[Interest] Problem with float texture rendering in QOpenGLWidget on Ivy Bridge/Haswell Intel GPUs on Windows
viktor.engelmann at qt.io
Wed Jun 21 12:28:38 CEST 2017
Haswell and Ivy Bridge indeed ring a bell here. We have a lot of
WebEngine bug reports that affect these GPUs only.
Can you create a bug report please?
OpenGL 3.2 context raises an eyebrow here, because just yesterday I have
seen a qtdiag output from a Debian 7 machine (2013 isn't THAT long ago)
with mesa 8.0.5, which only supports OpenGL 3.0.
On 21.06.2017 11:38, Elvis Stansvik wrote:
> 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.
> 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
> The issue is reported by me, here at VTKs GitLab:
> 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.
> Interest mailing list
> Interest at qt-project.org
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