[vtkusers] Hardware offscreen rendering (and its possible use for the Java wrappers)

[Luke Dodd]

Great.

I think I need to play around a little to see if performance would be
good enough. I implemented offscreen rendering in a pure OpenGL
project and glReadPixels managed to read off a 2048x2048 texture at
about 40fps, but that's on a brand new computer and not actually doing
anything with the data. This leads me to believe I should investigate
a little more...

I'll be in touch.

Best,
Luke Dodd


On 20 October 2011 15:41, Aashish Chaudhary
<aashish.chaudhary at kitware.com> wrote:
> On Thu, Oct 20, 2011 at 10:01 AM, Luke Dodd <luke.dodd at gmail.com> wrote:
>> Hi Aashish,
>>
>>> Quickly looked over your email. Correct me if I am wrong but it seems
>>> like you are looking for render to texture (+alternatives).
>>>
>>
>> That's correct.
>>
>>> It is not hard, the tricky part is to handle variations in OpenGL
>>> versions but it won't be that bad.  I have implemented two variations
>>> of it earlier ( for OpenGL 3.3 (used for deferred shading) and OpenGL
>>> ES (render to texture) ).
>>>
>>
>> Is this code in VTK? I know what I'm attempting to do is possible in
>> theory, I'm trying to avoid writing a whole vtkRenderWindow
>> implementation. It seems like there are bits of code in
>> vtkOpenGLRenderWindow/vtkXOpenGLRenderWindow which set up hardware
>> frame-buffers if Mesa isn't being used. When I turn the offscreen
>> rendering flag on a (blank) window still pops up. Should I attempt to
>> use this, or roll my own solution?
>
> No it is not VTK code yet :( .  I can help you writing implementation
> for this (and then once it is right, can merge to VTK). We can follow
> up on another thread if you are interested.
>
> Best,
>
>
>>
>> Best,
>> Luke Dodd
>>
>
>
>
> --
> | Aashish Chaudhary
> | R&D Engineer
> | Kitware Inc.
> | www.kitware.com
>