Program Listing for File IfcGeomRepresentation.h¶
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#ifndef IFCGEOMREPRESENTATION_H
#define IFCGEOMREPRESENTATION_H
#include <BRepMesh_IncrementalMesh.hxx>
#include <BRepGProp_Face.hxx>
#include <Poly_Triangulation.hxx>
#include <TColgp_Array1OfPnt.hxx>
#include <TColgp_Array1OfPnt2d.hxx>
#include <TopoDS.hxx>
#include <BRepTools.hxx>
#include <TopExp_Explorer.hxx>
#include <BRepAdaptor_Curve.hxx>
#include <GCPnts_QuasiUniformDeflection.hxx>
#include <Geom_SphericalSurface.hxx>
#include "../ifcgeom/IfcGeomIteratorSettings.h"
#include "../ifcgeom_schema_agnostic/IfcGeomMaterial.h"
#include "../ifcgeom/IfcRepresentationShapeItem.h"
#include <TopoDS_Compound.hxx>
namespace IfcGeom {
namespace Representation {
class IFC_GEOM_API Representation {
Representation(const Representation&); //N/A
Representation& operator =(const Representation&); //N/A
protected:
const ElementSettings settings_;
public:
explicit Representation(const ElementSettings& settings)
: settings_(settings)
{}
const ElementSettings& settings() const { return settings_; }
virtual ~Representation() {}
};
class IFC_GEOM_API BRep : public Representation {
private:
std::string id_;
const IfcGeom::IfcRepresentationShapeItems shapes_;
BRep(const BRep& other);
BRep& operator=(const BRep& other);
public:
BRep(const ElementSettings& settings, const std::string& id, const IfcGeom::IfcRepresentationShapeItems& shapes)
: Representation(settings)
, id_(id)
, shapes_(shapes)
{}
virtual ~BRep() {}
IfcGeom::IfcRepresentationShapeItems::const_iterator begin() const { return shapes_.begin(); }
IfcGeom::IfcRepresentationShapeItems::const_iterator end() const { return shapes_.end(); }
const IfcGeom::IfcRepresentationShapeItems& shapes() const { return shapes_; }
const std::string& id() const { return id_; }
TopoDS_Compound as_compound(bool force_meters = false) const;
bool calculate_volume(double&) const;
bool calculate_surface_area(double&) const;
bool calculate_projected_surface_area(const gp_Ax3& ax, double& along_x, double& along_y, double& along_z) const;
};
class IFC_GEOM_API Serialization : public Representation {
private:
std::string id_;
std::string brep_data_;
std::vector<double> surface_styles_;
public:
const std::string& brep_data() const { return brep_data_; }
const std::vector<double>& surface_styles() const { return surface_styles_; }
Serialization(const BRep& brep);
virtual ~Serialization() {}
const std::string& id() const { return id_; }
private:
Serialization();
Serialization(const Serialization&);
Serialization& operator=(const Serialization&);
};
template <typename P>
class Triangulation : public Representation {
private:
// A nested pair of floats and a material index to be able to store an XYZ coordinate in a map.
// TODO: Make this a std::tuple when compilers add support for that.
typedef typename std::pair<P, std::pair<P, P> > Coordinate;
typedef typename std::pair<int, Coordinate> VertexKey;
typedef std::map<VertexKey, int> VertexKeyMap;
typedef std::pair<int, int> Edge;
std::string id_;
std::vector<P> _verts;
std::vector<int> _faces;
std::vector<int> _edges;
std::vector<P> _normals;
std::vector<P> uvs_;
std::vector<int> _material_ids;
std::vector<Material> _materials;
size_t weld_offset_;
VertexKeyMap welds;
public:
const std::string& id() const { return id_; }
const std::vector<P>& verts() const { return _verts; }
const std::vector<int>& faces() const { return _faces; }
const std::vector<int>& edges() const { return _edges; }
const std::vector<P>& normals() const { return _normals; }
const std::vector<P>& uvs() const { return uvs_; }
const std::vector<int>& material_ids() const { return _material_ids; }
const std::vector<Material>& materials() const { return _materials; }
Triangulation(const BRep& shape_model)
: Representation(shape_model.settings())
, id_(shape_model.id())
, weld_offset_(0)
{
for ( IfcGeom::IfcRepresentationShapeItems::const_iterator iit = shape_model.begin(); iit != shape_model.end(); ++ iit ) {
// Don't weld vertices that belong to different items to prevent non-manifold situations.
