From 80192d945bbab9f63c5a9b85b0f3d3b3a1ad8079 Mon Sep 17 00:00:00 2001
From: Martin Schultz <Martin.Schultz@rwth-aachen.de>
Date: Wed, 29 Jun 2016 16:58:59 +0200
Subject: [PATCH] added code to write faceTexCoords to obj writer. fixes #25

---
 src/OpenMesh/Core/IO/exporter/BaseExporter.hh | 11 ++++
 src/OpenMesh/Core/IO/exporter/ExporterT.hh    | 32 ++++++++++
 src/OpenMesh/Core/IO/writer/OBJWriter.cc      | 59 ++++++++++++++++---
 src/Unittests/unittests_read_write_OBJ.cc     | 56 ++++++++++++++++++
 4 files changed, 150 insertions(+), 8 deletions(-)

diff --git a/src/OpenMesh/Core/IO/exporter/BaseExporter.hh b/src/OpenMesh/Core/IO/exporter/BaseExporter.hh
index b4717b8d..477d95a1 100644
--- a/src/OpenMesh/Core/IO/exporter/BaseExporter.hh
+++ b/src/OpenMesh/Core/IO/exporter/BaseExporter.hh
@@ -103,12 +103,23 @@ public:
   virtual Vec3f colorf(VertexHandle _vh)    const = 0;
   virtual Vec4f colorAf(VertexHandle _vh)   const = 0;
   virtual Vec2f  texcoord(VertexHandle _vh) const = 0;
+  virtual Vec2f  texcoord(HalfedgeHandle _heh) const = 0;
 
 
   // get face data
   virtual unsigned int
   get_vhandles(FaceHandle _fh,
 	       std::vector<VertexHandle>& _vhandles) const=0;
+  ///
+  /// \brief getHeh returns the HalfEdgeHandle that belongs to the face
+  ///  specified by _fh and has a toVertexHandle that corresponds to _vh.
+  /// \param _fh FaceHandle that is used to search for the half edge handle
+  /// \param _vh to_vertex_handle of the searched heh
+  /// \return HalfEdgeHandle or invalid HalfEdgeHandle if none is found.
+  ///
+  virtual HalfedgeHandle getHeh(FaceHandle _fh, VertexHandle _vh) const = 0;
+  virtual unsigned int
+  get_face_texcoords(std::vector<Vec2f>& _hehandles) const = 0;
   virtual Vec3f  normal(FaceHandle _fh)      const = 0;
   virtual Vec3uc color (FaceHandle _fh)      const = 0;
   virtual Vec4uc colorA(FaceHandle _fh)      const = 0;
diff --git a/src/OpenMesh/Core/IO/exporter/ExporterT.hh b/src/OpenMesh/Core/IO/exporter/ExporterT.hh
index d4276d14..9a9d9b3f 100644
--- a/src/OpenMesh/Core/IO/exporter/ExporterT.hh
+++ b/src/OpenMesh/Core/IO/exporter/ExporterT.hh
@@ -164,6 +164,13 @@ public:
 #endif
   }
 
+  Vec2f  texcoord(HalfedgeHandle _heh) const
+  {
+    return (mesh_.has_halfedge_texcoords2D()
+        ? vector_cast<Vec2f>(mesh_.texcoord2D(_heh))
+        : Vec2f(0.0f, 0.0f));
+  }
+
   // get edge data
 
   Vec3uc color(EdgeHandle _eh)    const
@@ -223,6 +230,31 @@ public:
     return count;
   }
 
