Dijkstra 的寻路不能正常工作，有时工作，有时锁定
Dijkstra's pathfinding not working properly, sometimes works and sometimes locks up
我的算法有问题，该算法应该实现 dijkstra 的路径查找算法。
问题是系统偶尔会锁定，我认为这与未正确建立连接、节点未正确更新或我列表中的某些内容未添加有关（听起来有点像我的意思是没有任何作用）...除了在某些情况下，它可以工作并找到正确的路径。
我通过缩小地图尺寸简化了网格，因为这样更容易查看输出中是否存在错误。希望有人知道我哪里出错了。我在 gameDev 中做了 post 类似的事情，但没有得到任何回应，我已经通过了那个问题并转移到这个问题上。
这是用 libgdx 制作的。
Connections.java
package com.comp452.tme21;
public class Connections {
private int cost;
private int x;
private int y;
public Connections(int cost, int x, int y) {
this.cost = cost;
this.x = x;
this.y = y;
}
public int getCost() {
return cost;
}
public void setCost(int cost) {
this.cost = cost;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}
FullNodeComparator.java
package com.comp452.tme21;
import java.util.Comparator;
public class FullNodeComparator implements Comparator<MapNode> {
@Override
public int compare(MapNode n1, MapNode n2) {
if (n1.getX() == n2.getX()) {
if (n1.getY() == n2.getY()) {
return 1;
}
}
return 0;
}
}
MapNode.java
package com.comp452.tme21;
import java.util.ArrayList;
public class MapNode {
private int costSoFar;
private int x;
private int y;
private int connectionX;
private int connectionY;
private final ArrayList connectionsList;
private final int MAPSIZE = Pathfinder.MAPSIZE - 1;
public ArrayList getConnectionsList() {
return connectionsList;
}
public MapNode(int costSoFar, int x, int y, int connectionX, int connectionY) {
this.costSoFar = costSoFar;
this.x = x;
this.y = y;
this.connectionX = connectionX;
this.connectionY = connectionY;
connectionsList = new ArrayList();
}
public int getCostSoFar() {
return costSoFar;
}
public void setCostSoFar(int costSoFar) {
this.costSoFar = costSoFar;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public int getConnectionX() {
return connectionX;
}
public void setConnectionX(int connectionX) {
this.connectionX = connectionX;
}
public int getConnectionY() {
return connectionY;
}
public void setConnectionY(int connectionY) {
this.connectionY = connectionY;
}
public void setConnections() {
int tileMap[][] = Pathfinder.getTileMap();
int testX = 0;
int testY = 0;
// Is node not at the top of the map...
if (this.y != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x][this.y + 1] != 0) {
// If connection isn't back to start node...
testX = this.x;
testY = this.y + 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the node directly above.
connectionsList.add(new Connections(tileMap[this.x][this.y + 1], this.x, this.y + 1));
System.out.println("TM Added connection from " + this.x + "," + this.y + " to " + this.x + "," + (this.y+1));
}
}
// Is node not at the left side of the map...
if (this.x != 1) {
// If not obstacle...
if (tileMap[this.x - 1][this.y + 1] != 0) {
// If connection isn't back to start node...
testX = this.x - 1;
testY = this.y + 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the top left node.
connectionsList.add(new Connections(tileMap[this.x - 1][this.y + 1], this.x - 1, this.y + 1));
System.out.println("TL Added connection from " + this.x + "," + this.y + " to " + (this.x-1) + "," + (this.y+1));
}
}
}
// Is node not at the right side of the map...
if (this.x != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x + 1][this.y + 1] != 0) {
// If connection isn't back to start node...
testX = this.x + 1;
testY = this.y + 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the top right node.
connectionsList.add(new Connections(tileMap[this.x + 1][this.y + 1 ], this.x + 1, this.y + 1));
System.out.println("TR Added connection from " + this.x + "," + this.y + " to " + (this.x+1) + "," + (this.y+1));
}
}
}
}
// Is node not at the left side of the screen...
