14 files changed, 57 insertions, 16 deletions

diff --git a/src/Entities/ArrowEntity.cpp b/src/Entities/ArrowEntity.cpp
index 3c1fabb1b..32952100c 100644
--- a/src/Entities/ArrowEntity.cpp
+++ b/src/Entities/ArrowEntity.cpp
@@ -21,6 +21,8 @@ cArrowEntity::cArrowEntity(cEntity * a_Creator, double a_X, double a_Y, double a
 {
 	SetSpeed(a_Speed);
 	SetMass(0.1);
+	SetGravity(-20.0f);
+	SetAirDrag(0.2f);
 	SetYawFromSpeed();
 	SetPitchFromSpeed();
 	LOGD("Created arrow %d with speed {%.02f, %.02f, %.02f} and rot {%.02f, %.02f}",
@@ -48,6 +50,8 @@ cArrowEntity::cArrowEntity(cPlayer & a_Player, double a_Force) :
 	{
 		m_PickupState = psInCreative;
 	}
+	SetGravity(-20.0f);
+	SetAirDrag(0.01f);
 }
 
 
diff --git a/src/Entities/Boat.cpp b/src/Entities/Boat.cpp
index 6177eb32f..4ad418be4 100644
--- a/src/Entities/Boat.cpp
+++ b/src/Entities/Boat.cpp
@@ -16,7 +16,9 @@
 cBoat::cBoat(double a_X, double a_Y, double a_Z) :
 	super(etBoat, a_X, a_Y, a_Z, 0.98, 0.7)
 {
-	SetMass(20.f);
+	SetMass(20.0f);
+	SetGravity(-16.0f);
+	SetAirDrag(0.05f);
 	SetMaxHealth(6);
 	SetHealth(6);
 }
diff --git a/src/Entities/Entity.cpp b/src/Entities/Entity.cpp
index c8df6b4b1..51cee248e 100644
--- a/src/Entities/Entity.cpp
+++ b/src/Entities/Entity.cpp
@@ -36,6 +36,7 @@ cEntity::cEntity(eEntityType a_EntityType, double a_X, double a_Y, double a_Z, d
 	m_bHasSentNoSpeed(true),
 	m_bOnGround(false),
 	m_Gravity(-9.81f),
+	m_AirDrag(0.02f),
 	m_LastPos(a_X, a_Y, a_Z),
 	m_IsInitialized(false),
 	m_WorldTravellingFrom(nullptr),
@@ -943,6 +944,7 @@ void cEntity::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 		{
 			// Normal gravity
 			fallspeed = m_Gravity * DtSec.count();
+			NextSpeed -= NextSpeed * (m_AirDrag * 20.0f) * DtSec.count();
 		}
 		NextSpeed.y += static_cast<float>(fallspeed);
 	}
@@ -999,7 +1001,7 @@ void cEntity::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 
 	NextSpeed += m_WaterSpeed;
 
-	if (NextSpeed.SqrLength() > 0.f)
+	if (NextSpeed.SqrLength() > 0.0f)
 	{
 		cTracer Tracer(GetWorld());
 		// Distance traced is an integer, so we round up from the distance we should go (Speed * Delta), else we will encounter collision detection failurse
@@ -1015,20 +1017,20 @@ void cEntity::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
 				// Block hit was within our projected path
 				// Begin by stopping movement in the direction that we hit something. The Normal is the line perpendicular to a 2D face and in this case, stores what block face was hit through either -1 or 1.
 				// For example: HitNormal.y = -1 : BLOCK_FACE_YM; HitNormal.y = 1 : BLOCK_FACE_YP
-				if (Tracer.HitNormal.x != 0.f)
+				if (Tracer.HitNormal.x != 0.0f)
 				{
-					NextSpeed.x = 0.f;
+					NextSpeed.x = 0.0f;
 				}
-				if (Tracer.HitNormal.y != 0.f)
+				if (Tracer.HitNormal.y != 0.0f)
 				{
-					NextSpeed.y = 0.f;
+					NextSpeed.y = 0.0f;
 				}
-				if (Tracer.HitNormal.z != 0.f)
+				if (Tracer.HitNormal.z != 0.0f)
 				{
-					NextSpeed.z = 0.f;
+					NextSpeed.z = 0.0f;
 				}
 
