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SquidLib platform-independent logic and utility code. Please refer to
https://github.com/SquidPony/SquidLib .
package squidpony.squidgrid.mapping;
import squidpony.squidgrid.Direction;
import squidpony.squidgrid.iterator.SquidIterators;
import squidpony.squidmath.Coord;
import java.util.*;
/**
* An algorithm to find rectangle areas in dungeons. It is a simpler and faster
* alternative to {@link RoomFinder}. You can execute
* {@code RectangleRoomsFinderTest} to see how it performs.
*
* @author smelC
*
* @see RoomFinder A fancier room finder
*/
public class RectangleRoomFinder {
protected final char[][] dungeon;
protected final int dungeonWidth;
protected final int dungeonHeight;
protected final Set floors;
/**
* The minimum number of cells that the diagonal of a room must have. Having
* 3 here means that, by default, only rooms at most 3x3 are considered.
*/
public int minimumDiagonal = 3;
/** {@code true} to restrict {@code this} to find square rooms */
public boolean onlySquareRooms = false;
public RectangleRoomFinder(char[][] dungeon) {
this.dungeon = dungeon;
this.dungeonWidth = dungeon.length;
this.dungeonHeight = dungeonWidth == 0 ? 0 : dungeon[0].length;
this.floors = new HashSet<>();
this.floors.add('.');
}
/**
* Adds a character considered as a floor.
*
* @param c
* @return {@code true} if {@code c} wasn't a floor character.
*/
public boolean addFloorCharacter(char c) {
return floors.add(c);
}
/**
* Removes a character from being considered as a floor.
*
* @param c
* @return {@code true} if {@code c} was a floor character.
*/
public boolean removeFloorCharacter(char c) {
return floors.remove(c);
}
/**
* @return The rectangles of the dungeon given at creation time.
*/
public List findRectangles() {
final List result = new ArrayList<>();
/*
* Every cell containing true indicates that this cell is included in an
* already-found room.
*/
final boolean[][] assigneds = new boolean[dungeonWidth][dungeonHeight];
final Iterator it = new SquidIterators.BottomLeftToTopRight(dungeonWidth, dungeonHeight);
nextBottomLeft: while (it.hasNext()) {
final Coord c = it.next();
/*
* Try to find the room's diagonal, from its bottom left to its top
* right
*/
Coord current = c;
int steps = 0;
while (!assigneds[c.x][c.y] && isFloor(dungeon[current.x][current.y])) {
current = current.translate(Direction.UP_RIGHT);
steps++;
}
if (steps < minimumDiagonal)
continue;
/*
* We have the diagonal. Let's check that this tentative room only
* contains (room-unassigned) floors.
*/
Rectangle r = new Rectangle.Impl(c, steps, steps);
Iterator cells = Rectangle.Utils.cells(r);
while (cells.hasNext()) {
final Coord inr = cells.next();
assert isInDungeon(inr);
if (!isFloor(dungeon[inr.x][inr.y]) || assigneds[inr.x][inr.y])
continue nextBottomLeft;
}
if (!onlySquareRooms) {
/* Try to extend it */
r = extendRoom(assigneds, r, Direction.LEFT);
r = extendRoom(assigneds, r, Direction.RIGHT);
r = extendRoom(assigneds, r, Direction.UP);
r = extendRoom(assigneds, r, Direction.DOWN);
}
/* Found a room! Let's record the cells. */
result.add(r);
cells = Rectangle.Utils.cells(r);
while (cells.hasNext()) {
final Coord inr = cells.next();
assigneds[inr.x][inr.y] = true;
}
}
return result;
}
/**
* @param assigneds
* Cells already in a room.
* @param d
* A cardinal direction.
* @return A variant of {@code r} extended to the direction {@code d}, if
* possible. {@code r} itself if unaffected.
*/
protected Rectangle extendRoom(boolean[][] assigneds, Rectangle r, Direction d) {
assert !d.isDiagonal();
Rectangle result = r;
while (true) {
Rectangle next = extendRoomOnce(assigneds, result, d);
if (next == result)
/* No change */
break;
else
result = next;
}
return result;
}
/**
* @param assigneds
* Cells already in a room. This array is muted by this call.
*/
protected Rectangle extendRoomOnce(boolean[][] assigneds, Rectangle r, Direction d) {
final Coord bl = r.getBottomLeft();
Coord first = null;
Direction way = null;
int steps = -1;
switch (d) {
case DOWN_LEFT:
case DOWN_RIGHT:
case NONE:
case UP_LEFT:
case UP_RIGHT:
throw new IllegalStateException(
"Unexpected direction in " + getClass().getSimpleName() + "::extendRoomOnce: " + d);
case DOWN:
first = bl.translate(Direction.DOWN);
way = Direction.RIGHT;
steps = r.getWidth();
break;
case LEFT:
first = bl.translate(Direction.LEFT);
way = Direction.UP;
steps = r.getHeight();
break;
case RIGHT:
first = bl.translate(r.getWidth() - 1, 0).translate(Direction.RIGHT);
way = Direction.UP;
steps = r.getHeight();
break;
case UP:
first = bl.translate(0, -r.getHeight() + 1).translate(Direction.UP);
way = Direction.RIGHT;
steps = r.getWidth();
break;
}
assert first != null;
Coord current = first;
assert 0 <= steps;
assert way != null;
while (0 < steps) {
if (!isInDungeon(current) || !isFloor(dungeon[current.x][current.y])
|| assigneds[current.x][current.y])
/* Cannot extend */
return r;
current = current.translate(way);
steps--;
}
final Rectangle result = Rectangle.Utils.extend(r, d);
assert validRoomCells(Rectangle.Utils.cells(result));
return result;
}
protected boolean isFloor(char c) {
return floors.contains(c);
}
protected boolean isInDungeon(Coord c) {
return 0 <= c.x && c.x < dungeonWidth && 0 <= c.y && c.y < dungeonHeight;
}
private boolean validRoomCells(Iterator cs) {
while (cs.hasNext()) {
final Coord c = cs.next();
if (!isInDungeon(c) || !isFloor(dungeon[c.x][c.y]))
return false;
}
return true;
}
}