vcglib/apps/sample/trimesh_allocate/trimesh_allocate.cpp

104 lines
4.3 KiB
C++

/****************************************************************************
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/*! \file trimesh_allocate.cpp
\ingroup code_sample
\brief the minimal example about creating and deleting elements
Attributes are a simple mechanism to associate user-defined 'attributes' to the simplicies and to the mesh.
\ref attributes for more Details
*/
#include<vcg/complex/complex.h>
#include<vcg/complex/algorithms/create/platonic.h>
class MyEdge;
class MyFace;
class MyVertex;
struct MyUsedTypes : public vcg::UsedTypes< vcg::Use<MyVertex> ::AsVertexType,
vcg::Use<MyFace> ::AsFaceType>{};
class MyVertex : public vcg::Vertex< MyUsedTypes, vcg::vertex::Coord3f,vcg::vertex::Normal3f>{};
class MyFace : public vcg::Face< MyUsedTypes, vcg::face::VertexRef, vcg::face::Normal3f> {};
class MyMesh : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> > {};
int main()
{
MyMesh m;
MyMesh::VertexIterator vi = vcg::tri::Allocator<MyMesh>::AddVertices(m,3);
MyMesh::FaceIterator fi = vcg::tri::Allocator<MyMesh>::AddFaces(m,1);
MyMesh::VertexPointer ivp[3];
ivp[0]=&*vi; vi->P()=MyMesh::CoordType ( 0.0, 0.0, 0.0); ++vi;
ivp[1]=&*vi; vi->P()=MyMesh::CoordType ( 1.0, 0.0, 0.0); ++vi;
ivp[2]=&*vi; vi->P()=MyMesh::CoordType ( 0.0, 1.0, 0.0); ++vi;
fi->V(0)=ivp[0];
fi->V(1)=ivp[1];
fi->V(2)=ivp[2];
// a potentially dangerous pointer to a mesh element
MyMesh::FacePointer fp = &m.face[0];
vcg::tri::Allocator<MyMesh>::PointerUpdater<MyMesh::FacePointer> pu;
// now the fp pointer could be no more valid due to eventual re-allocation of the m.face vector.
vcg::tri::Allocator<MyMesh>::AddVertices(m,3);
vcg::tri::Allocator<MyMesh>::AddFaces(m,1,pu);
// check if an update of the pointer is needed and do it.
if(pu.NeedUpdate()) pu.Update(fp);
// Now fill the mesh with an Icosahedron and then delete some faces
vcg::tri::Icosahedron(m);
vcg::tri::Allocator<MyMesh>::DeleteFace(m,m.face[1]);
vcg::tri::Allocator<MyMesh>::DeleteFace(m,m.face[3]);
// If you loop in a mesh with deleted elements you have to skip them!
for(fi = m.face.begin(); fi!=m.face.end(); ++fi )
{
if(!fi->IsD()) // <---- Check added
{
MyMesh::CoordType b = vcg::Barycenter(*fi);
}
}
// WRONG WAY of iterating: FN() != m.face.size() if there are deleted elements
for(int i=0;i<m.FN();++i)
{
if(!fi->IsD())
{
MyMesh::CoordType b = vcg::Barycenter(*fi);
}
}
// To remove the elements marked as deleted use
vcg::tri::Allocator<MyMesh>::CompactFaceVector(m);
vcg::tri::Allocator<MyMesh>::CompactVertexVector(m);
// finally lets copy this mesh onto another one.
MyMesh m2;
vcg::tri::Append<MyMesh,MyMesh>::MeshCopy(m2,m);
}