Always show the world border at least five blocks away

Previously, no indication that the world border exists would show if warning blocks was set to 0.

core/src/main/java/org/geysermc/geyser/session/GeyserSession.java

@@ -69,7 +69,10 @@ import com.nukkitx.protocol.bedrock.data.entity.EntityFlag;
 import com.nukkitx.protocol.bedrock.packet.*;
 import io.netty.channel.Channel;
 import io.netty.channel.EventLoop;
-import it.unimi.dsi.fastutil.ints.*;
+import it.unimi.dsi.fastutil.ints.Int2IntMap;
+import it.unimi.dsi.fastutil.ints.Int2IntOpenHashMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectMap;
+import it.unimi.dsi.fastutil.ints.Int2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.longs.Long2ObjectMap;
 import it.unimi.dsi.fastutil.longs.Long2ObjectOpenHashMap;
 import it.unimi.dsi.fastutil.objects.Object2ObjectOpenHashMap;
@@ -94,7 +97,6 @@ import org.geysermc.geyser.entity.type.Entity;
 import org.geysermc.geyser.entity.type.ItemFrameEntity;
 import org.geysermc.geyser.entity.type.Tickable;
 import org.geysermc.geyser.entity.type.player.SessionPlayerEntity;
-import org.geysermc.geyser.entity.type.player.SkullPlayerEntity;
 import org.geysermc.geyser.inventory.Inventory;
 import org.geysermc.geyser.inventory.PlayerInventory;
 import org.geysermc.geyser.inventory.recipe.GeyserRecipe;
@@ -1092,15 +1094,17 @@ public class GeyserSession implements GeyserConnection, CommandSender {
                 worldBorder.resize();
             }
 
-            if (!worldBorder.isWithinWarningBoundaries()) {
+            boolean shouldShowFog = !worldBorder.isWithinWarningBoundaries();
+            if (shouldShowFog || worldBorder.isCloseToBorderBoundaries()) {
                 // Show particles representing where the world border is
                 worldBorder.drawWall();
                 // Set the mood
-                if (!isInWorldBorderWarningArea) {
+                if (shouldShowFog && !isInWorldBorderWarningArea) {
                     isInWorldBorderWarningArea = true;
                     sendFog("minecraft:fog_crimson_forest");
                 }
-            } else if (isInWorldBorderWarningArea) {
+            }
+            if (!shouldShowFog && isInWorldBorderWarningArea) {
                 // Clear fog as we are outside the world border now
                 removeFog("minecraft:fog_crimson_forest");
                 isInWorldBorderWarningArea = false;

core/src/main/java/org/geysermc/geyser/session/cache/WorldBorder.java

@@ -139,6 +139,18 @@ public class WorldBorder {
         return position.getX() > minX && position.getX() < maxX && position.getZ() > minZ && position.getZ() < maxZ;
     }
 
+    private static final int CLOSE_TO_BORDER = 5;
+
+    /**
+     * @return if the player is close to the border boundaries. Used to always indicate a border even if there is no
+     * warning blocks set.
+     */
+    public boolean isCloseToBorderBoundaries() {
+        Vector3f position = session.getPlayerEntity().getPosition();
+        return !(position.getX() > minX + CLOSE_TO_BORDER && position.getX() < maxX - CLOSE_TO_BORDER
+                && position.getZ() > minZ + CLOSE_TO_BORDER && position.getZ() < maxZ - CLOSE_TO_BORDER);
+    }
+
     /**
      * Confirms that the entity is within world border boundaries when they move.
      * Otherwise, if {@code adjustPosition} is true, this function will push the player back.
@@ -246,16 +258,16 @@ public class WorldBorder {
         float particlePosY = entityPosition.getY();
         float particlePosZ = entityPosition.getZ();
 
-        if (entityPosition.getX() > warningMaxX) {
+        if (entityPosition.getX() > Math.min(warningMaxX, maxX - CLOSE_TO_BORDER)) {
             drawWall(Vector3f.from(maxX, particlePosY, particlePosZ), true);
         }
-        if (entityPosition.getX() < warningMinX) {
+        if (entityPosition.getX() < Math.max(warningMinX, minX + CLOSE_TO_BORDER)) {
             drawWall(Vector3f.from(minX, particlePosY, particlePosZ), true);
         }
-        if (entityPosition.getZ() > warningMaxZ) {
+        if (entityPosition.getZ() > Math.min(warningMaxZ, maxZ - CLOSE_TO_BORDER)) {
             drawWall(Vector3f.from(particlePosX, particlePosY, maxZ), false);
         }
-        if (entityPosition.getZ() < warningMinZ) {
+        if (entityPosition.getZ() < Math.max(warningMinZ, minZ + CLOSE_TO_BORDER)) {
             drawWall(Vector3f.from(particlePosX, particlePosY, minZ), false);
         }
     }