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VTBackTrackC::VTBackTrackC(void) VTBackTrackC::VTBackTrackC(const VTBackTrackC &) VTBackTrackC::operator=(const VTBackTrackC &) VTBackTrackC::~VTBackTrackC(void) VTBackTrackC::SetFlags(BooleanT,BooleanT,BooleanT) VTBackTrackC::OpenSolve(VTRingC,int) VTBackTrackC::Solve(VTRingC,int,BooleanT) VTBackTrackC::Setup(VTRingC) VTBackTrackC::Pair(ItTriC,ItTriC) VTBackTrackC::AddTwo(VTBoundC &,DLIterC &,int) VTBackTrackC::SeedBoundary(ItTriC) VTBackTrackC::PruneGrow(int,VTBoundC) VTBackTrackC::NoElbowGrow(VTBoundC &,DLIterC,int) VTBackTrackC::BoundaryNo(DLIterC) VTBackTrackC::ComputeResult(void)

VTBackTrackC
include	"amma/VTBackTrack.hh"
User Level:	Default
Library:	VTRing
Example:	cri.cc
Section:	default.Andrew Stoddart
In Scope:	std

Comments:
------------------------------------------------------------------------- ********** VTBackTrackC ************************************************** ------------------------------------------------------------------------- ------------------------------------------------------------------------- ------------------------------------------------------------------------- ------------------------------------------------------------------------- ********** VTBackTrackC ************************************************** ------------------------------------------------------------------------- A number of unnecessarily slow steps are marked SLOW in the .cc file It is not expected to use this code in speed critical applications. This class takes as input a closed triangular mesh. The mesh is converted to a mesh of 4-sided faces by pairing adjacent triangles It works by a variation of depth first search with backtracking whenever there is a problem. It need never backtrack further back than the last elbowless boundary. Future extensions should tackle open surfaces. Error message: "Complete failure in PruneGrow" needs attention The routine Compute Result is now fixed. -------------------------------------------------------------------------

SArray1dC mate;

stores chosen pair tri, -1 if not yet done

SArray1dC neighbour;

list of neighbours for each edge, -99 if does not exist 2d = 3 x N

BooleanT prtrace;

BooleanT diagfiles;

BooleanT testneck;

VTRingC vt;

PolopsC result;

int countmax;

int nfaces;

VTBackTrackC()

Null Constructor

VTBackTrackC(const VTBackTrackC & s)

Copy constructor

VTBackTrackC & operator=(const VTBackTrackC & s)

~VTBackTrackC()

Destructor

void SetFlags(BooleanT tn = TRUE,BooleanT tr = TRUE,BooleanT df = TRUE)

set the testneck, trace flags and the save diagnostic files flag

PolopsC OpenSolve(VTRingC vt,int n)

Solve the open surface and reurn a Polops

PolopsC Solve(VTRingC vt,int n,BooleanT trymany = TRUE)

Solve the closed surface and reurn a Polops

void Setup(VTRingC vtin)

setup the mate and neighbour arrays

void Pair(ItTriC it0,ItTriC it1)

write into mate array this pair

AddTypeT AddTwo(VTBoundC & b,DLIterC<VTDirEdgeC> & ide,int parity)

An attempt is made to add 2 triangles at the goven point. Any self intersection results in failure, parity will only used at nonelbow edges

VTBoundC SeedBoundary(ItTriC it0)

Seed the boundary with it0 and a neighbour - if it0 is on a SURFACE boundary the first adjacent tri is added

BooleanT PruneGrow(int n,VTBoundC b)

Grow region to completion in pairs by a pruned exhaustive search - intermediate regions with no elbows are stored - when a selfintersection is encountered an immediate backtrack takes place to the last stored region

BooleanT NoElbowGrow(VTBoundC & b,DLIterC<VTDirEdgeC> ide,int parity)

Starting with the suggested edge a pair of triangles is added to the region. When an elbow-less boundary is encountered the routine returns TRUE. If a selfintersection is encountered FALSE is returned. When the region is complete TRUE is returned.

int BoundaryNo(DLIterC<VTDirEdgeC> ide)

return the number of ide in the boudary list; 0=first, -1=not there

int ComputeResult()

Using the contents of the arrays "mate" and "neighbour" this routine builds the 4 sided face Polops. It returns the number of unused faces.