Moved Pathfinding to own class. This is a preparation for the improved visualization
This commit is contained in:
t-moe
@@ -82,6 +82,7 @@ public class Game {
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private int numUndos; //number of undos left
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private Random rand; //instance to get random numbers from
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private ArrayList<UpdateListener> updateListeners; //registered listeners
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private PathFinder pathfinder;
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public Game(){
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this(7);
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@@ -96,6 +97,7 @@ public class Game {
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public Game (int size) {
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rand = new Random(); // Initialize random object
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this.updateListeners = new ArrayList<UpdateListener>();
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this.pathfinder = new PathFinder();
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this.reset(size);
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}
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@@ -208,53 +210,8 @@ public class Game {
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* @return Shortest path between src and dst, or null if there is no path
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*/
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public List<Point> getPath(final Point src, final Point dst){
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ArrayList<Vertex> vertices = new ArrayList<Vertex>(); // List of vertices
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vertices.add(new Vertex(0, src));
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// Get a verticies list from the field data
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for(int i= 0; i < size; i++){
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for(int j = 0; j < size; j++){
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if(field[i][j] == 0 && (src.x!=i || src.y!=j)){ //field empty and not src
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vertices.add(new Vertex(Integer.MAX_VALUE, new Point(i, j)));
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}
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}
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}
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ArrayList<Vertex> allVerticies = new ArrayList<Vertex>(vertices); // List of vertices
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while(!vertices.isEmpty()){ // As long as there are vertices
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final Vertex u = findNearestVertex(vertices);
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vertices.remove(u); // Remove u from the set of vertices
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final Point[] offsets = {
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new Point(0,1),
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new Point(0,-1),
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new Point(1,0),
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new Point(-1,0)
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};
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for(int i = 0; i < 4; i++){ // for each neighbour of u ...
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final Point p = u.getPos();
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final Point offs = offsets[i];
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int x = p.x + offs.x;
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int y = p.y + offs.y;
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if(x<0 || y<0 || x>=size || y>= size) continue;
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final Vertex v = findVertex(x,y, vertices);
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//distanz_update(u,v)
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if(v!=null){
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int alternative = u.getDist()+1;
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if( alternative< v.getDist()) {
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v.setDist(alternative);
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v.setPrev(u);
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}
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}
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}
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}
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return reconstructShortestPath(allVerticies, src,dst);
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pathfinder.calculateCosts(field, size, src);
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return pathfinder.getPath(dst);
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}
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/**
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@@ -267,14 +224,11 @@ public class Game {
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if(getAvailUndo() > 0 && lastStates.size() > 0){
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lastStates.remove(lastStates.size() - 1).restore();
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numUndos--;
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emitUpdateEvent();
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emitUpdateEvent();
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return true;
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}
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return false;
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}
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@@ -345,82 +299,6 @@ public class Game {
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this.populateField();
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}
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/**
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* Finds the nearest vertex to start
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*
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* @author aaron
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* @param vertices
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* @return Nearest vertex to the fist element of the given vertices list.
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*/
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private Vertex findNearestVertex(final List<Vertex> vertices){
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Vertex tmp = vertices.get(0);
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for (int i = 1; i < vertices.size(); i++) {
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Vertex n = vertices.get(i);
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if(n.getDist() < tmp.getDist()) {
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tmp = n;
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}
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}
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return tmp;
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}
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/**
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* Helper function for pathfinding. Finds a vertex corresponding to the given coordinate.
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*
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* @author aaron
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* @param x
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* @param y
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* @param vertices
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* @return Vertex with the given position out of a list of vertices.
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*/
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private Vertex findVertex(int x, int y, final List<Vertex> vertices){
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return findVertex(new Point(x,y), vertices);
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}
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/**
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* Helper function for pathfinding. Finds a vertex corresponding to the given point.
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*
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* @author aaron
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* @param pos
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* @param vertices
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* @return Vertex with the given position out of a list of vertices.
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*/
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private Vertex findVertex(final Point pos, final List<Vertex> vertices){
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for (int i = 0; i < vertices.size(); i++) {
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Vertex n = vertices.get(i);
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if(n.getPos().equals(pos)) {
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return n;
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}
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}
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return null;
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}
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/**
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* Helper function for pathfinding. Returns shortest path between src and dst in a given set of vertices.
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*
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* @author aaron
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* @param vertices
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* @param src
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* @param dst
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* @return Shortest path between two given points in a list of vertices.
