Paper/nms-patches/EntityTrackerEntry.patch

--- a/net/minecraft/server/EntityTrackerEntry.java
+++ b/net/minecraft/server/EntityTrackerEntry.java
@@ -8,6 +8,11 @@
 import org.apache.logging.log4j.LogManager;
 import org.apache.logging.log4j.Logger;
 
+// CraftBukkit start
+import org.bukkit.entity.Player;
+import org.bukkit.event.player.PlayerVelocityEvent;
+// CraftBukkit end
+
 public class EntityTrackerEntry {
 
     private static final Logger p = LogManager.getLogger();
@@ -74,13 +79,13 @@
             this.broadcast(new PacketPlayOutAttachEntity(0, this.tracker, this.tracker.vehicle));
         }
 
-        if (this.tracker instanceof EntityItemFrame && this.m % 10 == 0) {
+        if (this.tracker instanceof EntityItemFrame /*&& this.m % 10 == 0*/) { // CraftBukkit - Moved below, should always enter this block
             EntityItemFrame entityitemframe = (EntityItemFrame) this.tracker;
             ItemStack itemstack = entityitemframe.getItem();
 
-            if (itemstack != null && itemstack.getItem() instanceof ItemWorldMap) {
+            if (this.m % 10 == 0 && itemstack != null && itemstack.getItem() instanceof ItemWorldMap) { // CraftBukkit - Moved this.m % 10 logic here so item frames do not enter the other blocks
                 WorldMap worldmap = Items.FILLED_MAP.getSavedMap(itemstack, this.tracker.world);
-                Iterator iterator = list.iterator();
+                Iterator iterator = this.trackedPlayers.iterator(); // CraftBukkit
 
                 while (iterator.hasNext()) {
                     EntityHuman entityhuman = (EntityHuman) iterator.next();
@@ -116,6 +121,19 @@
                 boolean flag = Math.abs(j1) >= 4 || Math.abs(k1) >= 4 || Math.abs(l1) >= 4 || this.m % 60 == 0;
                 boolean flag1 = Math.abs(l - this.yRot) >= 4 || Math.abs(i1 - this.xRot) >= 4;
 
+                // CraftBukkit start - Code moved from below
+                if (flag) {
+                    this.xLoc = i;
+                    this.yLoc = j;
+                    this.zLoc = k;
+                }
+
+                if (flag1) {
+                    this.yRot = l;
+                    this.xRot = i1;
+                }
+                // CraftBukkit end
+
                 if (this.m > 0 || this.tracker instanceof EntityArrow) {
                     if (j1 >= -128 && j1 < 128 && k1 >= -128 && k1 < 128 && l1 >= -128 && l1 < 128 && this.v <= 400 && !this.x && this.y == this.tracker.onGround) {
                         if ((!flag || !flag1) && !(this.tracker instanceof EntityArrow)) {
@@ -130,6 +148,11 @@
                     } else {
                         this.y = this.tracker.onGround;
                         this.v = 0;
+                        // CraftBukkit start - Refresh list of who can see a player before sending teleport packet
+                        if (this.tracker instanceof EntityPlayer) {
+                            this.scanPlayers(new java.util.ArrayList(this.trackedPlayers));
+                        }
+                        // CraftBukkit end
                         object = new PacketPlayOutEntityTeleport(this.tracker.getId(), i, j, k, (byte) l, (byte) i1, this.tracker.onGround);
                     }
                 }
@@ -154,6 +177,7 @@
                 }
 
                 this.b();
+                /* CraftBukkit start - Code moved up
                 if (flag) {
                     this.xLoc = i;
                     this.yLoc = j;
@@ -164,6 +188,7 @@
                     this.yRot = l;
                     this.xRot = i1;
                 }
+                // CraftBukkit end */
 
                 this.x = false;
             } else {
@@ -195,7 +220,27 @@
 
         ++this.m;
         if (this.tracker.velocityChanged) {
-            this.broadcastIncludingSelf(new PacketPlayOutEntityVelocity(this.tracker));
+            // CraftBukkit start - Create PlayerVelocity event
+            boolean cancelled = false;
+
+            if (this.tracker instanceof EntityPlayer) {
+                Player player = (Player) this.tracker.getBukkitEntity();
+                org.bukkit.util.Vector velocity = player.getVelocity();
+
+                PlayerVelocityEvent event = new PlayerVelocityEvent(player, velocity);
+                this.tracker.world.getServer().getPluginManager().callEvent(event);
+
+                if (event.isCancelled()) {
+                    cancelled = true;
+                } else if (!velocity.equals(event.getVelocity())) {
+                    player.setVelocity(velocity);
+                }
+            }
+
+            if (!cancelled) {
+                this.broadcastIncludingSelf(new PacketPlayOutEntityVelocity(this.tracker));
+            }
+            // CraftBukkit end
             this.tracker.velocityChanged = false;
         }
 