weld_offset_ += welds.size();
welds.clear();
int surface_style_id = -1;
if (iit->hasStyle()) {
Material adapter(&iit->Style());
std::vector<Material>::const_iterator jt = std::find(_materials.begin(), _materials.end(), adapter);
if (jt == _materials.end()) {
surface_style_id = (int)_materials.size();
_materials.push_back(adapter);
} else {
surface_style_id = (int)(jt - _materials.begin());
}
}
if (settings().get(IteratorSettings::APPLY_DEFAULT_MATERIALS) && surface_style_id == -1) {
Material material(IfcGeom::get_default_style(settings().element_type()));
std::vector<Material>::const_iterator mit = std::find(_materials.begin(), _materials.end(), material);
if (mit == _materials.end()) {
surface_style_id = (int)_materials.size();
_materials.push_back(material);
} else {
surface_style_id = (int)(mit - _materials.begin());
}
}
const TopoDS_Shape& s = iit->Shape();
const gp_GTrsf& trsf = iit->Placement();
// Triangulate the shape
try {
BRepMesh_IncrementalMesh(s, settings().deflection_tolerance(), false, settings().angular_tolerance());
} catch(...) {
Logger::Message(Logger::LOG_ERROR, "Failed to triangulate shape");
continue;
}
// Iterates over the faces of the shape
int num_faces = 0;
TopExp_Explorer exp;
for ( exp.Init(s,TopAbs_FACE); exp.More(); exp.Next(), ++num_faces ) {
TopoDS_Face face = TopoDS::Face(exp.Current());
TopLoc_Location loc;
Handle_Poly_Triangulation tri = BRep_Tool::Triangulation(face,loc);
if (tri.IsNull()) {
Logger::Message(Logger::LOG_ERROR, "Triangulation missing for face");
} else {
// A 3x3 matrix to rotate the vertex normals
const gp_Mat rotation_matrix = trsf.VectorialPart();
// Keep track of the number of times an edge is used
// Manifold edges (i.e. edges used twice) are deemed invisible
std::map<std::pair<int,int>,int> edgecount;
std::vector<std::pair<int,int> > edges_temp;
const TColgp_Array1OfPnt& nodes = tri->Nodes();
const TColgp_Array1OfPnt2d& uvs = tri->UVNodes();
std::vector<gp_XYZ> coords;
BRepGProp_Face prop(face);
std::map<int,int> dict;
// Vertex normals are only calculated if vertices are not welded and calculation is not disable explicitly.
const bool calculate_normals = !settings().get(IteratorSettings::WELD_VERTICES) &&
!settings().get(IteratorSettings::NO_NORMALS);
for( int i = 1; i <= nodes.Length(); ++ i ) {
coords.push_back(nodes(i).Transformed(loc).XYZ());
trsf.Transforms(*coords.rbegin());
dict[i] = addVertex(surface_style_id, *coords.rbegin());
if ( calculate_normals ) {
const gp_Pnt2d& uv = uvs(i);
gp_Pnt p;
gp_Vec normal_direction;
prop.Normal(uv.X(),uv.Y(),p,normal_direction);
gp_Vec normal(0., 0., 0.);
if (normal_direction.Magnitude() > 1.e-9) {
normal = gp_Dir(normal_direction.XYZ() * rotation_matrix);
} else {
Handle_Geom_Surface surf = BRep_Tool::Surface(face);
// Special case the normal at the poles of a spherical surface
if (surf->DynamicType() == STANDARD_TYPE(Geom_SphericalSurface)) {
if (fabs(fabs(uv.Y()) - M_PI / 2.) < 1.e-9) {
const bool is_top = uv.Y() > 0;
const bool is_forward = face.Orientation() == TopAbs_FORWARD;
const double z = (is_top == is_forward) ? 1. : -1.;
normal = gp_Dir(gp_XYZ(0, 0, z) * rotation_matrix);
}
}
// TODO: Do the same for conical surfaces, but they are rare in IFC.