if (this.x != 1) {
// If not obstacle...
if (tileMap[this.x - 1][this.y] != 0) {
// If connection isn't back to start node...
testX = this.x - 1;
testY = this.y;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the left node.
connectionsList.add(new Connections(tileMap[this.x - 1][this.y], this.x - 1, this.y));
System.out.println("LM Added connection from " + this.x + "," + this.y + " to " + (this.x-1) + "," + this.y);
}
}
}
// Is node not at the right side of the screen...
if (this.x != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x + 1][this.y] != 0) {
// If connection isn't back to start node...
testX = this.x + 1;
testY = this.y;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the right node.
connectionsList.add(new Connections(tileMap[this.x + 1][this.y], this.x + 1, this.y));
System.out.println("RM Added connection from " + this.x + "," + this.y + " to " + (this.x+1) + "," + this.y);
}
}
}
// Is node not at the bottom of the map...
if (this.y != 1) {
// If not obstacle...
if (tileMap[this.x][this.y - 1] != 0) {
// If connection isn't back to start node...
testX = this.x;
testY = this.y - 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the node directly below.
connectionsList.add(new Connections(tileMap[this.x][this.y - 1 ], this.x, this.y - 1));
System.out.println("BM Added connection from " + this.x + "," + this.y + " to " + this.x + "," + (this.y - 1));
}
}
// Is node not at the left side of the map...
if (this.x != 1) {
// If not obstacle...
if (tileMap[this.x - 1][this.y - 1] != 0) {
// If connection isn't back to start node...
testX = this.x - 1;
testY = this.y - 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the bottom left node.
connectionsList.add(new Connections(tileMap[this.x - 1][this.y - 1], this.x - 1, this.y - 1));
System.out.println("BL Added connection from " + this.x + "," + this.y + " to " + (this.x-1) + "," + (this.y-1));
}
}
}
// Is node not at the right side of the map...
if (this.x != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x + 1][this.y - 1] != 0) {
// If connection isn't back to start node...
testX = this.x + 1;
testY = this.y - 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the bottom right node.
connectionsList.add(new Connections(tileMap[this.x + 1][this.y - 1], this.x + 1, this.y - 1));
System.out.println("BR Added connection from " + this.x + "," + this.y + " to " + (this.x+1) + "," + (this.y-1));
}
}
}
}
}
public int compareTo(MapNode n2) {
if (x == n2.getX()) {
if (y == n2.getY()) {
return 1;
}
}
return 0;
}
}
NodeComparator.java
package com.comp452.tme21;
import java.util.Comparator;
public class NodeComparator implements Comparator<MapNode> {
@Override
public int compare(MapNode n1, MapNode n2) {
return Integer.compare(n1.getCostSoFar(), n2.getCostSoFar());
}
}
PathFinder.java
package com.comp452.tme21;
import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
import java.util.Stack;
public class Pathfinder extends ApplicationAdapter {
protected final static int MAPSIZE = 5; //17
SpriteBatch batch;
Texture openTile, grassTile, swampTile, obstacleTile;
Texture startTile, finishTile,drawingTile;
private Player player;
private Sprite playerSprite;
private Texture texture;
private final static int[][] tileMap = new int[MAPSIZE][MAPSIZE];
public static int[][] getTileMap() {
return tileMap;
}
private int startX;
private int startY;
private int finishX;
private int finishY;
private ArrayList closed;
private ArrayList open;
private MapNode startNode;
private MapNode currentNode;
private MapNode nextNode;
private MapNode testNode;
private ArrayList nodeConnectionsList;
private Connections nextConnection;
private Stack pathList;
@Override
public void create () {
generateTiles();
batch = new SpriteBatch();
openTile = new Texture("open.jpg");
grassTile = new Texture("grass.jpg");
swampTile = new Texture("swamp.jpg");
obstacleTile = new Texture("obstacle.jpg");
startTile = new Texture("start.jpg");
