[vtk-developers] VTK master, Qt 5, and Intel i915 driver on Ubuntu Linux

Marcus D. Hanwell marcus.hanwell at kitware.com
Wed May 14 14:23:35 EDT 2014


Hi,

This is mainly for the archives, and a note to myself to get to the
bottom of this. It appears to be a driver bug with Intel (I am using a
Core i7 laptop with the HD4000 chip, Dell Sputnik 2 laptop). If Qt 5
initializes any kind of context, even to test for capabilities, it
appears that VTK's context creation code fails to obtain an OpenGL
context with a depth buffer.

On the same machine in a different process VTK/ParaView was able to
initialize a valid context and render. In the end, the pragmatic fix
was to move from using QVTKWidget to QVTKWidget2 which makes use of
the QGLWidget as its base class and defers all context creation to Qt.
This was Ubuntu 14.04, I even updated the kernel to 3.15-rc2.

Many hours of little fun debugging, hopefully this will warn others
out there. The same code/application worked flawlessly on Linux with
nVidia binary drivers, and Mac OS X Snow Leopard with nVidia. Even the
sphere source failed, but it was most apparent with errors generated
by the volume renderer as it attempted to read the depth buffer. Even
checking the visual returned claimed a depth buffer with 24 bits, and
enabling the depth test resulted in no errors.

3D rendering is pretty sad without a depth buffer ;-)

Marcus


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