Center TNT sample grid points

Makes TNT calculations more accurate, among other things

Spigot-Server-Patches/0031-Center-TNT-grid-sample-points.patch

@@ -0,0 +1,36 @@
+From 540fb3b37e67af699dded843a702b512c5c991ea Mon Sep 17 00:00:00 2001
+From: Jedediah Smith <jedediah@silencegreys.com>
+Date: Wed, 6 Aug 2014 18:17:41 -0500
+Subject: [PATCH] Center TNT grid sample points
+
+More information at https://bugs.mojang.com/browse/MC-65697
+
+diff --git a/src/main/java/net/minecraft/server/World.java b/src/main/java/net/minecraft/server/World.java
+index e82cb35..a9f45f9 100644
+--- a/src/main/java/net/minecraft/server/World.java
++++ b/src/main/java/net/minecraft/server/World.java
+@@ -1894,6 +1894,12 @@ public abstract class World implements IBlockAccess {
+         double d1 = 1.0D / ((axisalignedbb.e - axisalignedbb.b) * 2.0D + 1.0D);
+         double d2 = 1.0D / ((axisalignedbb.f - axisalignedbb.c) * 2.0D + 1.0D);
+ 
++        // PaperSpigot start - Center TNT sample points for more accurate calculations
++        // Shift the sample points so they are centered on the BB
++        double xOffset = (1.0 - Math.floor(1.0 / d0) * d0) / 2.0;
++        double zOffset = (1.0 - Math.floor(1.0 / d2) * d2) / 2.0;
++        // PaperSpigot end
++
+         if (d0 >= 0.0D && d1 >= 0.0D && d2 >= 0.0D) {
+             int i = 0;
+             int j = 0;
+@@ -1906,7 +1912,7 @@ public abstract class World implements IBlockAccess {
+                         double d4 = axisalignedbb.b + (axisalignedbb.e - axisalignedbb.b) * (double) f1;
+                         double d5 = axisalignedbb.c + (axisalignedbb.f - axisalignedbb.c) * (double) f2;
+ 
+-                        if (this.a(vec3d2.b(d3, d4, d5), vec3d) == null) { // CraftBukkit
++                        if (this.a(vec3d2.b(xOffset + d3, d4, zOffset + d5), vec3d) == null) { // CraftBukkit // PaperSpigot
+                             ++i;
+                         }
+ 
+-- 
+1.9.1
+