finishTile = new Texture("finish.jpg");
texture = new Texture(Gdx.files.internal("player.png"));
playerSprite = new Sprite(texture);
player = new Player(playerSprite);
player.setGridX(startX);
player.setGridY(startY);
findThePath();
}
@Override
public void render () {
update(Gdx.graphics.getDeltaTime());
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
drawTiles();
player.draw(batch);
batch.end();
}
public void drawTiles() {
for (int i = 1; i < MAPSIZE; i ++) {
for (int j = 1; j < MAPSIZE; j++) {
if (tileMap[i][j] == 1) {
drawingTile = openTile;
}
else if (tileMap[i][j] == 3) {
drawingTile = grassTile;
}
else if (tileMap[i][j] == 4) {
drawingTile = swampTile;
}
else if (tileMap[i][j] == 0) {
drawingTile = obstacleTile;
}
else if (tileMap[i][j] == -1) {
drawingTile = startTile;
}
else if (tileMap[i][j] == 2) {
drawingTile = finishTile;
}
batch.draw(drawingTile, i * 32, j * 32);
}
}
}
public void update(float dt) {
player.update(dt);
}
public void generateTiles() {
int cost = 0;
Random rand = new Random();
for (int i = 1; i < MAPSIZE; i++) {
for (int j = 1; j < MAPSIZE; j++) {
int randomNum = rand.nextInt((4-1) +1) + 1;
switch (randomNum) {
case 1:
cost = 1;
break;
case 2:
cost = 3;
break;
case 3:
cost = 4;
break;
case 4:
cost = 0;
break;
}
tileMap[i][j] = cost;
}
}
startX = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
startY = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
startX = 1;
startY = 1;
tileMap[startX][startY] = -1;
finishX = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
finishY = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
finishX = 4;
finishY = 4;
tileMap[finishX][finishY] = 2;
}
public void findThePath() {
System.out.println("Start node is at " + startX + " " + startY);
startNode = new MapNode(0, startX, startY, 0, 0);
closed = new ArrayList();
open = new ArrayList();
open.add(startNode);
closed.clear();
while (open.size() > 0) {
Collections.sort(open, new NodeComparator());
currentNode = (MapNode) open.get(0);
currentNode.setConnections();
boolean nodeIsClosed = false;
boolean nodeIsOpen = false;
// If the smallest element is the goal node, stop.
if (currentNode.getX() == finishX && currentNode.getY() == finishY) {
System.out.println("Found last node at " + currentNode.getX() + " " + currentNode.getY());
closed.add(currentNode);
break;
}
else {
nodeConnectionsList = currentNode.getConnectionsList();
for (int i = 0; i < nodeConnectionsList.size(); i++) {
nextConnection = (Connections) nodeConnectionsList.get(i);
int nextX = nextConnection.getX();
int nextY = nextConnection.getY();
int nextCost = nextConnection.getCost();
nextNode = new MapNode(currentNode.getCostSoFar() + nextCost, nextX, nextY, currentNode.getX(), currentNode.getY());
// If node is already in the closed list, set flag to continue.
for (int j = 0; j < closed.size(); j++) {
testNode = (MapNode) closed.get(j);
if (nextNode.compareTo(testNode) == 1) {
nodeIsClosed = true;
}
}
// If flag is set, continue to next iteration.
if (nodeIsClosed) {
nodeIsClosed = false;
continue;
}
// If node is already in open list, check to see if it's better.
for (int j = 0; j < open.size(); j++) {
testNode = (MapNode) open.get(j);
if (nextNode.compareTo(testNode) == 1) {
nodeIsOpen = true;
if (nextNode.getCostSoFar() > testNode.getCostSoFar()){
// Do nothing.
break;
}
else {
System.out.println("Found better route to " + nextNode.getX() + " " + nextNode.getY());
System.out.println("From " + currentNode.getX() + " " + currentNode.getY());
testNode.setCostSoFar(nextNode.getCostSoFar());
testNode.setConnectionX(currentNode.getX());
testNode.setConnectionY(currentNode.getY());
break;
}
}
}
if (nodeIsOpen) {
nodeIsOpen = false;
}
else {
open.add(nextNode);
}
}
closed.add(new MapNode(currentNode.getCostSoFar(), currentNode.getX(), currentNode.getY(), currentNode.getConnectionX(), currentNode.getConnectionY()));
}
open.remove(0);
}
int totalCost = 0;
pathList = new Stack();
// Find the end node and get it's first connection.
