From 8c7a3d1822c3a926e395e3919836dad33503919b Mon Sep 17 00:00:00 2001
From: Luke <32024335+lukeeey@users.noreply.github.com>
Date: Wed, 8 Dec 2021 18:23:05 +0000
Subject: [PATCH] Show the nether fog when using the nether height workaround
 (#2663)

---
 .../geyser/session/GeyserSession.java         | 38 ++++++++++++++++++-
 .../geyser/session/cache/WorldBorder.java     | 17 ---------
 .../protocol/java/JavaLoginTranslator.java    |  3 ++
 .../geysermc/geyser/util/DimensionUtils.java  | 17 +++++++++
 core/src/main/resources/config.yml            |  7 ++--
 5 files changed, 59 insertions(+), 23 deletions(-)

diff --git a/core/src/main/java/org/geysermc/geyser/session/GeyserSession.java b/core/src/main/java/org/geysermc/geyser/session/GeyserSession.java
index a58d57503..2e3368356 100644
--- a/core/src/main/java/org/geysermc/geyser/session/GeyserSession.java
+++ b/core/src/main/java/org/geysermc/geyser/session/GeyserSession.java
@@ -461,6 +461,8 @@ public class GeyserSession implements GeyserConnection, CommandSender {
     @Setter
     private boolean waitingForStatistics = false;
 
+    private final Set<String> fogNameSpaces = new HashSet<>();
+
     private final Set<UUID> emotes;
 
     /**
@@ -1006,11 +1008,11 @@ public class GeyserSession implements GeyserConnection, CommandSender {
                 // Set the mood
                 if (!isInWorldBorderWarningArea) {
                     isInWorldBorderWarningArea = true;
-                    WorldBorder.sendFog(this, "minecraft:fog_crimson_forest");
+                    sendFog("minecraft:fog_crimson_forest");
                 }
             } else if (isInWorldBorderWarningArea) {
                 // Clear fog as we are outside the world border now
-                WorldBorder.removeFog(this);
+                removeFog("minecraft:fog_crimson_forest");
                 isInWorldBorderWarningArea = false;
             }
 
@@ -1490,4 +1492,36 @@ public class GeyserSession implements GeyserConnection, CommandSender {
             player.sendUpstreamPacket(emoteList);
         }
     }
+
+    /**
+     * Send the following fog IDs, as well as the cached ones, to the client.
+     *
+     * Fog IDs can be found here:
+     * https://wiki.bedrock.dev/documentation/fog-ids.html
+     *
+     * @param fogNameSpaces the fog ids to add
+     */
+    public void sendFog(String... fogNameSpaces) {
+        this.fogNameSpaces.addAll(Arrays.asList(fogNameSpaces));
+
+        PlayerFogPacket packet = new PlayerFogPacket();
+        packet.getFogStack().addAll(this.fogNameSpaces);
+        sendUpstreamPacket(packet);
+    }
+
+    /**
+     * Removes the following fog IDs from the client and the cache.
+     *
+     * @param fogNameSpaces the fog ids to remove
+     */
+    public void removeFog(String... fogNameSpaces) {
+        if (fogNameSpaces.length == 0) {
+            this.fogNameSpaces.clear();
+        } else {
+            this.fogNameSpaces.removeAll(Arrays.asList(fogNameSpaces));
+        }
+        PlayerFogPacket packet = new PlayerFogPacket();
+        packet.getFogStack().addAll(this.fogNameSpaces);
+        sendUpstreamPacket(packet);
+    }
 }
diff --git a/core/src/main/java/org/geysermc/geyser/session/cache/WorldBorder.java b/core/src/main/java/org/geysermc/geyser/session/cache/WorldBorder.java
index 5c486af49..01c5949c7 100644
--- a/core/src/main/java/org/geysermc/geyser/session/cache/WorldBorder.java
+++ b/core/src/main/java/org/geysermc/geyser/session/cache/WorldBorder.java
@@ -296,21 +296,4 @@ public class WorldBorder {
         effectPacket.setType(WORLD_BORDER_PARTICLE);
         session.getUpstream().sendPacket(effectPacket);
     }
-
-    /**
-     * Send the following fog IDs to the client
-     */
-    public static void sendFog(GeyserSession session, String... fogNameSpaces) {
-        PlayerFogPacket packet = new PlayerFogPacket();
-        Collections.addAll(packet.getFogStack(), fogNameSpaces);
-        session.sendUpstreamPacket(packet);
-    }
-
-    /**
-     * Clear any additional fog sent to the client
-     */
-    public static void removeFog(GeyserSession session) {
-        session.sendUpstreamPacket(new PlayerFogPacket());
-    }
-
 }
diff --git a/core/src/main/java/org/geysermc/geyser/translator/protocol/java/JavaLoginTranslator.java b/core/src/main/java/org/geysermc/geyser/translator/protocol/java/JavaLoginTranslator.java
index 855f5b144..76a867e30 100644
--- a/core/src/main/java/org/geysermc/geyser/translator/protocol/java/JavaLoginTranslator.java
+++ b/core/src/main/java/org/geysermc/geyser/translator/protocol/java/JavaLoginTranslator.java
@@ -116,6 +116,9 @@ public class JavaLoginTranslator extends PacketTranslator<ClientboundLoginPacket
 
