Avoiding specific Nodes about jumper

[mtdowling]

+1. This would be great. I currently am running into an issue in a tile based game where I want to path find to a node that isn't walkable, but attempting to walk into the node is the desired behavior (e.g., walking into a tavern increases health but the player can't actually walk through a tavern).

[vadi2]

You also want to allow avoiding edges along with nodes. I've run into practical examples where you, for example, don't want to completely block a room off (because it has several other exits that you do want to use) but just a particular exit between two rooms (it's temporarily inaccessible or you don't want to walk through there).

[Yonaba]

@mtdowling , @vadi2 : Can you please provide some sketches explaining the problem you are running into and the expected behaviour ?
It'll help, thanks.

[vadi2]

In my case I'm using an existing pathfinding system that's been developed and improved through the needs of players - we found that in practice, we need all of:

a) room-based locking: for when a room should not be entered into (you enter and die, for example, or it is enemy territory)
b) exits-based locking: particular exits can be disabled in a case where the logic dictates that you don't want to lock a room but a particular exit is unavailable, for example there is a door that you haven't got a key for
c) room-based weighting: some rooms take longer to cross than others (for example, a wading through a river - you'd rather pick 3 land tiles than 1 river tile)
d) exit-based weighting: some exits can be slower to traverse than others, for example there is rubble in them.

[Yonaba]

Thanks for all those details @vadi2,

a) Room-based locking
Should't this be solved by setting the underlying tiles as unwalkable ?

b) Exits-based locking
This is something I tried in the past. I wanted to see if was possible to pathfind with nodes that have specific rules for crossing: for instances, tiles that can only be entered from the north, etc. I implemented it via bitmasks (with this approach), but the result was not much satisfying, and most of al, it was not working really well (I think I did not investigated it well enough, though).
But I am willing to reconsider the problem (see #21). Hopefully, that will work.

c) Room-based weighting, d) Exit-based weighting
It reminds me of a features I wanted to take a look at (#9) and I feel like it potentially solves this. I wanted to include weighting for nodes. Actually, adding a weight value to a node is supposed to increade the penalty for going through that node. So that the pathfinder will attempt to avoid this very node without completely ignoring it. I actually implemented it already (as a side experiment in a different branch, but the intent was to provide a simple solution to avoid stacking when routing a group of agents). You can take a look at it here, and there's also a video available.

[vadi2]

(a) probably is, I included it for completeness.

The rest of the stuff is interesting - when I'll have time, I'll try using jumper out in Mudlet (mudlet.org). It's a C++ MUD client embedding Lua for scripting. Pathfinding is handled on the C++ side by Boost's A* implementation, with a rich API available to Lua (http://wiki.mudlet.org/w/Manual:Mapper_Functions). The map data is stored on the C++ side but every detail is retrievable in Lua, so you can in effect pull all the data out and use your own pathfinding algorithms - making it possible to play with Jumper in it.