for (int i = 0; i < closed.size(); i++) {
testNode = (MapNode) closed.get(i);
if (testNode.getX() == finishX) {
if (testNode.getY() == finishY) {
pathList.push(new Connections(totalCost, finishX, finishY));
System.out.println("finish x: " + finishX);
System.out.println("finish y: " + finishY);
System.out.println("FromX: " + testNode.getConnectionX());
System.out.println("FromY: " + testNode.getConnectionY());
totalCost = testNode.getCostSoFar();
System.out.println("Total Cost: " + totalCost);
System.out.println("---------");
closed.remove(i);
break;
}
}
}
int findingX = testNode.getConnectionX();
int findingY = testNode.getConnectionY();
do {
for (int i = 0; i < closed.size(); i++) {
testNode = (MapNode) closed.get(i);
if (testNode.getX() == findingX) {
if (testNode.getY() == findingX) {
System.out.println("x: " + findingX);
System.out.println("y: " + findingY);
System.out.println("FromX: " + testNode.getConnectionX());
System.out.println("FromY: " + testNode.getConnectionY());
totalCost = testNode.getCostSoFar();
System.out.println(totalCost);
System.out.println("---------");
pathList.push(new Connections(totalCost, findingX, findingY));
findingX = testNode.getConnectionX();
findingY = testNode.getConnectionY();
closed.remove(i);
break;
}
}
}
if (closed.isEmpty()) {
System.out.println("Closed list is empty");
break;
}
} while((findingX != 0 && findingY != 0) && (findingX != startX && findingY != startY));
Connections testConnection;
System.out.println("Path Size: " + pathList.size());
while (!pathList.empty()) {
testConnection = (Connections) pathList.pop();
System.out.println("TC X: " + testConnection.getX());
System.out.println("TC Y: " + testConnection.getY());
}
System.out.println("Done");
}
}
Player.java
package com.comp452.tme21;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.graphics.g2d.Sprite;
public class Player extends Sprite {
public int gridX;
public int gridY;
public Player(Sprite sprite) {
super(sprite);
}
@Override
public void draw(Batch batch) {
batch.draw(this.getTexture(), this.getX(), this.getY());
}
public void update(float dt) {
}
public int getCenterX() {
int centerX = (int) (getX() + getWidth() /2);
return centerX;
}
public int getCenterY() {
int centerY = (int) (getY() + getHeight() /2);
return centerY;
}
public int getGridX() {
int gX = (int) (getX() / 32);
return gX;
}
public int getGridY() {
int gY = (int) (getY() / 32);
return gY;
}
public void setGridX(int x) {
setX(x * 32);
}
public void setGridY(int y) {
setY(y * 32);
}
}
事实证明，这是一个非常简单而愚蠢的错误。
看看这行代码。你能看到错误吗？我花了好几个小时在几乎每一英寸的代码（我的调试版本）上搜索和大量的 println 语句，我终于看到了它。更正问题后，一切都按预期工作（有一些小的添加和代码清理，以及如果不存在路径时的捕获...但这从来都不是问题）。
if (testNode.getX() == findingX) {
if (testNode.getY() == findingX) {
当我终于看到这个时，我想 "how stupid!!!"。你现在看到了吗？
我的算法有问题，该算法应该实现 dijkstra 的路径查找算法。
问题是系统偶尔会锁定，我认为这与未正确建立连接、节点未正确更新或我列表中的某些内容未添加有关（听起来有点像我的意思是没有任何作用）...除了在某些情况下，它可以工作并找到正确的路径。
我通过缩小地图尺寸简化了网格，因为这样更容易查看输出中是否存在错误。希望有人知道我哪里出错了。我在 gameDev 中做了 post 类似的事情，但没有得到任何回应，我已经通过了那个问题并转移到这个问题上。
这是用 libgdx 制作的。
Connections.java
package com.comp452.tme21;
public class Connections {
private int cost;
private int x;
private int y;
public Connections(int cost, int x, int y) {
this.cost = cost;
this.x = x;
this.y = y;
}
public int getCost() {
return cost;
}
public void setCost(int cost) {
this.cost = cost;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
}
FullNodeComparator.java
package com.comp452.tme21;
import java.util.Comparator;
