我的统一脚本中可能有一个非常简单或非常复杂的问题。 简而言之，当尝试在下面所示的方法中的打开列表上使用 .Add 或 .Insert 方法时，Unity 编辑器将停止响应任何输入并挂起，直到在任务管理器中强制关闭。
有问题的方法：
private void addToOpen(location l){ //causes editor crash
int fScore = l.getF (); //f score of the location to add
int count = open.Count; //number of values in the list
int index = 0; //index to insert the location
Debug.Log ("count " + count);
while (index < count) {
if(fScore >= open[index].getF()){
break;
}
index++;
}
open.Insert(index, temp);
}
该代码正在尝试实现 A* 寻路算法。
我正在尝试将下面网页中的代码翻译成 C#。
http://www.raywenderlich.com/4970/how-to-implement-a-pathfinding-with-cocos2d-tutorial
我的脚本的大部分内容如下，以提供上下文：
using UnityEngine;
using System.Collections;
using System.Collections.Generic; //for lists
using System; //for broad use of "Exception"
public class MouseBasedMovement : MonoBehaviour {
public GameObject map; //Holds the map object
private MapDataA mapdataa; //stores reference to data script
public Camera mainCamera;
void Awake(){
mapdataa = map.GetComponent<MapDataA> (); //Links variable with component
}
//object for storing tile locations
public class location{
public int xCoor;
public int yCoor;
//methods rarely interact with f as it is usually ignored, I tried to keep it isolated from extra interactions and assignments
public int f;
location parent; //location the object came from in A* algorithm
public int g;
public int h;
public location(){
xCoor = 0;
yCoor = 0;
}
public location(int x, int y){
xCoor = x;
yCoor = y;
}
public location(location l){
//constructor creates a copy of the location but does not copy the F value
xCoor = l.getX ();
yCoor = l.getY ();
}
public location(int x, int y, location a, location b){ //constructor for a*
//x is x coordinate
//y is y coordinate
//a is starting position in algorithm ("from" tile)
//b is target position in algorithm ("to" tile)
xCoor = x;
yCoor = y;
//g , h , f
//g = getD(a, new location (x,y));
//h = getD(new location(x,y), b);
//f = getD(a, new location (x,y)) + getD(new location(x,y), b);
//--- seems I can not nest constructors, going to simply do the same job by not using the getD method and using the method's logic + code instead.
//private int getD(location a, location b){ //used for calculating g and h
//if G,
//a is the start point
//b is the current square
//if H,
//a is the current square
//b is the endpoint
// int total = Math.Abs (a.getY () - b.getY ()) + Math.Abs (a.getX () - b.getX ());
// return total;
//}
g = Math.Abs (a.getY () - y) + Math.Abs (a.getX () - x);
h = Math.Abs (y - b.getY ()) + Math.Abs (x - b.getX ());
f = (Math.Abs (a.getY () - y) + Math.Abs (a.getX () - x)) + (Math.Abs (y - b.getY ()) + Math.Abs (x - b.getX ()));
}
public void setX(int x){
xCoor = x;
}
public void setY(int y){
yCoor = y;
}
public int getX(){
return xCoor;
}
public int getY(){
return yCoor;
}
public void setParent(location p){
parent = p;
}
public location getParent(){
return parent;
}
public void setF(int i){
f = i;
}
public int getF(){
return f;
}
public void setG(int gset){
g = gset;
}
public int getG(){
return g;
}
public void setH(int hset){
h = hset;
}
public int getH(){
return h;
}
public bool compareTo(location c){
if ((c.getX () == this.getX ()) && (c.getY () == this.getY ())){
return true;
}else{
return false;
}
}
public string toString(){
string str = "x: " + xCoor + " y: " + yCoor;
return str;
}
}
List<location> open = new List<location> (); //A* open list
List<location> closed = new List<location> (); //A* closed list
//method for the A* pathfinding algorithm's implementation in player movement
//Helped greatly in writing this section:
//http://www.raywenderlich.com/4946/introduction-to-a-pathfinding
//http://www.raywenderlich.com/4970/how-to-implement-a-pathfinding-with-cocos2d-tutorial
public void aStar(location a, location b){
//a is starting position
//b is ending position
//checks to see if the destination is the same as the current position
if (a.compareTo (b) == true) {
Debug.Log ("Already There");
return;
}
//Checks to see if the id of the destination tile is 1, and thus innacessable
Debug.Log (mapdataa.mapData.GetLength (0));
Debug.Log (mapdataa.mapData.GetLength (1));
Debug.Log (b.getY ());
Debug.Log (b.getX ());
if (mapdataa.mapData[b.getY(), b.getX ()].getId () == 1){
Debug.Log ("Destination tile is inaccessable");
return;
}
//checks to see if the tile is highlighted (aka in range)
GameObject[] inRange = GameObject.FindGameObjectsWithTag ("moveTransparent");
bool found = false;
foreach (GameObject trans in inRange) {
if (trans.transform.position.x == b.getX () && trans.transform.position.y == b.getY ()){
//tile is within range
found = true;
}
}
if (found == false) { //This section has worked in testing.
