Flood algorithm added and (basic) tests performed.

src/main/java/ca/recrown/islandsurvivalcraft/floodfill/Floodable.java

@@ -0,0 +1,14 @@
+package ca.recrown.islandsurvivalcraft.floodfill;
+
+import ca.recrown.islandsurvivalcraft.types.Point2;
+
+public interface Floodable {
+    /**
+     * Called for every block. If it shouldn't be flooded, return false.
+     * Code to execute for flooding should be placed here.
+     * @param x the x coordinate.
+     * @param y the y coordinate.
+     * @return if this was a successful flooding.
+     */
+    public boolean flood(Point2 point);
+}

src/main/java/ca/recrown/islandsurvivalcraft/floodfill/Flooder.java

@@ -0,0 +1,43 @@
+package ca.recrown.islandsurvivalcraft.floodfill;
+
+import java.util.HashSet;
+import java.util.LinkedList;
+
+import ca.recrown.islandsurvivalcraft.types.Point2;
+
+public class Flooder {
+    private final HashSet<Point2> checked = new HashSet<>();
+    private final Point2 start;
+    private final Floodable floodable;
+
+    public Flooder(Point2 start, Floodable floodable) {
+        this.start = start;
+        this.floodable = floodable;
+    }
+
+    public Flooder(int xStart, int yStart, Floodable floodable) {
+        this(new Point2(xStart, yStart),  floodable);
+    }
+
+    public void start() {
+        if (!checked.add(start)) return;
+        if (!floodable.flood(start)) return;
+        LinkedList<Point2> queue = new LinkedList<>();
+        queue.add(start);
+        while (!queue.isEmpty()) {
+            Point2 p = queue.pop();
+
+            Point2 pE = new Point2(p.x + 1, p.y);
+            if (floodable.flood(pE)) queue.add(pE);
+
+            Point2 pW = new Point2(p.x - 1, p.y);
+            if (floodable.flood(pW)) queue.add(pW);
+
+            Point2 pN = new Point2(p.x, p.y + 1);
+            if (floodable.flood(pN)) queue.add(pN);
+
+            Point2 pS = new Point2(p.x, p.y - 1);
+            if (floodable.flood(pS)) queue.add(pS);
+        }
+    }
+}

src/test/java/ca/recrown/islandsurvivalcraft/floodfill/FloodFillTest.java

@@ -0,0 +1,102 @@
+package ca.recrown.islandsurvivalcraft.floodfill;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+import java.io.IOException;
+import java.io.InputStream;
+import java.util.ArrayList;
+import java.util.Scanner;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+import org.junit.jupiter.api.TestInstance;
+import org.junit.jupiter.api.TestInstance.Lifecycle;
+
+import ca.recrown.islandsurvivalcraft.types.Point2;
+
+@TestInstance(Lifecycle.PER_CLASS)
+public class FloodFillTest {
+    public byte[][] mapA;
+    public byte[][] mapB;
+
+    private class Flood implements Floodable {
+        private final byte[][] map;
+
+        public Flood(byte[][] map) {
+            this.map = map;
+        }
+
+        @Override
+        public boolean flood(Point2 point) {
+            try {
+                if (map[point.y][point.x] < 1) return false;
+            } catch (IndexOutOfBoundsException e) {
+                return false;
+            }
+
+            map[point.y][point.x] = 0;
+            return true;
+        }
+
+    }
+
+    private byte[][] readMap(String filename) throws IOException {
+        byte[][] map = null;
+        InputStream stream = getClass().getClassLoader().getResourceAsStream((filename));
+        Scanner scanner = new Scanner(stream);
+        String line = null;
+        ArrayList<byte[]> rows = new ArrayList<>();
+        while (scanner.hasNextLine()) {
+            line = scanner.nextLine();
+            char[] chars = line.toCharArray();
+            byte[] rowBytes = new byte[chars.length];
+            for (int i = 0; i < chars.length; i++) {
+                rowBytes[i] = (byte) Character.getNumericValue(chars[i]);
+            }
+            rows.add(rowBytes);
+        }
+        scanner.close();
+        map = new byte[rows.size()][rows.get(0).length];
+        for (int row = 0; row < rows.size(); row++) {
+            map[row] = rows.get(row);
+        }
+        return map;
+    }
+
+    @BeforeEach
+    public void reset() {
+        try {
+            mapA = readMap("DFSTestMapLargeA.txt");
+            mapB = readMap("DFSTestMapLargeB.txt");
+        } catch (IOException e) {
+            e.printStackTrace();
+        }
+    }
+
+    @Test
+    public void testFillMapA() {
+        Flooder flooder = new Flooder(new Point2(0, 0), new Flood(mapA));
+        flooder.start();
+        for (int y = 0; y < mapA.length; y++) {
+            for (int x = 0; x < mapA[y].length; x++) {
+                assertEquals(0, mapA[y][x], String.format("At: %d, %d", x, y));
+            }
+        }
+    }
+
+    @Test
+    public void testFillMapB() {
+        Flooder flooder = new Flooder(new Point2(0, 0), new Flood(mapB));
+        flooder.start();
+        for (int y = 0; y < mapB.length; y++) {
+            for (int x = 0; x < mapB[y].length; x++) {
+                if (x > 21 && y > 15 && x < 27) {
+                    assertTrue(mapB[y][x] > 0, String.format("At: %d, %d", x, y));
+                } else {
+                    assertEquals(0, mapB[y][x], String.format("At: %d, %d", x, y));
+                }
+            }
+        }
+    }
+}