Fix several off-by-one errors in view distance calculations

1. For NearbyPlayers, we need to be using the view distance, and
   not the load distance (which is +1 of the view distance).
2. Correctly clamp tick distance to view distance. Since
   load distance is +1 of view distance, we need to subtract
   one from the load distance when clamping.

Additionally, add checks inside ViewDistances to ensure that
the inputs are in range to catch future errors.

Also, clamp simulation distance, as values < 0 or above
MAX_VIEW_DISTANCE do not make sense to configure.

2 files changed, 52 insertions, 37 deletions

diff --git a/patches/server/0009-MC-Utils.patch b/patches/server/0009-MC-Utils.patch
index 98b049b563..9958d9735c 100644
--- a/patches/server/0009-MC-Utils.patch
+++ b/patches/server/0009-MC-Utils.patch
@@ -2599,7 +2599,7 @@ index 0000000000000000000000000000000000000000..c2d917c2eac55b8a4411a6e159f177f9
 +}
 diff --git a/src/main/java/ca/spottedleaf/moonrise/common/misc/NearbyPlayers.java b/src/main/java/ca/spottedleaf/moonrise/common/misc/NearbyPlayers.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..bb44de17a37082e57f2292a4f470740be1d09b11
+index 0000000000000000000000000000000000000000..7e440b4a46b040365df7317035e577d93e7d855d
 --- /dev/null
 +++ b/src/main/java/ca/spottedleaf/moonrise/common/misc/NearbyPlayers.java
 @@ -0,0 +1,273 @@
@@ -2727,7 +2727,7 @@ index 0000000000000000000000000000000000000000..bb44de17a37082e57f2292a4f470740b
 +        players[NearbyMapType.GENERAL_SMALL.ordinal()].update(chunk.x, chunk.z, GENERAL_SMALL_VIEW_DISTANCE);
 +        players[NearbyMapType.GENERAL_REALLY_SMALL.ordinal()].update(chunk.x, chunk.z, GENERAL_REALLY_SMALL_VIEW_DISTANCE);
 +        players[NearbyMapType.TICK_VIEW_DISTANCE.ordinal()].update(chunk.x, chunk.z, ChunkSystem.getTickViewDistance(player));
-+        players[NearbyMapType.VIEW_DISTANCE.ordinal()].update(chunk.x, chunk.z, ChunkSystem.getLoadViewDistance(player));
++        players[NearbyMapType.VIEW_DISTANCE.ordinal()].update(chunk.x, chunk.z, ChunkSystem.getViewDistance(player));
 +        players[NearbyMapType.SPAWN_RANGE.ordinal()].update(chunk.x, chunk.z, ChunkTickConstants.PLAYER_SPAWN_TRACK_RANGE); // Moonrise - chunk tick iteration
 +    }
 +
@@ -3311,7 +3311,7 @@ index 0000000000000000000000000000000000000000..4123edddc556c47f3f8d83523c125fd2
 +}
 diff --git a/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java b/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..f7cd0aa43d0b9249d0a317fab41fefa0d951bca0
+index 0000000000000000000000000000000000000000..58a99bc38e137431f10af36fa9e2d04fe61694aa
 --- /dev/null
 +++ b/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java
 @@ -0,0 +1,288 @@
@@ -3582,15 +3582,15 @@ index 0000000000000000000000000000000000000000..f7cd0aa43d0b9249d0a317fab41fefa0
 +    }
 +
 +    public static int getSendViewDistance(final ServerPlayer player) {
-+        return getLoadViewDistance(player) - 1;
++        return getViewDistance(player);
 +    }
 +
-+    public static int getLoadViewDistance(final ServerPlayer player) {
++    public static int getViewDistance(final ServerPlayer player) {
 +        final ServerLevel level = player.serverLevel();
 +        if (level == null) {
-+            return org.bukkit.Bukkit.getViewDistance() + 1;
++            return org.bukkit.Bukkit.getViewDistance();
 +        }
-+        return level.chunkSource.chunkMap.serverViewDistance + 1;
++        return level.chunkSource.chunkMap.serverViewDistance;
 +    }
 +
 +    public static int getTickViewDistance(final ServerPlayer player) {
@@ -6415,7 +6415,7 @@ index 799444e4101283c972a160742a9e2548e604173f..fb8c641604473a3853b2f8b9cd5c8a65
 +    // Paper end
  }
 diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
-index 031eed24638659f2633bef0ad2e178832ca058e9..a3550d84c273c9720491484382a4bc50dc3246a6 100644
+index 031eed24638659f2633bef0ad2e178832ca058e9..2e4e6fee48d0f6be3b23a109a7c661b27179ccaa 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
 @@ -2447,4 +2447,34 @@ public class CraftPlayer extends CraftHumanEntity implements Player {
@@ -6425,7 +6425,7 @@ index 031eed24638659f2633bef0ad2e178832ca058e9..a3550d84c273c9720491484382a4bc50
 +
 +    @Override
 +    public int getViewDistance() {
-+        return ca.spottedleaf.moonrise.common.util.ChunkSystem.getLoadViewDistance(this.getHandle()) - 1;
++        return ca.spottedleaf.moonrise.common.util.ChunkSystem.getViewDistance(this.getHandle());
 +    }
 +
 +    @Override
diff --git a/patches/server/1037-Moonrise-optimisation-patches.patch b/patches/server/1037-Moonrise-optimisation-patches.patch
index ef68a3fb2b..c2bbb5a373 100644
--- a/patches/server/1037-Moonrise-optimisation-patches.patch
+++ b/patches/server/1037-Moonrise-optimisation-patches.patch
@@ -18,7 +18,7 @@ Currently includes:
 See https://github.com/Tuinity/Moonrise
 
