From b691c43c44ff180d10e7d4a9afc83b98551ff586 Mon Sep 17 00:00:00 2001
From: daoge_cmd <3523206925@qq.com>
Date: Sun, 1 Mar 2026 12:16:08 +0800
Subject: Initial commit

---
 Minecraft.World/SetEntityMotionPacket.cpp | 113 ++++++++++++++++++++++++++++++
 1 file changed, 113 insertions(+)
 create mode 100644 Minecraft.World/SetEntityMotionPacket.cpp

(limited to 'Minecraft.World/SetEntityMotionPacket.cpp')

diff --git a/Minecraft.World/SetEntityMotionPacket.cpp b/Minecraft.World/SetEntityMotionPacket.cpp
new file mode 100644
index 00000000..a0749b74
--- /dev/null
+++ b/Minecraft.World/SetEntityMotionPacket.cpp
@@ -0,0 +1,113 @@
+#include "stdafx.h"
+#include <iostream>
+#include "InputOutputStream.h"
+#include "net.minecraft.world.entity.h"
+#include "PacketListener.h"
+#include "SetEntityMotionPacket.h"
+
+
+
+void SetEntityMotionPacket::_init(int id, double xd, double yd, double zd)
+{
+	this->id = id;
+	double m = 3.9;
+	if (xd < -m) xd = -m;
+	if (yd < -m) yd = -m;
+	if (zd < -m) zd = -m;
+	if (xd > m) xd = m;
+	if (yd > m) yd = m;
+	if (zd > m) zd = m;
+	xa = (int) (xd * 8000.0);
+	ya = (int) (yd * 8000.0);
+	za = (int) (zd * 8000.0);
+	// 4J - if we could transmit this as bytes (in 1/16 accuracy) then flag to do so
+	if( ( xa >= (-128 * 16 ) ) && ( ya >= (-128 * 16 ) ) && ( za >= (-128 * 16 ) ) &&
+		( xa < (128 * 16 ) ) && ( ya < (128 * 16 ) ) && ( za < (128 * 16 ) ) )
+	{
+		useBytes = true;
+	}
+	else
+	{
+		useBytes = false;
+	}
+}
+
+SetEntityMotionPacket::SetEntityMotionPacket() 
+{
+	_init(0, 0.0f, 0.0f, 0.0f);
+}
+
+SetEntityMotionPacket::SetEntityMotionPacket(shared_ptr<Entity> e)
+{
+	_init(e->entityId, e->xd, e->yd, e->zd);
+}
+
+SetEntityMotionPacket::SetEntityMotionPacket(int id, double xd, double yd, double zd)
+{
+	_init(id, xd, yd, zd);   
+}
+
+void SetEntityMotionPacket::read(DataInputStream *dis) //throws IOException 
+{
+	short idAndFlag = dis->readShort();
+	id = idAndFlag & 0x07ff;
+	if( idAndFlag & 0x0800 )
+	{
+		xa = (int)dis->readByte();
+		ya = (int)dis->readByte();
+		za = (int)dis->readByte();
+		xa = ( xa << 24 ) >> 24;
+		ya = ( ya << 24 ) >> 24;
+		za = ( za << 24 ) >> 24;
+		xa *= 16;
+		ya *= 16;
+		za *= 16;
+		useBytes = true;
+	}
+	else
+	{
+		xa = dis->readShort();
+		ya = dis->readShort();
+		za = dis->readShort();
+		useBytes = false;
+	}
+}
+
+void SetEntityMotionPacket::write(DataOutputStream *dos) //throws IOException 
+{
+	if( useBytes )
+	{
+		dos->writeShort(id | 0x800);
+		dos->writeByte(xa/16);
+		dos->writeByte(ya/16);
+		dos->writeByte(za/16);
+	}
+	else
+	{
+		dos->writeShort(id);
+		dos->writeShort(xa);
+		dos->writeShort(ya);
+		dos->writeShort(za);
+	}
+}
+
+void SetEntityMotionPacket::handle(PacketListener *listener)
+{
+	listener->handleSetEntityMotion(shared_from_this());
+}
+
+int SetEntityMotionPacket::getEstimatedSize()
+{
+	return useBytes ? 5 : 8;
+}
+
+bool SetEntityMotionPacket::canBeInvalidated()
+{
+	return true;
+}
+
+bool SetEntityMotionPacket::isInvalidatedBy(shared_ptr<Packet> packet)
+{
+	shared_ptr<SetEntityMotionPacket> target = dynamic_pointer_cast<SetEntityMotionPacket>(packet);
+	return target->id == id;
+}
-- 
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