Paper/Spigot-Server-Patches/0339-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/server/AxisAlignedBB.java b/src/main/java/net/minecraft/server/AxisAlignedBB.java
index 02c09f39848399a86d46bd17569b4f01a7b5ab1f..ed9b2f9adfecdc6d1b9925579ec510657adde11f 100644
--- a/src/main/java/net/minecraft/server/AxisAlignedBB.java
+++ b/src/main/java/net/minecraft/server/AxisAlignedBB.java
@@ -112,6 +112,7 @@ public class AxisAlignedBB {
         return this.b(vec3d.x, vec3d.y, vec3d.z);
     }
 
+    public final AxisAlignedBB expand(double x, double y, double z) { return b(x, y, z); } // Paper - OBFHELPER
     public AxisAlignedBB b(double d0, double d1, double d2) {
         double d3 = this.minX;
         double d4 = this.minY;
@@ -141,6 +142,12 @@ public class AxisAlignedBB {
         return new AxisAlignedBB(d3, d4, d5, d6, d7, d8);
     }
 
+    // Paper start
+    public AxisAlignedBB grow(double d0) {
+        return grow(d0, d0, d0);
+    }
+    // Paper end
+
     public AxisAlignedBB grow(double d0, double d1, double d2) {
         double d3 = this.minX - d0;
         double d4 = this.minY - d1;
@@ -200,6 +207,7 @@ public class AxisAlignedBB {
         return this.minX < d3 && this.maxX > d0 && this.minY < d4 && this.maxY > d1 && this.minZ < d5 && this.maxZ > d2;
     }
 
+    public final boolean contains(Vec3D vec3d) { return d(vec3d); } // Paper - OBFHELPER
     public boolean d(Vec3D vec3d) {
         return this.e(vec3d.x, vec3d.y, vec3d.z);
     }
@@ -233,6 +241,7 @@ public class AxisAlignedBB {
         return this.g(-d0);
     }
 
+    public final Optional<Vec3D> calculateIntercept(Vec3D vec3d, Vec3D vec3d1) { return b(vec3d, vec3d1); } // Paper - OBFHELPER
     public Optional<Vec3D> b(Vec3D vec3d, Vec3D vec3d1) {
         double[] adouble = new double[]{1.0D};
         double d0 = vec3d1.x - vec3d.x;
diff --git a/src/main/java/net/minecraft/server/Entity.java b/src/main/java/net/minecraft/server/Entity.java
index 915378493d9c5bb501b21eb7aca380580716f4c3..8832ffc0fcf9410ecc07ac100c2c8e3cd4dbddff 100644
--- a/src/main/java/net/minecraft/server/Entity.java
+++ b/src/main/java/net/minecraft/server/Entity.java
@@ -1419,6 +1419,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
         return this.c(f - 90.0F, f1);
     }
 
+    public final Vec3D getEyePosition(float partialTicks) { return j(partialTicks); } // Paper - OBFHELPER
     public final Vec3D j(float f) {
         if (f == 1.0F) {
             return new Vec3D(this.locX(), this.getHeadY(), this.locZ());
@@ -2056,6 +2057,7 @@ public abstract class Entity implements INamableTileEntity, ICommandListener, Ke
         return this.getPassengers().size() < 1;
     }
 
+    public final float getCollisionBorderSize() { return bf(); } // Paper - OBFHELPER
     public float bf() {
         return 0.0F;
     }
diff --git a/src/main/java/net/minecraft/server/EntityLiving.java b/src/main/java/net/minecraft/server/EntityLiving.java
index 7c239b95c9f8dfa76d397979e6b3fdcc9ff55022..f0202dcb31fe637caa6bd998edec4cbc1def8324 100644
--- a/src/main/java/net/minecraft/server/EntityLiving.java
+++ b/src/main/java/net/minecraft/server/EntityLiving.java
@@ -3514,6 +3514,37 @@ public abstract class EntityLiving extends Entity {
         return world.rayTrace(raytrace);
     }
 
