A little more on the "Tunneling" problem

I call it the "Tunneling" problem because when the player touches the wall it is teleported to it's opposite side.

I tracked it down, making an OnCollision Callback for the player. When the problem occurs, the %time variable passed to the callback was showing a "-0.0000" value which I thought was very strange.

In the engine : T2D/t2dPhysics.cc @ line 1747, in sweptPolyToPolyCollision, the pCollisionStatus->mCollisionTimeReal variable is what holds that info.

This variable wasn't actually -0.00, it was a very small negative number like -7e-7.
When it's a negative number it indicates that the polygons overlap and then they should be pushed away from one another. as the following code says :

// Set Overlapped Status.
    pCollisionStatus->mOverlapped = mLessThanZero(pCollisionStatus->mCollisionTimeReal);
	
    // Make sure the collision polygons are pushed away.
    // NOTE:- This is the overlap case.
    if ( (pCollisionStatus->mCollisionNormal * refLocalOffset) < 0.0f )
        pCollisionStatus->mCollisionNormal = -pCollisionStatus->mCollisionNormal;

BUT : in this case the polygons weren't really overlaped. Hence the very small number. what happens is that it reverts the normal, forcing the polygons to actually overlap and "tunnels" the player thru the wall.

I tried returning false when mCollisionTimeReal was very small, but that only made it ignore the collision and the player passed right thru the wall as if it wasn't there.

Any hints on how to solve this ? I beleive it must be related to Physics interpolation. When I raise the MaxInterpolation number, the problem increases.