couldn't get the picture like the Readme

[zhhezhhe]

When I run the main.py I couldn't got the picture. I just get the picture like

And I got the waring

WARNING: QOpenGLContext::swapBuffers() called with non-exposed window, behavior is undefined
WARNING: QOpenGLContext::swapBuffers() called with non-exposed window, behavior is undefined
/Users/zhenghe01/codes/vertex_visibility/depth.py:274: RuntimeWarning: invalid value encountered in less_equal
  visible_verts = depths <= dimg_depths + bias
/usr/local/lib/python2.7/site-packages/numpy/core/_methods.py:32: RuntimeWarning: invalid value encountered in reduce
  return umr_minimum(a, axis, None, out, keepdims, initial)
/usr/local/lib/python2.7/site-packages/numpy/core/_methods.py:28: RuntimeWarning: invalid value encountered in reduce
  return umr_maximum(a, axis, None, out, keepdims, initial)

[julienr]

Does vispy itself work ? Did you try some of the vispy examples ?