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CAGD_LIB
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CAGDCSRF.C
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C/C++ Source or Header
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1991-10-09
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/******************************************************************************
* CagdCSrf.c - Constructa surface using a set of curves. *
*******************************************************************************
* Written by Gershon Elber, Sep. 91. *
******************************************************************************/
#ifdef __MSDOS__
#include <stdlib.h>
#include <string.h>
#include <alloc.h>
#endif /* __MSDOS__ */
#include "cagd_loc.h"
/******************************************************************************
* Constructs a surface using a set of curves. Curves are made to be *
* compatible and then each is substituted in the resulting surface as a row. *
* Other direction order is at most the compatible curves order. If order is *
* less than number of curves a knot vector is formed uniformly (open end). *
******************************************************************************/
CagdSrfStruct *CagdSrfFromCrvs(CagdCrvStruct *CrvList)
{
CagdBType IsNotRational;
int i, j, NumCrvs, UOrder, VOrder, MaxCoord, Length;
CagdRType **SrfPoints;
CagdCrvStruct *Crv, **CrvVec;
CagdSrfStruct *Srf;
/* Find out how many curves we have and put them in a linear vector. */
/* Note the vector have a COPY of the curves so we can modify them. */
for (NumCrvs = 0, Crv = CrvList;
Crv != NULL;
NumCrvs++, Crv = Crv -> Pnext);
CrvVec = (CagdCrvStruct **) CagdMalloc(sizeof(CagdCrvStruct *) * NumCrvs);
for (i = 0, Crv = CrvList;
i < NumCrvs;
i++, Crv = Crv -> Pnext)
CrvVec[i] = CagdCrvCopy(Crv);
/* Traverse vector in a O(n^2) fashion and make all curves compatible. */
for (i = 0; i < NumCrvs - 1; i++)
for (j = i + 1; j < NumCrvs; j++)
CagdMakeCrvsCompatible(&CrvVec[i], &CrvVec[j], TRUE, TRUE);
/* Construct the surface. All required information is now available. */
UOrder = CrvVec[0] -> Order;
VOrder = MIN(NumCrvs, UOrder);
if (NumCrvs == VOrder && CrvVec[0] -> GType == CAGD_CBEZIER_TYPE) {
/* Allocate a bezier surface. */
Srf = BzrSrfNew(CrvVec[0] -> Length, NumCrvs, CrvVec[0] -> PType);
}
else {
/* Allocate a bspline surface. */
Srf = BspSrfNew(CrvVec[0] -> Length, NumCrvs, UOrder, VOrder,
CrvVec[0] -> PType);
CagdFree((VoidPtr) Srf -> UKnotVector);
Srf -> UKnotVector = BspKnotCopy(CrvVec[0] -> KnotVector,
CrvVec[0] -> Length + CrvVec[0] -> Order);
BspKnotUniformOpen(NumCrvs, VOrder, Srf -> VKnotVector);
}
/* Substitute each curve as a row into the surface mesh and delete it. */
SrfPoints = Srf -> Points;
i = 0;
MaxCoord = CAGD_NUM_OF_PT_COORD(CrvVec[0] -> PType),
IsNotRational = !CAGD_IS_RATIONAL_CRV(CrvVec[0]);
Length = CrvVec[0] -> Length;
for (j = 0; j < NumCrvs; j++) {
int k;
CagdRType **CrvPoints = CrvVec[j] -> Points;
for (k = IsNotRational; k <= MaxCoord; k++)
GEN_COPY(&SrfPoints[k][i], CrvPoints[k], sizeof(CagdRType) * Length);
CagdCrvFree(CrvVec[j]);
i += Length;
}
CagdFree((VoidPtr) CrvVec);
return Srf;
}