public class FullNodeComparator implements Comparator<MapNode> {
@Override
public int compare(MapNode n1, MapNode n2) {
if (n1.getX() == n2.getX()) {
if (n1.getY() == n2.getY()) {
return 1;
}
}
return 0;
}
}
MapNode.java
package com.comp452.tme21;
import java.util.ArrayList;
public class MapNode {
private int costSoFar;
private int x;
private int y;
private int connectionX;
private int connectionY;
private final ArrayList connectionsList;
private final int MAPSIZE = Pathfinder.MAPSIZE - 1;
public ArrayList getConnectionsList() {
return connectionsList;
}
public MapNode(int costSoFar, int x, int y, int connectionX, int connectionY) {
this.costSoFar = costSoFar;
this.x = x;
this.y = y;
this.connectionX = connectionX;
this.connectionY = connectionY;
connectionsList = new ArrayList();
}
public int getCostSoFar() {
return costSoFar;
}
public void setCostSoFar(int costSoFar) {
this.costSoFar = costSoFar;
}
public int getX() {
return x;
}
public void setX(int x) {
this.x = x;
}
public int getY() {
return y;
}
public void setY(int y) {
this.y = y;
}
public int getConnectionX() {
return connectionX;
}
public void setConnectionX(int connectionX) {
this.connectionX = connectionX;
}
public int getConnectionY() {
return connectionY;
}
public void setConnectionY(int connectionY) {
this.connectionY = connectionY;
}
public void setConnections() {
int tileMap[][] = Pathfinder.getTileMap();
int testX = 0;
int testY = 0;
// Is node not at the top of the map...
if (this.y != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x][this.y + 1] != 0) {
// If connection isn't back to start node...
testX = this.x;
testY = this.y + 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the node directly above.
connectionsList.add(new Connections(tileMap[this.x][this.y + 1], this.x, this.y + 1));
System.out.println("TM Added connection from " + this.x + "," + this.y + " to " + this.x + "," + (this.y+1));
}
}
// Is node not at the left side of the map...
if (this.x != 1) {
// If not obstacle...
if (tileMap[this.x - 1][this.y + 1] != 0) {
// If connection isn't back to start node...
testX = this.x - 1;
testY = this.y + 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the top left node.
connectionsList.add(new Connections(tileMap[this.x - 1][this.y + 1], this.x - 1, this.y + 1));
System.out.println("TL Added connection from " + this.x + "," + this.y + " to " + (this.x-1) + "," + (this.y+1));
}
}
}
// Is node not at the right side of the map...
if (this.x != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x + 1][this.y + 1] != 0) {
// If connection isn't back to start node...
testX = this.x + 1;
testY = this.y + 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the top right node.
connectionsList.add(new Connections(tileMap[this.x + 1][this.y + 1 ], this.x + 1, this.y + 1));
System.out.println("TR Added connection from " + this.x + "," + this.y + " to " + (this.x+1) + "," + (this.y+1));
}
}
}
}
// Is node not at the left side of the screen...
if (this.x != 1) {
// If not obstacle...
if (tileMap[this.x - 1][this.y] != 0) {
// If connection isn't back to start node...
testX = this.x - 1;
testY = this.y;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the left node.
connectionsList.add(new Connections(tileMap[this.x - 1][this.y], this.x - 1, this.y));
System.out.println("LM Added connection from " + this.x + "," + this.y + " to " + (this.x-1) + "," + this.y);
}
}
}
// Is node not at the right side of the screen...
