Paper/patches/server/0305-Fix-items-not-falling-correctly.patch
Bjarne Koll c5a10665b8
Remove wall-time / unused skip tick protection (#11412)
Spigot still maintains some partial implementation of "tick skipping", a
practice in which the MinecraftServer.currentTick field is updated not
by an increment of one per actual tick, but instead set to
System.currentTimeMillis() / 50. This behaviour means that the tracked
tick may "skip" a tick value in case a previous tick took more than the
expected 50ms.

To compensate for this in important paths, spigot/craftbukkit
implements "wall-time". Instead of incrementing/decrementing ticks on
block entities/entities by one for each call to their tick() method,
they instead increment/decrement important values, like
an ItemEntity's age or pickupDelay, by the difference of
`currentTick - lastTick`, where `lastTick` is the value of
`currentTick` during the last tick() call.

These "fixes" however do not play nicely with minecraft's simulation
distance as entities/block entities implementing the above behaviour
would "catch up" their values when moving from a non-ticking chunk to a
ticking one as their `lastTick` value remains stuck on the last tick in
a ticking chunk and hence lead to a large "catch up" once ticked again.

Paper completely removes the "tick skipping" behaviour (See patch
"Further-improve-server-tick-loop"), making the above precautions
completely unnecessary, which also rids paper of the previous described
incompatibility with non-ticking chunks.
2024-09-19 16:36:07 +02:00

43 lines
2.5 KiB
Diff

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: AJMFactsheets <AJMFactsheets@gmail.com>
Date: Fri, 17 Jan 2020 17:17:54 -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 Spigot's entity
activation range check from an item's move method.
diff --git a/src/main/java/net/minecraft/world/entity/item/ItemEntity.java b/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
index f9dfd6e7b610cfee75524a525ab0e72bed5522da..e110296a95441a13ec431d897796326b0277edb1 100644
--- a/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
+++ b/src/main/java/net/minecraft/world/entity/item/ItemEntity.java
@@ -175,7 +175,7 @@ public class ItemEntity extends Entity implements TraceableEntity {
}
}
- if (!this.onGround() || this.getDeltaMovement().horizontalDistanceSqr() > 9.999999747378752E-6D || (this.tickCount + this.getId()) % 4 == 0) {
+ if (!this.onGround() || this.getDeltaMovement().horizontalDistanceSqr() > 9.999999747378752E-6D || (this.tickCount + this.getId()) % 4 == 0) { // Paper - Diff on change
this.move(MoverType.SELF, this.getDeltaMovement());
float f = 0.98F;
diff --git a/src/main/java/org/spigotmc/ActivationRange.java b/src/main/java/org/spigotmc/ActivationRange.java
index 6d51464f6368151e8acc532414ee223714584e96..9fb9fa62c32445ac3c3883a6433759c86dcfc428 100644
--- a/src/main/java/org/spigotmc/ActivationRange.java
+++ b/src/main/java/org/spigotmc/ActivationRange.java
@@ -256,7 +256,7 @@ public class ActivationRange
isActive = true;
}
// Add a little performance juice to active entities. Skip 1/4 if not immune.
- } else if ( !entity.defaultActivationState && entity.tickCount % 4 == 0 && !ActivationRange.checkEntityImmunities( entity ) )
+ } else if ( !entity.defaultActivationState && (entity.tickCount + entity.getId()) % 4 == 0 && !ActivationRange.checkEntityImmunities( entity ) ) // Paper - Ensure checking item movement is offset from Spigot's entity activation range check
{
isActive = false;
}