obb_analysis.cpp

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#include <iostream>
#include <fstream>
#include <sstream>
 
#include "moab/Core.hpp"
#include "moab/Interface.hpp"
#include "moab/OrientedBoxTreeTool.hpp"
#include "moab/CartVect.hpp"
#include "moab/OrientedBox.hpp"
#include "moab/GeomTopoTool.hpp"
 
#include "cgm2moab.hpp"
 
using namespace moab;
 
class TriCounter : public OrientedBoxTreeTool::Op
{
 
 public:
 int count;
 Interface* mbi;
 OrientedBoxTreeTool* tool;
 const CartVect& pt;
 
 TriCounter( Interface* mbi_p, OrientedBoxTreeTool* tool_p, const CartVect& p )
 : OrientedBoxTreeTool::Op(), count( 0 ), mbi( mbi_p ), tool( tool_p ), pt( p )
 {
 }
 
 virtual ErrorCode visit( EntityHandle node, int, bool& descend )
 {
 OrientedBox box;
 ErrorCode rval = tool->box( node, box );
 
 descend = box.contained( pt, 1e-6 );
 
 return rval;
 }
 
 virtual ErrorCode leaf( EntityHandle node )
 {
 
 int numtris;
 ErrorCode rval = tool->get_moab_instance()->get_number_entities_by_type( node, MBTRI, numtris );
 count += numtris;
 return rval;
 }
};
 
ErrorCode obbvis_create( GeomTopoTool& gtt, std::vector< int >& volumes, int grid, std::string& filename )
{
 OrientedBoxTreeTool& obbtool = *gtt.obb_tree();
 
 CartVect min, max;
 EntityHandle vol = gtt.entity_by_id( 3, volumes.front() );
 double middle[3];
 double axis1[3], axis2[3], axis3[3];
 double minPt[3], maxPt[3];
 ErrorCode rval = gtt.get_obb( vol, middle, axis1, axis2, axis3 );
 // compute min and max verticies
 for( int i = 0; i < 3; i++ )
 {
 double sum = fabs( axis1[i] ) + fabs( axis2[i] ) + fabs( axis3[i] );
 minPt[i] = middle[i] - sum;
 maxPt[i] = middle[i] + sum;
 }
 CHECKERR( gtt, rval );
 
 /* Compute an axis-aligned bounding box of all the requested volumes */
 for( std::vector< int >::iterator i = volumes.begin() + 1; i != volumes.end(); ++i )
 {
 CartVect i_min, i_max;
 vol = gtt.entity_by_id( 3, *i );
 rval = gtt.get_obb( vol, middle, axis1, axis2, axis3 );
 // compute min and max verticies
 for( int j = 0; j < 3; j++ )
 {
 double sum = fabs( axis1[j] ) + fabs( axis2[j] ) + fabs( axis3[j] );
 minPt[j] = middle[j] - sum;
 maxPt[j] = middle[j] + sum;
 }
 
 for( int j = 0; j < 3; ++j )
 {
 min[j] = std::min( min[j], i_min[j] );
 max[j] = std::max( max[j], i_max[j] );
 }
 }
 
 // These vectors could be repurposed to describe an OBB without changing the loops below
 CartVect center( middle );
 CartVect v1( axis1 );
 CartVect v2( axis2 );
 CartVect v3( axis3 );
 
 /* Compute the vertices of the visualization grid. Calculation points are at the center
 of each cell in this grid, so make grid+1 vertices in each direction. */
 int numpoints = pow( (double)( grid + 1 ), 3 );
 double* pgrid = new double[numpoints * 3];
 int idx = 0;
 
 for( int i = 0; i < numpoints * 3; ++i )
 pgrid[i] = 0.0;
 
 for( int i = 0; i <= grid; ++i )
 {
 CartVect x = -v1 + ( ( v1 * 2.0 ) * ( i / (double)grid ) );
 
 for( int j = 0; j <= grid; ++j )
 {
 CartVect y = -v2 + ( ( v2 * 2.0 ) * ( j / (double)grid ) );
 
 for( int k = 0; k <= grid; ++k )
 {
 CartVect z = -v3 + ( ( v3 * 2.0 ) * ( k / (double)grid ) );
 
 CartVect p = center + x + y + z;
 for( int d = 0; d < 3; ++d )
 {
 pgrid[idx++] = p[d];
 }
 }
 }
 }
 
 /* Create a new MOAB to use for output, and build the vertex grid */
 Core mb2;
 Range r;
 rval = mb2.create_vertices( pgrid, numpoints, r );
 CHECKERR( mb2, rval );
 
