From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: "Sofiane H. Djerbi" <46628754+kugge@users.noreply.github.com>
Date: Wed, 10 May 2023 16:30:38 +0300
Subject: [PATCH] Strip raytracing for EntityLiving#hasLineOfSight

This has been benchmarked on a huge gold farm.
Resulting in significative performance improvements.

diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index f636bdf1075fa784ce7ee25478d4d94bacb05677..2da522f89a7c44208ca1ba9139efe723a519fabc 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3661,7 +3661,7 @@ public abstract class LivingEntity extends Entity implements Attackable {
             Vec3 vec3d1 = new Vec3(entity.getX(), entity.getEyeY(), entity.getZ());
 
             // 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;
+            return !(vec3d1.distanceToSqr(vec3d) > 128D * 128D) && this.level().rayTraceDirect(vec3d, vec3d1, net.minecraft.world.phys.shapes.CollisionContext.of(this)) == net.minecraft.world.phys.BlockHitResult.Type.MISS; // Paper - use distanceToSqr // Kaiiju - Pufferfish - Strip raytracing
         }
     }
 
diff --git a/src/main/java/net/minecraft/world/level/BlockGetter.java b/src/main/java/net/minecraft/world/level/BlockGetter.java
index 0e8746759752b692668886370181aa5db1fd0bb0..5e2f5e9c21009a71f671955df7a4135ce5cf5b08 100644
--- a/src/main/java/net/minecraft/world/level/BlockGetter.java
+++ b/src/main/java/net/minecraft/world/level/BlockGetter.java
@@ -68,6 +68,17 @@ public interface BlockGetter extends LevelHeightAccessor {
         });
     }
 
+    // Kaiiju start - Pufferfish - broken down variant of below rayTraceBlock, used by World#rayTraceDirect
+    @Nullable
+    default net.minecraft.world.phys.BlockHitResult.Type rayTraceBlockDirect(Vec3 vec3d, Vec3 vec3d1, BlockPos blockposition, BlockState iblockdata, net.minecraft.world.phys.shapes.CollisionContext voxelshapecoll) {
+        if (iblockdata.isAir()) return null;
+        VoxelShape voxelshape = ClipContext.Block.COLLIDER.get(iblockdata, this, blockposition, voxelshapecoll);
+        net.minecraft.world.phys.BlockHitResult movingobjectpositionblock = this.clipWithInteractionOverride(vec3d, vec3d1, blockposition, voxelshape, iblockdata);
+
+        return movingobjectpositionblock == null ? null : movingobjectpositionblock.getType();
+    }
+    // Kaiiju end
+
     // CraftBukkit start - moved block handling into separate method for use by Block#rayTrace
     default BlockHitResult clip(ClipContext raytrace1, BlockPos blockposition) {
             // Paper start - Prevent raytrace from loading chunks
diff --git a/src/main/java/net/minecraft/world/level/Level.java b/src/main/java/net/minecraft/world/level/Level.java
index fb71843793e699b2ccfaa3b7e4c2bb7d4826a706..42727a50ae11cd4d4aa65eb57638bfb164f1e4ac 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -432,6 +432,91 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
         return null;
     }
 
