Example #1
0
  private static int computeGScoreIncrease(Cell cell, Cell neighbour) {
    int diffX = Math.abs(cell.getXCoor() - neighbour.getXCoor());
    int diffY = Math.abs(cell.getYCoor() - neighbour.getYCoor());

    if (diffX > 0 && diffY > 0) {
      return 14; // diagonal
    } else {
      return 10; // orthogonal
    }
  }
Example #2
0
  private static List<Cell> retrieveNeighbouringCells(
      Cell[][] cells, Cell cell, Creature creature) {
    List<Cell> neighbours = new ArrayList<Cell>();

    int x = cell.getXCoor();
    int y = cell.getYCoor();

    // left
    if (x > 1) {
      // up
      if (y > 1) {
        neighbours.add(cells[x - 1][y - 1]);
        neighbours.add(cells[x][y - 1]);
      }

      // middle
      neighbours.add(cells[x - 1][y]);

      // down
      if (y + 1 < cells[0].length) {
        neighbours.add(cells[x - 1][y + 1]);
        neighbours.add(cells[x][y + 1]);
      }
    }

    // right
    if (x + 1 < cells.length) {
      // up
      if (y > 1) {
        neighbours.add(cells[x + 1][y - 1]);
      }

      // middle
      neighbours.add(cells[x + 1][y]);

      // down
      if (y + 1 < cells[0].length) {
        neighbours.add(cells[x + 1][y + 1]);
      }
    }

    List<Cell> finalNeighbours = new ArrayList<Cell>();

    for (Cell neighbour : neighbours) {
      if (neighbour.creatureAllowed(creature) && neighbour.getBase() == null) {
        finalNeighbours.add(neighbour);
      }
    }

    return finalNeighbours;
  }
Example #3
0
 private static int computeEstimatedCost(Cell currentCell, Cell to) {
   return 10
       * (Math.abs(currentCell.getXCoor() - to.getXCoor())
           + Math.abs(currentCell.getYCoor() - to.getYCoor()));
 }
Example #4
0
  private static List<Cell> findPath(Cell[][] cells, Cell from, Cell to, Creature creature)
      throws NoReachablePathException {
    List<Cell> openList = new ArrayList<Cell>();
    List<Cell> closedList = new ArrayList<Cell>();
    Map<Cell, Cell> cameFrom = new HashMap<Cell, Cell>();

    Map<Cell, Integer> gScore = new HashMap<Cell, Integer>();
    Map<Cell, Integer> fScore = new HashMap<Cell, Integer>();

    /** Initialize start */
    openList.add(from);
    gScore.put(from, 0);
    fScore.put(from, gScore.get(from) + computeEstimatedCost(from, to));

    Cell currentCell = null;

    while (!openList.isEmpty()) {
      /** Find cell with lowest f score */
      currentCell = null;

      int minFScore = Integer.MAX_VALUE;

      for (Cell cell : openList) {
        if (fScore.get(cell) < minFScore) {
          currentCell = cell;
          minFScore = fScore.get(cell);
        }
      }

      if (currentCell == null) {
        break;
      }

      System.out.println("Step: " + currentCell.getXCoor() + " - " + currentCell.getYCoor());

      // currentCell is now the cell in the open list with lowest f score

      if (currentCell == to) {
        return reconstructPath(cameFrom, to);
      }

      openList.remove(currentCell);
      closedList.add(currentCell);

      for (Cell neighbour : retrieveNeighbouringCells(cells, currentCell, creature)) {
        if (!closedList.contains(neighbour)) {
          int gScoreTentative =
              gScore.get(currentCell) + computeGScoreIncrease(currentCell, neighbour);

          if (!openList.contains(neighbour) || gScoreTentative <= gScore.get(neighbour)) {
            cameFrom.put(neighbour, currentCell);
            gScore.put(neighbour, gScoreTentative);
            fScore.put(neighbour, gScoreTentative + computeEstimatedCost(neighbour, to));

            if (!openList.contains(neighbour)) {
              openList.add(neighbour);
            }
          }
        }
      }
    }

    throw new NoReachablePathException();
  }