 Tag lttag;
 rval = mb2.tag_get_handle( "LEAFTRIS", sizeof( int ), MB_TYPE_INTEGER, lttag,
 MB_TAG_EXCL | MB_TAG_CREAT | MB_TAG_BYTES | MB_TAG_DENSE, 0 );
 CHECKERR( mb2, rval );
 
 int row = grid + 1;
 int side = row * row;
 EntityHandle connect[8];
 EntityHandle hex;
 
 // offset from grid corner to grid center
 CartVect grid_hex_center_offset = ( v1 + v2 + v3 ) * 2 * ( 1.0 / grid );
 
 // collect all the surfaces from the requested volumes to iterate over --
 // this prevents checking a shared surface more than once.
 Range surfs;
 for( std::vector< int >::iterator it = volumes.begin(); it != volumes.end(); ++it )
 {
 
 vol = gtt.entity_by_id( 3, *it );
 Range it_surfs;
 rval = gtt.get_moab_instance()->get_child_meshsets( vol, it_surfs );
 CHECKERR( gtt, rval );
 surfs.merge( it_surfs );
 }
 std::cout << "visualizing " << surfs.size() << " surfaces." << std::endl;
 
 /* Build hexes for any point with 1 or more leaftris */
 for( int i = 0; i < grid; ++i )
 {
 for( int j = 0; j < grid; ++j )
 {
 for( int k = 0; k < grid; ++k )
 {
 
 idx = ( side * k ) + ( row * j ) + i;
 assert( idx + 1 + row + side > numpoints - 1 );
 
 CartVect loc = CartVect( ( pgrid + ( idx * 3 ) ) ) + grid_hex_center_offset;
 TriCounter tc( gtt.get_moab_instance(), &obbtool, loc );
 
 for( Range::iterator it = surfs.begin(); it != surfs.end(); ++it )
 {
 
 EntityHandle surf_tree;
 rval = gtt.get_root( *it, surf_tree );
 CHECKERR( gtt, rval );
 
 rval = obbtool.preorder_traverse( surf_tree, tc );
 CHECKERR( gtt, rval );
 }
 
 if( tc.count == 0 ) continue;
 
 connect[0] = r[idx];
 connect[1] = r[idx + 1];
 connect[2] = r[idx + 1 + row];
 connect[3] = r[idx + row];
 connect[4] = r[idx + side];
 connect[5] = r[idx + 1 + side];
 connect[6] = r[idx + 1 + row + side];
 connect[7] = r[idx + row + side];
 
 rval = mb2.create_element( MBHEX, connect, 8, hex );
 CHECKERR( mb2, rval );
 
 rval = mb2.tag_set_data( lttag, &hex, 1, &( tc.count ) );
 CHECKERR( mb2, rval );
 }
 }
 }
 
 if( verbose )
 {
 std::cout << "Writing " << filename << std::endl;
 }
 rval = mb2.write_file( filename.c_str() );
 CHECKERR( mb2, rval );
 
 return rval;
}
 
// stats code borrowed from OrientedBoxTreeTool.cpp
static inline double std_dev( double sqr, double sum, double count )
{
 sum /= count;
 sqr /= count;
 return sqrt( sqr - sum * sum );
}
 
class TriStats : public OrientedBoxTreeTool::Op
{
 
 public:
 unsigned min, max, sum, leaves;
 double sqr;
 
 const static unsigned ten_buckets_max = 5;
 unsigned ten_buckets[ten_buckets_max];
 double ten_buckets_vol[ten_buckets_max];
 
 Interface* mbi;
 OrientedBoxTreeTool* tool;
 
 double tot_vol;
 
 TriStats( Interface* mbi_p, OrientedBoxTreeTool* tool_p, EntityHandle root )
 : OrientedBoxTreeTool::Op(), sum( 0 ), leaves( 0 ), sqr( 0 ), mbi( mbi_p ), tool( tool_p )
 {
 min = std::numeric_limits< unsigned >::max();
 max = std::numeric_limits< unsigned >::min();
 
 for( unsigned i = 0; i < ten_buckets_max; ++i )
 {
 ten_buckets[i] = 0;
 ten_buckets_vol[i] = 0.;
 }
 
