I'm looking to implement a pathfinding algorithm that will allow me to throw hundreds of spiders at the players in my grid-based game. I can implement this with A*, but I'm worried that that algorithm has too high of a "per spider" performance cost.
The "potential fields" approach looks really good to me, but my map is quite large and rebuilding the entire potential field sounds expensive (even on a background thread).
Unfortunately, there's no logical divisions on my map where I could separate the grid into smaller grids. And the map is quite dynamic (walls/bridges can be destroyed, which could have huge impacts on pathing).
Are there any options other than reducing the size of the map?