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//File Convert_ConeToBSplineSurface.cxx
//JCV 16/10/91
#include <Convert_ConeToBSplineSurface.ixx>
#include <gp.hxx>
#include <gp_Trsf.hxx>
static const Standard_Integer TheUDegree = 2;
static const Standard_Integer TheVDegree = 1;
static const Standard_Integer TheNbUKnots = 5;
static const Standard_Integer TheNbVKnots = 2;
static const Standard_Integer TheNbUPoles = 9;
static const Standard_Integer TheNbVPoles = 2;
static void ComputePoles( const Standard_Real R,
const Standard_Real A,
const Standard_Real U1,
const Standard_Real U2,
const Standard_Real V1,
const Standard_Real V2,
TColgp_Array2OfPnt& Poles)
{
Standard_Real deltaU = U2 - U1;
Standard_Integer i;
// Nombre de spans : ouverture maximale = 150 degres ( = PI / 1.2 rds)
Standard_Integer
nbUSpans = (Standard_Integer)IntegerPart( 1.2 * deltaU / PI) + 1;
Standard_Real AlfaU = deltaU / ( nbUSpans * 2);
Standard_Real x[TheNbVPoles];
Standard_Real z[TheNbVPoles];
x[0] = R + V1 * Sin(A);
z[0] = V1 * Cos(A);
x[1] = R + V2 * Sin(A);
z[1] = V2 * Cos(A);
Standard_Real UStart = U1;
Poles(1,1) = gp_Pnt(x[0]*Cos(UStart),x[0]*Sin(UStart),z[0]);
Poles(1,2) = gp_Pnt(x[1]*Cos(UStart),x[1]*Sin(UStart),z[1]);
for ( i = 1; i <= nbUSpans; i++) {
Poles( 2*i, 1) = gp_Pnt( x[0] * Cos(UStart+AlfaU) / Cos(AlfaU),
x[0] * Sin(UStart+AlfaU) / Cos(AlfaU),
z[0] );
Poles( 2*i, 2) = gp_Pnt( x[1] * Cos(UStart+AlfaU) / Cos(AlfaU),
x[1] * Sin(UStart+AlfaU) / Cos(AlfaU),
z[1] );
Poles(2*i+1,1) = gp_Pnt( x[0] * Cos(UStart+2*AlfaU),
x[0] * Sin(UStart+2*AlfaU),
z[0] );
Poles(2*i+1,2) = gp_Pnt( x[1] * Cos(UStart+2*AlfaU),
x[1] * Sin(UStart+2*AlfaU),
z[1] );
UStart += 2*AlfaU;
}
}
//=======================================================================
//function : Convert_ConeToBSplineSurface
//purpose :
//=======================================================================
Convert_ConeToBSplineSurface::Convert_ConeToBSplineSurface
(const gp_Cone& C ,
const Standard_Real U1,
const Standard_Real U2,
const Standard_Real V1,
const Standard_Real V2 )
: Convert_ElementarySurfaceToBSplineSurface (TheNbUPoles, TheNbVPoles,
TheNbUKnots, TheNbVKnots,
TheUDegree , TheVDegree )
{
Standard_Real deltaU = U2 - U1;
Standard_DomainError_Raise_if( (Abs(V2-V1) <= Abs(Epsilon(V1))) ||
(deltaU > 2*PI) ||
(deltaU < 0. ),
"Convert_ConeToBSplineSurface");
isuperiodic = Standard_False;
isvperiodic = Standard_False;
Standard_Integer i,j;
// construction du cone dans le repere de reference xOy.
// Nombre de spans : ouverture maximale = 150 degres ( = PI / 1.2 rds)
Standard_Integer
nbUSpans = (Standard_Integer)IntegerPart( 1.2 * deltaU / PI) + 1;
Standard_Real AlfaU = deltaU / ( nbUSpans * 2);
nbUPoles = 2 * nbUSpans + 1;
nbUKnots = nbUSpans + 1;
nbVPoles = 2;
nbVKnots = 2;
Standard_Real R = C.RefRadius();
Standard_Real A = C.SemiAngle();
ComputePoles( R, A, U1, U2, V1, V2, poles);
for ( i = 1; i<= nbUKnots; i++) {
uknots(i) = U1 + (i-1) * 2 * AlfaU;
umults(i) = 2;
}
umults(1)++; umults(nbUKnots)++;
vknots(1) = V1; vmults(1) = 2;
vknots(2) = V2; vmults(2) = 2;
// On replace la bspline dans le repere de la sphere.
// et on calcule les poids de la bspline.
Standard_Real W1;
gp_Trsf Trsf;
Trsf.SetTransformation( C.Position(), gp::XOY());
for ( i = 1; i <= nbUPoles; i++) {
if ( i % 2 == 0) W1 = Cos(AlfaU);
else W1 = 1.;
for ( j = 1; j <= nbVPoles; j++) {
weights( i, j) = W1;
poles( i, j).Transform( Trsf);
}
}
}
//=======================================================================
//function : Convert_ConeToBSplineSurface
//purpose :
//=======================================================================
Convert_ConeToBSplineSurface::Convert_ConeToBSplineSurface
(const gp_Cone& C ,
const Standard_Real V1,
const Standard_Real V2 )
: Convert_ElementarySurfaceToBSplineSurface (TheNbUPoles, TheNbVPoles,
TheNbUKnots, TheNbVKnots,
TheUDegree, TheVDegree)
{
Standard_DomainError_Raise_if( Abs(V2-V1) <= Abs(Epsilon(V1)),
"Convert_ConeToBSplineSurface");
Standard_Integer i,j;
isuperiodic = Standard_True;
isvperiodic = Standard_False;
// construction du cone dans le repere de reference xOy.
Standard_Real R = C.RefRadius();
Standard_Real A = C.SemiAngle();
ComputePoles( R, A, 0., 2.*PI, V1, V2, poles);
nbUPoles = 6;
nbUKnots = 4;
nbVPoles = 2;
nbVKnots = 2;
for ( i = 1; i <= nbUKnots; i++) {
uknots(i) = ( i-1) * 2. * PI /3.;
umults(i) = 2;
}
vknots(1) = V1; vmults(1) = 2;
vknots(2) = V2; vmults(2) = 2;
// On replace la bspline dans le repere du cone.
// et on calcule les poids de la bspline.
Standard_Real W;
gp_Trsf Trsf;
Trsf.SetTransformation( C.Position(), gp::XOY());
for ( i = 1; i <= nbUPoles; i++) {
if ( i % 2 == 0) W = 0.5; // = Cos(pi /3)
else W = 1.;
for ( j = 1; j <= nbVPoles; j++) {
weights( i, j) = W;
poles( i, j).Transform( Trsf);
}
}
}
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