2 files changed, 93 insertions, 0 deletions

diff --git a/src/Entities/Pawn.cpp b/src/Entities/Pawn.cpp
index 5476db468..ed26a080b 100644
--- a/src/Entities/Pawn.cpp
+++ b/src/Entities/Pawn.cpp
@@ -547,3 +547,81 @@ bool cPawn::DeductTotem(const eDamageType a_DamageType)
 	}
 	return false;
 }
+
+
+
+
+
+bool cPawn::FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, const Vector3i a_MinBoxCorner, const Vector3i a_MaxBoxCorner)
+{
+	/*
+	Algorithm:
+	Choose random destination.
+	Seek downwards, regardless of distance until the block is made of movement-blocking material: https://minecraft.fandom.com/wiki/Materials
+	Succeeds if no liquid or solid blocks prevents from standing at destination.
+	*/
+	auto & Random = GetRandomProvider();
+
+	for (unsigned int i = 0; i < a_NumTries; i++)
+	{
+		const int DestX = Random.RandInt(a_MinBoxCorner.x, a_MaxBoxCorner.x);
+		int DestY = Random.RandInt(a_MinBoxCorner.y, a_MaxBoxCorner.y);
+		const int DestZ = Random.RandInt(a_MinBoxCorner.z, a_MaxBoxCorner.z);
+
+		// Seek downwards from initial destination until we find a solid block or go into the void
+		BLOCKTYPE DestBlock = a_World.GetBlock({DestX, DestY, DestZ});
+		while ((DestY >= 0) && !cBlockInfo::IsSolid(DestBlock))
+		{
+			DestBlock = a_World.GetBlock({DestX, DestY, DestZ});
+			DestY--;
+		}
+
+		// Couldn't find a solid block so move to next attempt
+		if (DestY < 0)
+		{
+			continue;
+		}
+
+		// Succeed if blocks above destination are empty
+		bool Success = true;
+		for (int j = 1; j <= a_HeightRequired; j++)
+		{
+			BLOCKTYPE TestBlock = a_World.GetBlock({DestX, DestY + j, DestZ});
+			if (cBlockInfo::IsSolid(TestBlock) || IsBlockLiquid(TestBlock))
+			{
+				Success = false;
+				break;
+			}
+		}
+
+		if (!Success)
+		{
+			continue;
+		}
+
+		// Offsets for entity to be centred and standing on solid block
+		a_Destination = Vector3d(DestX + 0.5, DestY + 1, DestZ + 0.5);
+		return true;
+	}
+	return false;
+}
+
+
+
+
+
+bool cPawn::FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, const cBoundingBox a_BoundingBox)
+{
+	return FindTeleportDestination(a_World, a_HeightRequired, a_NumTries, a_Destination, a_BoundingBox.GetMin(), a_BoundingBox.GetMax());
+}
+
+
+
+
+
+bool cPawn::FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, Vector3i a_Centre, const int a_HalfCubeWidth)
+{
+	Vector3i MinCorner(a_Centre.x - a_HalfCubeWidth, a_Centre.y - a_HalfCubeWidth, a_Centre.z - a_HalfCubeWidth);
+	Vector3i MaxCorner(a_Centre.x + a_HalfCubeWidth, a_Centre.y + a_HalfCubeWidth, a_Centre.z + a_HalfCubeWidth);
+	return FindTeleportDestination(a_World, a_HeightRequired, a_NumTries, a_Destination, MinCorner, MaxCorner);
+}
diff --git a/src/Entities/Pawn.h b/src/Entities/Pawn.h
index 706c51e49..222e8f3b8 100644
--- a/src/Entities/Pawn.h
+++ b/src/Entities/Pawn.h
@@ -70,6 +70,21 @@ public:
 	/** Returns the entity effect, if it is currently applied or nullptr if not. */
 	cEntityEffect * GetEntityEffect(cEntityEffect::eType a_EffectType) const;
 
+	// tolua_begin
+
+	static bool FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, const Vector3i a_MinBoxCorner, const Vector3i a_MaxBoxCorner);
+
+	static bool FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, const cBoundingBox a_BoundingBox);
+
+	/** Used by enderman and chorus fruit.
+	Checks for valid destinations in a cube of length 2 * a_HalfCubeWidth centred at a_Centre.
+	Returns true and places destination in a_Destination if successful.
+	Returns false if destination could be found after a_NumTries attempts.
+	Details at: https://minecraft.fandom.com/wiki/Enderman#Teleportation. */
+	static bool FindTeleportDestination(cWorld & a_World, const int a_HeightRequired, const unsigned int a_NumTries, Vector3d & a_Destination, Vector3i a_Centre, const int a_HalfCubeWidth);
+
+	// tolua_end
+
 protected:
 
 	typedef std::map<cEntityEffect::eType, std::unique_ptr<cEntityEffect>> tEffectMap;