Added sample to show how to save in PLY a given PerVertex or PerFace attribute

apps/sample/sample.pro

@@ -2,6 +2,7 @@
 TEMPLATE      = subdirs
 SUBDIRS       = trimesh_allocate \
                 trimesh_attribute \
+                trimesh_attribute_saving \
                 trimesh_ball_pivoting \
                 trimesh_base  \
                 trimesh_closest \

apps/sample/trimesh_attribute_saving/trimesh_attribute_saving.cpp

@@ -0,0 +1,70 @@
+/****************************************************************************
+* VCGLib                                                            o o     *
+* Visual and Computer Graphics Library                            o     o   *
+*                                                                _   O  _   *
+* Copyright(C) 2004-2016                                           \/)\/    *
+* Visual Computing Lab                                            /\/|      *
+* ISTI - Italian National Research Council                           |      *
+*                                                                    \      *
+* All rights reserved.                                                      *
+*                                                                           *
+* This program is free software; you can redistribute it and/or modify      *
+* it under the terms of the GNU General Public License as published by      *
+* the Free Software Foundation; either version 2 of the License, or         *
+* (at your option) any later version.                                       *
+*                                                                           *
+* This program is distributed in the hope that it will be useful,           *
+* but WITHOUT ANY WARRANTY; without even the implied warranty of            *
+* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the             *
+* GNU General Public License (http://www.gnu.org/licenses/gpl.txt)          *
+* for more details.                                                         *
+*                                                                           *
+****************************************************************************/
+/*! \file trimesh_attribute.cpp
+\ingroup code_sample
+
+\brief the minimal example of using the attributes
+
+Attributes are a simple mechanism to associate user-defined 'attributes' to the simplicies and to the mesh.
+See the page '\ref attributes' for more details.
+*/
+
+#include<vcg/complex/complex.h>
+#include<vcg/complex/algorithms/create/platonic.h>
+#include<wrap/io_trimesh/export_ply.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, vcg::vertex::BitFlags>{};
+class MyFace    : public vcg::Face< MyUsedTypes, vcg::face::VertexRef, vcg::face::Normal3f, vcg::face::BitFlags> {};
+
+class MyMesh : public vcg::tri::TriMesh< std::vector<MyVertex>, std::vector<MyFace> > {};
+int main()
+{
+  MyMesh m;
+  Torus<MyMesh>(m, 3.0f, 1.0f);
+  //! [Adding an attribute]
+  // add a per-vertex attribute with type float named "GaussianCurvature"
+  MyMesh::PerVertexAttributeHandle<float> 
+      hv = vcg::tri::Allocator<MyMesh>:: GetPerVertexAttribute<float> (m,std::string("GaussianCurvature"));
+  // add a per-face attribute with type float named "FaceArea"
+  MyMesh::PerFaceAttributeHandle<float> 
+      hf = vcg::tri::Allocator<MyMesh>:: GetPerFaceAttribute<float> (m,std::string("FaceArea"));
+  //! [filling the attribute]
+  vcg::tri::Allocator<MyMesh>::ClearPerVertexAttribute<float>(m,hv, float(M_PI*2));
+  
+  ForEachFace(m, [&](MyFace &f){
+    hf[&f]=vcg::DoubleArea(f)*0.5f;
+    for(int i=0;i<3;++i)
+      hv[f.V(i)] -= vcg::Angle(f.P1(i)-f.P0(i),f.P2(i)-f.P0(i)); 
+  }); 
+  
+  //! [Saving two attributes in ply, one of the two disguised as quality]
+  vcg::tri::io::PlyInfo pi;
+  pi.AddPerVertexFloatAttribute("GaussianCurvature","quality");
+  pi.AddPerFaceFloatAttribute("FaceArea");
+  vcg::tri::io::ExporterPLY<MyMesh>::Save(m,"MeshWithCurvature.ply",true,pi);     
+}

apps/sample/trimesh_attribute_saving/trimesh_attribute_saving.pro

@@ -0,0 +1,3 @@
+include(../common.pri)
+TARGET = trimesh_attribute_saving
+SOURCES += trimesh_attribute_saving.cpp ../../../wrap/ply/plylib.cpp