@@ -213,6 +258,11 @@
             Set set = attributemapserver.getAttributes();
 
             if (!set.isEmpty()) {
+                // CraftBukkit start - Send scaled max health
+                if (this.tracker instanceof EntityPlayer) {
+                    ((EntityPlayer) this.tracker).getBukkitEntity().injectScaledMaxHealth(set, false);
+                }
+                // CraftBukkit end
                 this.broadcastIncludingSelf(new PacketPlayOutUpdateAttributes(this.tracker.getId(), set));
             }
 
@@ -263,6 +313,16 @@
         if (entityplayer != this.tracker) {
             if (this.c(entityplayer)) {
                 if (!this.trackedPlayers.contains(entityplayer) && (this.e(entityplayer) || this.tracker.attachedToPlayer)) {
+                    // CraftBukkit start - respect vanish API
+                    if (this.tracker instanceof EntityPlayer) {
+                        Player player = ((EntityPlayer) this.tracker).getBukkitEntity();
+                        if (!entityplayer.getBukkitEntity().canSee(player)) {
+                            return;
+                        }
+                    }
+
+                    entityplayer.removeQueue.remove(Integer.valueOf(this.tracker.getId()));
+                    // CraftBukkit end
                     this.trackedPlayers.add(entityplayer);
                     Packet packet = this.c();
 
@@ -281,6 +341,12 @@
                         AttributeMapServer attributemapserver = (AttributeMapServer) ((EntityLiving) this.tracker).getAttributeMap();
                         Collection collection = attributemapserver.c();
 
+                        // CraftBukkit start - If sending own attributes send scaled health instead of current maximum health
+                        if (this.tracker.getId() == entityplayer.getId()) {
+                            ((EntityPlayer) this.tracker).getBukkitEntity().injectScaledMaxHealth(collection, false);
+                        }
+                        // CraftBukkit end
+
                         if (!collection.isEmpty()) {
                             entityplayer.playerConnection.sendPacket(new PacketPlayOutUpdateAttributes(this.tracker.getId(), collection));
                         }
@@ -319,6 +385,11 @@
                         }
                     }
 
+                    // CraftBukkit start - Fix for nonsensical head yaw
+                    this.i = MathHelper.d(this.tracker.getHeadRotation() * 256.0F / 360.0F);
+                    this.broadcast(new PacketPlayOutEntityHeadRotation(this.tracker, (byte) i));
+                    // CraftBukkit end
+
                     if (this.tracker instanceof EntityLiving) {
                         EntityLiving entityliving = (EntityLiving) this.tracker;
                         Iterator iterator = entityliving.getEffects().iterator();
@@ -339,8 +410,10 @@
     }
 
     public boolean c(EntityPlayer entityplayer) {
-        double d0 = entityplayer.locX - (double) (this.xLoc / 32);
-        double d1 = entityplayer.locZ - (double) (this.zLoc / 32);
+        // CraftBukkit start - this.*Loc / 30 -> this.tracker.loc*
+        double d0 = entityplayer.locX - this.tracker.locX;
+        double d1 = entityplayer.locZ - this.tracker.locZ;
+        // CraftBukkit end
 
         return d0 >= (double) (-this.b) && d0 <= (double) this.b && d1 >= (double) (-this.b) && d1 <= (double) this.b && this.tracker.a(entityplayer);
     }
@@ -358,7 +431,10 @@
 
     private Packet c() {
         if (this.tracker.dead) {
-            EntityTrackerEntry.p.warn("Fetching addPacket for removed entity");
+            // CraftBukkit start - Remove useless error spam, just return
+            // EntityTrackerEntry.p.warn("Fetching addPacket for removed entity");
+            return null;
+            // CraftBukkit end
         }
 
         if (this.tracker instanceof EntityItem) {