api: Add getMirrorPoint to WorldPoint API

runelite-api/src/main/java/net/runelite/api/coords/WorldPoint.java

@@ -44,6 +44,14 @@ import net.runelite.api.Perspective;
 @Value
 public class WorldPoint
 {
+	private static final int[] REGION_MIRRORS = {
+		// Prifddinas
+		12894, 8755,
+		12895, 8756,
+		13150, 9011,
+		13151, 9012
+	};
+
 	/**
 	 * X-axis coordinate.
 	 */
@@ -373,4 +381,29 @@ public class WorldPoint
 	{
 		return position & (REGION_SIZE - 1);
 	}
+
+	/**
+	 * Translate a coordinate either between overworld and real, or real and overworld
+	 *
+	 * @param worldPoint
+	 * @param toOverworld whether to convert to overworld coordinates, or to real coordinates
+	 * @return
+	 */
+	public static WorldPoint getMirrorPoint(WorldPoint worldPoint, boolean toOverworld)
+	{
+		int region = worldPoint.getRegionID();
+		for (int i = 0; i < REGION_MIRRORS.length; i += 2)
+		{
+			int real = REGION_MIRRORS[i];
+			int overworld = REGION_MIRRORS[i + 1];
+
+			// Test against what we are converting from
+			if (region == (toOverworld ? real : overworld))
+			{
+				return fromRegion(toOverworld ? overworld : real,
+					worldPoint.getRegionX(), worldPoint.getRegionY(), worldPoint.getPlane());
+			}
+		}
+		return worldPoint;
+	}
 }

runelite-api/src/test/java/net/runelite/api/coords/WorldPointTest.java

@@ -0,0 +1,62 @@
+/*
+ * Copyright (c) 2021 Jordan Atwood <nightfirecat@protonmail.com>
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are met:
+ *
+ * 1. Redistributions of source code must retain the above copyright notice, this
+ *    list of conditions and the following disclaimer.
+ * 2. Redistributions in binary form must reproduce the above copyright notice,
+ *    this list of conditions and the following disclaimer in the documentation
+ *    and/or other materials provided with the distribution.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
+ * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
+ * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
+ * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
+ * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
+ * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
+ * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
+ * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+package net.runelite.api.coords;
+
+import static org.junit.Assert.assertEquals;
+import static org.junit.Assert.assertNotEquals;
+import org.junit.Test;
+
+public class WorldPointTest
+{
+	@Test
+	public void getGetMirrorPoint()
+	{
+		WorldPoint point, converted;
+
+		// Zalcano's entrance portal
+		point = new WorldPoint(3282, 6058, 0);
+		converted = WorldPoint.getMirrorPoint(point, true);
+		assertNotEquals(point, converted);
+
+		// Elven Crystal Chest, which is upstairs
+		point = new WorldPoint(3273, 6082, 2);
+		converted = WorldPoint.getMirrorPoint(point, true);
+		assertNotEquals(point, converted);
+
+		// Around the area of the Elite coordinate clue
+		point = new WorldPoint(2185, 3280, 0);
+		// To overworld
+		converted = WorldPoint.getMirrorPoint(point, true);
+		assertEquals(point, converted);
+		// To real
+		converted = WorldPoint.getMirrorPoint(point, false);
+		assertNotEquals(point, converted);
+
+		// Brugsen Bursen, Grand Exchange
+		point = new WorldPoint(3165, 3477, 0);
+		converted = WorldPoint.getMirrorPoint(point, false);
+		assertEquals(point, converted);
+	}
+}