 diff --git a/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java b/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java
-index f7cd0aa43d0b9249d0a317fab41fefa0d951bca0..fc029c8fb22a7c8eeb23bfc171812f6da91c60fa 100644
+index 58a99bc38e137431f10af36fa9e2d04fe61694aa..1d288e73fd8605676c0da676e068afb5b4b8abea 100644
 --- a/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java
 +++ b/src/main/java/ca/spottedleaf/moonrise/common/util/ChunkSystem.java
 @@ -2,11 +2,17 @@ package ca.spottedleaf.moonrise.common.util;
@@ -330,17 +330,17 @@ index f7cd0aa43d0b9249d0a317fab41fefa0d951bca0..fc029c8fb22a7c8eeb23bfc171812f6d
      }
  
      public static int getSendViewDistance(final ServerPlayer player) {
--        return getLoadViewDistance(player) - 1;
+-        return getViewDistance(player);
 +        return RegionizedPlayerChunkLoader.getAPISendViewDistance(player);
      }
  
-     public static int getLoadViewDistance(final ServerPlayer player) {
+     public static int getViewDistance(final ServerPlayer player) {
 -        final ServerLevel level = player.serverLevel();
 -        if (level == null) {
--            return org.bukkit.Bukkit.getViewDistance() + 1;
+-            return org.bukkit.Bukkit.getViewDistance();
 -        }
--        return level.chunkSource.chunkMap.serverViewDistance + 1;
-+        return RegionizedPlayerChunkLoader.getLoadViewDistance(player);
+-        return level.chunkSource.chunkMap.serverViewDistance;
++        return RegionizedPlayerChunkLoader.getAPIViewDistance(player);
      }
  