-				if (Tracer.HitNormal.y == 1.f)  // Hit BLOCK_FACE_YP, we are on the ground
+				if (Tracer.HitNormal.y == 1.0f)  // Hit BLOCK_FACE_YP, we are on the ground
 				{
 					m_bOnGround = true;
 				}
@@ -1971,7 +1973,7 @@ void cEntity::SteerVehicle(float a_Forward, float a_Sideways)
 	{
 		return;
 	}
-	if ((a_Forward != 0.f) || (a_Sideways != 0.f))
+	if ((a_Forward != 0.0f) || (a_Sideways != 0.0f))
 	{
 		m_AttachedTo->HandleSpeedFromAttachee(a_Forward, a_Sideways);
 	}
diff --git a/src/Entities/Entity.h b/src/Entities/Entity.h
index 9bb1837f1..dd6190ced 100644
--- a/src/Entities/Entity.h
+++ b/src/Entities/Entity.h
@@ -270,6 +270,10 @@ public:
 	float GetGravity(void) const { return m_Gravity; }
 	
 	void SetGravity(float a_Gravity) { m_Gravity = a_Gravity; }
+
+	float GetAirDrag(void) const { return m_AirDrag; }
+
+	void SetAirDrag(float a_AirDrag) { m_AirDrag = a_AirDrag; }
 	
 	/// Sets the rotation to match the speed vector (entity goes "face-forward")
 	void SetYawFromSpeed(void);
@@ -504,6 +508,12 @@ protected:
 	For realistic effects, this should be negative. For spaaaaaaace, this can be zero or even positive */
 	float m_Gravity;
 	
+	/** Stores the air drag that is applied to the entity every tick, measured in speed ratio per tick
+	Acts as air friction and slows down flight
+	Will be interpolated if the server tick rate varies
+	Data: http://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_LastPos;
diff --git a/src/Entities/FallingBlock.cpp b/src/Entities/FallingBlock.cpp
index 7301a3c9d..4a165909a 100644
--- a/src/Entities/FallingBlock.cpp
+++ b/src/Entities/FallingBlock.cpp
@@ -16,6 +16,8 @@ cFallingBlock::cFallingBlock(const Vector3i & a_BlockPosition, BLOCKTYPE a_Block
 	m_BlockMeta(a_BlockMeta),
 	m_OriginalPosition(a_BlockPosition)
 {
+	SetGravity(-16.0f);
+	SetAirDrag(0.02f);
 }
 
 
diff --git a/src/Entities/FireChargeEntity.cpp b/src/Entities/FireChargeEntity.cpp
index aba32602f..f6c665156 100644
--- a/src/Entities/FireChargeEntity.cpp
+++ b/src/Entities/FireChargeEntity.cpp
@@ -12,6 +12,7 @@ cFireChargeEntity::cFireChargeEntity(cEntity * a_Creator, double a_X, double a_Y
 {
 	SetSpeed(a_Speed);
 	SetGravity(0);
+	SetAirDrag(0);
 }
 
 
diff --git a/src/Entities/FireworkEntity.cpp b/src/Entities/FireworkEntity.cpp
index 32eaf669a..89f69f113 100644
--- a/src/Entities/FireworkEntity.cpp
+++ b/src/Entities/FireworkEntity.cpp
@@ -13,6 +13,8 @@ cFireworkEntity::cFireworkEntity(cEntity * a_Creator, double a_X, double a_Y, do
 	m_TicksToExplosion(a_Item.m_FireworkItem.m_FlightTimeInTicks),
 	m_FireworkItem(a_Item)
 {
+	SetGravity(0);
+	SetAirDrag(0);
 }
 
 
diff --git a/src/Entities/GhastFireballEntity.cpp b/src/Entities/GhastFireballEntity.cpp
index 9e4cb387e..c64fb2a17 100644
--- a/src/Entities/GhastFireballEntity.cpp
+++ b/src/Entities/GhastFireballEntity.cpp
@@ -12,6 +12,7 @@ cGhastFireballEntity::cGhastFireballEntity(cEntity * a_Creator, double a_X, doub
 {
 	SetSpeed(a_Speed);
 	SetGravity(0);
+	SetAirDrag(0);
 }
 
 
diff --git a/src/Entities/Minecart.cpp b/src/Entities/Minecart.cpp
index ee10cf6b3..3d56570ba 100644
--- a/src/Entities/Minecart.cpp
+++ b/src/Entities/Minecart.cpp
@@ -92,7 +92,9 @@ cMinecart::cMinecart(ePayload a_Payload, double a_X, double a_Y, double a_Z) :
 	m_DetectorRailPosition(0, 0, 0),
 	m_bIsOnDetectorRail(false)
 {
-	SetMass(20.f);
+	SetMass(20.0f);
+	SetGravity(-16.0f);
+	SetAirDrag(0.05f);
 	SetMaxHealth(6);
 	SetHealth(6);
 	SetWidth(1);
diff --git a/src/Entities/Pawn.cpp b/src/Entities/Pawn.cpp
index baf8a2f3b..fcb686e28 100644
--- a/src/Entities/Pawn.cpp
+++ b/src/Entities/Pawn.cpp
@@ -13,6 +13,8 @@ cPawn::cPawn(eEntityType a_EntityType, double a_Width, double a_Height) :
 	super(a_EntityType, 0, 0, 0, a_Width, a_Height)
 	, m_EntityEffects(tEffectMap())
 {
+	SetGravity(-32.0f);
+	SetAirDrag(0.02f);
 }
 
