[ODE] Holding bodies like in HL2

[michael kapelko]

Dave wrote in "How to hold objects (like in HL2)":
 >> * In your collision callback you need to treat ray / geom collisions
 >> as a special case, i.e. instead of the usual contact joint creation to
 >> get solid objects colliding you'd detect if "dGeomGetClass( geom ) ==
 >> dRayClass" and handle it differently.

 >> For this application you want to find the 'nearest colliding body
 >> which isn't the player' which will be the target for your gravity gun.

 >> The usual call to dCollide will return a number of collisions for the
 >> ray, in this case contact 'depth' field actually indicates the
 >> distance along the ray to the target. Ignoring the player's geom will
 >> allow you to get the nearest thing you're trying to grab with the gun
 >> simply using MIN.

So how to get the `nearest colliding body which isn't the player`?
Any ideas?
Thanks.