From be6b3b9b379ec6eb00bfa2d6fceff5e99a8d982d Mon Sep 17 00:00:00 2001 From: David Slovikosky Date: Fri, 12 Jun 2020 00:30:18 -0700 Subject: [PATCH] Fix missing chunks due to integer overflow (#3527) This patch fixes a bug in the WorldChunkManagerTheEnd 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. --- ...ssing-chunks-due-to-integer-overflow.patch | 29 +++++++++++++++++++ 1 file changed, 29 insertions(+) create mode 100644 Spigot-Server-Patches/Fix-missing-chunks-due-to-integer-overflow.patch diff --git a/Spigot-Server-Patches/Fix-missing-chunks-due-to-integer-overflow.patch b/Spigot-Server-Patches/Fix-missing-chunks-due-to-integer-overflow.patch new file mode 100644 index 0000000000..d4ccb46591 --- /dev/null +++ b/Spigot-Server-Patches/Fix-missing-chunks-due-to-integer-overflow.patch @@ -0,0 +1,29 @@ +From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001 +From: David Slovikosky +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 WorldChunkManagerTheEnd 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. + +diff --git a/src/main/java/net/minecraft/server/WorldChunkManagerTheEnd.java b/src/main/java/net/minecraft/server/WorldChunkManagerTheEnd.java +index 0000000000000000000000000000000000000000..0000000000000000000000000000000000000000 100644 +--- a/src/main/java/net/minecraft/server/WorldChunkManagerTheEnd.java ++++ b/src/main/java/net/minecraft/server/WorldChunkManagerTheEnd.java +@@ -0,0 +0,0 @@ public class WorldChunkManagerTheEnd extends WorldChunkManager { + int l = j / 2; + int i1 = i % 2; + int j1 = j % 2; +- float f = 100.0F - MathHelper.c((float) (i * i + j * j)) * 8.0F; ++ // Paper start - cast ints to long to avoid integer overflow ++ float f = 100.0F - MathHelper.sqrt((long) i * (long) i + (long) j * (long) j) * 8.0F; ++ // Paper end + + f = MathHelper.a(f, -100.0F, 80.0F); +