title: Python3 pip install vtk: OpenGL2 Error
body: <p>I'm trying to install vtk via pip for Python 3.5.1 under CentOS 7.2. It seems to install and work with the system Python 2.7 instead. I get an OpenGL driver incompatibility error with Python 3. </p>
  
  <p>I must use sudo. My attempts:</p>
  
  <ul>
  <li>sudo /path/to/pip3 install vtk</li>
  <li>sudo /path/to/python3 -m /path/to/pip3 install vtk</li>
  </ul>
  
  <p>When executing a simple cylinder <a href="https://lorensen.github.io/VTKExamples/site/Python/GeometricObjects/CylinderExample/" rel="nofollow noreferrer">example</a> Python 2 works properly. Python 3 error messaage:</p>
  
  <pre><code>ERROR: In /work/standalone-x64-build/VTK-source/Rendering/OpenGL2/vtkShaderProgram.cxx, line 446
  vtkShaderProgram (0x169d500): 0:31(12): error: extension `GL_EXT_gpu_shader4' unsupported in fragment shader
  </code></pre>
  
  <p>glxinfo output:</p>
  
  <pre><code>server glx vendor string: SGI
  server glx version string: 1.4
  client glx vendor string: Mesa Project and SGI
  client glx version string: 1.4
  GLX version: 1.4
  OpenGL vendor string: VMware, Inc.
  OpenGL renderer string: Gallium 0.4 on llvmpipe (LLVM 3.6, 128 bits)
  OpenGL version string: 2.1 Mesa 10.6.5
  OpenGL shading language version string: 1.30
  OpenGL ES profile version string: OpenGL ES 2.0 Mesa 10.6.5
  OpenGL ES profile shading language version string: OpenGL ES GLSL ES 1.0.16
  </code></pre>
  
  <p>I get the same error with Mesa 17.x. Has anyone installed this under Python 3 with success? What version of Mesa and/or llvm is compatible?</p>