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POjava how to make character follow Pathfinding
 

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  1. POjava how to make character follow Pathfinding
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    <p>After few days trying to understand and coding the A star pathfinding alogrithm wich i do understand now. I finally code it and make it work</p> <p>so now what i would like to know is how can i make my hero follow the path. any code snipet or example would be appreciated. i had an idea on how to do it but it didn't work unfortunately Thank you in advance. </p> <pre><code>import java.awt.event.ActionEvent; import java.awt.event.ActionListener; import java.awt.event.MouseAdapter; import java.awt.event.MouseEvent; import java.awt.event.MouseMotionListener; import java.util.logging.Level; import java.util.logging.Logger; import javax.swing.*; public class GameBoard extends JPanel implements ActionListener,Runnable{ private Thread game; private volatile boolean running=false; Map m; Player hero; Path path; AstarPathfinder p1; int targetX,targetY; int dir=0; public GameBoard () { //setSize(620,720); setBackground(Color.gray); setFocusable(true); requestFocus(); hero=new Player(); hero.setX(3/36); hero.setY(3/36); addMouseListener(new MouseAdapter() { public void mouseClicked(MouseEvent e) { handleMousePressed(e.getX(), e.getY()); } }); addMouseMotionListener(new MouseMotionListener() { public void mouseDragged(MouseEvent e) { // System.out.println("mouse dragged"); } public void mouseMoved(MouseEvent e) { //handleMouseMoved(e.getX(), e.getY()); } }); } private void handleMousePressed(int x, int y) { targetX=x /= 36; targetY=y/= 36; p1=new AstarPathfinder (); path=p1.PathFinding(hero.getX()/36, hero.getY()/36, targetX,targetY); repaint(); } public void startGame() { if(game==null|| !running) { game=new Thread(this); game.start(); running=true; } } @Override public void run() { while(running) { moveit(); try { Thread.sleep(5); } catch (InterruptedException ex) { Logger.getLogger(GameBoard.class.getName()).log(Level.SEVERE, null, ex); } } } public void moveit() { for(int x=0; x&lt;14; x++) { for(int y=0;y&lt;14;y++) { if (path != null) { if (path.contains(x,y)) { if(path.getX(x)&lt;hero.getX()){ hero.x-=1; } else if(path.getX(x)&gt; hero.getX()) { hero.x+=1; } if(path.getY(y)&lt; hero.getY()) { hero.y-=1; } else if(path.getY(y)&gt; hero.getY()) { hero.y+=1; } } } } } } @Override public void paint(Graphics g) { m=new Map(); m.OpenFile(); m.ReadFile(); m.CloseFile(); for(int y=0; y&lt;14; y++) { for(int x=0; x&lt;14; x++) { if(m.getMap(x, y).equals("g")) { g.drawImage(m.getGrass(), x*36, y*36, this); } if(m.getMap(x, y).equals("b")) { g.drawImage(m.getBlock(), x*36, y*36, this); } if(m.getMap(x, y).equals("d")) { g.drawImage(m.getDirt(), x*36, y*36, this); } if(m.getMap(x, y).equals("t")) { g.drawImage(m.getGOAL(), x*36, y*36, this); } if (path != null) { if (path.contains(x,y)) { g.setColor(Color.YELLOW); g.fillRect(x*36, y*36,19,19); } } } } } @Override public void addNotify() {//build in jpanel method super.addNotify(); ///donc quand le jpanel est en marche partir le jeu. startGame(); } @Override public void actionPerformed(ActionEvent e) { throw new UnsupportedOperationException("Not supported yet."); } } </code></pre> <p>end my entity class</p> <pre><code>public class Entity { int x, y, dx, dy; public Entity() { x = 0; y = 0; dx = 0; dy = 0; } public Entity(int xe, int ye) { this.x = xe; this.y = ye; } public int getDx() { return dx; } public void setDx(int dx) { this.dx = dx; } public int getDy() { return dy; } public void setDy(int dy) { this.dy = dy; } 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; } } </code></pre> <p>class player </p> <pre><code> import java.awt.Graphics; import java.awt.Image; import javax.swing.ImageIcon; public class Player extends Entity { private Image p; public Player() { super(); p=new ImageIcon("C:/Java/Prj/src/images/player.png").getImage(); } public Image getPlayer() { return p; } /* public void move(char d) { if(d=='d') this.x+=this.dx; this.y+=this.dy; }*/ public void drawPlayer(Graphics g) { g.drawImage(this.p,this.x,this.y,null); } } </code></pre> <p>my Astarpath class</p> <pre><code>enter code here import java.util.ArrayList; import java.util.LinkedList; import java.util.List; public class AstarPathfinder { LinkedList&lt;Node&gt; closed = new LinkedList(); LinkedList&lt;Node&gt; open = new LinkedList(); int newH, newF, newG, ndlength = 14; Node[][] nodes = new Node[ndlength][ndlength]; Path path; public AstarPathfinder() { for (int i = 0; i &lt; ndlength; i++) { for (int j = 0; j &lt; ndlength; j++) { nodes[i][j] = new Node(i, j); } } } public Path PathFinding(int sx, int sy, int tx, int ty) { Node start = nodes[sx][sy]; Node target = nodes[tx][ty]; start.g = 0; start.h = estimateCost(start, target); start.f = start.g + start.h; start.parent = null; open.add(start); while (open.size() != 0) { Node current = null; if (open.size() == 0) { System.out.println("aucune route/no possible road"); } current = getCurrent(); if (current == target) { //System.out.println("reach the target: " + target); break; } open.remove(current); closed.add(current); List&lt;Node&gt; neighbors = (List&lt;Node&gt;) createNeighbors(current); for (int k = 0; k &lt; neighbors.size(); k++) { Node neighborNode = neighbors.get(k); if (closed.contains(neighborNode)) { continue; } newG = current.g + 10;// + estimateDistance(current, neighborNode); newH = estimateCost(neighborNode, target); newF = newG + newH; if (newG &lt; neighborNode.g) { neighborNode.parent = current; neighborNode.h = newH; neighborNode.g = newG; neighborNode.f = newF; } if ((!open.contains(neighborNode)) &amp;&amp; !