diff --git a/Spigot-Server-Patches/0616-MC-4-Fix-item-position-desync.patch b/Spigot-Server-Patches/0616-MC-4-Fix-item-position-desync.patch new file mode 100644 index 0000000000..a6bc4262e6 --- /dev/null +++ b/Spigot-Server-Patches/0616-MC-4-Fix-item-position-desync.patch @@ -0,0 +1,84 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: BillyGalbreath +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 cdf1177ca7b4b1b0808176c455f62b395146da50..26db8a5d92d494e5f6ba9498d5a1aa555642a92b 100644 +--- a/src/main/java/com/destroystokyo/paper/PaperConfig.java ++++ b/src/main/java/com/destroystokyo/paper/PaperConfig.java +@@ -469,4 +469,9 @@ 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 ba73d14437cfdf07ef0f1f6266131c113c2741fd..f41aaa7623c052b9f4044898d1bdee898c03057a 100644 +--- a/src/main/java/net/minecraft/server/EntityItem.java ++++ b/src/main/java/net/minecraft/server/EntityItem.java +@@ -523,4 +523,16 @@ 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 1731a1bca5ad02fd8cd8701f49c10cb74ee6f503..2e7721a650c5a351b3584665bd236f92ef577761 100644 +--- a/src/main/java/net/minecraft/server/MathHelper.java ++++ b/src/main/java/net/minecraft/server/MathHelper.java +@@ -7,7 +7,7 @@ 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); + } +@@ -47,6 +47,7 @@ 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 e5da2b19c1177ba7f88f0aaad9d810bb313ce67b..8e48407fd405ac4c3eece7762b8155c5d0f00fa0 100644 +--- a/src/main/java/net/minecraft/server/PacketPlayOutEntity.java ++++ b/src/main/java/net/minecraft/server/PacketPlayOutEntity.java +@@ -15,11 +15,11 @@ public class PacketPlayOutEntity implements Packet { + 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() {}