Deleting all entities about hecs HOT 5 CLOSED

Thanks for the issue! World::clear should be easy; I'll bang that out some time today.

In general, adding/removing entities while iterating or querying has the same problems you'd encounter trying to add/remove elements from a Vec while iterating over it. I'm exploring possibilities, including elaborate interior mutability shenanigans and an analog to Vec::retain, but it's not yet clear what will be feasible.

from hecs.

Fixed in v0.1.2.

from hecs.

Nope. To achieve something similar, you should collect a list of entities to remove in a second pass. Feel free to open an issue if that turns out to be too costly for your application.

from hecs.

this seems inefficient for large numbers of entities.

Just as a side note, I'm not actually sure how true this is: the cost to delete entities is always linear with regard to the number of entities deleted (assuming constant entity size), and so is the amortized cost to create such a vector, and it's at large numbers where that amortization will be smoothest.

from hecs.

an analog to Vec::retain

Has this or something similar been implemented?

from hecs.