collisionRules lets us turn off collisions based on the roles of two actors. We do this with two sets. If A's second set contains an entry in B's first set, then we disable the collision. We also do this symmetrically with B and A. In essence, this means that the first set lets a Role say "here are special things about me", and the second set lets a Role say "I don't collide with things that are special in these ways."
The second set: properties that this role won't collide with
The first set: properties of this role
Readonly prerenderTasks to run before every render
Optional actor: ActorThis actor ignores collisions with Heroes
Indicate that the current Role should not ignore collisions with some other role
The role that should not be ignored
Code to run when there is a collision involving this role's Actor
A Passive role is for things that barely even count as being part of the game, like background images, HUD text, etc.