cuberite-2a/src/Generating/PieceGenerator.cpp

// PieceGenerator.cpp

// Implements the cBFSPieceGenerator class and cDFSPieceGenerator class
// representing base classes for generating structures composed of individual "pieces"

#include "Globals.h"
#include "PieceGenerator.h"
#include "VerticalStrategy.h"
#include "VerticalLimit.h"





////////////////////////////////////////////////////////////////////////////////
// cPiece:

bool cPiece::SetVerticalStrategyFromString(const AString & a_StrategyDesc, bool a_LogWarnings)
{
	auto strategy = CreateVerticalStrategyFromString(a_StrategyDesc, a_LogWarnings);
	if (strategy == nullptr)
	{
		return false;
	}
	m_VerticalStrategy = strategy;
	return true;
}





bool cPiece::SetVerticalLimitFromString(const AString & a_LimitDesc, bool a_LogWarnings)
{
	auto limit = CreateVerticalLimitFromString(a_LimitDesc, a_LogWarnings);
	if (limit == nullptr)
	{
		return false;
	}
	m_VerticalLimit = limit;
	return true;
}





Vector3i cPiece::RotatePos(const Vector3i & a_Pos, int a_NumCCWRotations) const
{
	Vector3i Size = GetSize();
	switch (a_NumCCWRotations)
	{
		case 0:
		{
			// No rotation needed
			return a_Pos;
		}
		case 1:
		{
			// 1 CCW rotation:
			return Vector3i(a_Pos.z, a_Pos.y, Size.x - a_Pos.x - 1);
		}
		case 2:
		{
			// 2 rotations ( = axis flip):
			return Vector3i(Size.x - a_Pos.x - 1, a_Pos.y, Size.z - a_Pos.z - 1);
		}
		case 3:
		{
			// 1 CW rotation:
			return Vector3i(Size.z - a_Pos.z - 1, a_Pos.y, a_Pos.x);
		}
	}
	ASSERT(!"Unhandled rotation");
	return a_Pos;
}





cPiece::cConnector cPiece::RotateMoveConnector(const cConnector & a_Connector, int a_NumCCWRotations, int a_MoveX, int a_MoveY, int a_MoveZ) const
{
	cPiece::cConnector res(a_Connector);

	// Rotate the res connector:
	switch (a_NumCCWRotations)
	{
		case 0:
		{
			// No rotation needed
			break;
		}
		case 1:
		{
			// 1 CCW rotation:
			res.m_Direction = cConnector::RotateDirectionCCW(res.m_Direction);
			break;
		}
		case 2:
		{
			// 2 rotations ( = axis flip):
			res.m_Direction = cConnector::RotateDirection(res.m_Direction);
			break;
		}
		case 3:
		{
			// 1 CW rotation:
			res.m_Direction = cConnector::RotateDirectionCW(res.m_Direction);
			break;
		}
	}
	res.m_Pos = RotatePos(a_Connector.m_Pos, a_NumCCWRotations);

	// Move the res connector:
	res.m_Pos.x += a_MoveX;
	res.m_Pos.y += a_MoveY;
	res.m_Pos.z += a_MoveZ;

	return res;
}





cCuboid cPiece::RotateHitBoxToConnector(
	const cPiece::cConnector & a_MyConnector,
	const Vector3i & a_ToConnectorPos,
	int a_NumCCWRotations
) const
{
	ASSERT(a_NumCCWRotations == (a_NumCCWRotations % 4));
	Vector3i ConnPos = RotatePos(a_MyConnector.m_Pos, a_NumCCWRotations);
	ConnPos = a_ToConnectorPos - ConnPos;
	return RotateMoveHitBox(a_NumCCWRotations, ConnPos.x, ConnPos.y, ConnPos.z);
}





cCuboid cPiece::RotateMoveHitBox(int a_NumCCWRotations, int a_MoveX, int a_MoveY, int a_MoveZ) const
{
	ASSERT(a_NumCCWRotations == (a_NumCCWRotations % 4));
	cCuboid res = GetHitBox();
	res.p1 = RotatePos(res.p1, a_NumCCWRotations);
	res.p2 = RotatePos(res.p2, a_NumCCWRotations);
	res.p1.Move(a_MoveX, a_MoveY, a_MoveZ);
	res.p2.Move(a_MoveX, a_MoveY, a_MoveZ);
	return res;
}





