GameMaker What's in_collision_tree?

[rytan451]

So I was programming, and I noticed this built-in variable in_collision_tree. It isn't in the documentation, so does anyone have any idea what it is, what it does, and how to use it?

 

[YellowAfterlife]

It indicates whether an instance is currently included in collision system's R-Tree. Instances are automatically added to the tree if they have collision events, or if they are being checked for via collision functions. Instances not in collision tree have no effect on performance as far as collision checking is concerned.

 

[rytan451]

Then, would it be possible to make an instance ignored by collision functions or events by setting in_collision_tree? Hmm... I'll test it tonight.

 

[Catastrophe]

I'm assuming it's read-only, and if it's not I wouldn't mess with it tbh.