+  unsigned int get_face_texcoords(std::vector<Vec2f>& _hehandles) const
+  {
+    unsigned int count(0);
+    _hehandles.clear();
+    for(typename Mesh::CHIter he_it=mesh_.halfedges_begin();
+        he_it != mesh_.halfedges_end(); ++he_it)
+    {
+      _hehandles.push_back(vector_cast<Vec2f>(mesh_.texcoord2D( *he_it)));
+      ++count;
+    }
+
+    return count;
+  }
+
+  HalfedgeHandle getHeh(FaceHandle _fh, VertexHandle _vh) const
+  {
+    typename Mesh::ConstFaceHalfedgeIter fh_it;
+    for(fh_it = mesh_.cfh_iter(_fh); fh_it.is_valid();++fh_it)
+    {
+      if(mesh_.to_vertex_handle(*fh_it) == _vh)
+        return *fh_it;
+    }
+    return *fh_it;
+  }
+
   Vec3f  normal(FaceHandle _fh)   const
   {
     return (mesh_.has_face_normals()
diff --git a/src/OpenMesh/Core/IO/writer/OBJWriter.cc b/src/OpenMesh/Core/IO/writer/OBJWriter.cc
index b1e8838a..d2f22e9a 100644
--- a/src/OpenMesh/Core/IO/writer/OBJWriter.cc
+++ b/src/OpenMesh/Core/IO/writer/OBJWriter.cc
@@ -257,6 +257,42 @@ write(std::ostream& _out, BaseExporter& _be, Options _opt, std::streamsize _prec
   if (useMatrial &&  _opt.check(Options::FaceColor) )
     _out << "mtllib " << objName_ << ".mat" << '\n';
 
+  std::map<Vec2f,int> texMap;
+  //collect Texturevertices from halfedges
+  if(_opt.check(Options::FaceTexCoord))
+  {
+    std::vector<Vec2f> texCoords;
+    //add all texCoords to map
+    unsigned int num = _be.get_face_texcoords(texCoords);
+    for(unsigned int i = 0; i < num ; ++i)
+    {
+      texMap[texCoords[i]] = i;
+    }
+  }
+
+  //collect Texturevertices from vertices
+  if(_opt.check(Options::VertexTexCoord))
+  {
+    for (int i=0, nF=_be.n_faces(); i<nF; ++i)
+    {
+      vh = VertexHandle(int(i));
+      t  = _be.texcoord(vh);
+      texMap[t] = i;
+    }
+  }
+
+  // assign each texcoord in the map its id
+  // and write the vt entries
+  if(_opt.check(Options::VertexTexCoord) || _opt.check(Options::FaceTexCoord))
+  {
+    int texCount = 0;
+    for(std::map<Vec2f,int>::iterator it = texMap.begin(); it != texMap.end() ; ++it)
+    {
+      _out << "vt " << it->first[0] << " " << it->first[1] << '\n';
+      it->second = ++texCount;
+    }
+  }
+
   // vertex data (point, normals, texcoords)
   for (i=0, nV=_be.n_vertices(); i<nV; ++i)
   {
@@ -268,17 +304,15 @@ write(std::ostream& _out, BaseExporter& _be, Options _opt, std::streamsize _prec
     _out << "v " << v[0] <<" "<< v[1] <<" "<< v[2] << '\n';
 
     if (_opt.check(Options::VertexNormal))
-      _out << "vn " << n[0] <<" "<< n[1] <<" "<< n[2] << '\n';
-
-    if (_opt.check(Options::VertexTexCoord))
-      _out << "vt " << t[0] <<" "<< t[1] << '\n';
+      _out << "vn " << n[0] <<" "<< n[1] <<" "<< n[2] << '\n';    
   }
 
   size_t lastMat = std::numeric_limits<std::size_t>::max();
 
   // we do not want to write seperators if we only write vertex indices
   bool onlyVertices =    !_opt.check(Options::VertexTexCoord)
-                      && !_opt.check(Options::VertexNormal);
+                      && !_opt.check(Options::VertexNormal)
+                      && !_opt.check(Options::FaceTexCoord);
 
   // faces (indices starting at 1 not 0)
   for (i=0, nF=_be.n_faces(); i<nF; ++i)
@@ -319,9 +353,18 @@ write(std::ostream& _out, BaseExporter& _be, Options _opt, std::streamsize _prec
         // write separator
         _out << "/" ;
 
-        // write vertex texture coordinate index
-        if (_opt.check(Options::VertexTexCoord))
-          _out  << idx;
+        //write texCoords index from halfedge
+        if(_opt.check(Options::FaceTexCoord))
+        {
+          _out << texMap[_be.texcoord(_be.getHeh(FaceHandle(int(i)),vhandles[j]))];
+        }
+
+        else
+        {
+          // write vertex texture coordinate index
+          if (_opt.check(Options::VertexTexCoord))
+            _out  << texMap[_be.texcoord(vh)];
+        }
 
