Paper/paper-server/nms-patches/net/minecraft/world/entity/vehicle/EntityMinecartAbstract.patch

--- a/net/minecraft/world/entity/vehicle/EntityMinecartAbstract.java
+++ b/net/minecraft/world/entity/vehicle/EntityMinecartAbstract.java
@@ -47,6 +47,14 @@
 import net.minecraft.world.phys.AxisAlignedBB;
 import net.minecraft.world.phys.Vec3D;
 
+// CraftBukkit start
+import org.bukkit.Location;
+import org.bukkit.craftbukkit.util.CraftLocation;
+import org.bukkit.entity.Vehicle;
+import org.bukkit.event.vehicle.VehicleEntityCollisionEvent;
+import org.bukkit.util.Vector;
+// CraftBukkit end
+
 public abstract class EntityMinecartAbstract extends VehicleEntity {
 
     private static final Vec3D LOWERED_PASSENGER_ATTACHMENT = new Vec3D(0.0D, 0.0D, 0.0D);
@@ -86,6 +94,17 @@
         enummap.put(BlockPropertyTrackPosition.NORTH_EAST, Pair.of(baseblockposition2, baseblockposition1));
     });
 
+    // CraftBukkit start
+    public boolean slowWhenEmpty = true;
+    private double derailedX = 0.5;
+    private double derailedY = 0.5;
+    private double derailedZ = 0.5;
+    private double flyingX = 0.95;
+    private double flyingY = 0.95;
+    private double flyingZ = 0.95;
+    public double maxSpeed = 0.4D;
+    // CraftBukkit end
+
     protected EntityMinecartAbstract(EntityTypes<?> entitytypes, World world) {
         super(entitytypes, world);
         this.targetDeltaMovement = Vec3D.ZERO;
@@ -126,7 +145,7 @@
                 object = new EntityMinecartRideable(worldserver, d0, d1, d2);
         }
 
-        Object object1 = object;
+        EntityMinecartAbstract object1 = (EntityMinecartAbstract) object; // CraftBukkit- decompile error
 
         EntityTypes.createDefaultStackConfig(worldserver, itemstack, entityhuman).accept(object1);
         return (EntityMinecartAbstract) object1;
@@ -270,6 +289,14 @@
 
     @Override
     public void tick() {
+        // CraftBukkit start
+        double prevX = this.getX();
+        double prevY = this.getY();
+        double prevZ = this.getZ();
+        float prevYaw = this.getYRot();
+        float prevPitch = this.getXRot();
+        // CraftBukkit end
+
         if (this.getHurtTime() > 0) {
             this.setHurtTime(this.getHurtTime() - 1);
         }
@@ -279,7 +306,7 @@
         }
 
         this.checkBelowWorld();
-        this.handleNetherPortal();
+        // this.handleNetherPortal(); // CraftBukkit - handled in postTick
         if (this.level().isClientSide) {
             if (this.lerpSteps > 0) {
                 this.lerpPositionAndRotationStep(this.lerpSteps, this.lerpX, this.lerpY, this.lerpZ, this.lerpYRot, this.lerpXRot);
@@ -332,6 +359,18 @@
             }
 
             this.setRot(this.getYRot(), this.getXRot());
+            // CraftBukkit start
+            org.bukkit.World bworld = this.level().getWorld();
+            Location from = new Location(bworld, prevX, prevY, prevZ, prevYaw, prevPitch);
+            Location to = CraftLocation.toBukkit(this.position(), bworld, this.getYRot(), this.getXRot());
+            Vehicle vehicle = (Vehicle) this.getBukkitEntity();
+
+            this.level().getCraftServer().getPluginManager().callEvent(new org.bukkit.event.vehicle.VehicleUpdateEvent(vehicle));
+
+            if (!from.equals(to)) {
+                this.level().getCraftServer().getPluginManager().callEvent(new org.bukkit.event.vehicle.VehicleMoveEvent(vehicle, from, to));
+            }
+            // CraftBukkit end
             if (this.getMinecartType() == EntityMinecartAbstract.EnumMinecartType.RIDEABLE && this.getDeltaMovement().horizontalDistanceSqr() > 0.01D) {
                 List<Entity> list = this.level().getEntities((Entity) this, this.getBoundingBox().inflate(0.20000000298023224D, 0.0D, 0.20000000298023224D), IEntitySelector.pushableBy(this));
 
@@ -342,8 +381,26 @@
                         Entity entity = (Entity) iterator.next();
 
