[vtk-developers] Offscreen rendering

[Ken Martin]

OffScreen does not require EGL or Mesa.  You should be able to do offscreen
with any opengl implementation.

When folks mention offscreen, sometimes they mean "rendering without an
xserver" or "rendering on a system without opengl 3.2"  for those cases you
can use EGL or Mesa or OSMesa depending on the issue.

In terms of putting it all into one there is some OpenGL initiative to
support this (I forget the name, gl virtual dispatch maybe) which could
handle it I think. Failing that you can do the test at runtime and then
dynamically load osmesa/mesa etc as needed. Some folks do that. I agree
having it built in and automatically selected would be nice. Not sure how
difficult it is though.



On Sat, Nov 24, 2018 at 2:59 PM Prabhu Ramachandran <prabhu at aero.iitb.ac.in>
wrote:

> On 11/23/18 10:01 AM, Ken Martin wrote:
>
> In vtk master I think the answer for all of those is to call
> OffScreenRenderingOn() prior to the first render.  Or after the first
> render to call
>
> ShowWindow(false)
> UseOffScreenBuffers(true)
>
>
> I see that you've centralized some of the code recently but you still need
> to enable EGL or Mesa at build time, and that can still be a bit tricky,
> right?
>
> Would it at all be possible to support one VTK build that has all the
> possible options available?  i.e. EGL, OSMesa, and the normal backend?  Or
> is that simply impossible to do on all platforms?  Would it make sense to
> bundle OSMesa with VTK?  At least on Linux this would make many things very
> convenient.
>
> Regards,
>
> Prabhu
>


-- 
Ken Martin PhD
Distinguished Engineer
Kitware Inc.
101 East Weaver Street
Carrboro, North Carolina
27510 USA

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