////////////////////////////////////////////////////////////////////////////////
// cPiece::cConnector:

cPiece::cConnector::cConnector(int a_X, int a_Y, int a_Z, int a_Type, eDirection a_Direction) :
	m_Pos(a_X, a_Y, a_Z),
	m_Type(a_Type),
	m_Direction(a_Direction)
{
}





cPiece::cConnector::cConnector(const Vector3i & a_Pos, int a_Type, eDirection a_Direction) :
	m_Pos(a_Pos),
	m_Type(a_Type),
	m_Direction(a_Direction)
{
}





Vector3i cPiece::cConnector::AddDirection(const Vector3i & a_Pos, eDirection a_Direction)
{
	switch (a_Direction)
	{
		case dirXM:       return Vector3i(a_Pos.x - 1, a_Pos.y,     a_Pos.z);
		case dirXP:       return Vector3i(a_Pos.x + 1, a_Pos.y,     a_Pos.z);
		case dirYM:       return Vector3i(a_Pos.x,     a_Pos.y - 1, a_Pos.z);
		case dirYP:       return Vector3i(a_Pos.x,     a_Pos.y + 1, a_Pos.z);
		case dirZM:       return Vector3i(a_Pos.x,     a_Pos.y,     a_Pos.z - 1);
		case dirZP:       return Vector3i(a_Pos.x,     a_Pos.y,     a_Pos.z + 1);
		case dirYM_XM_ZM: return Vector3i(a_Pos.x,     a_Pos.y - 1, a_Pos.z);
		case dirYM_XM_ZP: return Vector3i(a_Pos.x,     a_Pos.y - 1, a_Pos.z);
		case dirYM_XP_ZM: return Vector3i(a_Pos.x,     a_Pos.y - 1, a_Pos.z);
		case dirYM_XP_ZP: return Vector3i(a_Pos.x,     a_Pos.y - 1, a_Pos.z);
		case dirYP_XM_ZM: return Vector3i(a_Pos.x,     a_Pos.y + 1, a_Pos.z);
		case dirYP_XM_ZP: return Vector3i(a_Pos.x,     a_Pos.y + 1, a_Pos.z);
		case dirYP_XP_ZM: return Vector3i(a_Pos.x,     a_Pos.y + 1, a_Pos.z);
		case dirYP_XP_ZP: return Vector3i(a_Pos.x,     a_Pos.y + 1, a_Pos.z);
	}
	#if !defined(__clang__)
		ASSERT(!"Unknown connector direction");
		return a_Pos;
	#endif
}





const char * cPiece::cConnector::DirectionToString(eDirection a_Direction)
{
	switch (a_Direction)
	{
		case dirXM:       return "x-";
		case dirXP:       return "x+";
		case dirYM:       return "y-";
		case dirYP:       return "y+";
		case dirZM:       return "z-";
		case dirZP:       return "z+";
		case dirYM_XM_ZM: return "y-x-z-";
		case dirYM_XM_ZP: return "y-x-z+";
		case dirYM_XP_ZM: return "y-x+z-";
		case dirYM_XP_ZP: return "y-x+z+";
		case dirYP_XM_ZM: return "y+x-z-";
		case dirYP_XM_ZP: return "y+x-z+";
		case dirYP_XP_ZM: return "y+x+z-";
		case dirYP_XP_ZP: return "y+x+z+";
	}
	#if !defined(__clang__)
		ASSERT(!"Unknown connector direction");
		return "<unknown>";
	#endif
}





