Author Topic: Add Interpolated Hit Box (Read 12868 times)

jitspoe · « **on:** August 22, 2009, 07:22:09 PM »

As some of you have probably seen, it is actually possible for a paintball to pass "through" a player. This is because the server calculates collisions based discrete, static positions each frame. I've attached an image to illustrate (excuse the crude sketch). Blue is the player hit box and red is a paintball. Since the player is moving quickly, there is a gap between his position at frame "A" and frame "B". When the paintball does its collision check, it doesn't hit anything. On the client, however, the visual model is interpolated between the positions on frame A and frame B (otherwise movement would be really choppy), so he sees the player as being where the dotted lines are, and watches the ball pass through.

I'm proposing adding an additional hit box on the server that would attempt to represent the interpolated position of players that clients see. This should reduce shots flying through players as well as make it easier to hit lagging players. The existing bounding box will remain for those who are used to compensating for the interpolation.

http://dplogin.com/dplogin/featurevote/feature.php?id=10217

Rewind · « **Reply #1 on:** August 22, 2009, 08:17:47 PM »

I think this is a great idea. Would this also eliminate the problem of 'soccer balls' in pong mode going through people as well?

Eiii · « **Reply #2 on:** August 22, 2009, 08:42:33 PM »

I think this'd be a great idea, but keeping both the interpolated hitbox and the 'old' one at all time could make it significantly easier to kill players in some situations. IMO the better option would be to switch over to the interpolated hit detection entirely (once you know it works correctly), since you already have to lead/arc your shots the overall difference will probably not be too tough to adjust to.

jitspoe · « **Reply #3 on:** August 23, 2009, 12:45:32 AM »

Quote from: Eiii on August 22, 2009, 08:42:33 PM

I think this'd be a great idea, but keeping both the interpolated hitbox and the 'old' one at all time could make it significantly easier to kill players in some situations.

Is that a bad thing?

T3RR0R15T · « **Reply #4 on:** August 23, 2009, 06:13:24 AM »

Quote from: Rewind on August 22, 2009, 08:17:47 PM

Would this also eliminate the problem of 'soccer balls' in pong mode going through people as well?

Maybe. It is a little bit different there. The player is at one place (in front of the goal) and the ball is too fast.

EDIT: Do u plan to implement it to the next build or later or is it already in the build28 pretest?

jitspoe · « **Reply #5 on:** August 23, 2009, 05:20:15 PM »

Quote from: T3RR0R15T on August 23, 2009, 06:13:24 AM

EDIT: Do u plan to implement it to the next build or later or is it already in the build28 pretest?

This is a feature vote. It's not implemented.

Justinph5 · « **Reply #6 on:** August 26, 2009, 12:20:41 PM »

Is there a way to turn off the interpolation in the client? I've pretty much guessed that it was the issue with shots like that. Now I'm just curious to see how big the jump usually is when they're running.

jitspoe · « **Reply #7 on:** August 26, 2009, 08:27:40 PM »

Quote from: Justinph5 on August 26, 2009, 12:20:41 PM

Is there a way to turn off the interpolation in the client? I've pretty much guessed that it was the issue with shots like that. Now I'm just curious to see how big the jump usually is when they're running.

I thought there was, but it looks like cl_predict only shuts it off for you, and not other players. I made a quick hack to disable it and recorded a video from a demo:

http://www.xfire.com/video/120e38/ (really visible at 0:50-0:60)

I imagine it's even worse online with laggy players.

Justinph5 · « **Reply #8 on:** August 27, 2009, 12:26:29 AM »

Oh so thats what cl_predict does, I thought it did something with movement and key prediction

.

Anyways, thats pretty bad, its a definite +1, now I understand why ppl always go through lines.

Gamabunta · « **Reply #9 on:** August 27, 2009, 03:47:46 AM »

Finally! Warping players are hindrance to hit. Guess it will decrease the amount of 'WTF I HIT YOU!!!' exclamations

. Definitely voting +1.

Rick · « **Reply #10 on:** August 27, 2009, 04:05:07 AM »

no!!!!!!!!!

Cameron · « **Reply #11 on:** August 27, 2009, 05:05:23 AM »

Rick, we can be hit now

. I think thats how I survive on european servers

.

rafalluz · « **Reply #12 on:** August 27, 2009, 06:15:51 AM »

Excellent idea to deal with laggers imo

>>The existing bounding box will remain for those who are used to compensating for the interpolation.

IMO unnecessarily so. Those already compensating will quickly adapt to it and just keep compensating just for distance as it should be.

jitspoe · « **Reply #13 on:** August 27, 2009, 07:20:08 PM »

Quote from: Rick on August 27, 2009, 04:05:07 AM

no!!!!!!!!!

Care to explain why not?

Quote from: rafalluz on August 27, 2009, 06:15:51 AM

IMO unnecessarily so. Those already compensating will quickly adapt to it and just keep compensating just for distance as it should be.

Are you familiar with this community at all?

Also, not adding an additional hitbox will still suffer from the same issues. They'll just be offset. Keeping the existing bounding boxes will also be necessary for regular player collision.

RiMiNi · « **Reply #14 on:** August 27, 2009, 07:54:02 PM »

Quote from: jitspoe on August 27, 2009, 07:20:08 PM

Care to explain why not?

Quote from: Cameron on August 27, 2009, 05:05:23 AM

Rick, we can be hit now . I think thats how I survive on european servers .

cusoman · « **Reply #15 on:** August 27, 2009, 08:17:07 PM »

So far the idea of server side interpolated hit boxes seems great. Just a few things that came across my mind:

1. I don't see the reason behind keeping the old hit boxes as well as the interpolated ones, because the client only sees the interpolated ones. So the actual person shooting will not notice the changed hitboxes because they will infact be more accurate. Someone explain to me the neccessity to keep both the old and the new.

2. If you do keep the old and new hitboxes, does this mean its possible to hit a player in 2 different spots. If so that should not be possible.

3. I basically figured out that what the client sees is not the actual position of the player along time ago, and although I thought it was due to differences in fps, I managed to figure out ways to use speed to run through lines more efficiently. Hopefully running through lines will be more then just getting lots of speed on ice jumps now

+1 for interpolated hitboxes

- Cusoman

Cameron · « **Reply #16 on:** August 27, 2009, 08:23:47 PM »

Quote from: RiMiNi on August 27, 2009, 07:54:02 PM

Thats probably Ricks reasoning as well.

RiMiNi · « **Reply #17 on:** August 27, 2009, 08:24:13 PM »

I think part of the 'luck' with running through lines is just good timing with speed in-between balls.

Justinph5 · « **Reply #18 on:** August 27, 2009, 09:55:07 PM »

did you see the video? it also has a lot to do with this issue also.

rafalluz · « **Reply #19 on:** August 28, 2009, 03:51:14 AM »

Quote

Are you familiar with this community at all?

I fail to see how familiarity with specific online fps community affects whether one has a general skill of compensating for in-game latency or not.

Quote

Also, not adding an additional hitbox will still suffer from the same issues. They'll just be offset. Keeping the existing bounding boxes will also be necessary for regular player collision.

So why not move it as normal and just interpolate whenever time continuity in movement of bounding box is disrupted? I did not say to throw existing bb altogether just in my opinion having 2 at the same time is not necessary (just like Eiii and cusoman seem to think).