Maze not generating properly. Out of bounds exception. need quick fix
- by Dan Joseph Porcioncula
My maze generator seems to have a problem.
I am trying to generate something like the maze from http://mazeworks.com/mazegen/mazetut/index.htm .
My program displays this
http://a1.sphotos.ak.fbcdn.net/hphotos-ak-snc7/s320x320/374060_426350204045347_100000111130260_1880768_1572427285_n.jpg
and the error
Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: -1
at Grid.genRand(Grid.java:73)
at Grid.main(Grid.java:35)
How do I fix my generator program?
import java.awt.*;
import java.awt.Color;
import java.awt.Component;
import java.awt.Graphics;
import javax.swing.*;
import java.util.ArrayList;
public class Grid extends Canvas {
Cell[][] maze;
int size;
int pathSize;
double width, height;
ArrayList<int[]> coordinates = new ArrayList<int[]>();
public Grid(int size, int h, int w) {
this.size = size;
maze = new Cell[size][size];
for(int i = 0; i<size; i++){
for(int a =0; a<size; a++){
maze[i][a] = new Cell();
}
}
setPreferredSize(new Dimension(h, w));
}
public static void main(String[] args) {
JFrame y = new JFrame();
y.setLayout(new BorderLayout());
Grid f = new Grid(25, 400, 400);
y.add(f, BorderLayout.CENTER);
y.setSize(450, 450);
y.setVisible(true);
y.setDefaultCloseOperation(y.EXIT_ON_CLOSE);
f.genRand();
f.repaint();
}
public void push(int[] xy)
{
coordinates.add(xy);
int i = coordinates.size();
coordinates.ensureCapacity(i++);
}
public int[] pop() {
int[] x = coordinates.get((coordinates.size())-1);
coordinates.remove((coordinates.size())-1);
return x;
}
public int[] top() {
return coordinates.get((coordinates.size())-1);
}
public void genRand(){
// create a CellStack (LIFO) to hold a list of cell locations [x]
// set TotalCells = number of cells in grid
int TotalCells = size*size;
// choose a cell at random and call it CurrentCell
int m = randomInt(size);
int n = randomInt(size);
Cell curCel = maze[m][n];
// set VisitedCells = 1
int visCel = 1,d=0;
int[] q;
int h,o = 0,p = 0;
// while VisitedCells < TotalCells
while( visCel < TotalCells){
// find all neighbors of CurrentCell with all walls intact
if(maze[m-1][n].countWalls() == 4){d++;}
if(maze[m+1][n].countWalls() == 4){d++;}
if(maze[m][n-1].countWalls() == 4){d++;}
if(maze[m][n+1].countWalls() == 4){d++;}
// if one or more found
if(d!=0){
Point[] ls = new Point[4];
ls[0] = new Point(m-1,n);
ls[1] = new Point(m+1,n);
ls[2] = new Point(m,n-1);
ls[3] = new Point(m,n+1);
// knock down the wall between it and CurrentCell
h = randomInt(3);
switch(h){
case 0: o = (int)(ls[0].getX());
p = (int)(ls[0].getY());
curCel.destroyWall(2);
maze[o][p].destroyWall(1);
break;
case 1: o = (int)(ls[1].getX());
p = (int)(ls[1].getY());
curCel.destroyWall(1);
maze[o][p].destroyWall(2);
break;
case 2: o = (int)(ls[2].getX());
p = (int)(ls[2].getY());
curCel.destroyWall(3);
maze[o][p].destroyWall(0);
break;
case 3: o = (int)(ls[3].getX());
p = (int)(ls[3].getY());
curCel.destroyWall(0);
maze[o][p].destroyWall(3);
break;
}
// push CurrentCell location on the CellStack
push(new int[] {m,n});
// make the new cell CurrentCell
m = o; n = p;
curCel = maze[m][n];
// add 1 to VisitedCells
visCel++;
}
// else
else{
// pop the most recent cell entry off the CellStack
q = pop();
m = q[0]; n = q[1];
curCel = maze[m][n];
// make it CurrentCell
// endIf
}
// endWhile
}
}
public int randomInt(int s) { return (int)(s* Math.random());}
public void paint(Graphics g) {
int k, j;
width = getSize().width;
height = getSize().height;
double htOfRow = height / (size);
double wdOfRow = width / (size);
//checks verticals - destroys east border of cell
for (k = 0; k < size; k++) {
for (j = 0; j < size; j++) {
if(maze[k][j].checkWall(2)){
g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) (k * wdOfRow), (int) ((j+1) * htOfRow));
}}
}
//checks horizontal - destroys north border of cell
for (k = 0; k < size; k++) {
for (j = 0; j < size; j++) {
if(maze[k][j].checkWall(3)){
g.drawLine((int) (k * wdOfRow), (int) (j * htOfRow), (int) ((k+1) * wdOfRow), (int) (j * htOfRow));
}}
}
}
}
class Cell {
private final static int NORTH = 0;
private final static int EAST = 1;
private final static int WEST = 2;
private final static int SOUTH = 3;
private final static int NO = 4;
private final static int START = 1;
private final static int END = 2;
boolean[] wall = new boolean[4];
boolean[] border = new boolean[4];
boolean[] backtrack = new boolean[4];
boolean[] solution = new boolean[4];
private boolean isVisited = false;
private int Key = 0;
public Cell(){
for(int i=0;i<4;i++){wall[i] = true;}
}
public int countWalls(){
int i, k =0;
for(i=0; i<4; i++) {
if (wall[i] == true)
{k++;}
}
return k;}
public boolean checkWall(int x){
switch(x){
case 0: return wall[0];
case 1: return wall[1];
case 2: return wall[2];
case 3: return wall[3];
}
return true;
}
public void destroyWall(int x){
switch(x){
case 0: wall[0] = false; break;
case 1: wall[1] = false; break;
case 2: wall[2] = false; break;
case 3: wall[3] = false; break;
}
}
public void setStart(int i){Key = i;}
public int getKey(){return Key;}
public boolean checkVisit(){return isVisited;}
public void visitCell(){isVisited = true;}
}
