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0001 // Created on: 1991-09-09 0002 // Created by: Michel Chauvat 0003 // Copyright (c) 1991-1999 Matra Datavision 0004 // Copyright (c) 1999-2014 OPEN CASCADE SAS 0005 // 0006 // This file is part of Open CASCADE Technology software library. 0007 // 0008 // This library is free software; you can redistribute it and/or modify it under 0009 // the terms of the GNU Lesser General Public License version 2.1 as published 0010 // by the Free Software Foundation, with special exception defined in the file 0011 // OCCT_LGPL_EXCEPTION.txt. Consult the file LICENSE_LGPL_21.txt included in OCCT 0012 // distribution for complete text of the license and disclaimer of any warranty. 0013 // 0014 // Alternatively, this file may be used under the terms of Open CASCADE 0015 // commercial license or contractual agreement. 0016 0017 #ifndef _CSLib_HeaderFile 0018 #define _CSLib_HeaderFile 0019 0020 #include <Standard.hxx> 0021 #include <Standard_DefineAlloc.hxx> 0022 #include <Standard_Handle.hxx> 0023 0024 #include <CSLib_DerivativeStatus.hxx> 0025 #include <Standard_Boolean.hxx> 0026 #include <CSLib_NormalStatus.hxx> 0027 #include <TColgp_Array2OfVec.hxx> 0028 class gp_Vec; 0029 class gp_Dir; 0030 0031 0032 //! This package implements functions for basis geometric 0033 //! computation on curves and surfaces. 0034 //! The tolerance criterions used in this package are 0035 //! Resolution from package gp and RealEpsilon from class 0036 //! Real of package Standard. 0037 class CSLib 0038 { 0039 public: 0040 0041 DEFINE_STANDARD_ALLOC 0042 0043 0044 0045 //! The following functions computes the normal to a surface 0046 //! inherits FunctionWithDerivative from math 0047 //! 0048 //! Computes the normal direction of a surface as the cross product 0049 //! between D1U and D1V. 0050 //! If D1U has null length or D1V has null length or D1U and D1V are 0051 //! parallel the normal is undefined. 0052 //! To check that D1U and D1V are colinear the sinus of the angle 0053 //! between D1U and D1V is computed and compared with SinTol. 0054 //! The normal is computed if theStatus == Done else the theStatus gives the 0055 //! reason why the computation has failed. 0056 Standard_EXPORT static void Normal (const gp_Vec& D1U, const gp_Vec& D1V, const Standard_Real SinTol, CSLib_DerivativeStatus& theStatus, gp_Dir& Normal); 0057 0058 0059 //! If there is a singularity on the surface the previous method 0060 //! cannot compute the local normal. 0061 //! This method computes an approached normal direction of a surface. 0062 //! It does a limited development and needs the second derivatives 0063 //! on the surface as input data. 0064 //! It computes the normal as follow : 0065 //! N(u, v) = D1U ^ D1V 0066 //! N(u0+du,v0+dv) = N0 + DN/du(u0,v0) * du + DN/dv(u0,v0) * dv + Eps 0067 //! with Eps->0 so we can have the equivalence N ~ dN/du + dN/dv. 0068 //! DNu = ||DN/du|| and DNv = ||DN/dv|| 0069 //! 0070 //! . if DNu IsNull (DNu <= Resolution from gp) the answer Done = True 0071 //! the normal direction is given by DN/dv 0072 //! . if DNv IsNull (DNv <= Resolution from gp) the answer Done = True 0073 //! the normal direction is given by DN/du 0074 //! . if the two directions DN/du and DN/dv are parallel Done = True 0075 //! the normal direction is given either by DN/du or DN/dv. 0076 //! To check that the two directions are colinear the sinus of the 0077 //! angle between these directions is computed and compared with 0078 //! SinTol. 0079 //! . if DNu/DNv or DNv/DNu is lower or equal than Real Epsilon 0080 //! Done = False, the normal is undefined 0081 //! . if DNu IsNull and DNv is Null Done = False, there is an 0082 //! indetermination and we should do a limited development at 0083 //! order 2 (it means that we cannot omit Eps). 0084 //! . if DNu Is not Null and DNv Is not Null Done = False, there are 0085 //! an infinity of normals at the considered point on the surface. 0086 Standard_EXPORT static void Normal (const gp_Vec& D1U, const gp_Vec& D1V, const gp_Vec& D2U, const gp_Vec& D2V, const gp_Vec& D2UV, const Standard_Real SinTol, Standard_Boolean& Done, CSLib_NormalStatus& theStatus, gp_Dir& Normal); 0087 0088 0089 //! Computes the normal direction of a surface as the cross product 0090 //! between D1U and D1V. 0091 Standard_EXPORT static void Normal (const gp_Vec& D1U, const gp_Vec& D1V, const Standard_Real MagTol, CSLib_NormalStatus& theStatus, gp_Dir& Normal); 0092 0093 //! find the first order k0 of deriviative of NUV 0094 //! where: foreach order < k0 all the derivatives of NUV are 0095 //! null all the derivatives of NUV corresponding to the order 0096 //! k0 are collinear and have the same sens. 0097 //! In this case, normal at U,V is unique. 0098 Standard_EXPORT static void Normal (const Standard_Integer MaxOrder, const TColgp_Array2OfVec& DerNUV, const Standard_Real MagTol, const Standard_Real U, const Standard_Real V, const Standard_Real Umin, const Standard_Real Umax, const Standard_Real Vmin, const Standard_Real Vmax, CSLib_NormalStatus& theStatus, gp_Dir& Normal, Standard_Integer& OrderU, Standard_Integer& OrderV); 0099 0100 //! -- Computes the derivative of order Nu in the -- 0101 //! direction U and Nv in the direction V of the not -- 0102 //! normalized normal vector at the point P(U,V) The 0103 //! array DerSurf contain the derivative (i,j) of the surface 0104 //! for i=0,Nu+1 ; j=0,Nv+1 0105 Standard_EXPORT static gp_Vec DNNUV (const Standard_Integer Nu, const Standard_Integer Nv, const TColgp_Array2OfVec& DerSurf); 0106 0107 //! Computes the derivatives of order Nu in the direction Nu 0108 //! and Nv in the direction Nv of the not normalized vector 0109 //! N(u,v) = dS1/du * dS2/dv (cases where we use an osculating surface) 0110 //! DerSurf1 are the derivatives of S1 0111 Standard_EXPORT static gp_Vec DNNUV (const Standard_Integer Nu, const Standard_Integer Nv, const TColgp_Array2OfVec& DerSurf1, const TColgp_Array2OfVec& DerSurf2); 0112 0113 //! -- Computes the derivative of order Nu in the -- 0114 //! direction U and Nv in the direction V of the 0115 //! normalized normal vector at the point P(U,V) array 0116 //! DerNUV contain the derivative (i+Iduref,j+Idvref) 0117 //! of D1U ^ D1V for i=0,Nu ; j=0,Nv Iduref and Idvref 0118 //! correspond to a derivative of D1U ^ D1V which can 0119 //! be used to compute the normalized normal vector. 0120 //! In the regular cases , Iduref=Idvref=0. 0121 Standard_EXPORT static gp_Vec DNNormal (const Standard_Integer Nu, const Standard_Integer Nv, const TColgp_Array2OfVec& DerNUV, const Standard_Integer Iduref = 0, const Standard_Integer Idvref = 0); 0122 0123 }; 0124 0125 #endif // _CSLib_HeaderFile
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