From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: TwoLeggedCat <80929284+TwoLeggedCat@users.noreply.github.com>
Date: Sat, 29 May 2021 14:33:25 -0500
Subject: [PATCH] Line Of Sight Changes


diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index bce63453fb04db09b10550197f749c959b30a37e..62e8586d30950eed81868ccbb48212a426774da3 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3558,7 +3558,8 @@ public abstract class LivingEntity extends Entity implements Attackable {
             Vec3 vec3d = new Vec3(this.getX(), this.getEyeY(), this.getZ());
             Vec3 vec3d1 = new Vec3(entity.getX(), entity.getEyeY(), entity.getZ());
 
-            return vec3d1.distanceTo(vec3d) > 128.0D ? false : this.level().clip(new ClipContext(vec3d, vec3d1, ClipContext.Block.COLLIDER, ClipContext.Fluid.NONE, this)).getType() == HitResult.Type.MISS;
+            // Paper - diff on change - used in CraftLivingEntity#hasLineOfSight(Location) and CraftWorld#lineOfSightExists
+            return vec3d1.distanceToSqr(vec3d) > 128D * 128D ? false : this.level().clip(new ClipContext(vec3d, vec3d1, ClipContext.Block.COLLIDER, ClipContext.Fluid.NONE, this)).getType() == HitResult.Type.MISS;
         }
     }
 
diff --git a/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java b/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java
index 5bd5a059c5beeade313f74ba3c1fc63825bd286b..d7c9b421eb636c0642b73263f46f824b95c1614e 100644
--- a/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java
+++ b/src/main/java/org/bukkit/craftbukkit/CraftRegionAccessor.java
@@ -996,5 +996,16 @@ public abstract class CraftRegionAccessor implements RegionAccessor {
     public org.bukkit.NamespacedKey getKey() {
         return org.bukkit.craftbukkit.util.CraftNamespacedKey.fromMinecraft(this.getHandle().getLevel().dimension().location());
     }
+
+    public boolean lineOfSightExists(Location from, Location to) {
+        Preconditions.checkArgument(from != null, "from parameter in lineOfSightExists cannot be null");
+        Preconditions.checkArgument(to != null, "to parameter in lineOfSightExists cannot be null");
+        if (from.getWorld() != to.getWorld()) return false;
+        net.minecraft.world.phys.Vec3 vec3d = new net.minecraft.world.phys.Vec3(from.getX(), from.getY(), from.getZ());
+        net.minecraft.world.phys.Vec3 vec3d1 = new net.minecraft.world.phys.Vec3(to.getX(), to.getY(), to.getZ());
+        if (vec3d1.distanceToSqr(vec3d) > 128D * 128D) return false; //Return early if the distance is greater than 128 blocks
+
+        return this.getHandle().clip(new net.minecraft.world.level.ClipContext(vec3d, vec3d1, net.minecraft.world.level.ClipContext.Block.COLLIDER, net.minecraft.world.level.ClipContext.Fluid.NONE, null)).getType() == net.minecraft.world.phys.HitResult.Type.MISS;
+    }
     // Paper end
 }
diff --git a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
index b38d72e921c4705cae72eb65113b36c87e4250fd..61292952681727bcd651064619bff1b41c560d75 100644
--- a/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
+++ b/src/main/java/org/bukkit/craftbukkit/entity/CraftLivingEntity.java
@@ -29,6 +29,9 @@ import net.minecraft.world.entity.projectile.ThrownEgg;
 import net.minecraft.world.entity.projectile.ThrownEnderpearl;
 import net.minecraft.world.entity.projectile.ThrownExperienceBottle;
 import net.minecraft.world.entity.projectile.ThrownTrident;
+import net.minecraft.world.level.ClipContext;
+import net.minecraft.world.phys.HitResult;
+import net.minecraft.world.phys.Vec3;
 import org.apache.commons.lang.Validate;
 import org.bukkit.FluidCollisionMode;
 import org.bukkit.Location;
@@ -576,6 +579,18 @@ public class CraftLivingEntity extends CraftEntity implements LivingEntity {
         return this.getHandle().hasLineOfSight(((CraftEntity) other).getHandle());
     }
 
+    // Paper start
+    @Override
+    public boolean hasLineOfSight(Location loc) {
+        if (this.getHandle().level() != ((CraftWorld) loc.getWorld()).getHandle()) return false;
+        Vec3 vec3d = new Vec3(this.getHandle().getX(), this.getHandle().getEyeY(), this.getHandle().getZ());
+        Vec3 vec3d1 = new Vec3(loc.getX(), loc.getY(), loc.getZ());
+        if (vec3d1.distanceToSqr(vec3d) > 128D * 128D) return false; //Return early if the distance is greater than 128 blocks
+
+        return this.getHandle().level().clip(new ClipContext(vec3d, vec3d1, ClipContext.Block.COLLIDER, ClipContext.Fluid.NONE, this.getHandle())).getType() == HitResult.Type.MISS;
+    }
+    // Paper end
+
     @Override
     public boolean getRemoveWhenFarAway() {
         return this.getHandle() instanceof Mob && !((Mob) this.getHandle()).isPersistenceRequired();