Multi Target Path Implementation

Beginner Questions
1

Hi I implemented the example path from the scene examples on the asset file and it works perfectly. Now I want to implement a Multi Target Path to it, I saw MultiTargetPath.cs in the pathfinders folder of the asset. I have also read the multi target path example in the API but I still find it hard to follow. Do I extend the MultiTargetPath like the way I extended AIPath? I really do not know where to begin or how to use the MultiTargetPath.cs script since in the example it did not use this script at all.

2

Can anyone help me with using multi target path? I tried the example but it gives me the error

UnityEngine.Vector3[][]' toSystem.Collections.Generic.List<UnityEngine.Vector3>[]’

3

My problem is how to make this:

public void OnPathComplete (Path p) {
	path = p;
	currentWaypointIndex = 0;
	targetReached = false;
	canSearchAgain = true;
	
	if (closestOnPathCheck) {
		Vector3 p1 = p.startPoint;
		Vector3 p2 = GetFeetPosition ();
		float magn = Vector3.Distance (p1,p2);
		Vector3 dir = p2-p1;
		dir /= magn;
		int steps = (int)(magn/pickNextWaypointDist);
		for (int i=0;i<steps;i++) {
			CalculateVelocity (p1);
			p1 += dir;
		}

#if DEBUG
Debug.DrawLine (p1,p2,Color.red,1);
#endif
}

	TrySearchPath ();
}

Into something like this:

public void OnPathComplete (Path p) {
    Debug.Log ("Got Callback");
    
    if (p.error) {
        Debug.Log ("Ouch, the path returned an error\

Error: "+p.errorLog);
return;
}

    MultiTargetPath mp = p as MultiTargetPath;
    if (mp == null) {
        Debug.LogError ("The Path was no MultiTargetPath");
        return;
    }
    
    //All paths
    List<Vector3>[] paths = mp.vectorPaths;
    
    for (int i=0;i<paths.Length;i++) {
        //Plotting path i
        List<Vector3> path = paths[i];
        
        if (path == null) {
            Debug.Log ("Path number "+i+" could not be found");
            continue;
        }
        
        for (int j=0;j<path.Count-1;j++) {
            //Plot segment j to j+1 with a nice color got from Pathfinding.Mathfx.IntToColor
            Debug.DrawLine (path[j],path[j+1],Mathfx.IntToColor (i,0.5F));
        }
    }
}

I tried changing this path = p; to this----> MultiTargetPath mp = p as MultiTargetPath;
and

Vector3 p1 = p.startPoint; to this —> Vector3 p1 = mp.vectorPaths[0].startPoint;

But I still cant access the start Point. Can anybody please help me. I been messing around with the A* project for weeks now. If someone could create a sample scene with two paths it will be very helpful. Since the exaple in the documentation is giving me an error.

4

Hi

Hm… Maybe the names of my scripts aren’t the best. AIPath is a movement script for a character, MultiTargetPath is a path type, i.e it is used to find the best path from a single point to multiple possible target points.

See this example, I am not sure if it was the same one that you read. But this one definitely uses the MultiTargetPath class.
http://arongranberg.com/astar/docs/_multi_target_path_example_8cs-example.php

5

First of all thank you very much for answering.

Secondly, Yes after days of studying the code I realized that MultiTargetPath was namespaced as pathfinding so I needed not extend it just needed to use it using pathfinding. I tried to implement the example but I have been getting the error on this part List[] paths = mp.vectorPaths; which tells me that vectorPaths contrary to the documentation is not a List[] but a Vector3[][] therefore would give me the error Cannot implicitly convert type UnityEngine.Vector3[][]' toSystem.Collections.Generic.List<UnityEngine.Vector3>[]’

Third, I modified the AIPath script to use the MultiTargetPath and manually made a vector of 2 targets just to test if the seeker would return 2 paths and it worked. For reference I made changed the list data type to Vector[][] as shown below.

`

void Awake () {
seeker = GetComponent();
seeker.pathCallback += OnPathComplete;
}

public void SearchPath () {

Vector3[] endPoints = new Vector3[2];

	endPoints [0] = target1.position;
	endPoints [1] = target2.position;
	
	canSearchAgain = false;

	MultiTargetPath p = new MultiTargetPath (GetFeetPosition(),endPoints,null,null);
	seeker.StartMultiTargetPath (p);

}

public void OnPathComplete (Path p) {

	if (p.error) {
		Debug.Log ("Ouch, the path returned an error\

Error: "+p.errorLog);
return;
}

	MultiTargetPath mp = p as MultiTargetPath;

	if (mp == null) {
		Debug.LogError ("The Path was not a MultiTargetPath");
		return;
	}

	Vector3[][] paths = mp.vectorPaths;

	for (int i=0;i< mp.vectorPaths.Length;i++) {
		//Plotting path i
		Vector3[] path = mp.vectorPaths[i];
		
		if (path == null) {
			Debug.Log ("Path number "+i+" could not be found");
			continue;
		}
		
		for (int j=0;j<path.Length -1;j++) {
			Debug.DrawLine (path[j],path[j+1],Color.blue);
		}
	}

}
`

The only problem I got now is how could I check which path is the shortest path among all the paths found?

6

oh never mind I solved it by setting the public bool pathsForAll to false.