bool cPiece::cConnector::IsValidDirection(int a_Direction)
{
	switch (a_Direction)
	{
		case dirXM:
		case dirXP:
		case dirYM:
		case dirYP:
		case dirZM:
		case dirZP:
		case dirYM_XM_ZM:
		case dirYM_XM_ZP:
		case dirYM_XP_ZM:
		case dirYM_XP_ZP:
		case dirYP_XM_ZM:
		case dirYP_XM_ZP:
		case dirYP_XP_ZM:
		case dirYP_XP_ZP:
		{
			return true;
		}
	}
	return false;
}





cPiece::cConnector::eDirection cPiece::cConnector::RotateDirection(eDirection a_Direction)
{
	// 180-degree rotation:
	switch (a_Direction)
	{
		case dirXM:       return dirXP;
		case dirXP:       return dirXM;
		case dirYM:       return dirYM;
		case dirYP:       return dirYP;
		case dirZM:       return dirZM;
		case dirZP:       return dirZP;
		case dirYM_XM_ZM: return dirYM_XP_ZP;
		case dirYM_XM_ZP: return dirYM_XP_ZM;
		case dirYM_XP_ZM: return dirYM_XM_ZP;
		case dirYM_XP_ZP: return dirYM_XM_ZM;
		case dirYP_XM_ZM: return dirYP_XP_ZP;
		case dirYP_XM_ZP: return dirYP_XP_ZM;
		case dirYP_XP_ZM: return dirYP_XM_ZP;
		case dirYP_XP_ZP: return dirYP_XM_ZM;
	}
	#if !defined(__clang__)
		ASSERT(!"Unknown connector direction");
		return a_Direction;
	#endif
}





cPiece::cConnector::eDirection cPiece::cConnector::RotateDirectionCCW(eDirection a_Direction)
{
	// 90 degrees CCW rotation:
	switch (a_Direction)
	{
		case dirXM:       return dirZP;
		case dirXP:       return dirZM;
		case dirYM:       return dirYM;
		case dirYP:       return dirYP;
		case dirZM:       return dirXM;
		case dirZP:       return dirXP;
		case dirYM_XM_ZM: return dirYM_XM_ZP;
		case dirYM_XM_ZP: return dirYM_XP_ZP;
		case dirYM_XP_ZM: return dirYM_XM_ZM;
		case dirYM_XP_ZP: return dirYM_XP_ZM;
		case dirYP_XM_ZM: return dirYP_XM_ZP;
		case dirYP_XM_ZP: return dirYP_XP_ZP;
		case dirYP_XP_ZM: return dirYP_XM_ZM;
		case dirYP_XP_ZP: return dirYP_XP_ZM;
	}
	#if !defined(__clang__)
		ASSERT(!"Unknown connector direction");
		return a_Direction;
	#endif
}





cPiece::cConnector::eDirection cPiece::cConnector::RotateDirectionCW(eDirection a_Direction)
{
	// 90 degrees CW rotation:
	switch (a_Direction)
	{
		case dirXM:       return dirZM;
		case dirXP:       return dirZP;
		case dirYM:       return dirYM;
		case dirYP:       return dirYP;
		case dirZM:       return dirXP;
		case dirZP:       return dirXM;
		case dirYM_XM_ZM: return dirYM_XP_ZM;
		case dirYM_XM_ZP: return dirYM_XM_ZM;
		case dirYM_XP_ZM: return dirYM_XP_ZP;
		case dirYM_XP_ZP: return dirYM_XM_ZP;
		case dirYP_XM_ZM: return dirYP_XP_ZM;
		case dirYP_XM_ZP: return dirYP_XM_ZM;
		case dirYP_XP_ZM: return dirYP_XP_ZP;
		case dirYP_XP_ZP: return dirYP_XM_ZP;
	}
	#if !defined(__clang__)
		ASSERT(!"Unknown connector direction");
		return a_Direction;
	#endif
}





bool cPiece::cConnector::StringToDirection(const AString & a_Value, eDirection & a_Out)
{
	// First try converting as a number:
	int dirInt;
	if (StringToInteger(a_Value, dirInt))
	{
		if (!IsValidDirection(dirInt))
		{
			return false;
		}
		a_Out = static_cast<eDirection>(dirInt);
		return true;
	}