}
_normals.push_back(static_cast<P>(normal.X()));
_normals.push_back(static_cast<P>(normal.Y()));
_normals.push_back(static_cast<P>(normal.Z()));
}
}
const Poly_Array1OfTriangle& triangles = tri->Triangles();
for( int i = 1; i <= triangles.Length(); ++ i ) {
int n1,n2,n3;
if ( face.Orientation() == TopAbs_REVERSED )
triangles(i).Get(n3,n2,n1);
else triangles(i).Get(n1,n2,n3);
/* An alternative would be to calculate normals based
* on the coordinates of the mesh vertices */
/*
const gp_XYZ pt1 = coords[n1-1];
const gp_XYZ pt2 = coords[n2-1];
const gp_XYZ pt3 = coords[n3-1];
const gp_XYZ v1 = pt2-pt1;
const gp_XYZ v2 = pt3-pt2;
gp_Dir normal = gp_Dir(v1^v2);
_normals.push_back((float)normal.X());
_normals.push_back((float)normal.Y());
_normals.push_back((float)normal.Z());
*/
_faces.push_back(dict[n1]);
_faces.push_back(dict[n2]);
_faces.push_back(dict[n3]);
_material_ids.push_back(surface_style_id);
addEdge(dict[n1], dict[n2], edgecount, edges_temp);
addEdge(dict[n2], dict[n3], edgecount, edges_temp);
addEdge(dict[n3], dict[n1], edgecount, edges_temp);
}
for ( std::vector<std::pair<int,int> >::const_iterator jt = edges_temp.begin(); jt != edges_temp.end(); ++jt ) {
if (edgecount[*jt] == 1) {
// non manifold edge, face boundary
_edges.push_back(jt->first);
_edges.push_back(jt->second);
}
}
}
}
if (!_normals.empty() && settings().get(IfcGeom::IteratorSettings::GENERATE_UVS)) {
uvs_ = box_project_uvs(_verts, _normals);
}
if (num_faces == 0) {
// Edges are only emitted if there are no faces. A mixed representation of faces
// and loose edges is discouraged by the standard. An alternative would be to use
// TopExp_Explorer texp(s, TopAbs_EDGE, TopAbs_FACE) to find edges that do not
// belong to any face.
