// Created on: 1996-06-06 // Created by: Philippe MANGIN // Copyright (c) 1996-1999 Matra Datavision // Copyright (c) 1999-2014 OPEN CASCADE SAS // // This file is part of Open CASCADE Technology software library. // // This library is free software; you can redistribute it and/or modify it under // the terms of the GNU Lesser General Public License version 2.1 as published // by the Free Software Foundation, with special exception defined in the file // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT // distribution for complete text of the license and disclaimer of any warranty. // // Alternatively, this file may be used under the terms of Open CASCADE // commercial license or contractual agreement. #ifndef _GeomConvert_CompBezierSurfacesToBSplineSurface_HeaderFile #define _GeomConvert_CompBezierSurfacesToBSplineSurface_HeaderFile #include #include #include #include #include #include #include #include #include #include #include #include //! An algorithm to convert a grid of adjacent //! non-rational Bezier surfaces (with continuity CM) into a //! BSpline surface (with continuity CM). //! A CompBezierSurfacesToBSplineSurface object //! provides a framework for: //! - defining the grid of adjacent Bezier surfaces //! which is to be converted into a BSpline surface, //! - implementing the computation algorithm, and //! - consulting the results. //! Warning //! Do not attempt to convert rational Bezier surfaces using such an algorithm. //! Input is array of Bezier patch //! 1 2 3 4 -> VIndex [1, NbVPatches] -> VDirection //! ----------------------- //! 1 | | | | | //! ----------------------- //! 2 | | | | | //! ----------------------- //! 3 | | | | | //! ----------------------- //! UIndex [1, NbUPatches] Udirection //! //! Warning! Patches must have compatible parametrization class GeomConvert_CompBezierSurfacesToBSplineSurface { public: DEFINE_STANDARD_ALLOC //! Computes all the data needed to build a "C0" //! continuous BSpline surface equivalent to the grid of //! adjacent non-rational Bezier surfaces Beziers. //! Each surface in the Beziers grid becomes a natural //! patch, limited by knots values, on the BSpline surface //! whose data is computed. Surfaces in the grid must //! satisfy the following conditions: //! - Coincident bounding curves between two //! consecutive surfaces in a row of the Beziers grid //! must be u-isoparametric bounding curves of these two surfaces. //! - Coincident bounding curves between two //! consecutive surfaces in a column of the Beziers //! grid must be v-isoparametric bounding curves of these two surfaces. //! The BSpline surface whose data is computed has the //! following characteristics: //! - Its degree in the u (respectively v) parametric //! direction is equal to that of the Bezier surface //! which has the highest degree in the u //! (respectively v) parametric direction in the Beziers grid. //! - It is a "Piecewise Bezier" in both u and v //! parametric directions, i.e.: //! - the knots are regularly spaced in each //! parametric direction (i.e. the difference between //! two consecutive knots is a constant), and //! - all the multiplicities of the surface knots in a //! given parametric direction are equal to //! Degree, which is the degree of the BSpline //! surface in this parametric direction, except for //! the first and last knots for which the multiplicity is //! equal to Degree + 1. //! - Coincident bounding curves between two //! consecutive columns of Bezier surfaces in the //! Beziers grid become u-isoparametric curves, //! corresponding to knots values of the BSpline surface. //! - Coincident bounding curves between two //! consecutive rows of Bezier surfaces in the Beziers //! grid become v-isoparametric curves //! corresponding to knots values of the BSpline surface. //! Use the available consultation functions to access the //! computed data. This data may be used to construct the BSpline surface. //! Warning //! The surfaces in the Beziers grid must be adjacent, i.e. //! two consecutive Bezier surfaces in the grid (in a row //! or column) must have a coincident bounding curve. In //! addition, the location of the parameterization on each //! of these surfaces (i.e. the relative location of u and v //! isoparametric curves on the surface) is of importance //! with regard to the positioning of the surfaces