	// Compare to string representation:
	static const struct
	{
		const char * m_String;
		eDirection m_Value;
	} StringDirections[] =
	{
		{"x-", dirXM},
		{"x+", dirXP},
		{"y-", dirYM},
		{"y+", dirYP},
		{"z-", dirZM},
		{"z+", dirZP},
		{"y-x-z-", dirYM_XM_ZM},
		{"y-x-z+", dirYM_XM_ZP},
		{"y-x+z-", dirYM_XP_ZM},
		{"y-x+z+", dirYM_XP_ZP},
		{"y+x-z-", dirYP_XM_ZM},
		{"y+x-z+", dirYP_XM_ZP},
		{"y+x+z-", dirYP_XP_ZM},
		{"y+x+z+", dirYP_XP_ZP},

		// Alternate names, with slashes:
		{"y-/x-/z-", dirYM_XM_ZM},
		{"y-/x-/z+", dirYM_XM_ZP},
		{"y-/x+/z-", dirYM_XP_ZM},
		{"y-/x+/z+", dirYM_XP_ZP},
		{"y+/x-/z-", dirYP_XM_ZM},
		{"y+/x-/z+", dirYP_XM_ZP},
		{"y+/x+/z-", dirYP_XP_ZM},
		{"y+/x+/z+", dirYP_XP_ZP},
	};
	auto lcValue = StrToLower(a_Value);
	for (size_t i = 0; i < ARRAYCOUNT(StringDirections); i++)
	{
		if (strcmp(lcValue.c_str(), StringDirections[i].m_String) == 0)
		{
			a_Out = StringDirections[i].m_Value;
			return true;
		}
	}

	// Not understood, failure:
	return false;
}





////////////////////////////////////////////////////////////////////////////////
// cPlacedPiece:

cPlacedPiece::cPlacedPiece(const cPlacedPiece * a_Parent, const cPiece & a_Piece, const Vector3i & a_Coords, int a_NumCCWRotations) :
	m_Parent(a_Parent),
	m_Piece(&a_Piece),
	m_Coords(a_Coords),
	m_NumCCWRotations(a_NumCCWRotations),
	m_HasBeenMovedToGround(false)
{
	m_Depth = (m_Parent == nullptr) ? 0 : (m_Parent->GetDepth() + 1);
	m_HitBox = a_Piece.RotateMoveHitBox(a_NumCCWRotations, a_Coords.x, a_Coords.y, a_Coords.z);
	m_HitBox.Sort();
}





cPiece::cConnector cPlacedPiece::GetRotatedConnector(size_t a_Index) const
{
	cPiece::cConnectors Connectors = m_Piece->GetConnectors();
	ASSERT(Connectors.size() >= a_Index);
	return m_Piece->RotateMoveConnector(Connectors[a_Index], m_NumCCWRotations, m_Coords.x, m_Coords.y, m_Coords.z);
}





cPiece::cConnector cPlacedPiece::GetRotatedConnector(const cPiece::cConnector & a_Connector) const
{
	return m_Piece->RotateMoveConnector(a_Connector, m_NumCCWRotations, m_Coords.x, m_Coords.y, m_Coords.z);
}





void cPlacedPiece::MoveToGroundBy(int a_OffsetY)
{
	m_Coords.y += a_OffsetY;
	m_HasBeenMovedToGround = true;
}





////////////////////////////////////////////////////////////////////////////////
// cPieceGenerator:

cPieceGenerator::cPieceGenerator(cPiecePool & a_PiecePool, int a_Seed) :
	m_PiecePool(a_PiecePool),
	m_Noise(a_Seed),
	m_Seed(a_Seed)
{
}





void cPieceGenerator::FreePieces(cPlacedPieces & a_PlacedPieces)
{
	for (cPlacedPieces::iterator itr = a_PlacedPieces.begin(), end = a_PlacedPieces.end(); itr != end; ++itr)
	{
		delete *itr;
	}  // for itr - a_PlacedPieces[]
	a_PlacedPieces.clear();
}





cPlacedPiece * cPieceGenerator::PlaceStartingPiece(int a_BlockX, int a_BlockZ, cFreeConnectors & a_OutConnectors)
{
	m_PiecePool.Reset();
	int rnd = m_Noise.IntNoise2DInt(a_BlockX, a_BlockZ) / 7;

