Improve world border logic

Signed-off-by: Pablo Herrera <[email protected]>

util/src/main/java/tc/oc/pgm/util/bukkit/WorldBorders.java

@@ -1,49 +1,60 @@
 package tc.oc.pgm.util.bukkit;
 
 import org.bukkit.Location;
+import org.bukkit.World;
 import org.bukkit.WorldBorder;
+import org.bukkit.util.NumberConversions;
+import tc.oc.pgm.util.nms.NMSHacks;
 
-public interface WorldBorders {
+public class WorldBorders {
 
-  static boolean isInsideBorder(Location location) {
-    WorldBorder border = location.getWorld().getWorldBorder();
-    Location center = border.getCenter();
-    double radius = border.getSize() / 2d;
-    return Math.abs(location.getX() - center.getX()) < radius
-        && Math.abs(location.getZ() - center.getZ()) < radius;
+  private WorldBorders() {}
+
+  public static boolean isInsideBorder(Location location) {
+    BorderRect rect = new BorderRect(location.getWorld());
+    return location.getBlockX() >= rect.xMin
+        && location.getBlockX() <= rect.xMax
+        && location.getBlockZ() >= rect.zMin
+        && location.getBlockZ() <= rect.zMax;
   }
 
-  static boolean clampToBorder(Location location) {
-    WorldBorder border = location.getWorld().getWorldBorder();
-    Location center = border.getCenter();
-    double radius = border.getSize() / 2d;
-    double xMin = center.getX() - radius;
-    double xMax = center.getX() + radius;
-    double zMin = center.getZ() - radius;
-    double zMax = center.getZ() + radius;
+  public static boolean clampToBorder(Location location) {
+    BorderRect rect = new BorderRect(location.getWorld());
 
     boolean moved = false;
 
-    if (location.getX() < xMin) {
-      location.setX(xMin);
+    if (location.getX() <= rect.xMin) {
+      location.setX(rect.xMin + 0.5);
       moved = true;
-    }
-
-    if (location.getX() > xMax) {
-      location.setX(xMax);
+    } else if (location.getX() >= rect.xMax) {
+      location.setX(rect.xMax - 0.5);
       moved = true;
     }
 
-    if (location.getZ() < zMin) {
-      location.setZ(zMin);
+    if (location.getZ() <= rect.zMin) {
+      location.setZ(rect.zMin + 0.5);
       moved = true;
-    }
-
-    if (location.getZ() > zMax) {
-      location.setZ(zMax);
+    } else if (location.getZ() >= rect.zMax) {
+      location.setZ(rect.zMax - 0.5);
       moved = true;
     }
 
     return moved;
   }
+
+  private static class BorderRect {
+    public final int xMin, xMax, zMin, zMax;
+
+    public BorderRect(World world) {
+      WorldBorder border = world.getWorldBorder();
+      Location center = border.getCenter();
+      double radius = border.getSize() / 2d;
+      int maxWorldSize = NMSHacks.getMaxWorldSize(world);
+
+      xMin = Math.max(NumberConversions.floor(center.getX() - radius), -maxWorldSize);
+      xMax = Math.min(NumberConversions.ceil(center.getX() + radius), maxWorldSize);
+      zMin = Math.max(NumberConversions.floor(center.getZ() - radius), -maxWorldSize);
+      zMax = Math.min(NumberConversions.ceil(center.getZ() + radius), maxWorldSize);
+    }
+  }
 }

util/src/main/java/tc/oc/pgm/util/nms/NMSHacks.java

@@ -439,4 +439,8 @@ static AttributeMap buildAttributeMap(Player player) {
   static void postToMainThread(Plugin plugin, boolean priority, Runnable task) {
     INSTANCE.postToMainThread(plugin, priority, task);
   }
+
+  static int getMaxWorldSize(World world) {
+    return INSTANCE.getMaxWorldSize(world);
+  }
 }

util/src/main/java/tc/oc/pgm/util/nms/NMSHacksNoOp.java

@@ -302,4 +302,9 @@ public void postToMainThread(Plugin plugin, boolean priority, Runnable task) {
     // runs the task on the next tick, not a perfect replacement
     plugin.getServer().getScheduler().runTask(plugin, task);
   }
+
+  @Override
+  public int getMaxWorldSize(World world) {
+    return 29999984; // Vanilla's default
+  }
 }

util/src/main/java/tc/oc/pgm/util/nms/NMSHacksPlatform.java

@@ -208,4 +208,6 @@ Object teamPacket(
   AttributeMap buildAttributeMap(Player player);
 
   void postToMainThread(Plugin plugin, boolean priority, Runnable task);
+
+  int getMaxWorldSize(World world);
 }

util/src/main/java/tc/oc/pgm/util/nms/v1_8/NMSHacks1_8.java

@@ -966,6 +966,11 @@ public double getTPS() {
     return 20.0;
   }
 
+  @Override
+  public int getMaxWorldSize(World world) {
+    return ((CraftWorld) world).getHandle().getWorldBorder().l();
+  }
+
   enum TeamPacketFields {
     a,
     b,