if (this.x != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x + 1][this.y] != 0) {
// If connection isn't back to start node...
testX = this.x + 1;
testY = this.y;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the right node.
connectionsList.add(new Connections(tileMap[this.x + 1][this.y], this.x + 1, this.y));
System.out.println("RM Added connection from " + this.x + "," + this.y + " to " + (this.x+1) + "," + this.y);
}
}
}
// Is node not at the bottom of the map...
if (this.y != 1) {
// If not obstacle...
if (tileMap[this.x][this.y - 1] != 0) {
// If connection isn't back to start node...
testX = this.x;
testY = this.y - 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the node directly below.
connectionsList.add(new Connections(tileMap[this.x][this.y - 1 ], this.x, this.y - 1));
System.out.println("BM Added connection from " + this.x + "," + this.y + " to " + this.x + "," + (this.y - 1));
}
}
// Is node not at the left side of the map...
if (this.x != 1) {
// If not obstacle...
if (tileMap[this.x - 1][this.y - 1] != 0) {
// If connection isn't back to start node...
testX = this.x - 1;
testY = this.y - 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the bottom left node.
connectionsList.add(new Connections(tileMap[this.x - 1][this.y - 1], this.x - 1, this.y - 1));
System.out.println("BL Added connection from " + this.x + "," + this.y + " to " + (this.x-1) + "," + (this.y-1));
}
}
}
// Is node not at the right side of the map...
if (this.x != MAPSIZE) {
// If not obstacle...
if (tileMap[this.x + 1][this.y - 1] != 0) {
// If connection isn't back to start node...
testX = this.x + 1;
testY = this.y - 1;
if (testX == 1 && testY == 1) {
}
else {
// Add the connection to the bottom right node.
connectionsList.add(new Connections(tileMap[this.x + 1][this.y - 1], this.x + 1, this.y - 1));
System.out.println("BR Added connection from " + this.x + "," + this.y + " to " + (this.x+1) + "," + (this.y-1));
}
}
}
}
}
public int compareTo(MapNode n2) {
if (x == n2.getX()) {
if (y == n2.getY()) {
return 1;
}
}
return 0;
}
}
NodeComparator.java
package com.comp452.tme21;
import java.util.Comparator;
public class NodeComparator implements Comparator<MapNode> {
@Override
public int compare(MapNode n1, MapNode n2) {
return Integer.compare(n1.getCostSoFar(), n2.getCostSoFar());
}
}
PathFinder.java
package com.comp452.tme21;
import com.badlogic.gdx.ApplicationAdapter;
import com.badlogic.gdx.Gdx;
import com.badlogic.gdx.graphics.GL20;
import com.badlogic.gdx.graphics.Texture;
import com.badlogic.gdx.graphics.g2d.Sprite;
import com.badlogic.gdx.graphics.g2d.SpriteBatch;
import java.util.ArrayList;
import java.util.Collections;
import java.util.Random;
import java.util.Stack;
public class Pathfinder extends ApplicationAdapter {
protected final static int MAPSIZE = 5; //17
SpriteBatch batch;
Texture openTile, grassTile, swampTile, obstacleTile;
Texture startTile, finishTile,drawingTile;
private Player player;
private Sprite playerSprite;
private Texture texture;
private final static int[][] tileMap = new int[MAPSIZE][MAPSIZE];
public static int[][] getTileMap() {
return tileMap;
}
private int startX;
private int startY;
private int finishX;
private int finishY;
private ArrayList closed;
private ArrayList open;
private MapNode startNode;
private MapNode currentNode;
private MapNode nextNode;
private MapNode testNode;
private ArrayList nodeConnectionsList;
private Connections nextConnection;
private Stack pathList;
@Override
public void create () {
generateTiles();
batch = new SpriteBatch();
