[vtk-developers] Failing test rendering problem

[David Thompson]

Hi Mathieu,

> Also, another track could be investigated, the use of vtkRenderWindow::SetOffScreenRendering remove the need of any Front/Bak buffer fiddling, the image being always accessible. ...
> But we may encounter some problem with the offscreen rendering, (antialiasing? multisampling? i don't know much about it ).

I think you are correct in anticipating trouble. At least on some old platforms (and probably some newer ones, too) offscreen rendering is handled differently by the driver and often as software-only rendering. That would slow down many tests as well as make their results different from what users would see (making them not really test what we want).

However, I know a lot of developers want to be able to run image tests in the background without windows popping up. So I am all for adding it as an option dependent on some environment variable or command-line argument being set. It should not be the default, though.

	David