DGtal  1.5.beta
geometry/volumes/digitalPolyhedronBuilder3D.cpp

This example shows how to use the fully convex envelope to build a digital polyhedron from an arbitrary mesh. It uses DigitalConvexity::envelope for computations.

Digital polyhedra

For instance, you may call it on object "spot.obj" as

digitalPolyhedronBuilder3D ../examples/samples/spot.obj 0.005 7


The last parameter specifies whether you want to see vertices (1), edges (2) and faces (4), or any combination.

 Digital polyhedral model of 'spot.obj' at gridstep 0.005 Digital polyhedral model of 'spot.obj' at gridstep 0.005 (vertices and edges only)
namespace DGtal {
} // namespace DGtal {
#include <iostream>
#include <queue>
#include "DGtal/base/Common.h"
#include "DGtal/helpers/StdDefs.h"
#include "DGtal/io/viewers/Viewer3D.h"
#include "DGtal/shapes/Shapes.h"
#include "DGtal/shapes/SurfaceMesh.h"
#include "DGtal/geometry/volumes/DigitalConvexity.h"
#include "ConfigExamples.h"
using namespace std;
using namespace DGtal;
typedef Z3i::Space Space;
typedef Z3i::SCell SCell;
typedef std::vector<Point> PointRange;
int main( int argc, char** argv )
{
trace.info() << "Usage: " << argv[ 0 ] << " <input.obj> <h> <view>" << std::endl;
trace.info() << "\tComputes a digital polyhedron from an OBJ file" << std::endl;
trace.info() << "\t- input.obj: choose your favorite mesh" << std::endl;
trace.info() << "\t- h [==1]: the digitization gridstep" << std::endl;
trace.info() << "\t- view [==7]: display vertices(1), edges(2), faces(4)" << std::endl;
string filename = examplesPath + "samples/lion.obj";
std::string fn = argc > 1 ? argv[ 1 ] : filename; //< vol filename
double h = argc > 2 ? atof( argv[ 2 ] ) : 1.0;
int view = argc > 3 ? atoi( argv[ 3 ] ) : 7;
std::ifstream input( fn.c_str() );
if ( ! ok )
{
trace.error() << "Unable to read obj file : " << fn << std::endl;
return 1;
}
QApplication application(argc,argv);
typedef Viewer3D<Space,KSpace> MViewer;
MViewer viewer;
viewer.setWindowTitle("digitalPolyhedronBuilder3D");
viewer.show();
Point lo(-500,-500,-500);
Point up(500,500,500);
DigitalConvexity< KSpace > dconv( lo, up );
auto vertices = std::vector<Point>( surfmesh.nbVertices() );
for ( auto v : surfmesh )
{
RealPoint p = (1.0 / h) * surfmesh.position( v );
Point q ( (Integer) round( p[ 0 ] ),
(Integer) round( p[ 1 ] ),
(Integer) round( p[ 2 ] ) );
vertices[ v ] = q;
}
std::set< Point > faces_set, edges_set;
auto faceVertices = surfmesh.allIncidentVertices();
auto edgeVertices = surfmesh.allEdgeVertices();
trace.beginBlock( "Computing polyhedron" );
for ( int f = 0; f < surfmesh.nbFaces(); ++f )
{
for ( auto v : faceVertices[ f ] )
X.push_back( vertices[ v ] );
auto F = dconv.envelope( X, Algorithm::DIRECT );
faces_set.insert( F.cbegin(), F.cend() );
}
for ( int e = 0; e < surfmesh.nbEdges(); ++e )
{
{ vertices[ edgeVertices[ e ].first ],
vertices[ edgeVertices[ e ].second ] };
auto E = dconv.envelope( X, Algorithm::DIRECT );
edges_set.insert( E.cbegin(), E.cend() );
}
std::vector< Point > face_points, edge_points;
std::vector< Point > vertex_points = vertices;
std::sort( vertex_points.begin(), vertex_points.end() );
std::set_difference( faces_set.cbegin(), faces_set.cend(),
edges_set.cbegin(), edges_set.cend(),
std::back_inserter( face_points ) );
std::set_difference( edges_set.cbegin(), edges_set.cend(),
vertex_points.cbegin(), vertex_points.cend(),
std::back_inserter( edge_points ) );
auto total = vertex_points.size() + edge_points.size() + face_points.size();
trace.info() << "#vertex points=" << vertex_points.size() << std::endl;
trace.info() << "#edge points=" << edge_points.size() << std::endl;
trace.info() << "#face points=" << face_points.size() << std::endl;
trace.info() << "#total points=" << total << std::endl;
// display everything
Color colors[] = { Color::Black, Color( 100, 100, 100 ), Color( 200, 200, 200 ) };
if ( view & 0x1 )
{
viewer.setLineColor( colors[ 0 ] );
viewer.setFillColor( colors[ 0 ] );
for ( auto p : vertices ) viewer << p;
}
if ( view & 0x2 )
{
viewer.setLineColor( colors[ 1 ] );
viewer.setFillColor( colors[ 1 ] );
for ( auto p : edge_points ) viewer << p;
}
if ( view & 0x4 )
{
viewer.setLineColor( colors[ 2 ] );
viewer.setFillColor( colors[ 2 ] );
for ( auto p : face_points ) viewer << p;
}
viewer << MViewer::updateDisplay;
return application.exec();
}
// //
PointRange envelope(const PointRange &Z, EnvelopeAlgorithm algo=EnvelopeAlgorithm::DIRECT) const
std::ostream & error()
void beginBlock(const std::string &keyword="")
std::ostream & info()
double endBlock()
SurfMesh surfmesh
Z3i::SCell SCell
std::vector< Point > PointRange
Space::RealVector RealVector
DigitalPlane::Point Vector
Point::Coordinate Integer
DGtal is the top-level namespace which contains all DGtal functions and types.
Trace trace
Definition: Common.h:153
std::pair< typename graph_traits< DGtal::DigitalSurface< TDigitalSurfaceContainer > >::vertex_iterator, typename graph_traits< DGtal::DigitalSurface< TDigitalSurfaceContainer > >::vertex_iterator > vertices(const DGtal::DigitalSurface< TDigitalSurfaceContainer > &digSurf)
Aim: Represents an embedded mesh as faces and a list of vertices. Vertices may be shared among faces ...
Definition: SurfaceMesh.h:92
int main(int argc, char **argv)
MyPointD Point
Definition: testClone2.cpp:383
HyperRectDomain< Space > Domain
PointVector< 3, double > RealPoint