(closed.contains(neighborNode))) { open.add(neighborNode); neighborNode.parent = current; neighborNode.h = newH; neighborNode.g = newG; neighborNode.f = newF; } }//endloopfor }//end while path = new Path(); Node target2 = target; while (target2 != start) { path.prependStep(target2.x, target2.y); target2 = target2.parent; } path.prependStep(start.x, start.y); return path; } public int estimateCost(Node node1, Node node2) { float resultat; float dx = node1.x - node2.x; float dy = node1.y - node2.y; resultat = Math.abs((dx * dx) + (dy + dy)); resultat += resultat * 0.001; return (int) resultat; } /** * cette fonction perment de retourner le noeud courant * @return */ private Node getCurrent() { Node currentNode = null; int maxintf = open.size(); int minf = 1000000; for (int i = 0; i &lt; maxintf; i++) { Node node = (Node) open.get(i); if (node.f &lt; minf) { currentNode = node; } } return currentNode; } /** * Fontion permettant de trouver les 8 voisins */ private List&lt;Node&gt; createNeighbors(Node cnodes) { int i = cnodes.x; int j = cnodes.y; List&lt;Node&gt; neighbors = new ArrayList&lt;Node&gt;(); int indiceup = cnodes.x - 1; int indicedown = cnodes.x + 1; int indiceleft = cnodes.y - 1; int indiceright = cnodes.y + 1; if (indiceup &gt; -1) { neighbors.add(nodes[indiceup][cnodes.y]); } if (indicedown &lt; 14) { neighbors.add(nodes[indicedown][cnodes.y]); } if (indiceleft &gt; -1) { neighbors.add(nodes[cnodes.x][indiceleft]); } if (indiceright &lt; 14) { neighbors.add(nodes[cnodes.x][indiceright]); } return neighbors; } public class Node { int g = 0;//cost int h = 0;//heuristic int f = g;//f+g Node parent; int x, y; boolean visited; public Node(int x, int y) { this.x = x; this.y = y; this.visited = false; } public boolean isVisited() { return visited; } public void setVisited(boolean visited) { this.visited = visited; } public int getF() { return f; } public void setF(int f) { this.f = f; } public int getG() { return g; } public void setG(int g) { this.g = g; } public int getH() { return h; } public void setH(int h) { this.h = h; } public Node getParent() { return parent; } public void setParent(Node parent) { this.parent = parent; } } } </code></pre> <p>and here's the path class which i got from coke and code website. i build the whole thing from scratch i am trying to understand of course i will retype everything once i do understand :) sorry for the crappy code</p> <p>path class</p> <pre><code> import java.util.ArrayList; public class Path { /** The list of steps building up this path */ private ArrayList steps = new ArrayList(); /** * Create an empty path */ public Path() { } /** * Get the length of the path, i.e. the number of steps * * @return The number of steps in this path */ public int getLength() { return steps.size(); } /** * Get the step at a given index in the path * * @param index The index of the step to retrieve. Note this should * be &gt;= 0 and &lt; getLength(); * @return The step information, the position on the map. */ public Step getStep(int index) { return (Step) steps.get(index); } /** * Get the x coordinate for the step at the given index * * @param index The index of the step whose x coordinate should be retrieved * @return The x coordinate at the step */ public int getX(int index) { return getStep(index).x; } /** * Get the y coordinate for the step at the given index * * @param index The index of the step whose y coordinate should be retrieved * @return The y coordinate at the step */ public int getY(int index) { return getStep(index).y; } /** * Append a step to the path. * * @param x The x coordinate of the new step * @param y The y coordinate of the new step */ public void appendStep(int x, int y) { steps.add(new Step(x,y)); } /** * Prepend a step to the path. * * @param x The x coordinate of the new step * @param y The y coordinate of the new step */ public void prependStep(int x, int y) { steps.add(0, new Step(x, y)); } /** * Check if this path contains the given step * * @param x The x coordinate of the step to check for * @param y The y coordinate of the step to check for * @return True if the path contains the given step */ public boolean contains(int x, int y) { return steps.contains(new Step(x,y)); } /** * A single step within the path * * @author Kevin Glass */ public class Step { /** The x coordinate at the given step */ private int x; /** The y coordinate at the given step */ private int y; /** * Create a new step * * @param x The x coordinate of the new step * @param y The y coordinate of the new step */ public Step(int x, int y) { this.x = x; this.y = y; } /** * Get the x coordinate of the new step * * @return The x coodindate of the new step */ public int getX() { return x; } /** * Get the y coordinate of the new step * * @return The y coodindate of the new step */ public int getY() { return y; } /** * @see Object#hashCode() */ public int hashCode() { return x*y; } /** * @see Object#equals(Object) */ public boolean equals(Object other) { if (other instanceof Step) { Step o = (Step) other; return (o.x == x) &amp;&amp; (o.y == y); } return false; } } } </code></pre>
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    1. USThiefMaster
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      1. VTModeratorReview
    1. COIf your A* algorithm gives you the optimal path, or even the first choice for that optimal path, then that's what your "hero" should use. Without any more info about either your A* implementation or the problem it is being applied to, can't say much more than that.
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      1. POjava how to make character follow Pathfinding
      1. USScott Hunter
    2. COYou should probably try posting the code relevant to where you tried, but it didn't work.
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      1. USZéychin
 

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