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How to install

Add these 2 lines in your html file:

<script src="p5.js"></script>
<script src="pathfinder.js"></script>

How to use

Declaring

First of all you have to declare an instance of the Pathfinder class like this:

let pathfinder = new Pathfinder(60, 30, 20, true, Pathfinder.euclideanDistance);

The line above creates an 60x30 grid with 20pixel nodes where each node is walkable. The 4th parameter specifies whether the path can move diagonally or not. The 5th parameter is used to specify the distance function used. There are 2 built-in ones:

  • Pathfinder.euclideanDistance
  • Pathfinder.manhattanDistance

However, you can build your own. The function must take take (x1, y1, x2, y2) as arguements and return a number

Adding unwalkable nodes

You can start adding unwalkable nodes like this:

pathfinder.addUnwalkableNode(15, 8);

The line above declares that the pathfinder can not walk on the node with position (x=15, y=8).

You can also create rectangles with:

pathfinder.addUnwalkableRect(20, 13, 5, 10);

This creates an unwalkable rectangle in position (x=20, y=13) with 5 width and 10 height Note that adding obstacles is optional.

Finding path

Firstly you should specify what the start and target nodes are. You can do so with:

pathfinder.setStartNode(5, 3);
pathfinder.setTargetNode(25, 14);

You can start finding paths simply by:

let nodesList = pathfinder.getPath();

This will return a list of all the nodes that make up the path. The start position is (x=5, y=3) and the target position is (x=25, y=14). You can then access the position of the nodes with

nodesList[i].x
nodesList[i].y

Note that if the target node is unreachable then an empty list is returned.
Note that if the target node happens to be an unwalkable node then an empty list is returned.

Visualizing

There are a couple of functions that handle this and you have 2 options.

  1. Simple way:
pathfinder.drawEverything();

Note that this should be called after the pathfinder.getPath() has been called.

  1. Advanced way:
node.draw(); // Draws a single node with the correct color
pathfinder.drawUnwalkableNodes(); // Draws all unwalkable nodes
pathfinder.drawClosedTiles(); // Draws all the nodes in the closed list
pathfinder.drawOpenTiles(); // Draws all the nodes in the open list
pathfinder.drawPathTiles(); // Draws all the nodes generated by the path