      public static int getTickViewDistance(final ServerPlayer player) {
@@ -5545,10 +5545,10 @@ index 0000000000000000000000000000000000000000..003a857e70ead858e8437e3c1bfaf22f
 +}
 diff --git a/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/player/RegionizedPlayerChunkLoader.java b/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/player/RegionizedPlayerChunkLoader.java
 new file mode 100644
-index 0000000000000000000000000000000000000000..5a6defc4c4d30c06d4bba856847feb176950ca1e
+index 0000000000000000000000000000000000000000..dd2509996bfd08e8c3f9f2be042229eac6d7692d
 --- /dev/null
 +++ b/src/main/java/ca/spottedleaf/moonrise/patches/chunk_system/player/RegionizedPlayerChunkLoader.java
-@@ -0,0 +1,1090 @@
+@@ -0,0 +1,1092 @@
 +package ca.spottedleaf.moonrise.patches.chunk_system.player;
 +
 +import ca.spottedleaf.concurrentutil.util.ConcurrentUtil;
@@ -5557,6 +5557,7 @@ index 0000000000000000000000000000000000000000..5a6defc4c4d30c06d4bba856847feb17
 +import ca.spottedleaf.moonrise.common.misc.AllocatingRateLimiter;
 +import ca.spottedleaf.moonrise.common.misc.SingleUserAreaMap;
 +import ca.spottedleaf.moonrise.common.util.CoordinateUtils;
++import ca.spottedleaf.moonrise.common.util.MoonriseConstants;
 +import ca.spottedleaf.moonrise.common.util.TickThread;
 +import ca.spottedleaf.moonrise.patches.chunk_system.level.ChunkSystemLevel;
 +import ca.spottedleaf.moonrise.patches.chunk_system.level.ChunkSystemServerLevel;
@@ -5665,14 +5666,25 @@ index 0000000000000000000000000000000000000000..5a6defc4c4d30c06d4bba856847feb17
 +        int sendViewDistance
 +    ) {
 +        public ViewDistances setTickViewDistance(final int distance) {
++            if (distance != -1 && (distance < (0) || distance > (MoonriseConstants.MAX_VIEW_DISTANCE))) {
++                throw new IllegalArgumentException(Integer.toString(distance));
++            }
 +            return new ViewDistances(distance, this.loadViewDistance, this.sendViewDistance);
 +        }
 +
 +        public ViewDistances setLoadViewDistance(final int distance) {
++            // note: load view distance = api view distance + 1
++            if (distance != -1 && (distance < (2 + 1) || distance > (MoonriseConstants.MAX_VIEW_DISTANCE + 1))) {
++                throw new IllegalArgumentException(Integer.toString(distance));
++            }
 +            return new ViewDistances(this.tickViewDistance, distance, this.sendViewDistance);
 +        }
 +
 +        public ViewDistances setSendViewDistance(final int distance) {
++            // note: send view distance <= load view distance - 1
++            if (distance != -1 && (distance < (0) || distance > (MoonriseConstants.MAX_VIEW_DISTANCE))) {
++                throw new IllegalArgumentException(Integer.toString(distance));
++            }
 +            return new ViewDistances(this.tickViewDistance, this.loadViewDistance, distance);
 +        }
 +
@@ -5706,16 +5718,6 @@ index 0000000000000000000000000000000000000000..5a6defc4c4d30c06d4bba856847feb17
 +        return data.lastLoadDistance - 1;
 +    }
 +
-+    public static int getLoadViewDistance(final ServerPlayer player) {
-+        final ServerLevel level = player.serverLevel();
-+        final PlayerChunkLoaderData data = ((ChunkSystemServerPlayer)player).moonrise$getChunkLoader();
-+        if (data == null) {
-+            return ((ChunkSystemServerLevel)level).moonrise$getPlayerChunkLoader().getAPIViewDistance();
-+        }
-+        // view distance = load distance + 1
-+        return data.lastLoadDistance - 1;
-+    }
-+
 +    public static int getAPISendViewDistance(final ServerPlayer player) {
 +        final ServerLevel level = player.serverLevel();
 +        final PlayerChunkLoaderData data = ((ChunkSystemServerPlayer)player).moonrise$getChunkLoader();
@@ -6072,7 +6074,7 @@ index 0000000000000000000000000000000000000000..5a6defc4c4d30c06d4bba856847feb17
 +                                           final int playerLoadViewDistance, final int worldLoadViewDistance) {
 +            return Math.min(
 +                    playerTickViewDistance < 0 ? worldTickViewDistance : playerTickViewDistance,
-+                    playerLoadViewDistance < 0 ? worldLoadViewDistance : playerLoadViewDistance
++                    playerLoadViewDistance < 0 ? (worldLoadViewDistance - 1) : (playerLoadViewDistance - 1)
 +            );
 +        }
 +
@@ -24171,7 +24173,7 @@ index d9ad32acdf46a43a649334a3b736aeb7b3af21d1..fae17a075d7efaf24d916877dd5968eb
      public static final int RADIUS_AROUND_FULL_CHUNK = FULL_CHUNK_STEP.accumulatedDependencies().getRadius();
      public static final int MAX_LEVEL = 33 + RADIUS_AROUND_FULL_CHUNK;
 diff --git a/src/main/java/net/minecraft/server/level/ChunkMap.java b/src/main/java/net/minecraft/server/level/ChunkMap.java
-index 16e55cc94c8f6e204e4b7ab6ad8d32a6c443357f..80bbf77454ff34505196998bcfeaa3e40a4f639c 100644
+index e9b585387f6cbc454e7b16feb36a256e733c5488..67cfc3236a39008cfcf3acffefafda1a604b8573 100644
 --- a/src/main/java/net/minecraft/server/level/ChunkMap.java
 +++ b/src/main/java/net/minecraft/server/level/ChunkMap.java
 @@ -108,7 +108,7 @@ import org.slf4j.Logger;
@@ -25482,7 +25484,7 @@ index 16e55cc94c8f6e204e4b7ab6ad8d32a6c443357f..80bbf77454ff34505196998bcfeaa3e4
  
