From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Byteflux <byte@byteflux.net>
Date: Tue, 1 Mar 2016 23:45:08 -0600
Subject: [PATCH] Entity Origin API


diff --git a/src/main/java/net/minecraft/server/level/ServerLevel.java b/src/main/java/net/minecraft/server/level/ServerLevel.java
index 3fce997cc390136a16c941f0461b20d2bc046948..b1771e25c13b555d3316aca35f8a97ed4ce8f275 100644
--- a/src/main/java/net/minecraft/server/level/ServerLevel.java
+++ b/src/main/java/net/minecraft/server/level/ServerLevel.java
@@ -2215,6 +2215,15 @@ public class ServerLevel extends Level implements WorldGenLevel {
 
             entity.updateDynamicGameEventListener(DynamicGameEventListener::add);
             entity.valid = true; // CraftBukkit
+            // Paper start - Set origin location when the entity is being added to the world
+            if (entity.getOriginVector() == null) {
+                entity.setOrigin(entity.getBukkitEntity().getLocation());
+            }
+            // Default to current world if unknown, gross assumption but entities rarely change world
+            if (entity.getOriginWorld() == null) {
+                entity.setOrigin(entity.getOriginVector().toLocation(getWorld()));
+            }
+            // Paper end
         }
 
         public void onTrackingEnd(Entity entity) {
diff --git a/src/main/java/net/minecraft/world/entity/Entity.java b/src/main/java/net/minecraft/world/entity/Entity.java
index 0cd735648314872e98e310627247b9ad425ab64d..5cf04b209ae3fa6c52ad45e726343418d0de311f 100644
--- a/src/main/java/net/minecraft/world/entity/Entity.java
+++ b/src/main/java/net/minecraft/world/entity/Entity.java
@@ -304,7 +304,27 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
     public long activatedTick = Integer.MIN_VALUE;
     public void inactiveTick() { }
     // Spigot end
+    // Paper start
+    @javax.annotation.Nullable
+    private org.bukkit.util.Vector origin;
+    @javax.annotation.Nullable
+    private UUID originWorld;
+
+    public void setOrigin(@javax.annotation.Nonnull Location location) {
+        this.origin = location.toVector();
+        this.originWorld = location.getWorld().getUID();
+    }
 
+    @javax.annotation.Nullable
+    public org.bukkit.util.Vector getOriginVector() {
+        return this.origin != null ? this.origin.clone() : null;
+    }
+
+    @javax.annotation.Nullable
+    public UUID getOriginWorld() {
+        return this.originWorld;
+    }
+    // Paper end
     public float getBukkitYaw() {
         return this.yRot;
     }
@@ -1928,6 +1948,15 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
                 this.bukkitEntity.storeBukkitValues(nbt);
             }
             // CraftBukkit end
+            // Paper start - Save the entity's origin location
+            if (this.origin != null) {
+                UUID originWorld = this.originWorld != null ? this.originWorld : this.level != null ? this.level.getWorld().getUID() : null;
+                if (originWorld != null) {
+                    nbt.putUUID("Paper.OriginWorld", originWorld);
+                }
+                nbt.put("Paper.Origin", this.newDoubleList(origin.getX(), origin.getY(), origin.getZ()));
+            }
+            // Paper end
             return nbt;
         } catch (Throwable throwable) {
             CrashReport crashreport = CrashReport.forThrowable(throwable, "Saving entity NBT");
@@ -2054,6 +2083,20 @@ public abstract class Entity implements Nameable, EntityAccess, CommandSource {
             }
             // CraftBukkit end
 
+            // Paper start - Restore the entity's origin location
+            ListTag originTag = nbt.getList("Paper.Origin", 6);
+            if (!originTag.isEmpty()) {
+                UUID originWorld = null;
+                if (nbt.contains("Paper.OriginWorld")) {
+                    originWorld = nbt.getUUID("Paper.OriginWorld");
+                } else if (this.level != null) {
+                    originWorld = this.level.getWorld().getUID();
+                }
+                this.originWorld = originWorld;
+                origin = new org.bukkit.util.Vector(originTag.getDouble(0), originTag.getDouble(1), originTag.getDouble(2));
+            }
+            // Paper end
+
         } catch (Throwable throwable) {
             CrashReport crashreport = CrashReport.forThrowable(throwable, "Loading entity NBT");
             CrashReportCategory crashreportsystemdetails = crashreport.addCategory("Entity being loaded");
diff --git a/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java b/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java
index c125564cfca5c4a616e11b334a9ec7929ebea496..561b8d6fcf4d511fb026bcc2c02054e56589d0b7 100644
--- a/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java
+++ b/src/main/java/net/minecraft/world/entity/item/FallingBlockEntity.java
@@ -339,6 +339,14 @@ public class FallingBlockEntity extends Entity {
             this.blockState = Blocks.SAND.defaultBlockState();
         }
 
+        // Paper start - Try and load origin location from the old NBT tags for backwards compatibility
+        if (nbt.contains("SourceLoc_x")) {
+            int srcX = nbt.getInt("SourceLoc_x");
+            int srcY = nbt.getInt("SourceLoc_y");
+            int srcZ = nbt.getInt("SourceLoc_z");
+            this.setOrigin(new org.bukkit.Location(level.getWorld(), srcX, srcY, srcZ));
+        }
+        // Paper end
     }
 
     public void setHurtsEntities(float fallHurtAmount, int fallHurtMax) {
diff --git a/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java b/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java
index 43ec4bc45a3e553fbbf47aaf613f6e0aad2319cf..aa0dfd08aefbb9363ec96080432f0f75d71b0b95 100644
--- a/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java
+++ b/src/main/java/net/minecraft/world/entity/item/PrimedTnt.java
@@ -117,6 +117,14 @@ public class PrimedTnt extends Entity {
     @Override
     protected void readAdditionalSaveData(CompoundTag nbt) {
         this.setFuse(nbt.getShort("Fuse"));
+        // Paper start - Try and load origin location from the old NBT tags for backwards compatibility
+        if (nbt.contains("SourceLoc_x")) {
+            int srcX = nbt.getInt("SourceLoc_x");
+            int srcY = nbt.getInt("SourceLoc_y");
+            int srcZ = nbt.getInt("SourceLoc_z");
+            this.setOrigin(new org.bukkit.Location(level.getWorld(), srcX, srcY, srcZ));
+        }
+        // Paper end
     }
 
     @Nullable
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
index 55bf95017d58bb61f9c6af27335c88421c74c4aa..62c2780b165a520e85f17fdf5c0d1c29b7579ebc 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftEntity.java
@@ -1217,5 +1217,20 @@ public abstract class CraftEntity implements org.bukkit.entity.Entity {
 
         return ret;
     }
+
+    @Override
+    public Location getOrigin() {
+        Vector originVector = this.getHandle().getOriginVector();
+        if (originVector == null) {
+            return null;
+        }
+        World world = this.getWorld();
+        if (this.getHandle().getOriginWorld() != null) {
+            world = org.bukkit.Bukkit.getWorld(this.getHandle().getOriginWorld());
+        }
+
+        //noinspection ConstantConditions
+        return originVector.toLocation(world);
+    }
     // Paper end
 }