Fix for entities that players can hit through blocking reach/attack r…

…ay trace

src/main/java/ac/grim/grimac/utils/data/packetentity/PacketEntityArmorStand.java

@@ -0,0 +1,23 @@
+package ac.grim.grimac.utils.data.packetentity;
+
+import ac.grim.grimac.player.GrimPlayer;
+import com.github.retrooper.packetevents.protocol.entity.type.EntityType;
+
+import java.util.UUID;
+
+public class PacketEntityArmorStand extends PacketEntity {
+
+    public static final int MARKER_FLAG = 16;
+
+    boolean isMarker;
+
+    public PacketEntityArmorStand(GrimPlayer player, UUID uuid, EntityType type, double x, double y, double z, int extraData) {
+        super(player, uuid, type, x, y, z);
+        isMarker = (extraData & MARKER_FLAG) != 0;
+    }
+
+    @Override
+    public boolean canHit() {
+        return !isMarker;
+    }
+}

src/main/java/ac/grim/grimac/utils/data/packetentity/PacketEntityArrow.java

@@ -0,0 +1,18 @@
+package ac.grim.grimac.utils.data.packetentity;
+
+import ac.grim.grimac.player.GrimPlayer;
+import com.github.retrooper.packetevents.protocol.entity.type.EntityType;
+
+import java.util.UUID;
+
+public class PacketEntityArrow extends PacketEntity {
+
+    public PacketEntityArrow(GrimPlayer player, UUID uuid, EntityType type, double x, double y, double z) {
+        super(player, uuid, type, x, y, z);
+    }
+
+    @Override
+    public boolean canHit() {
+        return false;
+    }
+}

src/main/java/ac/grim/grimac/utils/data/packetentity/PacketEntityHook.java

@@ -13,4 +13,9 @@ public PacketEntityHook(GrimPlayer player, UUID uuid, EntityType type, double x,
         super(player, uuid, type, x, y, z);
         this.owner = owner;
     }
+
+    @Override
+    public boolean canHit() {
+        return false;
+    }
 }

src/main/java/ac/grim/grimac/utils/data/packetentity/TypedPacketEntity.java

@@ -47,6 +47,21 @@ public boolean isBoat() {
         return isBoat;
     }
 
+    // Mojang makes this default to true and overrides it for everything where it isn't
+    // That's too much work for us to replicate...
+    // This is temporary hack and technically wrong
+    /* By Default every entity in the game cannot be hit by player crosshair. This is overwritten as follows:
+      Most Boats, Minecart's, TNT, Falling Blocks, and LivingEntities can only be hit if they're not removed
+      Every single BlockAttachedEntity can be hit (Leashes and other decorations)
+      End Crystals and IntersecetionEntities can be hit
+      Ender Dragon entity itself cannot be hit but its parts can be
+      ArmorStands can only be hit if they're not removed AND they're not markers.
+      Of all Projectiles, only redirectable ones (Fireballs - not blaze fireballs, Wind Charge, and Breeze Wind charges) can be hit
+      Persistent Projectiles can only be hit if they're not on the ground and redirectable
+    */
+    // TLDR If we want to get 90% of the way there everything can be hit except for fishing rod bobbers, arrows, and marker armor stands
+    public boolean canHit() { return true; }
+
     public boolean isPushable() {
         // Players can only push living entities
         // Minecarts and boats are the only non-living that can push

src/main/java/ac/grim/grimac/utils/latency/CompensatedEntities.java

@@ -182,6 +182,10 @@ public void addEntity(int entityID, UUID uuid, EntityType entityType, Vector3d p
                 packetEntity = new PacketEntityHook(player, uuid, entityType, position.getX(), position.getY(), position.getZ(), data);
             } else if (EntityTypes.ENDER_DRAGON.equals(entityType)) {
                 packetEntity = new PacketEntityEnderDragon(player, uuid, entityID, position.getX(), position.getY(), position.getZ());
+            } else if (EntityTypes.isTypeInstanceOf(entityType, EntityTypes.ABSTRACT_ARROW)) {
+                packetEntity = new PacketEntityArrow(player, uuid, entityType, position.getX(), position.getY(), position.getZ());
+            } else if (EntityTypes.ARMOR_STAND.equals(entityType)) {
+                packetEntity = new PacketEntityArmorStand(player, uuid, entityType, position.getX(), position.getY(), position.getZ(), data);
             } else {
                 packetEntity = new PacketEntity(player, uuid, entityType, position.getX(), position.getY(), position.getZ());
             }

src/main/java/ac/grim/grimac/utils/nmsutil/BlockRayTrace.java

@@ -12,6 +12,7 @@
 import ac.grim.grimac.utils.data.HitData;
 import ac.grim.grimac.utils.data.Pair;
 import ac.grim.grimac.utils.data.packetentity.PacketEntity;
+import ac.grim.grimac.utils.data.packetentity.TypedPacketEntity;
 import ac.grim.grimac.utils.math.GrimMath;
 import com.github.retrooper.packetevents.protocol.attribute.Attributes;
 import com.github.retrooper.packetevents.protocol.player.ClientVersion;
@@ -28,6 +29,7 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.function.BiFunction;
+import java.util.stream.Collectors;
 
 public class BlockRayTrace {
 
@@ -292,7 +294,7 @@ public static HitData getNearestHitResult(GrimPlayer player, PacketEntity target
         PacketEntity closestEntity = null;
 
         // Check entities
-        for (PacketEntity entity : player.compensatedEntities.entityMap.values()) {
+        for (PacketEntity entity : player.compensatedEntities.entityMap.values().stream().filter(TypedPacketEntity::canHit).collect(Collectors.toList())) {
             SimpleCollisionBox box = null;
             // 1.7 and 1.8 players get a bit of extra hitbox (this is why you should use 1.8 on cross version servers)
             // Yes, this is vanilla and not uncertainty.  All reach checks have this or they are wrong.