Paper/patches/server/0444-MC-4-Fix-item-position-desync.patch
Spottedleaf da9d110d5b Remove chunk save reattempt patch
This patch does not appear to be doing anything useful, and may
hide errors.

Currently, the save logic does not run through this path either
so it did not do anything.

Additionally, properly implement support for handling
RegionFileSizeException in Moonrise.
2024-11-28 18:27:59 -08:00

51 lines
2.5 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 488ebd443903af812913437f1ade3002093f2470..a043ac10834562d357ef0b5aded2e916e2a0d056 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 * 4096.0);
+ return Math.round(value * 4096.0); // Paper - Fix MC-4; diff on change
}
@VisibleForTesting
static double decode(long value) {
- return (double)value / 4096.0;
+ return value / 4096.0; // Paper - Fix MC-4; 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 7a4aaa56f8d547ebc537657855d5fcdb4ef21e36..e08d20b65fdea46be94228b4b10ba1cb7b3beeb6 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -4479,6 +4479,16 @@ public abstract class Entity implements SyncedDataHolder, Nameable, EntityAccess
return;
}
// Paper end - Block invalid positions and bounding box
+ // 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 * 4096.0) * (1 / 4096.0);
+ y = Mth.lfloor(y * 4096.0) * (1 / 4096.0);
+ z = Mth.lfloor(z * 4096.0) * (1 / 4096.0);
+ }
+ }
+ // 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);