                         if (!(entity instanceof EntityHuman) && !(entity instanceof EntityIronGolem) && !(entity instanceof EntityMinecartAbstract) && !this.isVehicle() && !entity.isPassenger()) {
+                            // CraftBukkit start
+                            VehicleEntityCollisionEvent collisionEvent = new VehicleEntityCollisionEvent(vehicle, entity.getBukkitEntity());
+                            this.level().getCraftServer().getPluginManager().callEvent(collisionEvent);
+
+                            if (collisionEvent.isCancelled()) {
+                                continue;
+                            }
+                            // CraftBukkit end
                             entity.startRiding(this);
                         } else {
+                            // CraftBukkit start
+                            if (!this.isPassengerOfSameVehicle(entity)) {
+                                VehicleEntityCollisionEvent collisionEvent = new VehicleEntityCollisionEvent(vehicle, entity.getBukkitEntity());
+                                this.level().getCraftServer().getPluginManager().callEvent(collisionEvent);
+
+                                if (collisionEvent.isCancelled()) {
+                                    continue;
+                                }
+                            }
+                            // CraftBukkit end
                             entity.push(this);
                         }
                     }
@@ -355,6 +412,14 @@
                     Entity entity1 = (Entity) iterator1.next();
 
                     if (!this.hasPassenger(entity1) && entity1.isPushable() && entity1 instanceof EntityMinecartAbstract) {
+                        // CraftBukkit start
+                        VehicleEntityCollisionEvent collisionEvent = new VehicleEntityCollisionEvent(vehicle, entity1.getBukkitEntity());
+                        this.level().getCraftServer().getPluginManager().callEvent(collisionEvent);
+
+                        if (collisionEvent.isCancelled()) {
+                            continue;
+                        }
+                        // CraftBukkit end
                         entity1.push(this);
                     }
                 }
@@ -371,7 +436,7 @@
     }
 
     protected double getMaxSpeed() {
-        return (this.isInWater() ? 4.0D : 8.0D) / 20.0D;
+        return (this.isInWater() ? this.maxSpeed / 2.0D: this.maxSpeed); // CraftBukkit
     }
 
     public void activateMinecart(int i, int j, int k, boolean flag) {}
@@ -382,12 +447,16 @@
 
         this.setDeltaMovement(MathHelper.clamp(vec3d.x, -d0, d0), vec3d.y, MathHelper.clamp(vec3d.z, -d0, d0));
         if (this.onGround()) {
-            this.setDeltaMovement(this.getDeltaMovement().scale(0.5D));
+            // CraftBukkit start - replace magic numbers with our variables
+            this.setDeltaMovement(new Vec3D(this.getDeltaMovement().x * this.derailedX, this.getDeltaMovement().y * this.derailedY, this.getDeltaMovement().z * this.derailedZ));
+            // CraftBukkit end
         }
 
         this.move(EnumMoveType.SELF, this.getDeltaMovement());
         if (!this.onGround()) {
-            this.setDeltaMovement(this.getDeltaMovement().scale(0.95D));
+            // CraftBukkit start - replace magic numbers with our variables
+            this.setDeltaMovement(new Vec3D(this.getDeltaMovement().x * this.flyingX, this.getDeltaMovement().y * this.flyingY, this.getDeltaMovement().z * this.flyingZ));
+            // CraftBukkit end
         }
 
     }
@@ -583,7 +652,7 @@
     }
 
     protected void applyNaturalSlowdown() {
-        double d0 = this.isVehicle() ? 0.997D : 0.96D;
+        double d0 = this.isVehicle() || !this.slowWhenEmpty ? 0.997D : 0.96D; // CraftBukkit - add !this.slowWhenEmpty
         Vec3D vec3d = this.getDeltaMovement();
 
         vec3d = vec3d.multiply(d0, 0.0D, d0);
@@ -722,6 +791,14 @@
         if (!this.level().isClientSide) {
             if (!entity.noPhysics && !this.noPhysics) {
                 if (!this.hasPassenger(entity)) {
+                    // CraftBukkit start
+                    VehicleEntityCollisionEvent collisionEvent = new VehicleEntityCollisionEvent((Vehicle) this.getBukkitEntity(), entity.getBukkitEntity());
+                    this.level().getCraftServer().getPluginManager().callEvent(collisionEvent);
+
+                    if (collisionEvent.isCancelled()) {
+                        return;
+                    }
+                    // CraftBukkit end
                     double d0 = entity.getX() - this.getX();
                     double d1 = entity.getZ() - this.getZ();
                     double d2 = d0 * d0 + d1 * d1;
@@ -896,4 +973,26 @@
 
         private EnumMinecartType() {}
     }
+
+    // CraftBukkit start - Methods for getting and setting flying and derailed velocity modifiers
+    public Vector getFlyingVelocityMod() {
+        return new Vector(flyingX, flyingY, flyingZ);
+    }
+
+    public void setFlyingVelocityMod(Vector flying) {
+        flyingX = flying.getX();
+        flyingY = flying.getY();
+        flyingZ = flying.getZ();
+    }
+
+    public Vector getDerailedVelocityMod() {
+        return new Vector(derailedX, derailedY, derailedZ);
+    }
+
+    public void setDerailedVelocityMod(Vector derailed) {
+        derailedX = derailed.getX();
+        derailedY = derailed.getY();
+        derailedZ = derailed.getZ();
+    }
+    // CraftBukkit end
 }