in the //! Beziers grid. Care must be taken with respect to the //! above, as these properties are not checked and an //! error may occur if they are not satisfied. //! Exceptions //! Standard_NotImplemented if one of the Bezier //! surfaces of the Beziers grid is rational. Standard_EXPORT GeomConvert_CompBezierSurfacesToBSplineSurface(const TColGeom_Array2OfBezierSurface& Beziers); //! Build an Ci uniform (Rational) BSpline surface //! The highest Continuity Ci is imposed, like the //! maximal deformation is lower than . //! Warning: The Continuity C0 is imposed without any check. Standard_EXPORT GeomConvert_CompBezierSurfacesToBSplineSurface(const TColGeom_Array2OfBezierSurface& Beziers, const Standard_Real Tolerance, const Standard_Boolean RemoveKnots = Standard_True); //! Computes all the data needed to construct a BSpline //! surface equivalent to the adjacent non-rational //! Bezier surfaces Beziers grid. //! Each surface in the Beziers grid becomes a natural //! patch, limited by knots values, on the BSpline surface //! whose data is computed. Surfaces in the grid must //! satisfy the following conditions: //! - Coincident bounding curves between two //! consecutive surfaces in a row of the Beziers grid //! must be u-isoparametric bounding curves of these two surfaces. //! - Coincident bounding curves between two //! consecutive surfaces in a column of the Beziers //! grid must be v-isoparametric bounding curves of these two surfaces. //! The BSpline surface whose data is computed has the //! following characteristics: //! - Its degree in the u (respectively v) parametric //! direction is equal to that of the Bezier surface //! which has the highest degree in the u //! (respectively v) parametric direction in the Beziers grid. //! - Coincident bounding curves between two //! consecutive columns of Bezier surfaces in the //! Beziers grid become u-isoparametric curves //! corresponding to knots values of the BSpline surface. //! - Coincident bounding curves between two //! consecutive rows of Bezier surfaces in the Beziers //! grid become v-isoparametric curves //! corresponding to knots values of the BSpline surface. //! Knots values of the BSpline surface are given in the two tables: //! - UKnots for the u parametric direction (which //! corresponds to the order of Bezier surface columns in the Beziers grid), and //! - VKnots for the v parametric direction (which //! corresponds to the order of Bezier surface rows in the Beziers grid). //! The dimensions of UKnots (respectively VKnots) //! must be equal to the number of columns (respectively, //! rows) of the Beziers grid, plus 1 . //! UContinuity and VContinuity, which are both //! defaulted to GeomAbs_C0, specify the required //! continuity on the BSpline surface. If the required //! degree of continuity is greater than 0 in a given //! parametric direction, a deformation is applied locally //! on the initial surface (as defined by the Beziers grid) //! to satisfy this condition. This local deformation is not //! applied however, if it is greater than Tolerance //! (defaulted to 1.0 e-7). In such cases, the //! continuity condition is not satisfied, and the function //! IsDone will return false. A small tolerance value //! prevents any modification of the surface and a large //! tolerance value "smoothes" the surface. //! Use the available consultation functions to access the //! computed data. This data may be used to construct the BSpline surface. //! Warning //! The surfaces in the Beziers grid must be adjacent, i.e. //! two consecutive Bezier surfaces in the grid (in a row //! or column) must have a coincident bounding curve. In //! addition, the location of the parameterization on each //! of these surfaces (i.e. the relative location of u and v //! isoparametric curves on the surface) is of importance //! with regard to the positioning of the surfaces in the //! Beziers grid. Care must be taken with respect to the //! above, as these properties are not checked and an //! error may occur if they are not satisfied. //! Exceptions //! Standard_DimensionMismatch: //! - if the number of knots in the UKnots table (i.e. the //! length of the UKnots array) is not equal to the //! number of columns of Bezier surfaces in the //! Beziers grid plus 1, or //! - if the number of knots in the VKnots table (i.e. the //! length of the VKnots array) is not equal to the //! number of rows of Bezier surfaces in the Beziers grid, plus 1. //! Standard_ConstructionError: //! - if UContinuity and VContinuity are not equal to //! one of the following values: GeomAbs_C0, //! GeomAbs_C1, GeomAbs_C2 and GeomAbs_C3; or //! - if the number of columns in the Beziers grid is //! greater than 1, and the required degree of //! continuity in the u parametric direction is greater //! than that of the Bezier surface with the highest //! degree in the u parametric direction (in the Beziers grid), minus 1; or //! - if the number of rows in the Beziers grid is //! greater than 1, and the required degree of //! continuity in the v parametric direction is greater //! than that of the Bezier surface with the highest //! degree in the v parametric direction (in the Beziers grid), minus 1 . //! Standard_NotImplemented if one of the Bezier //! surfaces in the Beziers grid is rational. Standard_EXPORT GeomConvert_CompBezierSurfacesToBSplineSurface(const TColGeom_Array2OfBezierSurface& Beziers, const TColStd_Array1OfReal& UKnots, const TColStd_Array1OfReal& VKnots, const GeomAbs_Shape UContinuity = GeomAbs_C0, const GeomAbs_Shape VContinuity = GeomAbs_C0, const Standard_Real Tolerance = 1.0e-4); //! Returns the number of knots in the U direction //! of the BSpline surface whose data is computed in this framework. Standard_Integer NbUKnots() const; //! Returns number of poles in the U direction //! of the BSpline surface whose data is computed in this framework. Standard_Integer NbUPoles() const; //! Returns the number of knots in the V direction //! of the BSpline surface whose data is computed in this framework. Standard_Integer NbVKnots() const; //! Returns the number of poles in the V direction //! of the BSpline surface whose data is computed in this framework. Standard_Integer NbVPoles() const; //! Returns the table of poles of the BSpline surface //! whose data is computed in this framework. const Handle(TColgp_HArray2OfPnt)& Poles() const; //! Returns the knots table for the u parametric //! direction of the BSpline surface whose data is computed in this framework. const Handle(TColStd_HArray1OfReal)& UKnots() const; //! Returns the degree for the u parametric //! direction of the BSpline surface whose data is computed in this framework. Standard_Integer UDegree() const; //! Returns the knots table for the v parametric //! direction of the BSpline surface whose data is computed in this framework. const Handle(TColStd_HArray1OfReal)& VKnots() const; //! Returns the degree for the v parametric //! direction of the BSpline surface whose data is computed in this framework. Standard_Integer VDegree() const; //! Returns the multiplicities table for the u //! parametric direction of the knots of the BSpline //! surface whose data is computed in this framework. const Handle(TColStd_HArray1OfInteger)& UMultiplicities() const; //! -- Returns the multiplicities table for the v //! parametric direction of the knots of the BSpline //! surface whose data is computed in this framework. const Handle(TColStd_HArray1OfInteger)& VMultiplicities() const; //! Returns true if the conversion was successful. //! Unless an exception was raised at the time of //! construction, the conversion of the Bezier surface //! grid assigned to this algorithm is always carried out. //! IsDone returns false if the constraints defined at the //! time of construction cannot be respected. This occurs //! when there is an incompatibility between a required //! degree of continuity on the BSpline surface, and the //! maximum tolerance accepted for local deformations //! of the surface. In such a case the computed data //! does not satisfy all the initial constraints. Standard_EXPORT Standard_Boolean IsDone() const; protected: private: //! It used internally by the constructors. Standard_EXPORT void Perform (const TColGeom_Array2OfBezierSurface& Beziers); Standard_Integer myUDegree; Standard_Integer myVDegree; Handle(TColStd_HArray1OfInteger) myVMults; Handle(TColStd_HArray1OfInteger) myUMults; Handle(TColStd_HArray1OfReal) myUKnots; Handle(TColStd_HArray1OfReal) myVKnots; Handle(TColgp_HArray2OfPnt) myPoles; Standard_Boolean isrational; Standard_Boolean myDone; }; #include #endif // _GeomConvert_CompBezierSurfacesToBSplineSurface_HeaderFile