- fixed a bug with OBJReader that prevented the material color to be loaded correctly

- added a corresponding unittest

Thanks for the patch by Karthik Nathan

closes #1473

git-svn-id: http://www.openmesh.org/svnrepo/OpenMesh/trunk@823 fdac6126-5c0c-442c-9429-916003d36597

src/OpenMesh/Core/IO/reader/OBJReader.cc

@@ -574,9 +574,10 @@ read(std::istream& _in, BaseImporter& _bi, Options& _opt)
 
       }
 
-      fh = _bi.add_face(faceVertices);
-
+      // note that add_face can possibly triangulate the faces, which is why we have to
+      // store the current number of faces first
       size_t n_faces = _bi.n_faces();
+      fh = _bi.add_face(faceVertices);
 
       if (!vhandles.empty() && fh.is_valid() )
         _bi.add_face_texcoords(fh, vhandles[0], face_texcoords);

src/Unittests/TestFiles/square_material.mtl

@@ -0,0 +1,4 @@
+newmtl Colored
+Ka 0.500 0.500 0.500
+Kd 0.500 0.500 0.500
+Ks 0.500 0.500 0.500

src/Unittests/TestFiles/square_material.obj

@@ -0,0 +1,13 @@
+mtllib square_material.mtl
+
+v 0.000000 2.000000 0.000000
+v 0.000000 0.000000 0.000000
+v 2.000000 0.000000 0.000000
+v 2.000000 2.000000 0.000000
+vt 0.000000 1.000000 0.000000
+vt 0.000000 0.000000 0.000000
+vt 1.000000 0.000000 0.000000
+vt 1.000000 1.000000 0.000000
+
+usemtl Colored
+f 1/1 2/2 3/3 4/4

src/Unittests/unittests_read_write_OBJ.hh

@@ -185,6 +185,34 @@ TEST_F(OpenMeshReadWriteOBJ, LoadSimpleOBJCheckTexCoords) {
   mesh_.release_halfedge_texcoords2D();
 }
 
+/*
+ * Just load a obj file of a square with a material
+ */
+TEST_F(OpenMeshReadWriteOBJ, LoadObjWithMaterial) {
+
+  mesh_.clear();
+
+  mesh_.request_face_colors();
+
+  OpenMesh::IO::Options options;
+  options += OpenMesh::IO::Options::FaceColor;
+
+  std::string file_name = "square_material.obj";
+
+  bool ok = OpenMesh::IO::read_mesh(mesh_, file_name,options);
+
+  EXPECT_TRUE(ok) << file_name;
+
+  OpenMesh::FaceHandle fh = mesh_.face_handle(mesh_.halfedge_handle(0));
+
+  EXPECT_TRUE(fh.is_valid()) << "fh should be valid";
+
+  EXPECT_EQ(128,   mesh_.color(fh)[0] ) << "Wrong vertex color at vertex 0 component 0";
+  EXPECT_EQ(128,   mesh_.color(fh)[1] ) << "Wrong vertex color at vertex 0 component 1";
+  EXPECT_EQ(128,   mesh_.color(fh)[2] ) << "Wrong vertex color at vertex 0 component 2";
+
+  mesh_.release_face_colors();
+}
 
 /*
  * Just load a obj file of a cube with vertex colors defined directly after the vertex definitions