Maze Progress Bar - RecursiveGen

import java.util.ArrayList;
import java.lang.Math;

public class RecursiveGen {

  private boolean[][][] maze;
  private ArrayList<int[]> stack;
  private int[] currentPos;
  private int w, h;
  private int totalCells;

  public RecursiveGen(int w, int h) {
    this.w = w;
    this.h = h;
    init();
  }

  private static int[][] dirTab = {
    {0, -1},
    {1, 0},
    {0, 1},
    {-1, 0}
  };

  public void init() {
    maze = new boolean[w][h][4];
    for (int i = 0; i < w; i++) {
      for (int v = 0; v < h; v++) {
        for (int n = 0; n < 4; n++) {
          maze[i][v][n] = true;
        }
      }
    }
    stack = new ArrayList<int[]>();
    currentPos = new int[] {0, 0};
    stack.add(currentPos);
  }

  public boolean[][][] step() {
    //System.out.println(currentPos[0] + ":" + currentPos[1]);
    int[] availableCells = getAvailableCells(currentPos, maze);
    if (availableCells.length > 0) {
      stack.add(currentPos);
      int choice = availableCells[random(0, availableCells.length - 1)];
      removeWalls(currentPos, choice, maze);
      totalCells++;
      currentPos = addCoords(currentPos, dirTab[choice]);
      //System.out.println(currentPos[0] + ":" + currentPos[1]);
    } else {
      currentPos = stack.remove(stack.size()-1);
      //System.out.println(" <=" + currentPos[0] + ":" + currentPos[1]);
    }
    //System.out.println(stack.size());
    return maze;
  }

  public boolean checkCompleted() {
    return (stack.size() == 0);
  }

  public int getProgress() {
    return (int)((totalCells*1f/w*h)/100+.5f);
  }

  public boolean[][][] getMaze() {
    return maze;
  }

  private int[] getAvailableCells(int[] pos, boolean[][][] m) {
    ArrayList<Integer> options = new ArrayList<Integer>();
    if (!(pos[0] == m.length-1 && pos[1] == m[0].length-1)) {
      for (int i = 0; i < 4; i++) {
        if (!cellUsed(addCoords(pos, dirTab[i]), m)) {
          options.add(i);
        }
      }
    } else {
      m[m.length-1][m[0].length-1][2] = false;
      //System.out.println("----====End Located====----");
    }
    int[] result = new int[options.size()];
    for (int i = 0; i < result.length; i++) {
      result[i] = options.get(i);
    }
    return result;
  }

  private void removeWalls(int[] pos, int dir, boolean[][][] m) {
    m[pos[0]][pos[1]][dir] = false;
    int[] nPos = addCoords(pos, dirTab[dir]);
    //m[pos[0] + dirTab[dir][0]][pos[1] + dirTab[dir][1]][(dir+2)%4] = false;
    m[nPos[0]][nPos[1]][(dir+2)%4] = false;
  }

  private boolean cellUsed(int[] pos, boolean[][][] m) {
    if (pos[0] == -1 || pos[1] == -1 || pos[0] == m.length || pos[1] == m[0].length) {
      return true;
    }
    for (int i = 0; i < 4; i++) {
      if (!m[pos[0]][pos[1]][i]) {
        return true;
      }
    }
    return false;
  }

  private int random(int low, int high) {
    return (int)(Math.random()*(high+1-low)) + low;
  }

  private int[] addCoords(int[] a, int[] b) {
    return new int[] {a[0]+b[0], a[1]+b[1]};
  }

}