less_retarded_wiki/collision.md

Collision

Collision happens when two or more things want to occupy the same spot. This situation usually needs to be addressed somehow; then we talk about collision resolution. In programming there are different types of collisions, for example:

• hash collision: When two items produce the same hash, they will map to the same index in a hash table. Typical solution is to have a list at each table index so that multiple items can fit there.
• collision of bodies in a physics engine: See collision_detection. These collision are resolved by separating the bodies and updating their velocities so that they "bounce off" as in real life.
• request collision: General situation in which multiple clients request access to something that can be used only by one client at a time, e.g. a communication bus. Resolution is usually done by some kind of arbiter who decides, by whatever algorithm, who to grant the access to.