SparklyPaperMC/patches/server/0005-Strip-raytracing-for-EntityLiving-hasLineOfSight.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Paul Sauve <paul@technove.co>
Date: Sat, 31 Oct 2020 18:43:02 -0500
Subject: [PATCH] Strip raytracing for EntityLiving#hasLineOfSight

The IBlockAccess#rayTrace method is very wasteful in both allocations,
and in logic. While EntityLiving#hasLineOfSight provides static
parameters for collisions with blocks and fluids, the method still does
a lot of dynamic checks for both of these, which result in extra work.
As well, since the fluid collision option is set to NONE, the entire
fluid collision system is completely unneeded, yet used anyways.

Airplane
Copyright (C) 2020 Technove LLC

This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or
(at your option) any later version.

This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
GNU General Public License for more details.

You should have received a copy of the GNU General Public License
along with this program.  If not, see <http://www.gnu.org/licenses/>.

diff --git a/src/main/java/net/minecraft/world/entity/LivingEntity.java b/src/main/java/net/minecraft/world/entity/LivingEntity.java
index 24c629d5f26bc5aadebcf39a63930b3448525242..3a3d5d2d2861bd0c8836c95b5b0f9f2212372bc8 100644
--- a/src/main/java/net/minecraft/world/entity/LivingEntity.java
+++ b/src/main/java/net/minecraft/world/entity/LivingEntity.java
@@ -3431,7 +3431,10 @@ public abstract class LivingEntity extends Entity {
             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; // Paper - use distanceToSqr
+            // Airplane start
+            //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; // Paper - use distanceToSqr
+            return vec3d1.distanceToSqr(vec3d) > 128D * 128D ? false : this.level.rayTraceDirect(vec3d, vec3d1, net.minecraft.world.phys.shapes.CollisionContext.of(this)) == net.minecraft.world.phys.BlockHitResult.Type.MISS;
+            // Airplane end
         }
     }
 
diff --git a/src/main/java/net/minecraft/world/level/BlockGetter.java b/src/main/java/net/minecraft/world/level/BlockGetter.java
index ec781ab232d12cedb5f0236860377c4917c576d7..ced4b354e83ad68f8f1aacdefe2f0ce0035bd4a7 100644
--- a/src/main/java/net/minecraft/world/level/BlockGetter.java
+++ b/src/main/java/net/minecraft/world/level/BlockGetter.java
@@ -73,6 +73,16 @@ public interface BlockGetter extends LevelHeightAccessor {
         });
     }
 
+    // Airplane start - broken down variant of below rayTraceBlock, used by World#rayTraceDirect
+    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; // Tuinity - optimise air cases
+        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();
+    }
+    // Airplane end
+
     // CraftBukkit start - moved block handling into separate method for use by Block#rayTrace
     default BlockHitResult rayTraceBlock(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 61a4dea715689b0ce9247040db5dd2080ee2e167..a2bb8eee5ef4a5043026af20f78bb43a5006e6b4 100644
--- a/src/main/java/net/minecraft/world/level/Level.java
+++ b/src/main/java/net/minecraft/world/level/Level.java
@@ -453,6 +453,91 @@ public abstract class Level implements LevelAccessor, AutoCloseable {
         return null;
     }
 
+    // Airplane start - 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;
+    }
+    // Airplane end
+
     public boolean isInWorldBounds(BlockPos pos) {
         return pos.isValidLocation(this); // Paper - use better/optimized check
     }