edu.eci.arsw.blindway.mazegenerator.RecursiveMazeGenerator.java Source code

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Here is the source code for edu.eci.arsw.blindway.mazegenerator.RecursiveMazeGenerator.java

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package edu.eci.arsw.blindway.mazegenerator;

/**
 *
 * @author Hugo Alvarez
 */
import java.util.Collections;
import java.util.Arrays;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

/*
 * recursive backtracking algorithm
 * shamelessly borrowed from the ruby at
 * http://weblog.jamisbuck.org/2010/12/27/maze-generation-recursive-backtracking
 * http://rosettacode.org/wiki/Maze_generation#Java
 */
@Component
public class RecursiveMazeGenerator implements MazeGenerator {
    private int x;
    private int y;
    private int[][] maze;

    public RecursiveMazeGenerator() {

    }

    private void generateMaze(int cx, int cy) {
        DIR[] dirs = DIR.values();
        Collections.shuffle(Arrays.asList(dirs));
        for (DIR dir : dirs) {
            int nx = cx + dir.dx;
            int ny = cy + dir.dy;
            if (between(nx, x) && between(ny, y) && (maze[nx][ny] == 0)) {
                maze[cx][cy] |= dir.bit;
                maze[nx][ny] |= dir.opposite.bit;
                generateMaze(nx, ny);
            }
        }
    }

    private static boolean between(int v, int upper) {
        return (v >= 0) && (v < upper);
    }

    @Override
    public void build(int x, int y) {
        this.x = x;
        this.y = y;
        maze = new int[this.x][this.y];
        generateMaze(0, 0);
    }

    @Override
    public int[][] getMaze() {
        return maze;
    }

    private enum DIR {
        N(1, 0, -1), S(2, 0, 1), E(4, 1, 0), W(8, -1, 0);
        private final int bit;
        private final int dx;
        private final int dy;
        private DIR opposite;

        // use the static initializer to resolve forward references
        static {
            N.opposite = S;
            S.opposite = N;
            E.opposite = W;
            W.opposite = E;
        }

        private DIR(int bit, int dx, int dy) {
            this.bit = bit;
            this.dx = dx;
            this.dy = dy;
        }
    };
}