openTile = new Texture("open.jpg");
grassTile = new Texture("grass.jpg");
swampTile = new Texture("swamp.jpg");
obstacleTile = new Texture("obstacle.jpg");
startTile = new Texture("start.jpg");
finishTile = new Texture("finish.jpg");
texture = new Texture(Gdx.files.internal("player.png"));
playerSprite = new Sprite(texture);
player = new Player(playerSprite);
player.setGridX(startX);
player.setGridY(startY);
findThePath();
}
@Override
public void render () {
update(Gdx.graphics.getDeltaTime());
Gdx.gl.glClearColor(0, 0, 0, 1);
Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);
batch.begin();
drawTiles();
player.draw(batch);
batch.end();
}
public void drawTiles() {
for (int i = 1; i < MAPSIZE; i ++) {
for (int j = 1; j < MAPSIZE; j++) {
if (tileMap[i][j] == 1) {
drawingTile = openTile;
}
else if (tileMap[i][j] == 3) {
drawingTile = grassTile;
}
else if (tileMap[i][j] == 4) {
drawingTile = swampTile;
}
else if (tileMap[i][j] == 0) {
drawingTile = obstacleTile;
}
else if (tileMap[i][j] == -1) {
drawingTile = startTile;
}
else if (tileMap[i][j] == 2) {
drawingTile = finishTile;
}
batch.draw(drawingTile, i * 32, j * 32);
}
}
}
public void update(float dt) {
player.update(dt);
}
public void generateTiles() {
int cost = 0;
Random rand = new Random();
for (int i = 1; i < MAPSIZE; i++) {
for (int j = 1; j < MAPSIZE; j++) {
int randomNum = rand.nextInt((4-1) +1) + 1;
switch (randomNum) {
case 1:
cost = 1;
break;
case 2:
cost = 3;
break;
case 3:
cost = 4;
break;
case 4:
cost = 0;
break;
}
tileMap[i][j] = cost;
}
}
startX = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
startY = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
startX = 1;
startY = 1;
tileMap[startX][startY] = -1;
finishX = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
finishY = rand.nextInt(((MAPSIZE - 1) -1) +1) + 1;
finishX = 4;
finishY = 4;
tileMap[finishX][finishY] = 2;
}
public void findThePath() {
System.out.println("Start node is at " + startX + " " + startY);
startNode = new MapNode(0, startX, startY, 0, 0);
closed = new ArrayList();
open = new ArrayList();
open.add(startNode);
closed.clear();
while (open.size() > 0) {
Collections.sort(open, new NodeComparator());
currentNode = (MapNode) open.get(0);
currentNode.setConnections();
boolean nodeIsClosed = false;
boolean nodeIsOpen = false;
// If the smallest element is the goal node, stop.
if (currentNode.getX() == finishX && currentNode.getY() == finishY) {
System.out.println("Found last node at " + currentNode.getX() + " " + currentNode.getY());
closed.add(currentNode);
break;
}
else {
nodeConnectionsList = currentNode.getConnectionsList();
for (int i = 0; i < nodeConnectionsList.size(); i++) {
nextConnection = (Connections) nodeConnectionsList.get(i);
int nextX = nextConnection.getX();
int nextY = nextConnection.getY();
int nextCost = nextConnection.getCost();
nextNode = new MapNode(currentNode.getCostSoFar() + nextCost, nextX, nextY, currentNode.getX(), currentNode.getY());
// If node is already in the closed list, set flag to continue.
for (int j = 0; j < closed.size(); j++) {
testNode = (MapNode) closed.get(j);
if (nextNode.compareTo(testNode) == 1) {
nodeIsClosed = true;
}
}
// If flag is set, continue to next iteration.
if (nodeIsClosed) {
nodeIsClosed = false;
continue;
}
// If node is already in open list, check to see if it's better.
for (int j = 0; j < open.size(); j++) {
testNode = (MapNode) open.get(j);
if (nextNode.compareTo(testNode) == 1) {
nodeIsOpen = true;
if (nextNode.getCostSoFar() > testNode.getCostSoFar()){
// Do nothing.