	// Choose a random one of the starting pieces:
	cPieces StartingPieces = m_PiecePool.GetStartingPieces();
	int Total = 0;
	for (cPieces::const_iterator itr = StartingPieces.begin(), end = StartingPieces.end(); itr != end; ++itr)
	{
		Total += m_PiecePool.GetStartingPieceWeight(**itr);
	}
	cPiece * StartingPiece;
	if (Total > 0)
	{
		int Chosen = rnd % Total;
		StartingPiece = StartingPieces.front();
		for (cPieces::const_iterator itr = StartingPieces.begin(), end = StartingPieces.end(); itr != end; ++itr)
		{
			Chosen -= m_PiecePool.GetStartingPieceWeight(**itr);
			if (Chosen <= 0)
			{
				StartingPiece = *itr;
				break;
			}
		}
	}
	else
	{
		// All pieces returned zero weight, but we need one to start. Choose with equal chance:
		StartingPiece = StartingPieces[static_cast<size_t>(rnd) % StartingPieces.size()];
	}
	rnd = rnd >> 16;

	// Choose a random supported rotation:
	int Rotations[4] = {0};
	int NumRotations = 1;
	for (size_t i = 1; i < ARRAYCOUNT(Rotations); i++)
	{
		if (StartingPiece->CanRotateCCW(static_cast<int>(i)))
		{
			Rotations[NumRotations] = static_cast<int>(i);
			NumRotations += 1;
		}
	}
	int Rotation = Rotations[rnd % NumRotations];
	int BlockY = StartingPiece->GetStartingPieceHeight(a_BlockX, a_BlockZ);
	ASSERT(BlockY >= 0);  // The vertical strategy should have been provided and should give valid coords

	cPlacedPiece * res = new cPlacedPiece(nullptr, *StartingPiece, Vector3i(a_BlockX, BlockY, a_BlockZ), Rotation);

	// Place the piece's connectors into a_OutConnectors:
	const cPiece::cConnectors & Conn = StartingPiece->GetConnectors();
	for (cPiece::cConnectors::const_iterator itr = Conn.begin(), end = Conn.end(); itr != end; ++itr)
	{
		a_OutConnectors.push_back(
			cFreeConnector(res, StartingPiece->RotateMoveConnector(*itr, Rotation, a_BlockX, BlockY, a_BlockZ))
		);
	}

