Post #1552892
2025-11-21 21:55 UTC
This collision is actually properly modelled - a big innovation of HL2 was the extensive use of a real physics engine. The door and the guard are both physical objects, both have momentum, they impart an impulse on each other, and although the door hinge is frictionless, the guard's boots have some amount of friction with the floor.
Replies (1)
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@TomF@mastodon.gamedev.place 2025-11-21 21:55
On both versions, the door has just enough momentum to rotate the guard very slightly. The guard's friction on the floor is not quite enough to oppose this, and he rotates a tiny fraction of a degree. On the x87 version, this tiny rotation is enough to move his toe out of the way, the collision is resolved, and the door continues to swing open. All is well.