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/world/level/border/WorldBorder.java b/src/main/java/net/minecraft/world/level/border/WorldBorder.java
index 6ec5a1525d0b8ced8fe78d3eab29c5eb82996844..2442c287a7f26cfee10a19e9015558cdebdcf3ac 100644
--- a/src/main/java/net/minecraft/world/level/border/WorldBorder.java
+++ b/src/main/java/net/minecraft/world/level/border/WorldBorder.java
@@ -37,6 +37,18 @@ public class WorldBorder {
         return (double) (pos.getX() + 1) > this.getMinX() && (double) pos.getX() < this.getMaxX() && (double) (pos.getZ() + 1) > this.getMinZ() && (double) pos.getZ() < this.getMaxZ();
     }
 
+    // Paper start
+    private final BlockPos.MutableBlockPos mutPos = new BlockPos.MutableBlockPos();
+    public boolean isBlockInBounds(int chunkX, int chunkZ) {
+        this.mutPos.set(chunkX, 64, chunkZ);
+        return this.isWithinBounds(this.mutPos);
+    }
+    public boolean isChunkInBounds(int chunkX, int chunkZ) {
+        this.mutPos.set(((chunkX << 4) + 15), 64, (chunkZ << 4) + 15);
+        return this.isWithinBounds(this.mutPos);
+    }
+    // Paper end
+
     public boolean isWithinBounds(ChunkPos pos) {
         return (double) pos.getMaxBlockX() > this.getMinX() && (double) pos.getMinBlockX() < this.getMaxX() && (double) pos.getMaxBlockZ() > this.getMinZ() && (double) pos.getMinBlockZ() < this.getMaxZ();
     }
diff --git a/src/main/java/net/minecraft/world/level/chunk/ChunkGenerator.java b/src/main/java/net/minecraft/world/level/chunk/ChunkGenerator.java
index 30ee07433cfee7c7911dcea6d8bfc58eacf5833a..fff5c9d40a0bab8642376db3ec25cc1e8d666fa6 100644
--- a/src/main/java/net/minecraft/world/level/chunk/ChunkGenerator.java
+++ b/src/main/java/net/minecraft/world/level/chunk/ChunkGenerator.java
@@ -440,6 +440,7 @@ public abstract class ChunkGenerator implements BiomeManager.NoiseBiomeSource {
                     int l1 = i + i1 * j1;
                     int i2 = j + i1 * k1;
                     ChunkPos chunkcoordintpair = randomspreadstructureplacement.getPotentialFeatureChunk(l, l1, i2);
+                    if (!iworldreader.getWorldBorder().isChunkInBounds(chunkcoordintpair.x, chunkcoordintpair.z)) { continue; } // Paper
                     Iterator iterator = set.iterator();
 
                     while (iterator.hasNext()) {