Color values in OBJ file result in mangled vertex locations

[robonrrd]

Bug found in PyMesh, built from source on Ubuntu 22.04, with Python 3.10.6.

Loading an OBJ file with vertex colors results in mangled vertex locations.

Repro example, using this data in a file named test.obj:

v 1.27705 0.03530 -1.38656 0.943 0.924 0.926                                                                
v 1.28410 0.04127 -1.38629 0.941 0.922 0.924                                                                
v 1.29420 0.03978 -1.38603 0.936 0.917 0.919                                                                
f 1 2 3

Python 3.10.6 (main, Nov  2 2022, 18:53:38) [GCC 11.3.0] on linux
Type "help", "copyright", "credits" or "license" for more information.
>>> import pymesh
>>> m = pymesh.load_mesh('test.obj')
>>> m.vertices
array([[ 1.35424178,  0.03743372, -1.47037116],
       [ 1.36461211,  0.0438576 , -1.47320935],
       [ 1.38269231,  0.0425    , -1.48080128]])
>>> 

Removing the vertex colors (the trailing RGB triplet) allows the mesh to be loaded correctly.

Vertex colors are supported in the OBJ spec, so this is a bug in either PyMesh or a dependency.