Date: Fri, 29 Apr 2016 20:02:00 -0400
Subject: [PATCH] Improve Maps (in item frames) performance and bug fixes

Maps used a modified version of rendering to support plugin controlled
imaging on maps. The Craft Map Renderer is much slower than Vanilla,
causing maps in item frames to cause a noticeable hit on server performance.

This updates the map system to not use the Craft system if we detect that no
custom renderers are in use, defaulting to the much simpler Vanilla system.

Additionally, numerous issues to player position tracking on maps has been fixed.

diff --git a/net/minecraft/server/level/ServerLevel.java b/net/minecraft/server/level/ServerLevel.java
index 91a1330d7308c9faadaf773d056493e1df5dcd1e..1d7e9492a474c99dff372d6b57f1f195e42d5114 100644
--- a/net/minecraft/server/level/ServerLevel.java
+++ b/net/minecraft/server/level/ServerLevel.java
@@ -2296,7 +2296,9 @@ public class ServerLevel extends Level implements ServerEntityGetter, WorldGenLe
                         }
 
                         map.carriedByPlayers.remove(player);
-                        map.carriedBy.removeIf(holdingPlayer -> holdingPlayer.player == player);
+                        if (map.carriedBy.removeIf(holdingPlayer -> holdingPlayer.player == player)) {
+                            map.decorations.remove(player.getName().getString()); // Paper
+                        }
                     }
                 }
             }
diff --git a/net/minecraft/server/level/ServerPlayer.java b/net/minecraft/server/level/ServerPlayer.java
index e3a4cf9cd03670705391f4dc68f193d7cee656e0..f9c9485a051f5fa6d508b8a194c9f17657e1a0f4 100644
--- a/net/minecraft/server/level/ServerPlayer.java
+++ b/net/minecraft/server/level/ServerPlayer.java
@@ -2654,6 +2654,14 @@ public class ServerPlayer extends Player {
                 this.awardStat(Stats.DROP);
             }
 
+            // Paper start - remove player from map on drop
+            if (item.getItem() == net.minecraft.world.item.Items.FILLED_MAP) {
+                final MapItemSavedData mapData = MapItem.getSavedData(item, this.level());
+                if (mapData != null) {
+                    mapData.tickCarriedBy(this, item);
+                }
+            }
+            // Paper end - remove player from map on drop
             return itemEntity;
         }
     }
diff --git a/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java b/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java
index fd50bd77e4dc7b18240afe5505c6e6f0f869c127..f60c2f3a3dfc69f50225b6ee7333ada5e9dfd090 100644
--- a/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java
+++ b/net/minecraft/world/level/saveddata/maps/MapItemSavedData.java
@@ -67,6 +67,7 @@ public class MapItemSavedData extends SavedData {
     public final Map<String, MapDecoration> decorations = Maps.newLinkedHashMap();
     private final Map<String, MapFrame> frameMarkers = Maps.newHashMap();
     private int trackedDecorationCount;
+    private org.bukkit.craftbukkit.map.RenderData vanillaRender = new org.bukkit.craftbukkit.map.RenderData(); // Paper
 
     // CraftBukkit start
     public final org.bukkit.craftbukkit.map.CraftMapView mapView;
@@ -92,6 +93,7 @@ public class MapItemSavedData extends SavedData {
         // CraftBukkit start
         this.mapView = new org.bukkit.craftbukkit.map.CraftMapView(this);
         this.server = (org.bukkit.craftbukkit.CraftServer) org.bukkit.Bukkit.getServer();
+        this.vanillaRender.buffer = colors; // Paper
         // CraftBukkit end
     }
 
@@ -163,6 +165,7 @@ public class MapItemSavedData extends SavedData {
         if (byteArray.length == 16384) {
             mapItemSavedData.colors = byteArray;
         }
+        mapItemSavedData.vanillaRender.buffer = byteArray; // Paper
 
         RegistryOps<Tag> registryOps = levelRegistry.createSerializationContext(NbtOps.INSTANCE);
 
@@ -337,7 +340,7 @@ public class MapItemSavedData extends SavedData {
             this.trackedDecorationCount--;
         }
 
-        this.setDecorationsDirty();
+        if (mapDecoration != null) this.setDecorationsDirty(); // Paper - only mark dirty if a change occurs
     }
 
     public static void addTargetDecoration(ItemStack stack, BlockPos pos, String type, Holder<MapDecorationType> mapDecorationType) {
@@ -610,7 +613,16 @@ public class MapItemSavedData extends SavedData {
         @Nullable
         Packet<?> nextUpdatePacket(MapId mapId) {
             MapItemSavedData.MapPatch mapPatch;
-            org.bukkit.craftbukkit.map.RenderData render = MapItemSavedData.this.mapView.render((org.bukkit.craftbukkit.entity.CraftPlayer) this.player.getBukkitEntity()); // CraftBukkit
+            // Paper start
+            if (!this.dirtyData && this.tick % 5 != 0) {
+                // this won't end up sending, so don't render it!
+                this.tick++;
+                return null;
+            }
+
+            final boolean vanillaMaps = this.shouldUseVanillaMap();
+            org.bukkit.craftbukkit.map.RenderData render = !vanillaMaps ? MapItemSavedData.this.mapView.render((org.bukkit.craftbukkit.entity.CraftPlayer) this.player.getBukkitEntity()) : MapItemSavedData.this.vanillaRender; // CraftBukkit // Paper
+            // Paper end
             if (this.dirtyData) {
                 this.dirtyData = false;
                 mapPatch = this.createPatch(render.buffer); // CraftBukkit
@@ -623,6 +635,7 @@ public class MapItemSavedData extends SavedData {
                 this.dirtyDecorations = false;
                 // CraftBukkit start
                 java.util.Collection<MapDecoration> icons = new java.util.ArrayList<MapDecoration>();
+                if (vanillaMaps) this.addSeenPlayers(icons); // Paper
 
                 for (org.bukkit.map.MapCursor cursor : render.cursors) {
                     if (cursor.isVisible()) {
@@ -658,6 +671,23 @@ public class MapItemSavedData extends SavedData {
         private void markDecorationsDirty() {
             this.dirtyDecorations = true;
         }
+
+        // Paper start
+        private void addSeenPlayers(java.util.Collection<MapDecoration> icons) {
+            org.bukkit.entity.Player player = (org.bukkit.entity.Player) this.player.getBukkitEntity();
+            MapItemSavedData.this.decorations.forEach((name, mapIcon) -> {
+                // If this cursor is for a player check visibility with vanish system
+                org.bukkit.entity.Player other = org.bukkit.Bukkit.getPlayerExact(name); // Spigot
+                if (other == null || player.canSee(other)) {
+                    icons.add(mapIcon);
+                }
+            });
+        }
+
+        private boolean shouldUseVanillaMap() {
+            return mapView.getRenderers().size() == 1 && mapView.getRenderers().getFirst().getClass() == org.bukkit.craftbukkit.map.CraftMapRenderer.class;
+        }
+        // Paper end
     }
 
     record MapDecorationLocation(Holder<MapDecorationType> type, byte x, byte y, byte rot) {