Question

I started work on a dungeon crawler in C# and I’ve already coded the level generation.

However, I’ve run into a problem. My level map is stored in a 32×32 multidimensional array, and each tile is stored as a string. All the tiles except for the following (all of these names are the variable names that represent that tile) (mongroveplant, tree, hjalaplant, vnosplant, barraplant, weedplant, naroplant, deathweedplant, venustrap, strangulator, statue, emptiness and stonewall) cannot be walked over.

These tiles (which can be walked over), which constitute a much longer list, are found here: Walkable Tiles. In each entry in the 32×32 multidimensional array, every entry is a string.

How do I create a pathfinding algorithm that avoids all the tiles listed above, but can go through all the tiles listed in the link? I am trying to go from the “start” tile to the “exitlevel” tile.

Answer 1

The first thing I would remove is the notion of string. Parsing string isn’t quick in term of a video game. What you want, is to have flags for each tiles (bitfields). In the end, you will love flags because you can combine them!

[Flags]
public enum TileDescription
{ 
    Walkable,
    Trap,
    Altar,
    Door
}

They can also be stored at a int, which take far less space. Speed and space, two amazing notions.

As for the path-finding algo, there’s plenty of them out-there. But basically, you have a start point, a end point, and you must find the quickest way between both. The idea is to check the nearest “nodes” and see if you get closer or not of your goal. Each time, you repeat the check with the new node. If you get trapped, you rewind to the nodes that still had available paths.

You have some nice basic algo :

http://en.wikipedia.org/wiki/Dijkstra%27s_algorithm

http://en.wikipedia.org/wiki/A*_search_algorithm

However, long range pathfinding is ALWAYS extremely costly. You will have to limit the pathfinding to a specific range around the origin. Parsing a whole 32×32 maze could take a lot of time to find the quickest route. In most case, when you are beyond a specific range, you move your NPC up to the closest point, then repeat the pathfinding when it reaches it, or while reaching it. The trick to pathfinding is to do it over many frames and never to try to process it all at once.