+    // Kaiiju start - Pufferfish - broken down method of raytracing for EntityLiving#hasLineOfSight, replaces IBlockAccess#rayTrace(RayTrace)
+    public net.minecraft.world.phys.BlockHitResult.Type rayTraceDirect(net.minecraft.world.phys.Vec3 vec3d, net.minecraft.world.phys.Vec3 vec3d1, net.minecraft.world.phys.shapes.CollisionContext voxelshapecoll) {
+        // most of this code comes from IBlockAccess#a(RayTrace, BiFunction, Function), but removes the needless functions
+        if (vec3d.equals(vec3d1)) {
+            return net.minecraft.world.phys.BlockHitResult.Type.MISS;
+        }
+
+        double endX = Mth.lerp(-1.0E-7D, vec3d1.x, vec3d.x);
+        double endY = Mth.lerp(-1.0E-7D, vec3d1.y, vec3d.y);
+        double endZ = Mth.lerp(-1.0E-7D, vec3d1.z, vec3d.z);
+
+        double startX = Mth.lerp(-1.0E-7D, vec3d.x, vec3d1.x);
+        double startY = Mth.lerp(-1.0E-7D, vec3d.y, vec3d1.y);
+        double startZ = Mth.lerp(-1.0E-7D, vec3d.z, vec3d1.z);
+
+        int currentX = Mth.floor(startX);
+        int currentY = Mth.floor(startY);
+        int currentZ = Mth.floor(startZ);
+
+        BlockPos.MutableBlockPos currentBlock = new BlockPos.MutableBlockPos(currentX, currentY, currentZ);
+
+        LevelChunk chunk = this.getChunkIfLoaded(currentBlock);
+        if (chunk == null) {
+            return net.minecraft.world.phys.BlockHitResult.Type.MISS;
+        }
+
+        net.minecraft.world.phys.BlockHitResult.Type initialCheck = this.rayTraceBlockDirect(vec3d, vec3d1, currentBlock, chunk.getBlockState(currentBlock), voxelshapecoll);
+
+        if (initialCheck != null) {
+            return initialCheck;
+        }
+
+        double diffX = endX - startX;
+        double diffY = endY - startY;
+        double diffZ = endZ - startZ;
+
+        int xDirection = Mth.sign(diffX);
+        int yDirection = Mth.sign(diffY);
+        int zDirection = Mth.sign(diffZ);
+
+        double normalizedX = xDirection == 0 ? Double.MAX_VALUE : (double) xDirection / diffX;
+        double normalizedY = yDirection == 0 ? Double.MAX_VALUE : (double) yDirection / diffY;
+        double normalizedZ = zDirection == 0 ? Double.MAX_VALUE : (double) zDirection / diffZ;
+
+        double normalizedXDirection = normalizedX * (xDirection > 0 ? 1.0D - Mth.frac(startX) : Mth.frac(startX));
+        double normalizedYDirection = normalizedY * (yDirection > 0 ? 1.0D - Mth.frac(startY) : Mth.frac(startY));
+        double normalizedZDirection = normalizedZ * (zDirection > 0 ? 1.0D - Mth.frac(startZ) : Mth.frac(startZ));
+
+        net.minecraft.world.phys.BlockHitResult.Type result;
+
+        do {
+            if (normalizedXDirection > 1.0D && normalizedYDirection > 1.0D && normalizedZDirection > 1.0D) {
+                return net.minecraft.world.phys.BlockHitResult.Type.MISS;
+            }
+
+            if (normalizedXDirection < normalizedYDirection) {
+                if (normalizedXDirection < normalizedZDirection) {
+                    currentX += xDirection;
+                    normalizedXDirection += normalizedX;
+                } else {
+                    currentZ += zDirection;
+                    normalizedZDirection += normalizedZ;
+                }
+            } else if (normalizedYDirection < normalizedZDirection) {
+                currentY += yDirection;
+                normalizedYDirection += normalizedY;
+            } else {
+                currentZ += zDirection;
+                normalizedZDirection += normalizedZ;
+            }
+
+            currentBlock.set(currentX, currentY, currentZ);
+            if (chunk.getPos().x != currentBlock.getX() >> 4 || chunk.getPos().z != currentBlock.getZ() >> 4) {
+                chunk = this.getChunkIfLoaded(currentBlock);
+                if (chunk == null) {
+                    return net.minecraft.world.phys.BlockHitResult.Type.MISS;
+                }
+            }
+            result = this.rayTraceBlockDirect(vec3d, vec3d1, currentBlock, chunk.getBlockState(currentBlock), voxelshapecoll);
+        } while (result == null);
+
+        return result;
+    }
+    // Kaiiju end
+
     public boolean isInWorldBounds(BlockPos pos) {
         return pos.isInsideBuildHeightAndWorldBoundsHorizontal(this); // Paper - use better/optimized check
     }