Dice library [Licence: NYSL Version 0.9982]

DiceBuilder.java

public class DiceBuilder {
  private final boolean[][] dat = new boolean[6][4];
	private final boolean[] visited = new boolean[6];
	private static final String[] map = { "4...", "0123", "5..." };
	private int si = 1, sj = 0;

	public boolean[][] build(boolean[][] in) {
		dfs(new DiceState(), si, sj, in);
		return dat;
	}

	void dfs(DiceState ds, int i, int j, boolean[][] in) {
		if (inRec(i, j) && map[i].charAt(j) != '.' && !visited[ds.cf]) {
			visited[ds.cf] = true;
			for (int d = 0; d < 4; d++)
				dat[ds.cf][(ds.cd + d) % 4] = in[map[i].charAt(j) - '0'][d];
			for (int d = 0; d < 4; d++)
				dfs(ds.roll(d), i + di[d], j + dj[d], in);
		}
	}

	private static final int[] di = { -1, 0, 1, 0 };
	private static final int[] dj = { 0, -1, 0, 1 };

	private static boolean inRec(int i, int j) {
		return i >= 0 && j >= 0 && i < map.length && j < map[0].length();
	}
}

DiceState.java

public class DiceState {
	private static final int[][] FM = { { 4, 5, 1, 2 }, { 4, 2, 1, 5 } };
	private static final int[][] DR = { { 1, 3, 3, 3 }, { 3, 1, 1, 1 } };
	// { 1, 2, 3, 6, 5, 4 } { U, L, D, R }
	public final int cf, cd;

	private DiceState(int cf, int cd) {
		this.cf = cf;
		this.cd = cd;
	}

	public DiceState() {
		this(0, 0);
	}

	public DiceState roll(int d) {
		int f = cf % 2;
		int c = (cd + d) % 4;
		return new DiceState((cf + FM[f][c]) % 6, (cd + DR[f][c]) % 4);
	}
}