Collision problem

Did anyone notice collision problems, when running on lower fps around 20 {on mobiles}? Still didn't found any solution to this and altough i plan to use WKWebview, i would expect them to work even on 20 fps!

It gets extremly annoying when jumping on an enemy do hurt your character

Tunneling is an inherent problem of collision detection using discrete timesteps ; the framerate is actually irrelevant, as this can always happen as long as an object is moving "fast enough" (compared to its size).

I haven't used the physics module of C2 yet, so I don't know any good solution from top of my head, but see if you find anything that relates to continuous collision detection (CCD, raychecks, extrusion, etc.) ; otherwise you might have to do some linecheck or swept surfaces manually.

Alternatively, maybe use an additional bigger hitbox that's big enough given your level design to prevent tunneling ; knowing that when your larger box detects a collision but your smaller one doesn't, a collision *might* have happened, and you'll need more computations to know what actually happened

Hi Refeuh,

actually, it only happens on my iphone. On my desktop, it didn't happen a single time and i checked that a lot of times. Therefore i asume, that it caused by lower fps.

Will try though with a biger bounding box how it behaves...

Tunneling is an inherent problem of collision detection using discrete timesteps ; the framerate is actually irrelevant, as this can always happen as long as an object is moving "fast enough" (compared to its size).

I haven't used the physics module of C2 yet, so I don't know any good solution from top of my head, but see if you find anything that relates to continuous collision detection (CCD, raychecks, extrusion, etc.) ; otherwise you might have to do some linecheck or swept surfaces manually.

Alternatively, maybe use an additional bigger hitbox that's big enough given your level design to prevent tunneling ; knowing that your large box detects a collision but your smaller one doesn't, a collision *might* have happened, and you'll need more computations to know what actually happened

[quote:3k8y5269]it only happens on my iphone. On my desktop, it didn't happen a single time and i checked that a lot of times

There is a correlation between framerate, object size and object speed that explains when tunneling can or cannot happen. What I meant when I said the framerate was "irrelevant" is that 30 or 60fps, or even 120fps, doesn't guarantee consistent collision detection ; if you had smaller or faster moving objects at 60fps, you could see the same issue.

Commercial games use solutions that work decently in all situations ; for example a bullet in a first person shooter, a small and fast moving object, is never actually a bullet from a physics representation point of view, it's a line, and physics raychecks are used to compute collisions so that bullets don't through thin walls.

As for doing this with C2... No idea, honestly. But the problem is well-known.

'Hope that helps a bit !

Maybe... if you have animations for moves like dashing, falling, etc. use larger hitboxes specifically on these to counterbalance the movement speed. Assume a minimum framerate of 15fps, and given the size and speed of your object, and the size of other entities, you should know the size of a hitbox that can never tunnel through enemies or environment bits.

Maybe... if you have animations for moves like dashing, falling, etc. use larger hitboxes specifically on these to counterbalance the movement speed. Assume a minimum framerate of 15fps, and given the size and speed of your object, and the size of other entities, you should know the size of a hitbox that can never tunnel through enemies or environment bits.

I just tested on Webview+ and there's no errors. So that's one good message. I tried to make the bounding box of my character bigger, but that didn't helped.