Re: [Algorithms] Kinematic Collision

[<Pau...@sc...>]

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Hi Johan,

>     Step 1:
>     If our current position is our target position we can end, otherwise 

> do a capsulesweep from our current position to our target position + a 
> small bias, if no collision is reported we can end otherwise continue to 

> step 2

This biasing is part of your problem, instead of biasing you need to do 
something similar yet different:

When doing your swept shape-cast, you need an inner-hull shape of slighter 
smaller radius than the outer hull. Then, when you get a TOI intersection 
(which would obviously embed your outer hull in the ground, and the inner 
hull just touching), you can 'move back' the whole shape so that the outer 
hull is just touching. This means that next frame you won't find yourself 
initially embedded in the ground.

Ideally, you wouldn't need to move the shape back and you'd have some kind 
of method for finding the TOI which puts your shape some known distance 
from the ground (i.e. the distance from the outer hull to the inner), but 
this routine is more expensive than a straight intersection test.


>     Step 3:
>     Find the vector from the new position and the target location and 
> retrieve the reflection/tangent components. Set new target position to 
> the new current position and add both components scaled by a
>     bounce/friction value [0, 1] to it..
> 
>     * NormalMotion = NormalComponent * Bounce
>     * TangentMotion = TangentComponent * Friction
>     * NewTargetPosition = NewPosition + NormalMotion + TangentMotion

Here, ideally, you'd give your character a velocity vector and then you 
can project his velocity into the plane of the normal of the contact point 
(and subtract friction in the tangential velocity direction, as you 
mentioned). As others have said you could make it a rigid body, but i 
don't think you need to go that far for just a character capsule.

Cheers, Paul.
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