Backport Fix items not falling correctly (Resolves #2835) (#2884)

Spigot-Server-Patches/0428-Fix-items-not-falling-correctly.patch

@@ -0,0 +1,32 @@
+From 208d64fae2cd3292ad4e8f7e8ca00ada20ff5b9a Mon Sep 17 00:00:00 2001
+From: AJMFactsheets <AJMFactsheets@gmail.com>
+Date: Mon, 20 Jan 2020 17:05:05 -0600
+Subject: [PATCH] Fix items not falling correctly
+
+Since 1.14, Mojang has added an optimization which skips checking if
+an item should fall every fourth tick.
+
+However, Spigot's entity activation range class also has an
+optimization which skips ticking active entities every fourth tick.
+This can result in a state where an item will never properly fall
+due to its move method never being called.
+
+This patch resolves the conflict by offsetting checking an item's
+move method from Spigot's entity activation range check.
+
+diff --git a/src/main/java/net/minecraft/server/EntityItem.java b/src/main/java/net/minecraft/server/EntityItem.java
+index df26cef6..4fe33aad 100644
+--- a/src/main/java/net/minecraft/server/EntityItem.java
++++ b/src/main/java/net/minecraft/server/EntityItem.java
+@@ -85,7 +85,7 @@ public class EntityItem extends Entity {
+                 }
+             }
+ 
+-            if (!this.onGround || b(this.getMot()) > 9.999999747378752E-6D || (this.ticksLived + this.getId()) % 4 == 0) {
++            if (!this.onGround || b(this.getMot()) > 9.999999747378752E-6D || this.ticksLived % 4 == 3) { // Paper - Ensure checking item movement is always offset from Spigot's entity activation range check
+                 this.move(EnumMoveType.SELF, this.getMot());
+                 float f = 0.98F;
+ 
+-- 
+2.17.1
+