Paper/patches/server/0524-MC-4-Fix-item-position-desync.patch
Jake Potrebic 9147456fc9
Updated Upstream (CraftBukkit/Spigot) (#8815)
Upstream has released updates that appear to apply and compile correctly.
This update has not been tested by PaperMC and as with ANY update, please do your own testing

CraftBukkit Changes:
ab8ace685 SPIGOT-7236: Bone meal doesn't increase use statistic
7dcb59b8e Avoid switch on material in previous commit

Spigot Changes:
19641c75 SPIGOT-7235: World.Spigot#strikeLightningEffect doesn't do anything
2023-01-27 12:52:04 -08:00

51 lines
2.4 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: BillyGalbreath <blake.galbreath@gmail.com>
Date: Tue, 8 Dec 2020 20:24:52 -0600
Subject: [PATCH] MC-4: Fix item position desync
This fixes item position desync (MC-4) by running the item coordinates
through the encode/decode methods of the packet that causes the precision
loss, which forces the server to lose the same precision as the client
keeping them in sync.
diff --git a/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java b/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java
index 5ca3ad7b3d7606accd0a58b3c708fadb349608f7..4b6e0fe2fabcc55007fd8979e81f66df9c0278b7 100644
--- a/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java
+++ b/src/main/java/net/minecraft/network/protocol/game/VecDeltaCodec.java
@@ -9,12 +9,12 @@ public class VecDeltaCodec {
@VisibleForTesting
static long encode(double value) {
- return Math.round(value * 4096.0D);
+ return Math.round(value * 4096.0D); // Paper - diff on change
}
@VisibleForTesting
static double decode(long value) {
- return (double)value / 4096.0D;
+ return (double)value / 4096.0D; // Paper - diff on change
}
public Vec3 decode(long x, long y, long z) {
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index d8dfd84a8e97e0e852362e1424e50c2f00fe6458..9833207c4d29a082cd68d52e72490e7a314f420c 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -4029,6 +4029,16 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
return;
}
// Paper end - rewrite chunk system
+ // Paper start - fix MC-4
+ if (this instanceof ItemEntity) {
+ if (io.papermc.paper.configuration.GlobalConfiguration.get().misc.fixEntityPositionDesync) {
+ // encode/decode from ClientboundMoveEntityPacket
+ x = Mth.lfloor(x * 4096.0D) * (1 / 4096.0D);
+ y = Mth.lfloor(y * 4096.0D) * (1 / 4096.0D);
+ z = Mth.lfloor(z * 4096.0D) * (1 / 4096.0D);
+ }
+ }
+ // Paper end - fix MC-4
if (this.position.x != x || this.position.y != y || this.position.z != z) {
this.position = new Vec3(x, y, z);
int i = Mth.floor(x);