break;
}
else {
System.out.println("Found better route to " + nextNode.getX() + " " + nextNode.getY());
System.out.println("From " + currentNode.getX() + " " + currentNode.getY());
testNode.setCostSoFar(nextNode.getCostSoFar());
testNode.setConnectionX(currentNode.getX());
testNode.setConnectionY(currentNode.getY());
break;
}
}
}
if (nodeIsOpen) {
nodeIsOpen = false;
}
else {
open.add(nextNode);
}
}
closed.add(new MapNode(currentNode.getCostSoFar(), currentNode.getX(), currentNode.getY(), currentNode.getConnectionX(), currentNode.getConnectionY()));
}
open.remove(0);
}
int totalCost = 0;
pathList = new Stack();
// Find the end node and get it's first connection.
for (int i = 0; i < closed.size(); i++) {
testNode = (MapNode) closed.get(i);
if (testNode.getX() == finishX) {
if (testNode.getY() == finishY) {
pathList.push(new Connections(totalCost, finishX, finishY));
System.out.println("finish x: " + finishX);
System.out.println("finish y: " + finishY);
System.out.println("FromX: " + testNode.getConnectionX());
System.out.println("FromY: " + testNode.getConnectionY());
totalCost = testNode.getCostSoFar();
System.out.println("Total Cost: " + totalCost);
System.out.println("---------");
closed.remove(i);
break;
}
}
}
int findingX = testNode.getConnectionX();
int findingY = testNode.getConnectionY();
do {
for (int i = 0; i < closed.size(); i++) {
testNode = (MapNode) closed.get(i);
if (testNode.getX() == findingX) {
if (testNode.getY() == findingX) {
System.out.println("x: " + findingX);
System.out.println("y: " + findingY);
System.out.println("FromX: " + testNode.getConnectionX());
System.out.println("FromY: " + testNode.getConnectionY());
totalCost = testNode.getCostSoFar();
System.out.println(totalCost);
System.out.println("---------");
pathList.push(new Connections(totalCost, findingX, findingY));
findingX = testNode.getConnectionX();
findingY = testNode.getConnectionY();
closed.remove(i);
break;
}
}
}
if (closed.isEmpty()) {
System.out.println("Closed list is empty");
break;
}
} while((findingX != 0 && findingY != 0) && (findingX != startX && findingY != startY));
Connections testConnection;
System.out.println("Path Size: " + pathList.size());
while (!pathList.empty()) {
testConnection = (Connections) pathList.pop();
System.out.println("TC X: " + testConnection.getX());
System.out.println("TC Y: " + testConnection.getY());
}
System.out.println("Done");
}
}
Player.java
package com.comp452.tme21;
import com.badlogic.gdx.graphics.g2d.Batch;
import com.badlogic.gdx.graphics.g2d.Sprite;
public class Player extends Sprite {
public int gridX;
public int gridY;
public Player(Sprite sprite) {
super(sprite);
}
@Override
public void draw(Batch batch) {
batch.draw(this.getTexture(), this.getX(), this.getY());
}
public void update(float dt) {
}
public int getCenterX() {
int centerX = (int) (getX() + getWidth() /2);
return centerX;
}
public int getCenterY() {
int centerY = (int) (getY() + getHeight() /2);
return centerY;
}
public int getGridX() {
int gX = (int) (getX() / 32);
return gX;
}
public int getGridY() {
int gY = (int) (getY() / 32);
return gY;
}
public void setGridX(int x) {
setX(x * 32);
}
public void setGridY(int y) {
setY(y * 32);
}
}
事实证明，这是一个非常简单而愚蠢的错误。
看看这行代码。你能看到错误吗？我花了好几个小时在几乎每一英寸的代码（我的调试版本）上搜索和大量的 println 语句，我终于看到了它。更正问题后，一切都按预期工作（有一些小的添加和代码清理，以及如果不存在路径时的捕获...但这从来都不是问题）。
if (testNode.getX() == findingX) {
if (testNode.getY() == findingX) {
当我终于看到这个时，我想 "how stupid!!!"。你现在看到了吗？