From 5a2163d7e6ffa0c5c568be41257fb726d452b3b9 Mon Sep 17 00:00:00 2001
From: Mat <mail@mathias.is>
Date: Sat, 7 Mar 2020 13:56:02 +0200
Subject: Don't send entity velocity for boats (#4488)

* Don't send entity velocity for boats
---
 src/Entities/Boat.cpp   | 29 +++++++++++++++++++++++++++++
 src/Entities/Boat.h     |  1 +
 src/Entities/Entity.cpp |  2 +-
 src/Entities/Entity.h   |  8 ++++----
 4 files changed, 35 insertions(+), 5 deletions(-)

diff --git a/src/Entities/Boat.cpp b/src/Entities/Boat.cpp
index c88df4952..d0ac27228 100644
--- a/src/Entities/Boat.cpp
+++ b/src/Entities/Boat.cpp
@@ -39,6 +39,35 @@ void cBoat::SpawnOn(cClientHandle & a_ClientHandle)
 
 
 
+void cBoat::BroadcastMovementUpdate(const cClientHandle * a_Exclude)
+{
+	// Process packet sending every two ticks
+	if (GetWorld()->GetWorldAge() % 2 != 0)
+	{
+		return;
+	}
+
+	Vector3i Diff = (GetPosition() * 32.0).Floor() - (m_LastSentPosition * 32.0).Floor();
+
+	if (Diff.HasNonZeroLength())  // Have we moved?
+	{
+		if ((abs(Diff.x) <= 127) && (abs(Diff.y) <= 127) && (abs(Diff.z) <= 127))  // Limitations of a Byte
+		{
+			m_World->BroadcastEntityRelMove(*this, Vector3<Int8>(Diff), a_Exclude);
+		}
+		else
+		{
+			// Too big a movement, do a teleport
+			m_World->BroadcastTeleportEntity(*this, a_Exclude);
+		}
+		m_LastSentPosition = GetPosition();
+	}
+}
+
+
+
+
+
 bool cBoat::DoTakeDamage(TakeDamageInfo & TDI)
 {
 	m_LastDamage = 10;
diff --git a/src/Entities/Boat.h b/src/Entities/Boat.h
index aa6dc0637..3b9889fc1 100644
--- a/src/Entities/Boat.h
+++ b/src/Entities/Boat.h
@@ -39,6 +39,7 @@ public:
 
 	// cEntity overrides:
 	virtual void SpawnOn(cClientHandle & a_ClientHandle) override;
+	virtual void BroadcastMovementUpdate(const cClientHandle * a_Exclude = nullptr) override;
 	virtual void OnRightClicked(cPlayer & a_Player) override;
 	virtual bool DoTakeDamage(TakeDamageInfo & TDI) override;
 	virtual void Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
diff --git a/src/Entities/Entity.cpp b/src/Entities/Entity.cpp
index 983cc96be..206e6af60 100644
--- a/src/Entities/Entity.cpp
+++ b/src/Entities/Entity.cpp
@@ -44,6 +44,7 @@ cEntity::cEntity(eEntityType a_EntityType, Vector3d a_Pos, double a_Width, doubl
 	m_bOnGround(false),
 	m_Gravity(-9.81f),
 	m_AirDrag(0.02f),
+	m_LastSentPosition(a_Pos),
 	m_LastPosition(a_Pos),
 	m_EntityType(a_EntityType),
 	m_World(nullptr),
@@ -65,7 +66,6 @@ cEntity::cEntity(eEntityType a_EntityType, Vector3d a_Pos, double a_Width, doubl
 	m_HeadYaw(0.0),
 	m_Rot(0.0, 0.0, 0.0),
 	m_Position(a_Pos),
-	m_LastSentPosition(a_Pos),
 	m_WaterSpeed(0, 0, 0),
 	m_Mass (0.001),  // Default 1g
 	m_Width(a_Width),
diff --git a/src/Entities/Entity.h b/src/Entities/Entity.h
index b151f745d..563db7b9e 100644
--- a/src/Entities/Entity.h
+++ b/src/Entities/Entity.h
@@ -656,6 +656,10 @@ protected:
 	Data: https://minecraft.gamepedia.com/Entity#Motion_of_entities */
 	float m_AirDrag;
 
+	/** Last position sent to client via the Relative Move or Teleport packets (not Velocity)
+	Only updated if cEntity::BroadcastMovementUpdate() is called! */
+	Vector3d m_LastSentPosition;
+
 	Vector3d m_LastPosition;
 
 	eEntityType m_EntityType;
@@ -752,10 +756,6 @@ private:
 	/** Position of the entity's XZ center and Y bottom */
 	Vector3d m_Position;
 
-	/** Last position sent to client via the Relative Move or Teleport packets (not Velocity)
-	Only updated if cEntity::BroadcastMovementUpdate() is called! */
-	Vector3d m_LastSentPosition;
-
 	/** Measured in meter / second */
 	Vector3d m_WaterSpeed;
 
-- 
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