2017-06-21 11:38 GMT+02:00 Elvis Stansvik <elvst...@gmail.com>: > This may or may not be a Qt issue. > > I'm trying to help the VTK folks narrow down a problem with their new > QVTKOpenGLWidget, which is a newly-introduced QOpenGLWidget-based > class for letting VTK render into a QOpenGLWidget. > > The problem manifests itself as volume renderings not showing up on > Windows machines with Ivy Bridge (e.g HD4000) and Haswell (e.g. > HD4600) Intel GPUs when using the new class. VTKs volume rendering is > done using float textures. > > Volume renderings works fine on the same machines when using "plain" > VTK. This is when VTK itself sets up the OpenGL context (using GLEW I > believe), but apart from that, the rendering pipeline is exactly the > same I think. This is what leads me to believe that the issue is > something specific to QOpenGLWidget, or to how VTK uses it.
I should clarify: I mean the rendering pipeline for volume rendering in VTK is exactly the same when using "plain" (non-Qt) VTK (which works), as when using QVTKOpenGLWidget. The only difference (AFAIK) is in how the OpenGL context is set up (GLEW or QOpenGLWidget). (The VTK issue I linked also has a minimal VTK testcase I wrote, where you can switch between using QVTKOpenGLWidget or plain VTK rendering by passing or not passing a command line parameter). Elvis > > VTK requests a OpenGL 3.2 core context, and through some debugging, > I've verified that VTK is actually getting the context that it is > requesting. > > The issue is reported by me, here at VTKs GitLab: > > https://gitlab.kitware.com/vtk/vtk/issues/17058 > > The report contains some more information, such as the generated > fragment shader that VTKs volume rendering backend is using, and a GL > report from the problematic machine. > > Does this specific issue (float texture rendering not showing up on > these semi-old Intel GPUs) ring a bell to anyone else? > > Many thanks for any tips/pointers/leads on how to debug this. > > I'm really interested in getting this issue in VTK fixed, since > laptops with these GPUs are quite common. It's also affecting recent > versions of ParaView, which has (just like me) recently ported to the > new QVTKOpenGLWidget. > > Elvis _______________________________________________ Interest mailing list Interest@qt-project.org http://lists.qt-project.org/mailman/listinfo/interest