	return res;
}





bool cPieceGenerator::TryPlacePieceAtConnector(
	const cPlacedPiece & a_ParentPiece,
	const cPiece::cConnector & a_Connector,
	cPlacedPieces & a_OutPieces,
	cPieceGenerator::cFreeConnectors & a_OutConnectors
)
{
	// Translation of direction - direction -> number of CCW rotations needed:
	// You need DirectionRotationTable[rot2][rot1] CCW turns to connect rot1 to rot2 (they are opposite)
	// -1 if not possible
	static const int DirectionRotationTable[14][14] =
	{
		/*              YM, YP, ZM, ZP, XM, XP, YM-XM-ZM, YM-XM-ZP, YM-XP-ZM, YM-XP-ZP, YP-XM-ZM, YP-XM-ZP, YP-XP-ZM, YP-XP-ZP */
		/* YM */       { 0, -1, -1, -1, -1, -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1},
		/* YP */       {-1, -1, -1, -1, -1, -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1},
		/* ZM */       {-1, -1,  2,  0,  1,  3,       -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1},
		/* ZP */       {-1, -1,  0,  2,  3,  1,       -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1},
		/* XM */       {-1, -1,  3,  1,  2,  0,       -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1},
		/* XP */       {-1, -1,  1,  3,  0,  2,       -1,       -1,       -1,       -1,       -1,       -1,       -1,       -1},
		/* YM-XM-ZM */ {-1, -1, -1, -1, -1, -1,       -1,       -1,       -1,       -1,        0,        3,        1,        2},
		/* YM-XM-ZP */ {-1, -1, -1, -1, -1, -1,       -1,       -1,       -1,       -1,        1,        0,        2,        3},
		/* YM-XP-ZM */ {-1, -1, -1, -1, -1, -1,       -1,       -1,       -1,       -1,        3,        2,        0,        1},
		/* YM-XP-ZP */ {-1, -1, -1, -1, -1, -1,       -1,       -1,       -1,       -1,        2,        1,        3,        0},
		/* YP-XM-ZM */ {-1, -1, -1, -1, -1, -1,        0,        3,        1,        2,       -1,       -1,       -1,       -1},
		/* YP-XM-ZP */ {-1, -1, -1, -1, -1, -1,        1,        0,        2,        3,       -1,       -1,       -1,       -1},
		/* YP-XP-ZM */ {-1, -1, -1, -1, -1, -1,        3,        2,        0,        1,       -1,       -1,       -1,       -1},
		/* YP-XP-ZP */ {-1, -1, -1, -1, -1, -1,        2,        1,        3,        0,       -1,       -1,       -1,       -1},
	};

	// Get a list of available connections:
	ASSERT(a_Connector.m_Direction < ARRAYCOUNT(DirectionRotationTable));
	const int * RotTable = DirectionRotationTable[a_Connector.m_Direction];
	cConnections Connections;
	int WantedConnectorType = -a_Connector.m_Type;
	cPieces AvailablePieces = m_PiecePool.GetPiecesWithConnector(WantedConnectorType);
	Connections.reserve(AvailablePieces.size());
	Vector3i ConnPos = cPiece::cConnector::AddDirection(a_Connector.m_Pos, a_Connector.m_Direction);  // The position at which the new connector should be placed - 1 block away from the current connector
	int WeightTotal = 0;
	for (cPieces::iterator itrP = AvailablePieces.begin(), endP = AvailablePieces.end(); itrP != endP; ++itrP)
	{
		// Get the relative chance of this piece being generated in this path:
		int Weight = m_PiecePool.GetPieceWeight(a_ParentPiece, a_Connector, **itrP);
		if (Weight <= 0)
		{
			continue;
		}

		// Try fitting each of the piece's connector:
		cPiece::cConnectors Connectors = (*itrP)->GetConnectors();
		auto verticalLimit = (*itrP)->GetVerticalLimit();
		for (cPiece::cConnectors::iterator itrC = Connectors.begin(), endC = Connectors.end(); itrC != endC; ++itrC)
		{
			if (itrC->m_Type != WantedConnectorType)
			{
				continue;
			}
			// This is a same-type connector, find out how to rotate to it:
			ASSERT(itrC->m_Direction < ARRAYCOUNT(DirectionRotationTable[0]));
			int NumCCWRotations = RotTable[itrC->m_Direction];
			if ((NumCCWRotations < 0) || !(*itrP)->CanRotateCCW(NumCCWRotations))
			{
				// Doesn't support this rotation
				continue;
			}

			// Check if the piece's VerticalLimit allows this connection:
			if ((verticalLimit != nullptr) && (!verticalLimit->CanBeAtHeight(ConnPos.x, ConnPos.z, ConnPos.y - itrC->m_Pos.y)))
			{
				continue;
			}

			if (!CheckConnection(a_Connector, ConnPos, **itrP, *itrC, NumCCWRotations, a_OutPieces))
			{
				// Doesn't fit in this rotation
				continue;
			}
			// Fits, add it to list of possibile connections:
			Connections.push_back(cConnection(**itrP, *itrC, NumCCWRotations, Weight));
			WeightTotal += Weight;
		}  // for itrC - Connectors[]
	}  // for itrP - AvailablePieces[]
	if (Connections.empty())
	{
		// No available connections, bail out
		return false;
	}
	ASSERT(WeightTotal > 0);