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*/
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private List<Point> reconstructShortestPath(final List<Vertex> vertices, final Point src, final Point dst){
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ArrayList<Point> path = new ArrayList<Point>();
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path.add(dst);
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Vertex u = findVertex(dst, vertices);
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if(u==null) {
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return null;
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}
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while(u.getPrev()!=null){
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u= u.getPrev();
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path.add(0, u.getPos());
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}
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if(u!=findVertex(src, vertices)){
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return null;
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}
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return path;
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}
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/**
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* Calculates the next game step. This method will either call populateField, or it will cleanup blocks
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*
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289
src/ch/bfh/sevennotseven/PathFinder.java
Normal file
289
src/ch/bfh/sevennotseven/PathFinder.java
Normal file
@@ -0,0 +1,289 @@
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package ch.bfh.sevennotseven;
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import java.awt.Point;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* Class which provides helper to find the shortest path between two points
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* Based on pseudo-code from https://de.wikipedia.org/wiki/Dijkstra-Algorithmus#Algorithmus_in_Pseudocode
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* @author aaron/timo
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*
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*/
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public class PathFinder {
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/**
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*
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* Helper class which represents a Node/Vertex of a Graph
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*
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*/
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public static class Vertex {
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/* Class Members */
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private int dist;
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private Point pos;
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private Vertex prev;
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/**
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* Costructor
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*
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* @author aaron
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* @param int dist
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* @param Point pos
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*/
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public Vertex(int dist, Point pos) {
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this.dist = dist;
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this.pos = pos;
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this.prev = null;
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}
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/**
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* Set the distance
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*
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* @author aaron
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* @param int dist
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*/
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public void setDist(int dist){
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this.dist = dist;
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}
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/**
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* Set current position
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*
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* @author aaron
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* @param Point pos
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*/
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public void setPos(Point pos){
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this.pos = pos;
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}
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/**
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* Set previous vertex
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*
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* @author aaron
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* @param Vertex prev
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*/
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public void setPrev(Vertex prev){
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this.prev = prev;
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}
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/**
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* Get the distance
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*
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* @author aaron
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* @return int dist
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*/
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public int getDist(){
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return this.dist;
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}
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/**
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* Get current position
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*
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* @author aaron
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* @return Point pos
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*/
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public Point getPos(){
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return this.pos;
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}
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/**
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* Get previous vertex
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*
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* @author aaron
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* @return Vertex prev
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*/
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public Vertex getPrev(){
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return this.prev;
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}
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}
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private ArrayList<Vertex> verticies = null;
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private Point lastSrc = null;
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private int[][] lastField = null;
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private int lastSize;
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/**
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* Calculates the cost to reach each block starting from point src
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* @param field game field
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* @param size game size
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* @param src starting point
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*/
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public void calculateCosts(final int[][] field, int size, final Point src) {
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ArrayList<Vertex> vertices = new ArrayList<Vertex>(); // List of vertices
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vertices.add(new Vertex(0, src));
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// Get a verticies list from the field data
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for(int i= 0; i < size; i++){
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for(int j = 0; j < size; j++){
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if(field[i][j] == 0 && (src.x!=i || src.y!=j)){ //field empty and not src
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vertices.add(new Vertex(Integer.MAX_VALUE, new Point(i, j)));
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}
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}
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}
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ArrayList<Vertex> allVerticies = new ArrayList<Vertex>(vertices); // List of vertices
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while(!vertices.isEmpty()){ // As long as there are vertices
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final Vertex u = findNearestVertex(vertices);
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vertices.remove(u); // Remove u from the set of vertices
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final Point[] offsets = {
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new Point(0,1),
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new Point(0,-1),
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new Point(1,0),
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new Point(-1,0)
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};
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for(int i = 0; i < 4; i++){ // for each neighbour of u ...
