Having trouble with a pathfinding script

Unity Engine
1

Hi, I wrote this script for pathfinding:

using UnityEngine;
using System.Collections;


public class SmartMove : MonoBehaviour {
	Transform[] pathNodes;	
	
	public void CalculatePath(Transform startingNode, Transform destinationNode) {
		pathNodes = new Transform[1];

		AddNode(startingNode, startingNode, destinationNode, false);
	}
	
	void AddNode(Transform nodeToAdd, Transform startingNode, Transform destinationNode, bool hasReachedDestination) {
		if(!hasReachedDestination) {
			Transform[] tempOpenNodes = new Transform[pathNodes.Length+1];
			tempOpenNodes[pathNodes.Length] = nodeToAdd;
			
			pathNodes = new Transform[tempOpenNodes.Length];
			pathNodes = tempOpenNodes;

			CalculateOpenNodes(nodeToAdd, startingNode, destinationNode);
		}
			
		if(hasReachedDestination)
			GameObject.Find("PathfindingManager").GetComponent<PathfindingTest>().TakePath(pathNodes);	

	}
	
	void CalculateOpenNodes(Transform currentNode, Transform startingNode, Transform destinationNode) {
		bool atDestination = false;
		
		Transform currentBestNode = null;
		Transform[] neighbors = currentNode.GetComponent<Tile>().neighbors;	
		
		foreach(Transform currentNeighbor in neighbors) {
			if (currentNeighbor != null) {
				if (currentBestNode == null)
					currentBestNode = currentNeighbor;
				
				int F = (int)Mathf.Round(Vector3.Distance(currentNeighbor.position, startingNode.position));
				int H = (int)Mathf.Round(Vector3.Distance(currentNeighbor.position, destinationNode.position));
				int currentG = F + H;
				
				int smallestF = (int)Mathf.Round(Vector3.Distance(currentBestNode.position, startingNode.position));
				int smallestH = (int)Mathf.Round(Vector3.Distance(currentBestNode.position, destinationNode.position));
				int smallestG = smallestF + smallestH;			
				
				if(currentG < smallestG)
					currentBestNode = currentNeighbor;
				
				if (currentNeighbor == destinationNode)
					atDestination = true;
			}
		}
				
		AddNode(currentBestNode, startingNode, destinationNode, atDestination);
		
	}

}

It’s a very simplified version of A* pathfinding as explained here. I’m a fairly inexperienced programmer, so this has been a real challenge to come up with. However, it crashes the editor, and I can’t figure out why. Could somebody please give it a quick run through and point out any obvious mistakes?

Thanks, Havoc

EDIT: Aaaand the script looks like crap. You’ll have to copy it into your favorite text editor to decode it. Sorry about that, can’t format any better. >.<

2

Hmmm… have you sort the open list?

In situations like this, I usually disable my code section by section to find out which part goes wrong. Or starting from an empty function, then add codes in small steps.

I just wrote an A* yesterday, but I am using JavaScript rather than C#.

Here is a more straight forward overview of A*
http://theory.stanford.edu/~amitp/GameProgramming/ImplementationNotes.html

3

Ah, thanks. I’ll look into the link you provided.

In answer to your question, no. I tried a simpler method, so I skipped the open and closed lists entirely. I now see after further research that that makes this code useless. Thanks for replying!