//tile was never found to be within range
Debug.Log ("Tile not in range/Tile not highlighted");
return;
}
//begin A* actual algorithm implementation here
bool pathFound = false;
open.Add(new location ((int)transform.position.x, (int)transform.position.y, a, b)); //adds initial location of playable to open list
//testing
Debug.Log ("open[0]: " + open[0].toString ());
Debug.Log (open.Count);
//end testing
//above was previously an addToOpen method call, but I changed it to add, it SHOULD not affect logic, and may fix bugs
location current = new location ();
location temp = new location ();
//Something in here (main algorithmic loop) is causing the crash
do{
//Get the lowest F score step
//Because the list is ordered, the first step always has the lowest F score
current = open[0];
//add the current step to the closed list
closed.Add (current);
//remove the current step from the open list
open.RemoveAt (0);
//if current is the desired tile coordinate, the algorithm is complete
if(current.compareTo (b)){
pathFound = true;
temp = current;
Debug.Log ("Path Found");
//LOOK INTO THIS! PARENT CHILD STRUCTURE NEEDS TO BE CONSIDERED
do{
Debug.Log (temp);
temp = temp.getParent();
}while(temp != null);
break;
}
//get the adjacent tiles to the current step
location[] adjSteps = getAdjacent (current,a,b);
foreach (location loc in adjSteps){
//check if the step isn't already in the closed set
if (closed.Contains (loc)){
continue; //effectively ignores it
}
//check if the step is already in the open list
//NOTE: the line here in the source material is iffy, there might be functionality that I am not implementing
if (open.Contains (loc) == false){
//aka, not in the open list
//set current step as the parent
loc.setParent (current); //3
//G score is parent g score + 1 (cost to move from parent to it)
loc.setG (current.getG () + 1); //4
//compute H score
loc.setH (getD (loc, b)); //5
//adding it to the open list
addToOpen(loc);
}else{
//aka, already in the open list
int index = open.IndexOf (loc);
//loc = open[index];
//check to see if the G score is equal to the parent g score + cost to move(1)
if(current.getG () + 1 < open[index].getG ()){
//The G score is equal to the parent G score + the cost to move to it
open[index].setG (current.getG () + 1);
//because the G score changed, f may change too
//so to keep the open list ordered, we have to remove and reinsert it
location locB = new location(open[index]); //added to circumvent bug
//remove from the list
open.RemoveAt (index);
//reinsert it
addToOpen (locB); //replaced loc with locB to circumvent bug
}
}
}
}while(open.Count > 0);
if (!pathFound) { //no path found
Debug.Log ("The algorithm failed to discover a path");
}
}
private void addToOpen(location l){ //causes editor crash
int fScore = l.getF (); //f score of the location to add
int count = open.Count; //number of values in the list
int index = 0; //index to insert the location
Debug.Log ("count " + count);
while (index < count) {
if(fScore >= open[index].getF()){
break;
}
index++;
}
open.Insert(index, temp);
}
//majorly reworked to prohibit returning null values to avoid editor crash while fixing bugs
private location[] getAdjacent(location l, location a, location b){
location[] adjacents = new location[4];
GameObject[] inRange = GameObject.FindGameObjectsWithTag ("moveTransparent");
bool found = false;
int counter = 0;
//up
location up = new location (l.getX (), l.getY () + 1,a ,b);
foreach (GameObject trans in inRange) {
