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Remove wall-time / unused skip tick protection

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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.
This commit is contained in:
Bjarne Koll
2024-09-16 23:07:29 +02:00
parent 883f50eb19
commit c8efaa46cb
3 changed files with 55 additions and 62 deletions
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18
paper-server/patches/sources/net/minecraft/world/level/block/entity/BrewingStandBlockEntity.java.patch
View File

@@ -34,7 +34,7 @@
public int fuel;
protected final ContainerData dataAccess;
+ // CraftBukkit start - add fields and methods
+ private int lastTick = MinecraftServer.currentTick;
+ // private int lastTick = MinecraftServer.currentTick; // Paper - remove anti tick skipping measures / wall time
+ public List<HumanEntity> transaction = new java.util.ArrayList<HumanEntity>();
+ private int maxStack = MAX_STACK;
@@ -89,18 +89,16 @@
setChanged(world, pos, state);
}
@@ -116,12 +170,17 @@
@@ -116,12 +170,15 @@
boolean flag1 = blockEntity.brewTime > 0;
ItemStack itemstack1 = (ItemStack) blockEntity.items.get(3);
+ // CraftBukkit start - Use wall time instead of ticks for brewing
+ int elapsedTicks = MinecraftServer.currentTick - blockEntity.lastTick;
+ blockEntity.lastTick = MinecraftServer.currentTick;
+ // Paper - remove anti tick skipping measures / wall time
+
if (flag1) {
- --blockEntity.brewTime;
- boolean flag2 = blockEntity.brewTime == 0;
+ blockEntity.brewTime -= elapsedTicks;
+ --blockEntity.brewTime; // Paper - remove anti tick skipping measures / wall time - revert to vanilla
+ boolean flag2 = blockEntity.brewTime <= 0; // == -> <=
+ // CraftBukkit end
@@ -110,7 +108,7 @@
} else if (!flag || !itemstack1.is(blockEntity.ingredient)) {
blockEntity.brewTime = 0;
}
@@ -129,7 +188,11 @@
@@ -129,7 +186,11 @@
setChanged(world, pos, state);
} else if (flag && blockEntity.fuel > 0) {
--blockEntity.fuel;
@@ -123,7 +121,7 @@
blockEntity.ingredient = itemstack1.getItem();
setChanged(world, pos, state);
}
@@ -185,14 +248,36 @@
@@ -185,14 +246,36 @@
}
}
@@ -163,7 +161,7 @@
itemstack.shrink(1);
ItemStack itemstack1 = itemstack.getItem().getCraftingRemainder();
@@ -200,12 +285,12 @@
@@ -200,12 +283,12 @@
if (itemstack.isEmpty()) {
itemstack = itemstack1;
} else {
@@ -179,7 +177,7 @@
}
@Override
@@ -231,12 +316,12 @@
@@ -231,12 +314,12 @@
@Override
public boolean canPlaceItem(int slot, ItemStack stack) {