In a regular map generated by recast, it looks very irregular unlike the maps used
in WHCA* that the map is composed of rectangular tiles. Therefore, how would I
implement cooperative pathfinding in this case? Let's say a poly a reserved,

if the poly is very long, it somehow will block the way of other pathfinding agents...
Thanks
Jack

I wanted to comment on this ages ago, but I was travelling. I have read a bit about the algorithm, although I don't remember it all. It wasn't originally created for a navmesh, there may be some variant by now. In general I have a few suggestions:

• Set limitations on how the navmesh is created, e.g. max length, max length to width ratio. If the navmesh is created externally maybe subdivide existing cells.
• Detect choke points and only apply WHCA to those areas.
• Do time-slice reservation on a different basis than the navmesh, e.g. base it on a grid, or a further subdivision of the navmesh.