From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Aikar <aikar@aikar.co>
Date: Tue, 20 Dec 2016 15:15:11 -0500
Subject: [PATCH] Bound Treasure Maps to World Border

Make it so a Treasure Map does not target a structure outside of the
World Border, where players are not even able to reach.

This also would help the case where a players close to the border, and one
that is outside happens to be closer, but unreachable, yet another reachable
one is in border that would of been missed.

diff --git a/src/main/java/net/minecraft/server/StructureGenerator.java b/src/main/java/net/minecraft/server/StructureGenerator.java
index 68510457b527e61bf60bf1e7dfd664578172c00a..3880559505af742f1ab36f7959dc7fbd1e5da1b3 100644
--- a/src/main/java/net/minecraft/server/StructureGenerator.java
+++ b/src/main/java/net/minecraft/server/StructureGenerator.java
@@ -138,6 +138,7 @@ public abstract class StructureGenerator<C extends WorldGenFeatureConfiguration>
                             int i2 = l + k * k1;
                             int j2 = i1 + k * l1;
                             ChunkCoordIntPair chunkcoordintpair = this.a(structuresettingsfeature, j, seededrandom, i2, j2);
+                            if (!iworldreader.getWorldBorder().isChunkInBounds(chunkcoordintpair.x, chunkcoordintpair.z)) { continue; } // Paper
                             IChunkAccess ichunkaccess = iworldreader.getChunkAt(chunkcoordintpair.x, chunkcoordintpair.z, ChunkStatus.STRUCTURE_STARTS);
                             StructureStart<?> structurestart = structuremanager.a(SectionPosition.a(ichunkaccess.getPos(), 0), this, ichunkaccess);
 
diff --git a/src/main/java/net/minecraft/server/WorldBorder.java b/src/main/java/net/minecraft/server/WorldBorder.java
index d5c0d394feaf8bb991245dbdcc6252cf45eac13d..0ef92a320d132b443e76276b2c34a4626cf187db 100644
--- a/src/main/java/net/minecraft/server/WorldBorder.java
+++ b/src/main/java/net/minecraft/server/WorldBorder.java
@@ -26,6 +26,18 @@ public class WorldBorder {
         return (double) (blockposition.getX() + 1) > this.e() && (double) blockposition.getX() < this.g() && (double) (blockposition.getZ() + 1) > this.f() && (double) blockposition.getZ() < this.h();
     }
 
+    // Paper start
+    private final BlockPosition.MutableBlockPosition mutPos = new BlockPosition.MutableBlockPosition();
+    public boolean isBlockInBounds(int chunkX, int chunkZ) {
+        this.mutPos.setValues(chunkX, 64, chunkZ);
+        return this.isInBounds(this.mutPos);
+    }
+    public boolean isChunkInBounds(int chunkX, int chunkZ) {
+        this.mutPos.setValues(((chunkX << 4) + 15), 64, (chunkZ << 4) + 15);
+        return this.isInBounds(this.mutPos);
+    }
+    // Paper end
+
     public boolean isInBounds(ChunkCoordIntPair chunkcoordintpair) {
         return (double) chunkcoordintpair.f() > this.e() && (double) chunkcoordintpair.d() < this.g() && (double) chunkcoordintpair.g() > this.f() && (double) chunkcoordintpair.e() < this.h();
     }