	// Choose a random connection from the list, based on the weights:
	int rnd = (m_Noise.IntNoise3DInt(a_Connector.m_Pos.x, a_Connector.m_Pos.y, a_Connector.m_Pos.z) / 7) % WeightTotal;
	size_t ChosenIndex = 0;
	for (cConnections::const_iterator itr = Connections.begin(), end = Connections.end(); itr != end; ++itr, ++ChosenIndex)
	{
		rnd -= itr->m_Weight;
		if (rnd <= 0)
		{
			// This is the piece to choose
			break;
		}
	}
	cConnection & Conn = Connections[ChosenIndex];

	// Place the piece:
	Vector3i NewPos = Conn.m_Piece->RotatePos(Conn.m_Connector.m_Pos, Conn.m_NumCCWRotations);
	ConnPos -= NewPos;
	cPlacedPiece * PlacedPiece = new cPlacedPiece(&a_ParentPiece, *(Conn.m_Piece), ConnPos, Conn.m_NumCCWRotations);
	a_OutPieces.push_back(PlacedPiece);

	// Add the new piece's connectors to the list of free connectors:
	cPiece::cConnectors Connectors = Conn.m_Piece->GetConnectors();
	for (cPiece::cConnectors::const_iterator itr = Connectors.begin(), end = Connectors.end(); itr != end; ++itr)
	{
		if (itr->m_Pos.Equals(Conn.m_Connector.m_Pos))
		{
			// This is the connector through which we have been connected to the parent, don't add
			continue;
		}
		a_OutConnectors.push_back(cFreeConnector(PlacedPiece, Conn.m_Piece->RotateMoveConnector(*itr, Conn.m_NumCCWRotations, ConnPos.x, ConnPos.y, ConnPos.z)));
	}

	return true;
}





bool cPieceGenerator::CheckConnection(
	const cPiece::cConnector & a_ExistingConnector,
	const Vector3i & a_ToPos,
	const cPiece & a_Piece,
	const cPiece::cConnector & a_NewConnector,
	int a_NumCCWRotations,
	const cPlacedPieces & a_OutPieces
)
{
	// For each placed piece, test the hitbox against the new piece:
	cCuboid RotatedHitBox = a_Piece.RotateHitBoxToConnector(a_NewConnector, a_ToPos, a_NumCCWRotations);
	RotatedHitBox.Sort();
	for (cPlacedPieces::const_iterator itr = a_OutPieces.begin(), end = a_OutPieces.end(); itr != end; ++itr)
	{
		if ((*itr)->GetHitBox().DoesIntersect(RotatedHitBox))
		{
			return false;
		}
	}
	return true;
}





//*
// DEBUG:
void cPieceGenerator::DebugConnectorPool(const cPieceGenerator::cFreeConnectors & a_ConnectorPool, size_t a_NumProcessed)
{
	printf("  Connector pool: " SIZE_T_FMT " items\n", a_ConnectorPool.size() - a_NumProcessed);
	size_t idx = 0;

	typedef cPieceGenerator::cFreeConnectors::difference_type difType;

	for (auto itr = a_ConnectorPool.cbegin() + static_cast<difType>(a_NumProcessed), end = a_ConnectorPool.cend(); itr != end; ++itr, ++idx)
	{
		printf("    " SIZE_T_FMT ": {%d, %d, %d}, type %d, direction %s, depth %d\n",
			idx,
			itr->m_Connector.m_Pos.x, itr->m_Connector.m_Pos.y, itr->m_Connector.m_Pos.z,
			itr->m_Connector.m_Type,
			cPiece::cConnector::DirectionToString(itr->m_Connector.m_Direction),
			itr->m_Piece->GetDepth()
		);
	}  // for itr - a_ConnectorPool[]
}
//*/





