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MC-4 Fix item position desync

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BillyGalbreath 2020-12-14 09:05:29 -06:00
parent c184de4050
commit 3e5a38ccf5
1 changed files with 84 additions and 0 deletions
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Spigot-Server-Patches/MC-4-Fix-item-position-desync.patch Normal file
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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/com/destroystokyo/paper/PaperConfig.java b/src/main/java/com/destroystokyo/paper/PaperConfig.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java
+++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java
@@ -0,0 +0,0 @@ public class PaperConfig {
private static void trackPluginScoreboards() {
trackPluginScoreboards = getBoolean("settings.track-plugin-scoreboards", false);
}
+
+ public static boolean fixEntityPositionDesync = true;
+ private static void fixEntityPositionDesync() {
+ fixEntityPositionDesync = getBoolean("settings.fix-entity-position-desync", fixEntityPositionDesync);
+ }
}
diff --git a/src/main/java/net/minecraft/server/EntityItem.java b/src/main/java/net/minecraft/server/EntityItem.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/server/EntityItem.java
+++ b/src/main/java/net/minecraft/server/EntityItem.java
@@ -0,0 +0,0 @@ public class EntityItem extends Entity {
public Packet<?> P() {
return new PacketPlayOutSpawnEntity(this);
}
+
+ // Paper start - fix MC-4
+ public void setPositionRaw(double x, double y, double z) {
+ if (com.destroystokyo.paper.PaperConfig.fixEntityPositionDesync) {
+ // encode/decode from PacketPlayOutEntity
+ x = MathHelper.floorLong(x * 4096.0D) * (1 / 4096.0D);
+ y = MathHelper.floorLong(y * 4096.0D) * (1 / 4096.0D);
+ z = MathHelper.floorLong(z * 4096.0D) * (1 / 4096.0D);
+ }
+ super.setPositionRaw(x, y, z);
+ }
+ // Paper end - fix MC-4
}
diff --git a/src/main/java/net/minecraft/server/MathHelper.java b/src/main/java/net/minecraft/server/MathHelper.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/server/MathHelper.java
+++ b/src/main/java/net/minecraft/server/MathHelper.java
@@ -0,0 +0,0 @@ import java.util.function.IntPredicate;
public class MathHelper {
public static final float a = c(2.0F);
- private static final float[] b = (float[]) SystemUtils.a((Object) (new float[65536]), (afloat) -> {
+ private static final float[] b = (float[]) SystemUtils.a((new float[65536]), (afloat) -> { // Paper - decompile error
for (int i = 0; i < afloat.length; ++i) {
afloat[i] = (float) Math.sin((double) i * 3.141592653589793D * 2.0D / 65536.0D);
}
@@ -0,0 +0,0 @@ public class MathHelper {
return d0 < (double) i ? i - 1 : i;
}
+ public static long floorLong(double d0) { return d(d0); } // Paper - OBFHELPER
public static long d(double d0) {
long i = (long) d0;
diff --git a/src/main/java/net/minecraft/server/PacketPlayOutEntity.java b/src/main/java/net/minecraft/server/PacketPlayOutEntity.java
index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644
--- a/src/main/java/net/minecraft/server/PacketPlayOutEntity.java
+++ b/src/main/java/net/minecraft/server/PacketPlayOutEntity.java
@@ -0,0 +0,0 @@ public class PacketPlayOutEntity implements Packet<PacketListenerPlayOut> {
protected boolean i;
public static long a(double d0) {
- return MathHelper.d(d0 * 4096.0D);
+ return MathHelper.d(d0 * 4096.0D); // Paper - check EntityItem#setPositionRaw on update
}
public static Vec3D a(long i, long j, long k) {
- return (new Vec3D((double) i, (double) j, (double) k)).a(2.44140625E-4D);
+ return (new Vec3D((double) i, (double) j, (double) k)).a(2.44140625E-4D); // Paper - check EntityItem#setPositionRaw on update
}
public PacketPlayOutEntity() {}