for (TopExp_Explorer texp(s, TopAbs_EDGE); texp.More(); texp.Next()) {
BRepAdaptor_Curve crv(TopoDS::Edge(texp.Current()));
GCPnts_QuasiUniformDeflection tessellater(crv, settings().deflection_tolerance());
int n = tessellater.NbPoints();
int previous = -1;
for (int i = 1; i <= n; ++i) {
gp_XYZ p = tessellater.Value(i).XYZ();
int current = addVertex(surface_style_id, p);
std::vector<std::pair<int, int>> segments;
if (i > 1) {
segments.push_back(std::make_pair(previous, current));
}
if (settings().get(IfcGeom::IteratorSettings::EDGE_ARROWS)) {
// In case you want direction arrows on your edges
double u = tessellater.Parameter(i);
gp_XYZ p2, p3;
gp_Pnt tmp;
gp_Vec tmp2;
crv.D1(u, tmp, tmp2);
gp_Dir d1, d2, d3, d4;
d1 = tmp2;
if (texp.Current().Orientation() == TopAbs_REVERSED) {
d1 = -d1;
}
if (fabs(d1.Z()) < 0.5) {
d2 = d1.Crossed(gp::DZ());
} else {
d2 = d1.Crossed(gp::DY());
}
d3 = d1.XYZ() + d2.XYZ();
d4 = d1.XYZ() - d2.XYZ();
p2 = p - d3.XYZ() / 10.;
p3 = p - d4.XYZ() / 10.;
trsf.Transforms(p2);
trsf.Transforms(p3);
trsf.Transforms(p);
int left = addVertex(surface_style_id, p2);
int right = addVertex(surface_style_id, p3);
segments.push_back(std::make_pair(left, current));
segments.push_back(std::make_pair(right, current));
}
for (auto& s : segments) {
_edges.push_back(s.first);
_edges.push_back(s.second);
_material_ids.push_back(surface_style_id);
}
previous = current;
}
}
}
BRepTools::Clean(s);
}
}
virtual ~Triangulation() {}
static std::vector<P> box_project_uvs(const std::vector<P> &vertices, const std::vector<P> &normals)
{
std::vector<P> uvs;
uvs.resize(vertices.size() / 3 * 2);
for (size_t uv_idx = 0, v_idx = 0;
uv_idx < uvs.size() && v_idx < vertices.size() && v_idx < normals.size();
uv_idx += 2, v_idx += 3) {
P n_x = normals[v_idx], n_y = normals[v_idx + 1], n_z = normals[v_idx + 2];
P v_x = vertices[v_idx], v_y = vertices[v_idx + 1], v_z = vertices[v_idx + 2];
if (std::abs(n_x) > std::abs(n_y) && std::abs(n_x) > std::abs(n_z)) {
uvs[uv_idx] = v_z;
uvs[uv_idx + 1] = v_y;
}
if (std::abs(n_y) > std::abs(n_x) && std::abs(n_y) > std::abs(n_z)) {
uvs[uv_idx] = v_x;
uvs[uv_idx + 1] = v_z;
}
if (std::abs(n_z) > std::abs(n_x) && std::abs(n_z) > std::abs(n_y)) {
uvs[uv_idx] = v_x;
uvs[uv_idx + 1] = v_y;
}
}
return uvs;
}
private:
// Welds vertices that belong to different faces
int addVertex(int material_index, const gp_XYZ& p) {
const bool convert = settings().get(IteratorSettings::CONVERT_BACK_UNITS);
const P X = static_cast<P>(convert ? (p.X() / settings().unit_magnitude()) : p.X());
const P Y = static_cast<P>(convert ? (p.Y() / settings().unit_magnitude()) : p.Y());
const P Z = static_cast<P>(convert ? (p.Z() / settings().unit_magnitude()) : p.Z());
int i = (int) _verts.size() / 3;
if (settings().get(IteratorSettings::WELD_VERTICES)) {
const VertexKey key = std::make_pair(material_index, std::make_pair(X, std::make_pair(Y, Z)));
typename VertexKeyMap::const_iterator it = welds.find(key);
if ( it != welds.end() ) return it->second;
i = (int) welds.size() + weld_offset_;
welds[key] = i;
}
_verts.push_back(X);
_verts.push_back(Y);
_verts.push_back(Z);
return i;
}
inline void addEdge(int n1, int n2, std::map<std::pair<int,int>,int>& edgecount, std::vector<std::pair<int,int> >& edges_temp) {
const Edge e = Edge( (std::min)(n1,n2),(std::max)(n1,n2) );
if ( edgecount.find(e) == edgecount.end() ) edgecount[e] = 1;
else edgecount[e] ++;
edges_temp.push_back(e);
}
Triangulation();
Triangulation(const Triangulation&);
Triangulation& operator=(const Triangulation&);
};
}
}
#endif