         if (!newDimension.equals(session.getDimension())) {
             DimensionUtils.switchDimension(session, newDimension);
+        } else if (DimensionUtils.isCustomBedrockNetherId() && newDimension.equalsIgnoreCase(DimensionUtils.NETHER)) {
+            // If the player is spawning into the "fake" nether, send them some fog
+            session.sendFog("minecraft:fog_hell");
         }
 
         ChunkUtils.loadDimensionTag(session, packet.getDimension());
diff --git a/core/src/main/java/org/geysermc/geyser/util/DimensionUtils.java b/core/src/main/java/org/geysermc/geyser/util/DimensionUtils.java
index c729c0b1e..b405914ed 100644
--- a/core/src/main/java/org/geysermc/geyser/util/DimensionUtils.java
+++ b/core/src/main/java/org/geysermc/geyser/util/DimensionUtils.java
@@ -58,6 +58,8 @@ public class DimensionUtils {
 
     public static void switchDimension(GeyserSession session, String javaDimension) {
         int bedrockDimension = javaToBedrock(javaDimension);
+        int previousDimension = javaToBedrock(session.getDimension());
+
         Entity player = session.getPlayerEntity();
 
         session.getChunkCache().clear();
@@ -102,6 +104,17 @@ public class DimensionUtils {
         // TODO - fix this hack of a fix by sending the final dimension switching logic after sections have been sent.
         // The client wants sections sent to it before it can successfully respawn.
         ChunkUtils.sendEmptyChunks(session, player.getPosition().toInt(), 3, true);
+
+        // If the bedrock nether height workaround is enabled, meaning the client is told it's in the end dimension,
+        // we check if the player is entering the nether and apply the nether fog to fake the fact that the client
+        // thinks they are in the end dimension.
+        if (BEDROCK_NETHER_ID == 2) {
+            if (bedrockDimension == BEDROCK_NETHER_ID) {
+                session.sendFog("minecraft:fog_hell");
+            } else if (previousDimension == BEDROCK_NETHER_ID) {
+                session.removeFog("minecraft:fog_hell");
+            }
+        }
     }
 
     /**
@@ -163,4 +176,8 @@ public class DimensionUtils {
         }
         return currentDimension.equals(OVERWORLD) ? NETHER : OVERWORLD;
     }
+
+    public static boolean isCustomBedrockNetherId() {
+        return BEDROCK_NETHER_ID == 2;
+    }
 }
diff --git a/core/src/main/resources/config.yml b/core/src/main/resources/config.yml
index f690b50ee..8c5737a39 100644
--- a/core/src/main/resources/config.yml
+++ b/core/src/main/resources/config.yml
@@ -148,10 +148,9 @@ allow-custom-skulls: true
 # This option requires a restart of Geyser in order to change its setting.
 add-non-bedrock-items: true
 
-# Bedrock prevents building and displaying blocks above Y127 in the Nether -
-# enabling this config option works around that by changing the Nether dimension ID
-# to the End ID. The main downside to this is that the sky will resemble that of
-# the end sky in the nether, but ultimately it's the only way for this feature to work.
+# Bedrock prevents building and displaying blocks above Y127 in the Nether.
+# This config option works around that by changing the Nether dimension ID to the End ID. 
+# The main downside to this is that the entire Nether will have the same red fog rather than having different fog for each biome.
 above-bedrock-nether-building: false
 
 # Force clients to load all resource packs if there are any.