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动态寻路A*Unity3D C#

path-finding artificial-intelligence unity3d c#

WiseDev · 技术社区 · 9 年前

我正尝试在Unity3D中使用A*寻路,如果目标保持静止,它就会起作用。然而,如果目标移动,单位仍将遵循相同的路径。找到下面每个单元的代码(附在导引头对象上):

using UnityEngine;
using System.Collections;

public class Unit : MonoBehaviour {

    public Transform target;
    float speed = 20;
    Vector3[] path;
    int targetIndex;

void Start() {
    PathRequestManager.RequestPath(transform.position,target.position, OnPathFound);
}

public void OnPathFound(Vector3[] newPath, bool pathSuccessful) {
    if (pathSuccessful) {
        path = newPath;
        StopCoroutine("FollowPath");
        StartCoroutine("FollowPath");
    }
}

IEnumerator FollowPath() {
    Vector3 currentWaypoint = path[0];

    while (true) {
        if (transform.position == currentWaypoint) {
            targetIndex ++;
            if (targetIndex >= path.Length) {
                yield break;
            }
            currentWaypoint = path[targetIndex];
        }


        transform.position = Vector3.MoveTowards(transform.position,currentWaypoint,speed * Time.deltaTime);
        yield return null;

    }
}

public void OnDrawGizmos() {
    if (path != null) {
        for (int i = targetIndex; i < path.Length; i ++) {
            Gizmos.color = Color.black;
            Gizmos.DrawCube(path[i], Vector3.one);

            if (i == targetIndex) {
                Gizmos.DrawLine(transform.position, path[i]);
            }
            else {
                Gizmos.DrawLine(path[i-1],path[i]);
            }
        }
    }
}

}

现在,如果我尝试通过将void Start()更改为void Update()来使用它进行动态路径查找(目标移动和路径更新),这将不起作用。该响应将导致奇怪的单元行为,一直来回移动或未完成路径等。现在我不知道这件事的确切原因,可能是因为验尸程序? 无论如何,我如何才能更改代码,从而获得正确的动态路径查找结果?

提前谢谢!

另外,所有剩余的源代码都可以在这里找到: http://bit.ly/pathfindingSource

2 回复 | 直到 9 年前

Jerry Switalski 9 年前

只要该逻辑的设计不是最佳的,那么当到达下一个航路点时,尝试重新计算路径:

IEnumerator FollowPath() {
    Vector3 currentWaypoint = path[0];

    while (true) {
        if (transform.position == currentWaypoint) {

           PathRequestManager.RequestPath(transform.position,target.position, OnPathFound);

targetIndex = 0;
            targetIndex ++;
            if (targetIndex >= path.Length) {
                yield break;
            }
            currentWaypoint = path[targetIndex];
        }


        transform.position = Vector3.MoveTowards(transform.position,currentWaypoint,speed * Time.deltaTime);
        yield return null;

    }

如果你想进行动态寻路,你需要在每次到达下一个航路点时重新计算路径,或者有其他逻辑,比如当一些对象移动时触发一个事件,你需要重新计算路径。

WiseDev 9 年前

我已经“解决”了这个问题,现在有了一个足够好的解决方案。

首先,我通过在每个航路点请求一条新路径,使寻路变得动态。其次,即使在到达目标后,路径查找仍在继续,通过一些逻辑,检查每一帧单元是否足够远,以重复协同程序。如果是,则停止旧的协同程序并启动新的协同程序。

下面是代码:

using UnityEngine;
using System.Collections;

public class Unit : MonoBehaviour {

public Transform target;
float speed = 20;
Vector3[] path;
int targetIndex;

bool  newRequestReady;

void Start() {
    PathRequestManager.RequestPath(transform.position,target.position, OnPathFound);

    newRequestReady = false;
}

void Update(){
    float distance = Vector3.Distance (transform.position, target.position);
    Debug.Log(distance);

    if(distance < 5){
        StopCoroutine("FollowPath");
        newRequestReady = true;
    }
    else if(distance >=10 && newRequestReady){
        PathRequestManager.RequestPath(transform.position,target.position, OnPathFound);
        StopCoroutine("FollowPath");
        newRequestReady = false;

    }
}

public void OnPathFound(Vector3[] newPath, bool pathSuccessful) {
    if (pathSuccessful) {
        path = newPath;
        StopCoroutine("FollowPath");
        StartCoroutine("FollowPath");
    }
}

IEnumerator FollowPath() {
    Vector3 currentWaypoint = path[0];

    while (true) {

        if (transform.position == currentWaypoint) {
            PathRequestManager.RequestPath(transform.position,target.position,OnPathFound);
            targetIndex=0;

            targetIndex ++;
            //Debug.Log(currentWaypoint);

            if (targetIndex >= path.Length) {
                targetIndex =0;
                path = new Vector3[0];
            //yield break;
            }
            currentWaypoint = path[targetIndex];
        }
            transform.position = Vector3.MoveTowards(transform.position,currentWaypoint,speed * Time.deltaTime);

        yield return null;
    }
}


}