feat: Add BlockAreac#distanceSquared

engine-tests/src/test/java/org/terasology/engine/world/block/BlockAreaTest.java

@@ -150,4 +150,30 @@ public void testIntersectsArea(BlockArea other, boolean intersecting) {
         BlockArea area = new BlockArea(0, 0, 3, 3);
         assertEquals(intersecting, area.intersectsBlockArea(other));
     }
+
+    static Stream<Arguments> testDistanceSquaredArgs() {
+        return Stream.of(
+                Arguments.of(new BlockArea(0, 0, 3, 3), -3, -3, 8),
+                Arguments.of(new BlockArea(0, 0, 3, 3), 1, 2, 0),
+                Arguments.of(new BlockArea(0, 0, 3, 3), -2, -2, 2),
+                Arguments.of(new BlockArea(0, 0, 3, 3), 0, 5, 1),
+
+                Arguments.of(new BlockArea(-1, -1, 4, 4), 5, 5, 0),
+                Arguments.of(new BlockArea(-1, -1, 4, 4), 6, 6, 2),
+                Arguments.of(new BlockArea(-1, -1, 4, 4), 1, 2, 0),
+                Arguments.of(new BlockArea(-1, -1, 4, 4), 0, 6, 1)
+        );
+    }
+
+    @ParameterizedTest
+    @MethodSource("testDistanceSquaredArgs")
+    public void testDistanceSquared(BlockArea area, int x, int y, int val) {
+        assertEquals(val, area.distanceSquared(x, y));
+    }
+
+    @Test
+    public void testDistanceSquaredVector() {
+        BlockArea area = new BlockArea(0, 0, 3, 3);
+        assertEquals(8, area.distanceSquared(new Vector2i(-3, -3)));
+    }
 }

engine/src/main/java/org/terasology/engine/world/block/BlockArea.java

@@ -51,6 +51,7 @@ public BlockArea(BlockAreac other) {
 
     // -- reset ------------------------------------------------------------------------------------------------------//
 
+    @SuppressWarnings("checkstyle:HiddenField")
     public BlockArea set(int minX, int minY, int maxX, int maxY) {
         Preconditions.checkArgument(minX <= maxX || (minX == INVALID.minX() && maxX == INVALID.maxX()));
         Preconditions.checkArgument(minY <= maxY || (minY == INVALID.minY() && maxY == INVALID.maxY()));
@@ -359,4 +360,24 @@ public int hashCode() {
     public String toString() {
         return "BlockArea[(" + this.minX + ", " + this.minY + ")...(" + this.maxX + ", " + this.maxY + ")]";
     }
+
+    @Override
+    public long distanceSquared(Vector2ic p) {
+        return distanceSquared(p.x(), p.y());
+    }
+
+    @Override
+    public long distanceSquared(int px, int py) {
+        //center = min + width / 2 = min + (max - min) / 2
+        // 2 * center  = 2 * min + max - min = min + max
+        int cx2 = minX() + maxX();
+        int cy2 = minY() + maxY();
+
+        //     dx = p - center - width / 2
+        // 2 * dx = 2 * px - 2 * center - width
+        //     dx = (2 * px - 2 * center - width) / 2
+        long dx = Math.max(Math.abs(2 * px - cx2) - getSizeX(), 0) / 2;
+        long dy = Math.max(Math.abs(2 * py - cy2) - getSizeY(), 0) / 2;
+        return dx * dx + dy * dy;
+    }
 }

engine/src/main/java/org/terasology/engine/world/block/BlockAreac.java

@@ -518,6 +518,25 @@ default boolean intersectsBlockArea(BlockAreac other) {
                 && this.minX() <= other.maxX() && this.minY() <= other.maxY();
     }
 
+    // -- distance --------------------------------------------------------------------------------------------------//
+
+    /**
+     * The squared distance to a point {@code p}.
+     *
+     * @param p the coordinates of the point
+     * @return the squared distance between this area and the point {@code p}
+     */
+    long distanceSquared(Vector2ic p);
+
+    /**
+     * The squared distance to a point {@code p} given by coordinates (x, y).
+     *
+     * @param px the x coordinate of the point
+     * @param py the y coordinate of the point
+     * @return the squared distance between this area and the point {@code p}
+     */
+    long distanceSquared(int px, int py);
+
     // ---------------------------------------------------------------------------------------------------------------//
     boolean equals(Object obj);