+//================================================================================
+/*!
+ * \brief Checks validity of generated faces
+ */
+//================================================================================
+
+bool StdMeshers_Quadrangle_2D::check()
+{
+ const bool isOK = true;
+ if ( !myCheckOri || myQuadList.empty() || !myQuadList.front() || !myHelper )
+ return isOK;
+
+ TopoDS_Face geomFace = TopoDS::Face( myHelper->GetSubShape() );
+ SMESHDS_Mesh* meshDS = myHelper->GetMeshDS();
+ SMESHDS_SubMesh* fSubMesh = meshDS->MeshElements( geomFace );
+ bool toCheckUV;
+ if ( geomFace.Orientation() >= TopAbs_INTERNAL ) geomFace.Orientation( TopAbs_FORWARD );
+
+ // Get a reference orientation sign
+
+ double okSign;
+ {
+ TError err;
+ TSideVector wireVec =
+ StdMeshers_FaceSide::GetFaceWires( geomFace, *myHelper->GetMesh(), true, err );
+ StdMeshers_FaceSidePtr wire = wireVec[0];
+
+ // find a right angle VERTEX
+ int iVertex;
+ double maxAngle = -1e100;
+ for ( int i = 0; i < wire->NbEdges(); ++i )
+ {
+ int iPrev = myHelper->WrapIndex( i-1, wire->NbEdges() );
+ const TopoDS_Edge& e1 = wire->Edge( iPrev );
+ const TopoDS_Edge& e2 = wire->Edge( i );
+ double angle = myHelper->GetAngle( e1, e2, geomFace, wire->FirstVertex( i ));
+ if (( maxAngle < angle ) &&
+ ( 5.* M_PI/180 < angle && angle < 175.* M_PI/180 ))
+ {
+ maxAngle = angle;
+ iVertex = i;
+ }
+ }
+ if ( maxAngle < -2*M_PI ) return isOK;
+
+ // get a sign of 2D area of a corner face
+
+ int iPrev = myHelper->WrapIndex( iVertex-1, wire->NbEdges() );
+ const TopoDS_Edge& e1 = wire->Edge( iPrev );
+ const TopoDS_Edge& e2 = wire->Edge( iVertex );
+
+ gp_Vec2d v1, v2; gp_Pnt2d p;
+ double u[2];
+ {
+ bool rev = ( e1.Orientation() == TopAbs_REVERSED );
+ Handle(Geom2d_Curve) c = BRep_Tool::CurveOnSurface( e1, geomFace, u[0], u[1] );
+ c->D1( u[ !rev ], p, v1 );
+ if ( !rev )
+ v1.Reverse();
+ }
+ {
+ bool rev = ( e2.Orientation() == TopAbs_REVERSED );
+ Handle(Geom2d_Curve) c = BRep_Tool::CurveOnSurface( e2, geomFace, u[0], u[1] );
+ c->D1( u[ rev ], p, v2 );
+ if ( rev )
+ v2.Reverse();
+ }
+
+ okSign = v2 ^ v1;
+
+ if ( maxAngle < 0 )
+ okSign *= -1;
+ }
+
+ // Look for incorrectly oriented faces
+
+ std::list<const SMDS_MeshElement*> badFaces;
+
+ const SMDS_MeshNode* nn [ 8 ]; // 8 is just for safety
+ gp_UV uv [ 8 ];
+ SMDS_ElemIteratorPtr fIt = fSubMesh->GetElements();
+ while ( fIt->more() ) // loop on faces bound to a FACE
+ {
+ const SMDS_MeshElement* f = fIt->next();
+
+ const int nbN = f->NbCornerNodes();
+ for ( int i = 0; i < nbN; ++i )
+ nn[ i ] = f->GetNode( i );
+
+ const SMDS_MeshNode* nInFace = 0;
+ if ( myHelper->HasSeam() )
+ for ( int i = 0; i < nbN && !nInFace; ++i )
+ if ( !myHelper->IsSeamShape( nn[i]->getshapeId() ))
+ nInFace = nn[i];
+
+ toCheckUV = true;
+ for ( int i = 0; i < nbN; ++i )
+ uv[ i ] = myHelper->GetNodeUV( geomFace, nn[i], nInFace, &toCheckUV );
+
+ switch ( nbN ) {
+ case 4:
+ {
+ double sign1 = getArea( uv[0], uv[1], uv[2] );
+ double sign2 = getArea( uv[0], uv[2], uv[3] );
+ if ( sign1 * sign2 < 0 )
+ {
+ sign2 = getArea( uv[1], uv[2], uv[3] );
+ sign1 = getArea( uv[1], uv[3], uv[0] );
+ if ( sign1 * sign2 < 0 )
+ continue; // this should not happen
+ }
+ if ( sign1 * okSign < 0 )
+ badFaces.push_back ( f );
+ break;
+ }
+ case 3:
+ {
+ double sign = getArea( uv[0], uv[1], uv[2] );
+ if ( sign * okSign < 0 )
+ badFaces.push_back ( f );
+ break;
+ }
+ default:;
+ }
+ }
+
+ if ( !badFaces.empty() )
+ {
+ SMESH_subMesh* fSM = myHelper->GetMesh()->GetSubMesh( geomFace );
+ SMESH_ComputeErrorPtr& err = fSM->GetComputeError();
+ err.reset ( new SMESH_ComputeError( COMPERR_ALGO_FAILED,
+ "Inverted elements generated"));
+ err->myBadElements.swap( badFaces );
+
+ return !isOK;
+ }
+
+ return isOK;
+}
+
+//================================================================================