From cbfc740ad0ade4b8f03648ea52c16368d3a026a8 Mon Sep 17 00:00:00 2001
From: jclever77 <82078401+jclever77@users.noreply.github.com>
Date: Fri, 30 Apr 2021 07:39:10 -0400
Subject: Added functionality: mobs now enter boats and minecarts (#5214)

* Added functionality: mobs now enter boats and minecarts when coming into collision with them.

* Fixed basic style errors, nothing else

* Added self to contributors and reverted .gitignore to original state.
---
 src/Entities/Boat.cpp     | 47 +++++++++++++++++++++++++++++++++++++++++++++++
 src/Entities/Boat.h       |  1 +
 src/Entities/Minecart.cpp | 35 +++++++++++++++++++++++++++++++++++
 3 files changed, 83 insertions(+)

(limited to 'src/Entities')

diff --git a/src/Entities/Boat.cpp b/src/Entities/Boat.cpp
index 1016773e9..cd66c523b 100644
--- a/src/Entities/Boat.cpp
+++ b/src/Entities/Boat.cpp
@@ -14,6 +14,36 @@
 
 
 
+class cBoatCollisionCallback
+{
+public:
+	cBoatCollisionCallback(cBoat * a_Boat, cEntity * a_Attachee) :
+		m_Boat(a_Boat), m_Attachee(a_Attachee)
+	{
+	}
+
+	bool operator()(cEntity & a_Entity)
+	{
+		// Checks if boat is empty and if given entity is a mob
+		if ((m_Attachee == nullptr) && (a_Entity.IsMob()))
+		{
+			// if so attach and return true
+			a_Entity.AttachTo(m_Boat);
+			return true;
+		}
+
+		return false;
+	}
+
+protected:
+	cBoat * m_Boat;
+	cEntity * m_Attachee;
+};
+
+
+
+
+
 cBoat::cBoat(Vector3d a_Pos, eMaterial a_Material) :
 	Super(etBoat, a_Pos, 1.375f, 0.5625f),
 	m_LastDamage(0), m_ForwardDirection(0),
@@ -311,3 +341,20 @@ cItem cBoat::MaterialToItem(eMaterial a_Material)
 
 
 
+
+void cBoat::HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a_Chunk)
+{
+	/** Special version of cEntity::HandlePhysics(...) function for boats, checks if mobs
+	colliding with the boat can be attached and does if that's the case, then returns to
+	normal physics calcualtions */
+
+	// Calculate boat's bounding box, run collision callback on all entities in said box
+	cBoatCollisionCallback BoatCollisionCallback(this, m_Attachee);
+	Vector3d BoatPosition = GetPosition();
+	cBoundingBox bbBoat(
+		Vector3d(BoatPosition.x, floor(BoatPosition.y), BoatPosition.z), GetWidth() / 2, GetHeight());
+	m_World->ForEachEntityInBox(bbBoat, BoatCollisionCallback);
+
+	// Return to calculating physics normally
+	Super::HandlePhysics(a_Dt, a_Chunk);
+}
diff --git a/src/Entities/Boat.h b/src/Entities/Boat.h
index 4a583a26c..455e740e2 100644
--- a/src/Entities/Boat.h
+++ b/src/Entities/Boat.h
@@ -48,6 +48,7 @@ public:
 	virtual bool DoTakeDamage(TakeDamageInfo & TDI) override;
 	virtual void Tick(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 	virtual void HandleSpeedFromAttachee(float a_Forward, float a_Sideways) override;
+	virtual void HandlePhysics(std::chrono::milliseconds a_Dt, cChunk & a_Chunk) override;
 
 	int GetLastDamage(void) const { return m_LastDamage; }
 	int GetForwardDirection(void) const { return m_ForwardDirection; }
diff --git a/src/Entities/Minecart.cpp b/src/Entities/Minecart.cpp
index 1f454c857..123965916 100644
--- a/src/Entities/Minecart.cpp
+++ b/src/Entities/Minecart.cpp
@@ -21,6 +21,35 @@
 
 
 
+class cMinecartAttachCallback
+{
+public:
+	cMinecartAttachCallback(cMinecart * a_Minecart, cEntity * a_Attachee) :
+		m_Minecart(a_Minecart), m_Attachee(a_Attachee)
+	{
+	}
+
+	bool operator () (cEntity & a_Entity)
+	{
+		// Check if minecart is empty and if given entity is a mob
+		if ((m_Attachee == nullptr) && (a_Entity.IsMob()))
+		{
+			// if so, attach to minecart and return true
+			a_Entity.AttachTo(m_Minecart);
+			return true;
+		}
+		return false;
+	}
+
+protected:
+	cMinecart * m_Minecart;
+	cEntity * m_Attachee;
+};
+
+
+
+
+
 class cMinecartCollisionCallback
 {
 public:
@@ -1054,6 +1083,12 @@ bool cMinecart::TestEntityCollision(NIBBLETYPE a_RailMeta)
 		return false;
 	}
 
+	// Collision was true, create bounding box for minecart, call attach callback for all entities within that box
+	cMinecartAttachCallback MinecartAttachCallback(this, m_Attachee);
+	Vector3d MinecartPosition = GetPosition();
+	cBoundingBox bbMinecart(Vector3d(MinecartPosition.x, floor(MinecartPosition.y), MinecartPosition.z), GetWidth() / 2, GetHeight());
+	m_World->ForEachEntityInBox(bbMinecart, MinecartAttachCallback);
+
 	switch (a_RailMeta)
 	{
 		case E_META_RAIL_ZM_ZP:
-- 
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