if (trans.transform.position.x == up.getX () && trans.transform.position.y == up.getY ()){
//tile is within range
found = true;
}
}
if ((found == true) && (mapdataa.mapData [up.getY (), up.getX ()].getId () == 0)) { //if tile is within range and is acessable
adjacents [counter] = up; //add it to the list
counter++;
}
found = false; //reset found variable
//down
location down = new location (l.getX (), l.getY () -1,a,b);
foreach (GameObject trans in inRange) {
if (trans.transform.position.x == down.getX () && trans.transform.position.y == down.getY ()){
//tile is within range
found = true;
}
}
if ((found == true) && (mapdataa.mapData [down.getY (), down.getX ()].getId () == 0)) { //if tile is within range and is acessable
adjacents [counter] = down; //add it to the list
counter++;
}
found = false; //reset found variable
//left
location left = new location (l.getX () -1, l.getY (),a,b);
foreach (GameObject trans in inRange) {
if (trans.transform.position.x == left.getX () && trans.transform.position.y == left.getY ()){
//tile is within range
found = true;
}
}
if ((found == true) && (mapdataa.mapData [left.getY (), left.getX ()].getId () == 0)) { //if tile is within range and is acessable
adjacents [counter] = left; //add it to the list
counter++;
}
found = false; //reset found variable
//right
location right = new location (l.getX () +1, l.getY (),a,b);
foreach (GameObject trans in inRange) {
if (trans.transform.position.x == right.getX () && trans.transform.position.y == right.getY ()){
//tile is within range
found = true;
}
}
if ((found == true) && (mapdataa.mapData [right.getY (), right.getX ()].getId () == 0)) { //if tile is within range and is acessable
adjacents [counter] = right; //add it to the list
counter++;
}
found = false; //reset found variable
if (counter < 4) { //if statement is logically useless, but for the sake of trying to get to work, I'm leaving it as is. Once it runs, try removing the if statement and test again.
adjacents = retract (adjacents, 4-counter);
}
return adjacents;
}
private int getD(location a, location b){ //used for calculating g and h
//implements the "Manhatten method" of determining total vertical and horizontal distance on a grid
//if G,
//a is the start point
//b is the current square
//if H,
//a is the current square
//b is the endpoint
int total = Math.Abs (a.getY () - b.getY ()) + Math.Abs (a.getX () - b.getX ());
return total;
}
bool ran = false;
public void Update(){
if (ran == false) {
highlight ();
ran = true;
}
if (Input.GetMouseButtonDown (0)) { //if left click
Debug.Log ("Begin Update method A* implementation testing");
aStar (new location((int)transform.position.x,(int)transform.position.y),new location((int)((((mainCamera.transform.position.x * 64) - (.5 * Screen.width)) + Input.mousePosition.x) / 64),(int)((((mainCamera.transform.position.y * 64) - (.5 * Screen.height)) + Input.mousePosition.y) / 64)));
Debug.Log ("End Update method A* implementation testing");
}
}
}
我无法真正调试它，因为我没有完整的上下文，但这是我通过查看源代码的猜测
//This line seems to cause the editor crash
open.Insert (index, l);
我们来看看这里使用的变量：
openindex也许您已经发现了问题：列表有 0 个元素，而您正尝试在位置 1 处插入一个元素。C#（或者 CLR）不太喜欢这种情况，只是抛出一个异常（至少在Visual Studio）。
崩溃的部分很有趣。由于您使用的是 Unity，我假设您使用 MonoDevelop 作为编辑器。编辑器会在每次异常时崩溃吗？ （尝试
int a=1/0首先，
open.InsertRange(index, temp)open.Insert(index, l)其次，当您添加相邻图块时，您不会更新 F 分数。如果它是一个新的图块，您设置 G 和 H 但不设置 F。如果它已经在打开列表中，您甚至可以评论“因为 G 分数改变，f 也可能改变”，但您不更新 F。并且 F 总是会改变，因为 F = G + H。
也许退一步思考算法应该如何工作。使用教程的简介或来自Wikipedia的文章以及一些伪代码。
如果它仍然卡在某个地方，请在 aStar 循环中添加一些 Debug.Log() ，以便您可以跟踪算法正在做什么。建议测试一个小世界，否则你会迷路;)