Paper/patches/server/0253-Add-LivingEntity-getTargetEntity.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: BillyGalbreath <Blake.Galbreath@GMail.com>
Date: Sat, 22 Sep 2018 00:33:08 -0500
Subject: [PATCH] Add LivingEntity#getTargetEntity


diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 279fa00fd9043e1995f22c79f47d0b41c27bd933..43eddcd8496ff2f089119f6632acfe1b56466c3d 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -127,6 +127,7 @@ import net.minecraft.world.level.storage.loot.LootTable;
 import net.minecraft.world.level.storage.loot.parameters.LootContextParamSets;
 import net.minecraft.world.level.storage.loot.parameters.LootContextParams;
 import net.minecraft.world.phys.AABB;
+import net.minecraft.world.phys.EntityHitResult;
 import net.minecraft.world.phys.HitResult;
 import net.minecraft.world.phys.Vec3;
 import net.minecraft.world.scores.PlayerTeam;
@@ -4041,6 +4042,38 @@ public abstract class LivingEntity extends Entity implements Attackable {
         return this.level().clip(raytrace);
     }
 
+    public @Nullable EntityHitResult getTargetEntity(int maxDistance) {
+        if (maxDistance < 1 || maxDistance > 120) {
+            throw new IllegalArgumentException("maxDistance must be between 1-120");
+        }
+
+        Vec3 start = this.getEyePosition(1.0F);
+        Vec3 direction = this.getLookAngle();
+        Vec3 end = start.add(direction.x * maxDistance, direction.y * maxDistance, direction.z * maxDistance);
+
+        List<Entity> entityList = this.level().getEntities(this, getBoundingBox().expandTowards(direction.x * maxDistance, direction.y * maxDistance, direction.z * maxDistance).inflate(1.0D, 1.0D, 1.0D), EntitySelector.NO_SPECTATORS.and(Entity::isPickable));
+
+        double distance = 0.0D;
+        EntityHitResult result = null;
+
+        for (Entity entity : entityList) {
+            final double inflationAmount = (double) entity.getPickRadius();
+            AABB aabb = entity.getBoundingBox().inflate(inflationAmount, inflationAmount, inflationAmount);
+            Optional<Vec3> rayTraceResult = aabb.clip(start, end);
+
+            if (rayTraceResult.isPresent()) {
+                Vec3 rayTrace = rayTraceResult.get();
+                double distanceTo = start.distanceToSqr(rayTrace);
+                if (distanceTo < distance || distance == 0.0D) {
+                    result = new EntityHitResult(entity, rayTrace);
+                    distance = distanceTo;
+                }
+            }
+        }
+
+        return result;
+    }
+
     public int shieldBlockingDelay = this.level().paperConfig().misc.shieldBlockingDelay;
 
     public int getShieldBlockingDelay() {
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
index f58c9edd68b02bbca10897320fae63cee1562fe3..9a159f0c7489d2924dabe3fd250d844899ae5761 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
@@ -1,5 +1,6 @@
 package org.bukkit.craftbukkit.entity;
 
+import com.destroystokyo.paper.entity.TargetEntityInfo;
 import com.google.common.base.Preconditions;
 import com.google.common.collect.Sets;
 import java.util.ArrayList;
@@ -226,6 +227,39 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
         }
         return null;
     }
+
+    public Entity getTargetEntity(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.world.phys.EntityHitResult rayTrace = rayTraceEntity(maxDistance, ignoreBlocks);
+        return rayTrace == null ? null : rayTrace.getEntity().getBukkitEntity();
+    }
+
+    public TargetEntityInfo getTargetEntityInfo(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.world.phys.EntityHitResult rayTrace = rayTraceEntity(maxDistance, ignoreBlocks);
+        return rayTrace == null ? null : new TargetEntityInfo(rayTrace.getEntity().getBukkitEntity(), new org.bukkit.util.Vector(rayTrace.getLocation().x, rayTrace.getLocation().y, rayTrace.getLocation().z));
+    }
+
+    @Override
+    public RayTraceResult rayTraceEntities(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.world.phys.EntityHitResult rayTrace = this.rayTraceEntity(maxDistance, ignoreBlocks);
+        return rayTrace == null ? null : new org.bukkit.util.RayTraceResult(org.bukkit.craftbukkit.util.CraftVector.toBukkit(rayTrace.getLocation()), rayTrace.getEntity().getBukkitEntity());
+    }
+
+    public net.minecraft.world.phys.EntityHitResult rayTraceEntity(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.world.phys.EntityHitResult rayTrace = getHandle().getTargetEntity(maxDistance);
+        if (rayTrace == null) {
+            return null;
+        }
+        if (!ignoreBlocks) {
+            net.minecraft.world.phys.HitResult rayTraceBlocks = getHandle().getRayTrace(maxDistance, net.minecraft.world.level.ClipContext.Fluid.NONE);
+            if (rayTraceBlocks != null) {
+                net.minecraft.world.phys.Vec3 eye = getHandle().getEyePosition(1.0F);
+                if (eye.distanceToSqr(rayTraceBlocks.getLocation()) <= eye.distanceToSqr(rayTrace.getLocation())) {
+                    return null;
+                }
+            }
+        }
+        return rayTrace;
+    }
     // Paper end
 
     @Override