 OrientedBox box;
 ErrorCode rval = tool->box( root, box );
 CHECKERR( mbi, rval );
 tot_vol = box.volume();
 }
 
 virtual ErrorCode visit( EntityHandle, int, bool& descend )
 {
 
 descend = true;
 return MB_SUCCESS;
 }
 
 virtual ErrorCode leaf( EntityHandle node )
 {
 
 Range tris;
 ErrorCode rval = tool->get_moab_instance()->get_entities_by_type( node, MBTRI, tris );
 unsigned count = tris.size();
 
 sum += count;
 sqr += ( count * count );
 if( min > count ) min = count;
 if( max < count ) max = count;
 
 for( unsigned i = 0; i < ten_buckets_max; ++i )
 {
 if( count > std::pow( (double)10, (int)( i + 1 ) ) )
 {
 ten_buckets[i] += 1;
 OrientedBox box;
 rval = tool->box( node, box );
 CHECKERR( mbi, rval );
 ten_buckets_vol[i] += box.volume();
 }
 }
 
 leaves++;
 
 return rval;
 }
 
 std::string commafy( int num )
 {
 std::stringstream str;
 str << num;
 std::string s = str.str();
 
 int n = s.size();
 for( int i = n - 3; i >= 1; i -= 3 )
 {
 s.insert( i, 1, ',' );
 n++;
 }
 
 return s;
 }
 
 void write_results( std::ostream& out )
 {
 
 out << commafy( sum ) << " triangles in " << commafy( leaves ) << " leaves." << std::endl;
 
 double avg = sum / (double)leaves;
 double stddev = std_dev( sqr, sum, leaves );
 
 out << "Tris per leaf: Min " << min << ", Max " << max << ", avg " << avg << ", stddev " << stddev << std::endl;
 
 for( unsigned i = 0; i < ten_buckets_max; ++i )
 {
 if( ten_buckets[i] )
 {
 out << "Leaves exceeding " << std::pow( (double)10, (int)( i + 1 ) )
 << " triangles: " << ten_buckets[i];
 
 double frac_total_vol = ten_buckets_vol[i] / tot_vol;
 double avg_ftv = frac_total_vol / ten_buckets[i];
 
 out << " (avg " << avg_ftv * 100.0 << "% of OBB volume)" << std::endl;
 }
 }
 }
};
 
/* no longer supported
static std::string make_property_string( DagMC& dag, EntityHandle eh, std::vector<std::string>
&properties )
{
 ErrorCode ret;
 std::string propstring;
 for( std::vector<std::string>::iterator p = properties.begin();
 p != properties.end(); ++p )
 {
 if( dag.has_prop( eh, *p ) ){
 std::vector< std::string> vals;
 ret = dag.prop_values( eh, *p, vals );
 CHECKERR(dag,ret);
 propstring += *p;
 if( vals.size() == 1 ){
 propstring += "=";
 propstring += vals[0];
 }
 else if( vals.size() > 1 ){
 // this property has multiple values, list within brackets
 propstring += "=[";
 for( std::vector<std::string>::iterator i = vals.begin();
 i != vals.end(); ++i )
 {
 propstring += *i;
 propstring += ",";
 }
 // replace the last trailing comma with a close braket
 propstring[ propstring.length()-1 ] = ']';
 }
 propstring += ", ";
 }
 }
 if( propstring.length() ){
 propstring.resize( propstring.length() - 2 ); // drop trailing comma
 }
 return propstring;
}
*/
 
ErrorCode obbstat_write( GeomTopoTool& gtt,
 std::vector< int >& volumes,
 std::vector< std::string >& properties,
 std::ostream& out )
{
 
 ErrorCode ret = MB_SUCCESS;
 OrientedBoxTreeTool& obbtool = *gtt.obb_tree();
 
 // can assume that volume numbers are valid.
 for( std::vector< int >::iterator i = volumes.begin(); i != volumes.end(); ++i )
 {
 EntityHandle vol_root;
 EntityHandle vol = gtt.entity_by_id( 3, *i );
 CHECKERR( gtt, ret );
 
 if( vol == 0 )
 {
 std::cerr << "ERROR: volume " << *i << " has no entity." << std::endl;
 continue;
 }
 
 ret = gtt.get_root( vol, vol_root );
 CHECKERR( gtt, ret );
 
 out << "\nVolume " << *i << " " << std::flush;
 
 if( gtt.is_implicit_complement( vol ) ) out << "(implicit complement) ";
 out << std::endl;
 
 // get all surfaces in volume
 Range surfs;
 ret = gtt.get_moab_instance()->get_child_meshsets( vol, surfs );
 CHECKERR( gtt, ret );
 
 out << " with " << surfs.size() << " surfaces" << std::endl;
 
 TriStats ts( gtt.get_moab_instance(), &obbtool, vol_root );
 ret = obbtool.preorder_traverse( vol_root, ts );
 CHECKERR( gtt, ret );
 ts.write_results( out );
 
 if( verbose )
 {
 out << "Surface list: " << std::flush;
 for( Range::iterator j = surfs.begin(); j != surfs.end(); ++j )
 {
 out << gtt.global_id( *j );
 if( j + 1 != surfs.end() ) out << ",";
 }
 out << std::endl;
 ret = obbtool.stats( vol_root, out );
 CHECKERR( gtt, ret );
 }
 
 out << "\n ------------ " << std::endl;
 }
 
 return ret;
}