PaperMC/patches/server/0407-Fix-missing-chunks-due-to-integer-overflow.patch
MiniDigger | Martin 1ebaffacf5 some compile fixes
2023-09-22 19:31:02 +02:00

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1.6 KiB
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From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: David Slovikosky <davidslovikosky@gmail.com>
Date: Tue, 9 Jun 2020 00:10:03 -0700
Subject: [PATCH] Fix missing chunks due to integer overflow
This patch fixes a bug in the EndIslandDensityFunction class where the distance
from 0,0 squared overflows the maximum size of an integer. The overflow leads
to hard chunk borders around 370,000 blocks from 0,0. After this cutoff there
is a few hundred thousand block gap before end land resuming to generate at
530,000 blocks from spawn. This is due to the integer flipping back and forth.
The fix for the issue is quite simple, casting chunk coordinates to longs
allows the distance calculation to avoid overflow and work as intended.
This issue is being tracked in Mojira ticket MC-159283
diff --git a/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java b/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
index cbebb6682740c67f9abf5c45f9a5bb9db23974c6..39927a9b24a033e95d09d2201323e2b87c1b4d4e 100644
--- a/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
+++ b/src/main/java/net/minecraft/world/level/levelgen/DensityFunctions.java
@@ -502,7 +502,7 @@ public final class DensityFunctions {
int j = z / 2;
int k = x % 2;
int l = z % 2;
- float f = 100.0F - Mth.sqrt((float)(x * x + z * z)) * 8.0F;
+ float f = 100.0F - Mth.sqrt((long) x * (long) x + (long) z * (long) z) * 8.0F; // Paper - cast ints to long to avoid integer overflow
f = Mth.clamp(f, -100.0F, 80.0F);
for(int m = -12; m <= 12; ++m) {