From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Allink <arclicious@vivaldi.net>
Date: Thu, 21 Apr 2022 13:52:32 +0100
Subject: [PATCH] Limit amount of vehicle collision checks to 3 and discard
 vehicles if they collide with more than 15 other entities


diff --git a/src/main/java/net/minecraft/world/entity/vehicle/AbstractMinecart.java b/src/main/java/net/minecraft/world/entity/vehicle/AbstractMinecart.java
index 9948a28dae4edba877c13ef0156be5ff58df3fa2..9e25d4a3384d0157b99f7bd4d5f7edce032ece6b 100644
--- a/src/main/java/net/minecraft/world/entity/vehicle/AbstractMinecart.java
+++ b/src/main/java/net/minecraft/world/entity/vehicle/AbstractMinecart.java
@@ -8,6 +8,7 @@ import com.mojang.datafixers.util.Pair;
 import java.util.Iterator;
 import java.util.List;
 import java.util.Map;
+import java.util.concurrent.TimeUnit; // Scissors
 import javax.annotation.Nullable;
 import net.minecraft.BlockUtil;
 import net.minecraft.Util;
@@ -107,6 +108,7 @@ public abstract class AbstractMinecart extends Entity {
     private double flyingX = 0.949999988079071D; // Paper - restore vanilla precision
     private double flyingY = 0.949999988079071D; // Paper - restore vanilla precision
     private double flyingZ = 0.949999988079071D; // Paper - restore vanilla precision
+    private long lastLargeCollision = 0L; // Scissors - Add a collision debounce
     public double maxSpeed = 0.4D;
     // CraftBukkit end
 
@@ -434,8 +436,10 @@ public abstract class AbstractMinecart extends Entity {
             if (this.getMinecartType() == AbstractMinecart.Type.RIDEABLE && this.getDeltaMovement().horizontalDistanceSqr() > 0.01D) {
                 List<Entity> list = this.level().getEntities((Entity) this, this.getBoundingBox().inflate(0.20000000298023224D, 0.0D, 0.20000000298023224D), EntitySelector.pushableBy(this));
 
-                if (!list.isEmpty()) {
-                    for (int l = 0; l < list.size(); ++l) {
+                // Scissors start
+                if (!list.isEmpty() && (System.currentTimeMillis() - lastLargeCollision) >= TimeUnit.SECONDS.toMillis(5)) { // Using TimeUnit for better code readability
+                    for (int l = 0; l < Math.min(3, list.size()); ++l) {
+                // Scissors end
                         Entity entity = (Entity) list.get(l);
 
                         if (!(entity instanceof Player) && !(entity instanceof IronGolem) && !(entity instanceof AbstractMinecart) && !this.isVehicle() && !entity.isPassenger()) {
@@ -462,6 +466,14 @@ public abstract class AbstractMinecart extends Entity {
                             entity.push(this);
                         }
                     }
+
+                    // Scissors start - Add a collision debounce
+                    if (list.size() > 15) {
+                        this.discard();
+                    } else if (list.size() > 3) {
+                        lastLargeCollision = System.currentTimeMillis();
+                    }
+                    // Scissors end
                 }
             } else {
                 Iterator iterator = this.level().getEntities(this, this.getBoundingBox().inflate(0.20000000298023224D, 0.0D, 0.20000000298023224D)).iterator();
diff --git a/src/main/java/net/minecraft/world/entity/vehicle/Boat.java b/src/main/java/net/minecraft/world/entity/vehicle/Boat.java
index 35aeba4e8430e6419caa9db4a0b931a994228618..289eb39b15a283b0d9dbc33823f3a73f87202907 100644
--- a/src/main/java/net/minecraft/world/entity/vehicle/Boat.java
+++ b/src/main/java/net/minecraft/world/entity/vehicle/Boat.java
@@ -5,6 +5,7 @@ import com.google.common.collect.UnmodifiableIterator;
 import java.util.Iterator;
 import java.util.List;
 import java.util.function.IntFunction;
+import java.util.concurrent.TimeUnit; // Scissors
 import javax.annotation.Nullable;
 import net.minecraft.BlockUtil;
 import net.minecraft.core.BlockPos;
@@ -109,6 +110,7 @@ public class Boat extends Entity implements VariantHolder<Boat.Type> {
     public double unoccupiedDeceleration = -1;
     public boolean landBoats = false;
     // CraftBukkit end
+    private long lastLargeCollision = 0L; // Scissors - Add a collision debounce
 
     public Boat(EntityType<? extends Boat> type, Level world) {
         super(type, world);
@@ -421,10 +423,10 @@ public class Boat extends Entity implements VariantHolder<Boat.Type> {
         this.checkInsideBlocks();
         List<Entity> list = this.level().getEntities((Entity) this, this.getBoundingBox().inflate(0.20000000298023224D, -0.009999999776482582D, 0.20000000298023224D), EntitySelector.pushableBy(this));
 
-        if (!list.isEmpty()) {
+        if (!list.isEmpty() && (System.currentTimeMillis() - lastLargeCollision) >= TimeUnit.SECONDS.toMillis(5)) { // Scissors - add collision debounce, using TimeUnit for better code readability
             boolean flag = !this.level().isClientSide && !(this.getControllingPassenger() instanceof Player);
 
-            for (int j = 0; j < list.size(); ++j) {
+            for (int j = 0; j < Math.min(3, list.size()); ++j) { // Scissors - Limit amount of vehicle collision checks to 3 maximum
                 Entity entity = (Entity) list.get(j);
 
                 if (!entity.hasPassenger((Entity) this)) {
@@ -435,6 +437,14 @@ public class Boat extends Entity implements VariantHolder<Boat.Type> {
                     }
                 }
             }
+
+            // Scissors start - Add collision debounce
+            if (list.size() > 15) {
+                this.discard();
+            } else if (list.size() > 3) {
+                lastLargeCollision = System.currentTimeMillis();
+            }
+            // Scissors end
         }
 
     }