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 Mike Kremer committed Jun 05, 2009 1 /** \page tutorial_01 First Steps - Building a cude  Jan Möbius committed Feb 06, 2009 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63  This small example shows: \li How to declare your type \c MyMesh, \li How to add vertices and faces to a mesh, \li How to write a mesh using the IO functions. For each program the first step is to define your type \c MyMesh. %OpenMesh supports general polygonal meshes (faces are polygons with varying number of vertices) as well as specialized triangle meshes (all faces are triangles). In this example we want to build a cube from six quadrangles, therefore we choose the polygonal mesh. %OpenMesh also supports different mesh kernels, specifying how all the vertices, edges, and faces are stored internally (see also \ref mesh_kernels_group). However, the storage must provide an array like interface. For the tutorial we use the supplied ArrayKernel. The predefined combinations of TriMesh/PolyMesh and the kernel are contained in \c %OpenMesh/Core/Mesh/Types/, we use the PolyMesh_ArrayKernelT. \dontinclude build_cube.cc \skipline PolyMesh_ArrayKernel \skipline MyMesh Now since we have declared our type \c MyMesh, we only have to add 8 vertices and 6 quadrangles to build a cube. Adding a vertex is done using the add_vertex method. It gets a coordinate and returns a handle to the inserted vertex. We store all handles in an array, since we need them for specifying the faces. \skipline vhandle[0] \until vhandle[3]
In order to add a face to the mesh, we have to build a vector holding the handles to the face's vertices. This vector is passed to the \c add_face method. The following block will create a face from the first four vertices: \skipline face_vhandles \until add_face
The orientation of the face is defined by the order in which the vertices are given: If you look at the frontfacing side of the polygon, then the vertices are in counter-clockwise order. After creating all of the six faces, we want to write the resulting mesh to standard output. %OpenMesh provides some basic input/output methods in the namespace OpenMesh::IO: \skipline write_
To use the IO facility of %OpenMesh make sure that the include MeshIO.hh is included first. \dontinclude build_cube.cc \skipline MeshIO \until PolyMesh_ArrayKernel
The complete source looks like this: \include build_cube.cc  Mike Kremer committed Jun 05, 2009 64 **/