          public void updatePlayers(List<ServerPlayer> players) {
 diff --git a/src/main/java/net/minecraft/server/level/DistanceManager.java b/src/main/java/net/minecraft/server/level/DistanceManager.java
-index f7c2c03749d6be25bf33afd61e1da120770b3432..7a9e7fc688e48d18a6a884f02f768ae652326aae 100644
+index f7c2c03749d6be25bf33afd61e1da120770b3432..746f61661e22d22f2acbbe54a5933e57fbca45b2 100644
 --- a/src/main/java/net/minecraft/server/level/DistanceManager.java
 +++ b/src/main/java/net/minecraft/server/level/DistanceManager.java
 @@ -34,58 +34,57 @@ import net.minecraft.world.level.ChunkPos;
@@ -25754,7 +25756,7 @@ index f7c2c03749d6be25bf33afd61e1da120770b3432..7a9e7fc688e48d18a6a884f02f768ae6
      }
  
      public void removePlayer(SectionPos pos, ServerPlayer player) {
-@@ -284,160 +175,89 @@ public abstract class DistanceManager {
+@@ -284,160 +175,93 @@ public abstract class DistanceManager {
          if (objectset != null) objectset.remove(player); // Paper - some state corruption happens here, don't crash, clean up gracefully
          if (objectset == null || objectset.isEmpty()) { // Paper
              this.playersPerChunk.remove(i);
@@ -25805,8 +25807,12 @@ index f7c2c03749d6be25bf33afd61e1da120770b3432..7a9e7fc688e48d18a6a884f02f768ae6
 -            this.simulationDistance = simulationDistance;
 -            this.tickingTicketsTracker.replacePlayerTicketsLevel(this.getPlayerTicketLevel());
 -        }
-+        ((ca.spottedleaf.moonrise.patches.chunk_system.level.ChunkSystemServerLevel)this.moonrise$getChunkMap().level).moonrise$getPlayerChunkLoader().setTickDistance(simulationDistance); // Paper - rewrite chunk system
++        // Paper start - rewrite chunk system
++        // note: vanilla does not clamp to 0, but we do simply because we need a min of 0
++        final int clamped = net.minecraft.util.Mth.clamp(simulationDistance, 0, ca.spottedleaf.moonrise.common.util.MoonriseConstants.MAX_VIEW_DISTANCE);
  