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final Point p = u.getPos();
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final Point offs = offsets[i];
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int x = p.x + offs.x;
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int y = p.y + offs.y;
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if(x<0 || y<0 || x>=size || y>= size) continue;
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final Vertex v = findVertex(x,y, vertices);
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//distanz_update(u,v)
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if(v!=null){
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int alternative = u.getDist()+1; //alternative has cost of current path + 1 (=cost to reach neighbor)
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if( alternative< v.getDist()) {
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v.setDist(alternative);
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v.setPrev(u);
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}
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}
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}
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}
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lastSrc = src;
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verticies = allVerticies;
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lastField = field;
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lastSize = size;
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}
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/**
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* Seeks the shortest path to dst without crossing any walls
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* @author aaron
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* @param dst
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* @return Shortest path between src and dst, or null if there is no path
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*/
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public List<Point> getPath(final Point dst){
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if(lastSrc==null || verticies == null || lastField == null) return null;
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ArrayList<Point> path = new ArrayList<Point>();
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path.add(dst);
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Vertex u = findVertex(dst, verticies);
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if(u==null) {
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return null;
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}
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while(u.getPrev()!=null){
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u= u.getPrev();
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path.add(0, u.getPos());
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}
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if(u!=findVertex(lastSrc, verticies)){
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return null;
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}
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return path;
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}
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/**
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* Returns all points which are reachable from src, without crossing any walls
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* @return
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*/
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public List<Point> getReachablePoints() {
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if(lastSrc==null || verticies == null || lastField == null) return null;
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ArrayList<Point> res = new ArrayList<Point>();
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for(int x=0; x<lastSize; x++) {
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for(int y=0; y<lastSize; y++) {
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if(lastSrc.x == x && lastSrc.y ==y) continue;
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if(lastField[x][y]!=0) continue;
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Vertex u = findVertex(x, y, verticies);
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if(u==null) continue;
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if(u.getPrev()!=null && u.getDist()!=Integer.MAX_VALUE) {
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res.add(u.getPos());
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}
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}
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}
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return res;
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}
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/**
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* Returns all points which are UNreachable from src, without crossing any walls
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* @return
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*/
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public List<Point> getUnreachablePoints() {
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if(lastSrc==null || verticies == null || lastField == null) return null;
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ArrayList<Point> res = new ArrayList<Point>();
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for(int x=0; x<lastSize; x++) {
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for(int y=0; y<lastSize; y++) {
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if(lastSrc.x == x && lastSrc.y ==y) continue;
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if(lastField[x][y]!=0) continue;
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Vertex u = findVertex(x, y, verticies);
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if(u==null|| u.getPrev() == null) {
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res.add(u.getPos());
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}
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}
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}
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return res;
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}
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/**
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* Finds the nearest vertex to start
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*
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* @author aaron
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* @param vertices
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* @return Nearest vertex to the fist element of the given vertices list.
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*/
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private Vertex findNearestVertex(final List<Vertex> vertices){
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Vertex tmp = vertices.get(0);
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for (int i = 1; i < vertices.size(); i++) {
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Vertex n = vertices.get(i);
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if(n.getDist() < tmp.getDist()) {
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tmp = n;
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}
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}
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return tmp;
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}
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/**
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* Helper function for pathfinding. Finds a vertex corresponding to the given coordinate.
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*
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* @author aaron
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* @param x
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* @param y
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* @param vertices
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* @return Vertex with the given position out of a list of vertices.
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*/
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private Vertex findVertex(int x, int y, final List<Vertex> vertices){
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return findVertex(new Point(x,y), vertices);
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}
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/**
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* Helper function for pathfinding. Finds a vertex corresponding to the given point.
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*
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* @author aaron
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* @param pos
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* @param vertices
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* @return Vertex with the given position out of a list of vertices.
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*/
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private Vertex findVertex(final Point pos, final List<Vertex> vertices){
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for (int i = 0; i < vertices.size(); i++) {
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Vertex n = vertices.get(i);
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if(n.getPos().equals(pos)) {
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return n;
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}
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}
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return null;
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}
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}
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@@ -1,90 +0,0 @@
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package ch.bfh.sevennotseven;
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import java.awt.Point;
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/**
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* Vertex class which abstracts vertices as an object.
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*
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* @author aaron
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*/
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public class Vertex {
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/* Class Members */
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private int dist;
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private Point pos;
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private Vertex prev;
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/**
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* Costructor
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*
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* @author aaron
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* @param int dist
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* @param Point pos
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*/
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public Vertex(int dist, Point pos) {
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this.dist = dist;
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this.pos = pos;
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this.prev = null;
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}
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/**
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* Set the distance
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*
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* @author aaron
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* @param int dist
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*/
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public void setDist(int dist){
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this.dist = dist;
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}
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/**
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* Set current position
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*
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* @author aaron
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* @param Point pos
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*/
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public void setPos(Point pos){
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this.pos = pos;
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}
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/**
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* Set previous vertex
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*
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* @author aaron
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* @param Vertex prev
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*/
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public void setPrev(Vertex prev){
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this.prev = prev;
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}
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/**
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* Get the distance
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*
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* @author aaron
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* @return int dist
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*/
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public int getDist(){
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return this.dist;
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}
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/**
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* Get current position
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*
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* @author aaron
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* @return Point pos
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*/
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public Point getPos(){
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return this.pos;
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}
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/**
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* Get previous vertex
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*
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* @author aaron
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* @return Vertex prev
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*/
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public Vertex getPrev(){
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return this.prev;
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}
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}
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Reference in New Issue
Block a user