////////////////////////////////////////////////////////////////////////////////
// cPieceGenerator::cConnection:

cPieceGenerator::cConnection::cConnection(cPiece & a_Piece, cPiece::cConnector & a_Connector, int a_NumCCWRotations, int a_Weight) :
	m_Piece(&a_Piece),
	m_Connector(a_Connector),
	m_NumCCWRotations(a_NumCCWRotations),
	m_Weight(a_Weight)
{
}





////////////////////////////////////////////////////////////////////////////////
// cPieceGenerator::cFreeConnector:

cPieceGenerator::cFreeConnector::cFreeConnector(cPlacedPiece * a_Piece, const cPiece::cConnector & a_Connector) :
	m_Piece(a_Piece),
	m_Connector(a_Connector)
{
}





////////////////////////////////////////////////////////////////////////////////
// cBFSPieceGenerator:

cBFSPieceGenerator::cBFSPieceGenerator(cPiecePool & a_PiecePool, int a_Seed) :
	super(a_PiecePool, a_Seed)
{
}





void cBFSPieceGenerator::PlacePieces(int a_BlockX, int a_BlockZ, int a_MaxDepth, cPlacedPieces & a_OutPieces)
{
	a_OutPieces.clear();
	cFreeConnectors ConnectorPool;

	// Place the starting piece:
	a_OutPieces.push_back(PlaceStartingPiece(a_BlockX, a_BlockZ, ConnectorPool));

	/*
	// DEBUG:
	printf("Placed the starting piece at {%d, %d, %d}\n", a_BlockX, a_BlockY, a_BlockZ);
	cCuboid Hitbox = a_OutPieces[0]->GetHitBox();
	Hitbox.Sort();
	printf("  Hitbox: {%d, %d, %d} - {%d, %d, %d} (%d * %d * %d)\n",
		Hitbox.p1.x, Hitbox.p1.y, Hitbox.p1.z,
		Hitbox.p2.x, Hitbox.p2.y, Hitbox.p2.z,
		Hitbox.DifX() + 1, Hitbox.DifY() + 1, Hitbox.DifZ() + 1
	);
	DebugConnectorPool(ConnectorPool, 0);
	//*/

	// Place pieces at the available connectors:
	/*
	Instead of removing them one by one from the pool, we process them sequentially and take note of the last
	processed one. To save on memory, once the number of processed connectors reaches a big number, a chunk
	of the connectors is removed.
	*/
	size_t NumProcessed = 0;
	while (ConnectorPool.size() > NumProcessed)
	{
		cFreeConnector & Conn = ConnectorPool[NumProcessed];
		if (Conn.m_Piece->GetDepth() < a_MaxDepth)
		{
			if (TryPlacePieceAtConnector(*Conn.m_Piece, Conn.m_Connector, a_OutPieces, ConnectorPool))
			{
				/*
				// DEBUG:
				const cPlacedPiece * NewPiece = a_OutPieces.back();
				const Vector3i & Coords = NewPiece->GetCoords();
				printf("Placed a new piece at {%d, %d, %d}, rotation %d\n", Coords.x, Coords.y, Coords.z, NewPiece->GetNumCCWRotations());
				cCuboid Hitbox = NewPiece->GetHitBox();
				Hitbox.Sort();
				printf("  Hitbox: {%d, %d, %d} - {%d, %d, %d} (%d * %d * %d)\n",
					Hitbox.p1.x, Hitbox.p1.y, Hitbox.p1.z,
					Hitbox.p2.x, Hitbox.p2.y, Hitbox.p2.z,
					Hitbox.DifX() + 1, Hitbox.DifY() + 1, Hitbox.DifZ() + 1
				);
				DebugConnectorPool(ConnectorPool, NumProcessed + 1);
				//*/
			}
		}
		NumProcessed++;
		if (NumProcessed > 1000)
		{
			typedef cPieceGenerator::cFreeConnectors::difference_type difType;
			ConnectorPool.erase(ConnectorPool.begin(), ConnectorPool.begin() + static_cast<difType>(NumProcessed));
			NumProcessed = 0;
		}
	}
}