[vtk-developers] glxMakeCurrent and Hardware Picking issue

Lisa Sobierajski Avila lisa.avila at kitware.com
Fri Jun 15 01:16:26 EDT 2001

Hello Mark,

At 06:47 PM 6/14/2001, Mark Beall wrote:
>Does the browser window get rendered like any other window (e.g.
>by calling vtkRenderWindow::Render)?
>If so, wouldn't everything work if at the start of rendering,
>the render window saved the old context, set the current context
>to what it wants it to be, then when it is done, changes it
>back to what it was before.

No, this does not work because the renders are actually intermingled. If 
you have three actors in a renderer in a render window, plus you have the 
pipeline browser then when render is called on the render window, actor A 
is rendered, which means the mapper is updates and all connected filters 
are update. Each mapper / filter update causes a render in another window. 
This occurs AFTER the initial render started, and before actor A actually 

>This actually wouldn't solve the hardware picking problem since
>there needs to be a means to not switch contexts, but it does
>seem that it would put the context changes in the right place
>and eliminate the need to check them each time an actor is

There is no way to eliminate the check unless you eliminate the update. We 
can add a special render-but-don't-update mode that won't check or do any 
context switching - that also solves the pick problem (mostly).


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