BoundBox.cpp

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#include "moab/Interface.hpp"
#include "moab/BoundBox.hpp"
 
// this is used for spherical elements, bounding box needs to be updated due to curvature
#include "moab/IntxMesh/IntxUtils.hpp"
 
namespace moab
{
ErrorCode BoundBox::update( Interface& iface, const Range& elems, bool spherical, double radius )
{
 ErrorCode rval;
 bMin = CartVect( HUGE_VAL );
 bMax = CartVect( -HUGE_VAL );
 
 CartVect coords;
 EntityHandle const *conn = NULL, *conn2 = NULL;
 int len = 0, len2 = 0;
 Range::const_iterator i;
 CartVect coordverts[27]; // maximum nodes per element supported by MOAB
 
 // vertices
 const Range::const_iterator elem_begin = elems.lower_bound( MBEDGE );
 for( i = elems.begin(); i != elem_begin; ++i )
 {
 rval = iface.get_coords( &*i, 1, coords.array() );
 if( MB_SUCCESS != rval ) return rval;
 update_min( coords.array() );
 update_max( coords.array() );
 }
 
 // elements with vertex-handle connectivity list
 const Range::const_iterator poly_begin = elems.lower_bound( MBPOLYHEDRON, elem_begin );
 std::vector< EntityHandle > dum_vector;
 for( i = elem_begin; i != poly_begin; ++i )
 {
 rval = iface.get_connectivity( *i, conn, len, true, &dum_vector );
 if( MB_SUCCESS != rval ) return rval;
 
 rval = iface.get_coords( conn, len, &( coordverts[0][0] ) );
 if( MB_SUCCESS != rval ) return rval;
 for( int j = 0; j < len; ++j )
 {
 update_min( coordverts[j].array() );
 update_max( coordverts[j].array() );
 }
 // if spherical, use gnomonic projection to improve the computed box
 // it is used now for coupling only
 if( spherical ) update_box_spherical_elem( coordverts, len, radius );
 }
 
 // polyhedra
 const Range::const_iterator set_begin = elems.lower_bound( MBENTITYSET, poly_begin );
 for( i = poly_begin; i != set_begin; ++i )
 {
 rval = iface.get_connectivity( *i, conn, len, true );
 if( MB_SUCCESS != rval ) return rval;
 
 for( int j = 0; j < len; ++j )
 {
 rval = iface.get_connectivity( conn[j], conn2, len2 );
 if( MB_SUCCESS != rval ) return rval;
 rval = iface.get_coords( conn2, len2, &( coordverts[0][0] ) );
 if( MB_SUCCESS != rval ) return rval;
 for( int k = 0; k < len2; ++k )
 {
 update_min( coordverts[k].array() );
 update_max( coordverts[k].array() );
 }
 }
 }
 
 // sets
 BoundBox box;
 for( i = set_begin; i != elems.end(); ++i )
 {
 Range tmp_elems;
 rval = iface.get_entities_by_handle( *i, tmp_elems );
 if( MB_SUCCESS != rval ) return rval;
 rval = box.update( iface, tmp_elems, spherical, radius );
 if( MB_SUCCESS != rval ) return rval;
 
 update( box );
 }
 
 return MB_SUCCESS;
}
void BoundBox::update_box_spherical_elem( const CartVect* verts, int len, double R )
{
 // decide first the gnomonic plane, based on first coordinate
 int plane = -1;
 CartVect pos;
 IntxUtils::decide_gnomonic_plane( verts[0], plane );
 double in_plane_positions[20]; // at most polygons with 10 edges; do we need to revise this?
 for( int i = 0; i < len && i < 10; i++ )
 IntxUtils::gnomonic_projection( verts[i], R, plane, in_plane_positions[2 * i], in_plane_positions[2 * i + 1] );
 // look for points on the intersection between edges in gnomonic plane and coordinate axes
 // if yes, reverse projection of intx point, and update box
 double oriented_area2 = 0;
 // if oriented area is != zero, it means the origin is inside the polygon, so we need to upgrade
 // the box with the origin, so we do not miss anything (the top of the dome)
 for( int i = 0; i < len; i++ )
 {
 int i1 = ( i + 1 ) % len; // next vertex in polygon
 // check intx with x axis
 double ax = in_plane_positions[2 * i], ay = in_plane_positions[2 * i + 1];
 double bx = in_plane_positions[2 * i1], by = in_plane_positions[2 * i1 + 1];
 if( ay * by < 0 ) // it intersects with x axis
 {
 double alfa = ay / ( ay - by );
 double xintx = ax + alfa * ( bx - ax );
 IntxUtils::reverse_gnomonic_projection( xintx, 0, R, plane, pos );
 update_min( pos.array() );
 update_max( pos.array() );
 }
 if( ax * bx < 0 ) // it intersects with y axis
 {
 double alfa = ax / ( ax - bx );
 double yintx = ay + alfa * ( by - ay );
 IntxUtils::reverse_gnomonic_projection( 0, yintx, R, plane, pos );
 update_min( pos.array() );
 update_max( pos.array() );
 }
 oriented_area2 += ( ax * by - ay * bx );
 }
 if( fabs( oriented_area2 ) > R * R * 1.e-6 ) // origin is in the interior, add the center
 {
 IntxUtils::reverse_gnomonic_projection( 0, 0, R, plane, pos );
 update_min( pos.array() );
 update_max( pos.array() );
 }
}
} // namespace moab