//File Convert_CylinderToBSplineSurface.cxx //JCV 16/10/91 #include #include #include 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 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 UStart = U1; Poles(1,1) = gp_Pnt(R*Cos(UStart),R*Sin(UStart),V1); Poles(1,2) = gp_Pnt(R*Cos(UStart),R*Sin(UStart),V2); for ( i = 1; i <= nbUSpans; i++) { Poles( 2*i, 1) = gp_Pnt( R * Cos(UStart+AlfaU) / Cos(AlfaU), R * Sin(UStart+AlfaU) / Cos(AlfaU), V1 ); Poles( 2*i, 2) = gp_Pnt( R * Cos(UStart+AlfaU) / Cos(AlfaU), R * Sin(UStart+AlfaU) / Cos(AlfaU), V2 ); Poles(2*i+1,1) = gp_Pnt( R * Cos(UStart+2*AlfaU), R * Sin(UStart+2*AlfaU), V1 ); Poles(2*i+1,2) = gp_Pnt( R * Cos(UStart+2*AlfaU), R * Sin(UStart+2*AlfaU), V2 ); UStart += 2*AlfaU; } } //======================================================================= //function : Convert_CylinderToBSplineSurface //purpose : //======================================================================= Convert_CylinderToBSplineSurface::Convert_CylinderToBSplineSurface (const gp_Cylinder& Cyl, 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_CylinderToBSplineSurface"); isuperiodic = Standard_False; isvperiodic = Standard_False; Standard_Integer i,j; // construction du cylindre 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 = Cyl.Radius(); ComputePoles( R, 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( Cyl.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_CylinderToBSplineSurface //purpose : //======================================================================= Convert_CylinderToBSplineSurface::Convert_CylinderToBSplineSurface (const gp_Cylinder& Cyl, 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_CylinderToBSplineSurface"); Standard_Integer i,j; isuperiodic = Standard_True; isvperiodic = Standard_False; // construction du cylindre dans le repere de reference xOy. Standard_Real R = Cyl.Radius(); ComputePoles( R, 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( Cyl.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); } } }