Don't send entity velocity for boats (cuberite#4488)

* Don't send entity velocity for boats

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;

src/Entities/Boat.h

@@ -39,6 +39,7 @@ class cBoat :
 
 	// 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;

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),

src/Entities/Entity.h

@@ -656,6 +656,10 @@ class cEntity
 	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 @@ class cEntity
 	/** 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;