/** * One of 9 possible directions an object can move on a 2D board of squares. * Includes the 8 cardinal and intermediate compass directions (N, NE, E, etc.) * plus HERE, which means the current square. *
* Also provides a number of methods that can be called on a Direction object.
* Modifiers indicate the change involved with moving the given direction on
* a 2D board of squares. Whether for (row, col) or (x, y), the origin (0,0)
* is assumed to the top-left of the board or screen.
*
* @author Zach Tomaszewski
* @version 19 Nov 2008
*/
public enum Direction {
N, NE, E, SE, S, SW, W, NW, HERE;
/**
* Returns the X/column change on the screen that is associated with
* this direction: -1 for W, 0 for N/S, and +1 for E.
*/
public int getColModifier() {
int mod;
switch (this) {
case NW:
case W:
case SW:
mod = -1;
break;
case NE:
case E:
case SE:
mod = +1;
break;
default:
mod = 0;
break;
}
return mod;
}
/**
* Returns the Y/row change on the screen that is associated with
* this direction: -1 for N, 0 for E/W, and +1 for south.
*/
public int getRowModifier() {
int mod;
switch (this) {
case N:
case NE:
case NW:
mod = -1;
break;
case S:
case SE:
case SW:
mod = +1;
break;
default:
mod = 0;
break;
}
return mod;
}
/** As {@link #getColModifier()} */
public int getXModifier() {
return this.getColModifier();
}
/** As {@link #getRowModifier()} */
public int getYModifier() {
return this.getRowModifier();
}
/**
* Returns the direction that is the opposite of this one.
* For example, Direction.NE.reverse() == Direction.SW
.
* (The opposite of HERE is still HERE though.)
*/
public Direction reverse() {
if (this == HERE) {
return this;
}else {
int reversed = (this.ordinal() + 4) % 8;
Direction[] dirs = Direction.values();
return dirs[reversed];
}
}
}