         // write vertex normal index
         if ( _opt.check(Options::VertexNormal) ) {
diff --git a/src/Unittests/unittests_read_write_OBJ.cc b/src/Unittests/unittests_read_write_OBJ.cc
index 2b502d0f..6d6019fe 100644
--- a/src/Unittests/unittests_read_write_OBJ.cc
+++ b/src/Unittests/unittests_read_write_OBJ.cc
@@ -202,6 +202,62 @@ TEST_F(OpenMeshReadWriteOBJ, LoadSimpleOBJCheckTexCoords) {
   mesh_.release_halfedge_texcoords2D();
 }
 
+/*
+ * Just load and store obj file of a cube and checks the halfedge texCoords
+ */
+TEST_F(OpenMeshReadWriteOBJ, LoadStoreSimpleOBJCheckTexCoords) {
+
+  mesh_.clear();
+
+  mesh_.request_halfedge_texcoords2D();
+
+  OpenMesh::IO::Options options;
+  options += OpenMesh::IO::Options::FaceTexCoord;
+
+  std::string file_name = "cube-minimal-texCoords.obj";
+
+  bool ok = OpenMesh::IO::read_mesh(mesh_, file_name,options);
+
+  EXPECT_TRUE(ok) << file_name;
+
+
+
+  options.clear();
+  options += OpenMesh::IO::Options::FaceTexCoord;
+  bool writeOk = OpenMesh::IO::write_mesh(mesh_,"writeTest.obj",options);
+  EXPECT_TRUE(writeOk) << "writeTest.obj";
+  mesh_.release_halfedge_texcoords2D();
+
+  Mesh loadedMesh_;
+  loadedMesh_.clear();
+
+  loadedMesh_.request_halfedge_texcoords2D();
+
+  options.clear();
+  options += OpenMesh::IO::Options::FaceTexCoord;
+  bool readOk = OpenMesh::IO::read_mesh(loadedMesh_, "writeTest.obj",options);
+  EXPECT_TRUE(readOk) << file_name;
+  EXPECT_EQ(1, loadedMesh_.texcoord2D(mesh_.halfedge_handle(0))[0] ) << "Wrong texCoord at halfedge 0 component 0";
+  EXPECT_EQ(1, loadedMesh_.texcoord2D(mesh_.halfedge_handle(0))[1] ) << "Wrong texCoord at halfedge 0 component 1";
+
+  EXPECT_EQ(3, loadedMesh_.texcoord2D(mesh_.halfedge_handle(10))[0] ) << "Wrong texCoord at halfedge 1 component 0";
+  EXPECT_EQ(3, loadedMesh_.texcoord2D(mesh_.halfedge_handle(10))[1] ) << "Wrong texCoord at halfedge 1 component 1";
+
+  EXPECT_EQ(6, loadedMesh_.texcoord2D(mesh_.halfedge_handle(19))[0] ) << "Wrong texCoord at halfedge 4 component 0";
+  EXPECT_EQ(6, loadedMesh_.texcoord2D(mesh_.halfedge_handle(19))[1] ) << "Wrong texCoord at halfedge 4 component 1";
+
+  EXPECT_EQ(7, loadedMesh_.texcoord2D(mesh_.halfedge_handle(24))[0] ) << "Wrong texCoord at halfedge 7 component 0";
+  EXPECT_EQ(7, loadedMesh_.texcoord2D(mesh_.halfedge_handle(24))[1] ) << "Wrong texCoord at halfedge 7 component 1";
+
+  EXPECT_EQ(9, loadedMesh_.texcoord2D(mesh_.halfedge_handle(30))[0] ) << "Wrong texCoord at halfedge 9 component 0";
+  EXPECT_EQ(9, loadedMesh_.texcoord2D(mesh_.halfedge_handle(30))[1] ) << "Wrong texCoord at halfedge 9 component 1";
+
+  EXPECT_EQ(12, loadedMesh_.texcoord2D(mesh_.halfedge_handle(35))[0] ) << "Wrong texCoord at halfedge 11 component 0";
+  EXPECT_EQ(12, loadedMesh_.texcoord2D(mesh_.halfedge_handle(35))[1] ) << "Wrong texCoord at halfedge 11 component 1";
+
+  loadedMesh_.release_halfedge_texcoords2D();
+}
+
 /*
  * Just load a obj file of a cube and checks the 3d halfedge texCoords
  */
-- 
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