+    public MovingObjectPositionEntity getTargetEntity(int maxDistance) {
+        if (maxDistance < 1 || maxDistance > 120) {
+            throw new IllegalArgumentException("maxDistance must be between 1-120");
+        }
+
+        Vec3D start = this.getEyePosition(1.0F);
+        Vec3D direction = this.getLookDirection();
+        Vec3D end = start.add(direction.x * maxDistance, direction.y * maxDistance, direction.z * maxDistance);
+
+        List<Entity> entityList = world.getEntities(this, getBoundingBox().expand(direction.x * maxDistance, direction.y * maxDistance, direction.z * maxDistance).grow(1.0D, 1.0D, 1.0D), IEntitySelector.canAITarget().and(Entity::isInteractable));
+
+        double distance = 0.0D;
+        MovingObjectPositionEntity result = null;
+
+        for (Entity entity : entityList) {
+            AxisAlignedBB aabb = entity.getBoundingBox().grow((double) entity.getCollisionBorderSize());
+            Optional<Vec3D> rayTraceResult = aabb.calculateIntercept(start, end);
+
+            if (rayTraceResult.isPresent()) {
+                Vec3D rayTrace = rayTraceResult.get();
+                double distanceTo = start.distanceSquared(rayTrace);
+                if (distanceTo < distance || distance == 0.0D) {
+                    result = new MovingObjectPositionEntity(entity, rayTrace);
+                    distance = distanceTo;
+                }
+            }
+        }
+
+        return result;
+    }
+
     public int shieldBlockingDelay = world.paperConfig.shieldBlockingDelay;
 
     public int getShieldBlockingDelay() {
diff --git a/src/main/java/net/minecraft/server/IEntitySelector.java b/src/main/java/net/minecraft/server/IEntitySelector.java
index e8e7532493c973ce10d94a41676859674fc4e6f6..50f342c5f6e1ee5865646af0327567d7005a9ca5 100644
--- a/src/main/java/net/minecraft/server/IEntitySelector.java
+++ b/src/main/java/net/minecraft/server/IEntitySelector.java
@@ -17,6 +17,7 @@ public final class IEntitySelector {
     public static final Predicate<Entity> e = (entity) -> {
         return !(entity instanceof EntityHuman) || !entity.isSpectator() && !((EntityHuman) entity).isCreative();
     };
+    public static Predicate<Entity> canAITarget() { return f; } // Paper - OBFHELPER
     public static final Predicate<Entity> f = (entity) -> {
         return !(entity instanceof EntityHuman) || !entity.isSpectator() && !((EntityHuman) entity).isCreative() && entity.world.getDifficulty() != EnumDifficulty.PEACEFUL;
     };
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
index 63f46a4c6fda5a08f89d68da879ce4ad83056cf5..607f0bca1ca454bd60aad82df81702bf15e0ff4a 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
@@ -221,6 +221,33 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
             new com.destroystokyo.paper.block.TargetBlockInfo(org.bukkit.craftbukkit.block.CraftBlock.at(getHandle().world, ((net.minecraft.server.MovingObjectPositionBlock)rayTrace).getBlockPosition()),
                 net.minecraft.server.MCUtil.toBukkitBlockFace(((net.minecraft.server.MovingObjectPositionBlock)rayTrace).getDirection()));
     }
+
+    public Entity getTargetEntity(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.server.MovingObjectPositionEntity rayTrace = rayTraceEntity(maxDistance, ignoreBlocks);
+        return rayTrace == null ? null : rayTrace.getEntity().getBukkitEntity();
+    }
+
+    public com.destroystokyo.paper.entity.TargetEntityInfo getTargetEntityInfo(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.server.MovingObjectPositionEntity rayTrace = rayTraceEntity(maxDistance, ignoreBlocks);
+        return rayTrace == null ? null : new com.destroystokyo.paper.entity.TargetEntityInfo(rayTrace.getEntity().getBukkitEntity(), new org.bukkit.util.Vector(rayTrace.getPos().x, rayTrace.getPos().y, rayTrace.getPos().z));
+    }
+
+    public net.minecraft.server.MovingObjectPositionEntity rayTraceEntity(int maxDistance, boolean ignoreBlocks) {
+        net.minecraft.server.MovingObjectPositionEntity rayTrace = getHandle().getTargetEntity(maxDistance);
+        if (rayTrace == null) {
+            return null;
+        }
+        if (!ignoreBlocks) {
+            net.minecraft.server.MovingObjectPosition rayTraceBlocks = getHandle().getRayTrace(maxDistance, net.minecraft.server.RayTrace.FluidCollisionOption.NONE);
+            if (rayTraceBlocks != null) {
+                net.minecraft.server.Vec3D eye = getHandle().getEyePosition(1.0F);
+                if (eye.distanceSquared(rayTraceBlocks.getPos()) <= eye.distanceSquared(rayTrace.getPos())) {
+                    return null;
+                }
+            }
+        }
+        return rayTrace;
+    }
     // Paper end
 
     @Override