 
diff --git a/src/Entities/Pickup.cpp b/src/Entities/Pickup.cpp
index 9f2609894..f2f76dbf9 100644
--- a/src/Entities/Pickup.cpp
+++ b/src/Entities/Pickup.cpp
@@ -91,7 +91,8 @@ cPickup::cPickup(double a_PosX, double a_PosY, double a_PosZ, const cItem & a_It
 	, m_bCollected(false)
 	, m_bIsPlayerCreated(IsPlayerCreated)
 {
-	SetGravity(-10.5f);
+	SetGravity(-16.0f);
+	SetAirDrag(0.02f);
 	SetMaxHealth(5);
 	SetHealth(5);
 	SetSpeed(a_SpeedX, a_SpeedY, a_SpeedZ);
diff --git a/src/Entities/ProjectileEntity.cpp b/src/Entities/ProjectileEntity.cpp
index 4684e3e09..05b7669cd 100644
--- a/src/Entities/ProjectileEntity.cpp
+++ b/src/Entities/ProjectileEntity.cpp
@@ -227,6 +227,8 @@ cProjectileEntity::cProjectileEntity(eKind a_Kind, cEntity * a_Creator, double a
 	),
 	m_IsInGround(false)
 {
+	SetGravity(-12.0f);
+	SetAirDrag(0.01f);
 }
 
 
@@ -242,6 +244,8 @@ cProjectileEntity::cProjectileEntity(eKind a_Kind, cEntity * a_Creator, const Ve
 	SetSpeed(a_Speed);
 	SetYawFromSpeed();
 	SetPitchFromSpeed();
+	SetGravity(-12.0f);
+	SetAirDrag(0.01f);
 }
 
 
@@ -349,9 +353,11 @@ void cProjectileEntity::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a
 		return;
 	}
 	
-	const Vector3d PerTickSpeed = GetSpeed() / 20;
+	auto DtSec = std::chrono::duration_cast<std::chrono::duration<double>>(a_Dt);
+
+	const Vector3d DeltaSpeed = GetSpeed() * DtSec.count();
 	const Vector3d Pos = GetPosition();
-	const Vector3d NextPos = Pos + PerTickSpeed;
+	const Vector3d NextPos = Pos + DeltaSpeed;
 
 	// Test for entity collisions:
 	cProjectileEntityCollisionCallback EntityCollisionCallback(this, Pos, NextPos);
@@ -388,8 +394,8 @@ void cProjectileEntity::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a
 	
 	// Add slowdown and gravity effect to the speed:
 	Vector3d NewSpeed(GetSpeed());
-	NewSpeed.y += m_Gravity / 20;
-	NewSpeed *= TracerCallback.GetSlowdownCoeff();
+	NewSpeed.y += m_Gravity * DtSec.count();
+	NewSpeed -= NewSpeed * (m_AirDrag * 20.0f) * DtSec.count();
 	SetSpeed(NewSpeed);
 	SetYawFromSpeed();
 	SetPitchFromSpeed();
diff --git a/src/Entities/TNTEntity.cpp b/src/Entities/TNTEntity.cpp
index a89d2f300..d849bd4c9 100644
--- a/src/Entities/TNTEntity.cpp
+++ b/src/Entities/TNTEntity.cpp
@@ -12,6 +12,8 @@ cTNTEntity::cTNTEntity(double a_X, double a_Y, double a_Z, int a_FuseTicks) :
 	super(etTNT, a_X, a_Y, a_Z, 0.98, 0.98),
 	m_FuseTicks(a_FuseTicks)
 {
+	SetGravity(-16.0f);
+	SetAirDrag(0.02f);
 }
 
 
@@ -22,6 +24,8 @@ cTNTEntity::cTNTEntity(const Vector3d & a_Pos, int a_FuseTicks) :
 	super(etTNT, a_Pos.x, a_Pos.y, a_Pos.z, 0.98, 0.98),
 	m_FuseTicks(a_FuseTicks)
 {
+	SetGravity(-16.0f);
+	SetAirDrag(0.4f);
 }
 
 
diff --git a/src/Entities/WitherSkullEntity.cpp b/src/Entities/WitherSkullEntity.cpp
index a7e774bba..dc95e3edd 100644
--- a/src/Entities/WitherSkullEntity.cpp
+++ b/src/Entities/WitherSkullEntity.cpp
@@ -16,6 +16,8 @@ cWitherSkullEntity::cWitherSkullEntity(cEntity * a_Creator, double a_X, double a
 	super(pkWitherSkull, a_Creator, a_X, a_Y, a_Z, 0.25, 0.25)
 {
 	SetSpeed(a_Speed);
+	SetGravity(0);
+	SetAirDrag(0);
 }