From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Dreeam <61569423+Dreeam-qwq@users.noreply.github.com>
Date: Sat, 6 Apr 2024 22:57:41 -0400
Subject: [PATCH] Optimize Minecart collisions

Co-authored-by: MrHua269 <wangxyper@163.com>

Skip tick collisions to to prevent lag causing by massive stacked Minecart
Useful for anarchy server.

diff --git a/src/main/java/net/minecraft/world/entity/EntitySelector.java b/src/main/java/net/minecraft/world/entity/EntitySelector.java
index f1b9e83206cc67e6ef29ebe088351b0aaa5eb349..e0a51e269aa076def275710174d3654d07e1a7aa 100644
--- a/src/main/java/net/minecraft/world/entity/EntitySelector.java
+++ b/src/main/java/net/minecraft/world/entity/EntitySelector.java
@@ -63,6 +63,13 @@ public final class EntitySelector {
     }
     public static Predicate<Entity> pushable(Entity entity, boolean ignoreClimbing) {
         // Paper end - Climbing should not bypass cramming gamerule
+
+        // Leaf start - Optimize Minecart collisions
+        if (entity instanceof net.minecraft.world.entity.vehicle.AbstractMinecart) {
+            return x -> true;
+        }
+        // Leaf end - Optimize Minecart collisions
+
         PlayerTeam scoreboardteam = entity.getTeam();
         Team.CollisionRule scoreboardteambase_enumteampush = scoreboardteam == null ? Team.CollisionRule.ALWAYS : scoreboardteam.getCollisionRule();
 
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 337bd2011c471361653c317004f8380c9fddfc47..52c105f5634ec8495e2e4c05adcc8217eb352e63 100644
--- a/src/main/java/net/minecraft/world/entity/vehicle/AbstractMinecart.java
+++ b/src/main/java/net/minecraft/world/entity/vehicle/AbstractMinecart.java
@@ -386,15 +386,15 @@ public abstract class AbstractMinecart extends VehicleEntity {
                 this.level().getCraftServer().getPluginManager().callEvent(new org.bukkit.event.vehicle.VehicleMoveEvent(vehicle, from, to));
             }
             // CraftBukkit end
-            if (this.getMinecartType() == AbstractMinecart.Type.RIDEABLE && this.getDeltaMovement().horizontalDistanceSqr() > 0.01D) {
+            // Leaf start - Optimize Minecart collision handling
+            // The logic below is used to get list of entities around Minecart
+            // and handle behaviors for their collisions with each other
+            if (!org.dreeam.leaf.config.modules.opt.OptimizeMinecart.enabled || this.tickCount % org.dreeam.leaf.config.modules.opt.OptimizeMinecart.skipTickCount == 0) {
+            if (this.getMinecartType() == AbstractMinecart.Type.RIDEABLE && (org.dreeam.leaf.config.modules.opt.OptimizeMinecart.enabled || 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()) {
-                    Iterator iterator = list.iterator();
-
-                    while (iterator.hasNext()) {
-                        Entity entity = (Entity) iterator.next();
-
+                    for (Entity entity : list) {
                         if (!(entity instanceof Player) && !(entity instanceof IronGolem) && !(entity instanceof AbstractMinecart) && !this.isVehicle() && !entity.isPassenger()) {
                             // CraftBukkit start
                             VehicleEntityCollisionEvent collisionEvent = new VehicleEntityCollisionEvent(vehicle, entity.getBukkitEntity());
@@ -421,11 +421,7 @@ public abstract class AbstractMinecart extends VehicleEntity {
                     }
                 }
             } else {
-                Iterator iterator1 = this.level().getEntities(this, this.getBoundingBox().inflate(0.20000000298023224D, 0.0D, 0.20000000298023224D)).iterator();
-
-                while (iterator1.hasNext()) {
-                    Entity entity1 = (Entity) iterator1.next();
-
+                for (Entity entity1 : this.level().getEntities(this, this.getBoundingBox().inflate(0.20000000298023224D, 0.0D, 0.20000000298023224D))) {
                     if (!this.hasPassenger(entity1) && entity1.isPushable() && entity1 instanceof AbstractMinecart) {
                         // CraftBukkit start
                         VehicleEntityCollisionEvent collisionEvent = new VehicleEntityCollisionEvent(vehicle, entity1.getBukkitEntity());
@@ -439,6 +435,8 @@ public abstract class AbstractMinecart extends VehicleEntity {
                     }
                 }
             }
+            }
+            // Leaf end
 
             this.updateInWaterStateAndDoFluidPushing();
             if (this.isInLava()) {
diff --git a/src/main/java/org/dreeam/leaf/config/modules/opt/OptimizeMinecart.java b/src/main/java/org/dreeam/leaf/config/modules/opt/OptimizeMinecart.java
new file mode 100644
index 0000000000000000000000000000000000000000..4e7b953f1b9db2a20c88d75ba9df3fa62be70658
--- /dev/null
+++ b/src/main/java/org/dreeam/leaf/config/modules/opt/OptimizeMinecart.java
@@ -0,0 +1,24 @@
+package org.dreeam.leaf.config.modules.opt;
+
+import org.dreeam.leaf.config.ConfigModules;
+import org.dreeam.leaf.config.EnumConfigCategory;
+
+public class OptimizeMinecart extends ConfigModules {
+
+    public String getBasePath() {
+        return EnumConfigCategory.PERF.getBaseKeyName() + ".optimize-minecart";
+    }
+
+    public static boolean enabled = false;
+    public static int skipTickCount = 30;
+
+    @Override
+    public void onLoaded() {
+        enabled = config.getBoolean(getBasePath() + ".enabled", enabled, """
+                Enable this feature to handle a large amount of stacked minecarts better.
+                By skipping tick collisions to reduce expensive getEntities
+                and bukkit event calls, useful for anarchy servers.
+                """);
+        skipTickCount = config.getInt(getBasePath() + ".skip-tick-count", skipTickCount);
+    }
+}