Integrate Recast for navmeshes about sanctify-game

[sessamekesh]

8966e4a basically did everything but figuring out Swarm. That'll be a battle for another day, eh?

[sessamekesh]

Brain dump here because I really don't think I'm any better equipped to think about Swarm today than I will be in three months after having completely forgotten about everything Detour related

• Recast build system is basically a string of black magic nonsense that I basically just hacked from their example pages, default values, and educated guesses.
• Navmesh is generated for the practice arena, but it's a bit wonky and doesn't seem to really want to handle that center tower very gracefully.
• String pulling algorithm is used in the server navigation system, it's working well.

[sessamekesh]

Okay okay okay last comment.

There was one weird detail in recast_compiler.cc - I manually set all flags to 0x01. Without this, every poly was unwalkable, and would fail the dtNavMeshQuery lookup because the query would find no walkable tiles!

By setting it to something at least, dtNavMeshQuery is able to succeed.

For a different game, these tiles could have been labelled as something, and each one of them could have had its own navigation capabilities and costs! E.g., some tiles can only be walked, some must be flown, etc.