++        ((ca.spottedleaf.moonrise.patches.chunk_system.level.ChunkSystemServerLevel)this.moonrise$getChunkMap().level).moonrise$getPlayerChunkLoader().setTickDistance(clamped);
++        // Paper end - rewrite chunk system
      }
  
      public int getNaturalSpawnChunkCount() {
@@ -25940,7 +25946,7 @@ index f7c2c03749d6be25bf33afd61e1da120770b3432..7a9e7fc688e48d18a6a884f02f768ae6
      private class ChunkTicketTracker extends ChunkTracker {
  
          private static final int MAX_LEVEL = ChunkLevel.MAX_LEVEL + 1;
-@@ -483,7 +303,7 @@ public abstract class DistanceManager {
+@@ -483,7 +307,7 @@ public abstract class DistanceManager {
          public int runDistanceUpdates(int distance) {
              return this.runUpdates(distance);
          }
@@ -25949,7 +25955,7 @@ index f7c2c03749d6be25bf33afd61e1da120770b3432..7a9e7fc688e48d18a6a884f02f768ae6
  
      private class FixedPlayerDistanceChunkTracker extends ChunkTracker {
  
-@@ -563,6 +383,7 @@ public abstract class DistanceManager {
+@@ -563,6 +387,7 @@ public abstract class DistanceManager {
          }
      }
  
@@ -25957,7 +25963,7 @@ index f7c2c03749d6be25bf33afd61e1da120770b3432..7a9e7fc688e48d18a6a884f02f768ae6
      private class PlayerTicketTracker extends DistanceManager.FixedPlayerDistanceChunkTracker {
  
          private int viewDistance = 0;
-@@ -657,5 +478,5 @@ public abstract class DistanceManager {
+@@ -657,5 +482,5 @@ public abstract class DistanceManager {
          private boolean haveTicketFor(int distance) {
              return distance <= this.viewDistance;
          }
@@ -28060,7 +28066,7 @@ index b7d29389a357f142237cecd75f8ca91cf1eb6b5b..e4b0dc3121101d54394a0c3a413dabf8
          this.generatingStep = generationStep;
          this.cache = chunks;
 diff --git a/src/main/java/net/minecraft/server/players/PlayerList.java b/src/main/java/net/minecraft/server/players/PlayerList.java
-index 88299abf563a041ade1683b66b43103b0eeeea0d..61f3ee42aaad1641c92df3eb60d699b9dd5679e3 100644
+index 88299abf563a041ade1683b66b43103b0eeeea0d..7f5686571ace6155247e085560fcc8919e67734c 100644
 --- a/src/main/java/net/minecraft/server/players/PlayerList.java
 +++ b/src/main/java/net/minecraft/server/players/PlayerList.java
 @@ -1420,7 +1420,7 @@ public abstract class PlayerList {
@@ -28072,6 +28078,15 @@ index 88299abf563a041ade1683b66b43103b0eeeea0d..61f3ee42aaad1641c92df3eb60d699b9
          Iterator iterator = this.server.getAllLevels().iterator();
  
          while (iterator.hasNext()) {
+@@ -1435,7 +1435,7 @@ public abstract class PlayerList {
+ 
+     public void setSimulationDistance(int simulationDistance) {
+         this.simulationDistance = simulationDistance;
+-        this.broadcastAll(new ClientboundSetSimulationDistancePacket(simulationDistance));
++        //this.broadcastAll(new ClientboundSetSimulationDistancePacket(simulationDistance)); // Paper - rewrite chunk system
+         Iterator iterator = this.server.getAllLevels().iterator();
+ 
+         while (iterator.hasNext()) {
 diff --git a/src/main/java/net/minecraft/util/BitStorage.java b/src/main/java/net/minecraft/util/BitStorage.java
 index 68648c5a5e3ff079f832092af0f2f801c42d1ede..e4e153cb8899e70273aa150b8ea26907cf68b15c 100644
 --- a/src/main/java/net/minecraft/util/BitStorage.java
@@ -36264,7 +36279,7 @@ index 4a5a0e33af16369f665bf39e70238e4e5a5486da..696152286a4d16fa51a23ff6e15fb297
  
      // Paper start - implement pointers
 diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
-index 2bce60712c0fc53d019e1f9a76b05c95c0682141..775989ebd426b6b31fba68a649c6658d082e1e58 100644
+index 7e3552390c7dd11a79fd95d3543707cc5d652c66..71ed0230baf3115a53a8ce8f0a5c72f01954fffc 100644
 --- a/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
 +++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftPlayer.java
 @@ -3513,7 +3513,9 @@ public class CraftPlayer extends CraftHumanEntity implements Player {