QT 5.4 OpenGL aliasing problem

[ed3D]

What QSurfaceFormat setting do I need to set to prevent aliasing?

Currently I'm using:

fmt.setProfile(QSurfaceFormat::CoreProfile);
fmt.setOption(QSurfaceFormat::StereoBuffers);
fmt.setRenderableType( QSurfaceFormat::OpenGL );

fmt.setSamples(4);

[timday]

I certainly notice a difference in my apps between fmt.setSamples(1) and fmt.setSamples(16), at least for whether polygon edges appear "jaggy" or not. What GPU HW are you using? Got screenshots?

[ed3D]

How do I post a screen shot?

Another name for the problems maybe Z fighting.

GPU HW is Quadro 5000.

[timday]

Z-fighting is a completely different issue from aliasing. Maybe you need to set/check/increase the QSurfaceFormat::depthSize property (I've no idea what the default is).

If your z-buffer precision is as good as it can be, glPolygonOffset and/or controlling draw-order are next lines of defence against z-fighting.

I seem to remember the old forum allowed image upload; but maybe I'm thinking of the Jira (bugtracker). The markdown formatting here would let you link to a URL hosted elsewhere though (and maybe include it inline).