[osg-users] [Compute Program executed on useprogram :/?!]

[Julien Valentin]

Hi Robert 
If I don't misunderstood:
Using a dedicated class for CS would introducing a new base class "Dispatchable" for Drawable(vas) and DispatchCompute(no vas) that would replace Drawable as Renderleaf.
Is that what you think about? 

Cheers


robertosfield wrote:
> Hi Julien,
> 
> The Compute shader work is a submission I merged from the community, I
> clearly didn't think deeply enough about the submission when I merged
> it though, as in hindisight having the glDispatchCompute directly
> coupled with the useProgram is wrong - on several different counts.
> 
> The correct way to do it would be to have some explictly mechanism for
> calling the dispatch compute, either as a draw callback as you later
> suggest, or as a osg::Drawable or osg::StateAttribute it it's own
> right.  I will need to reflect more on the issue but my first thought
> is that glDispatchCompute is a bit similar to glDrawArrays/Elements in
> that it's the point when you have stopped configure state (input data)
> and now want to GPU to do some direct work.   Given this similarity a
> drawable association or some kind seems most appropriate.  It might be
> the the numGroupsX,Y and Z should be moved out of osg::Program as well
> - which pushes us towards having a dedicated osg::DispatchCompute
> class.
> 
> Robert.
> 
> On 18 November 2017 at 01:31, Julien Valentin
> <> wrote:
> 
> > Hi all
> > I ran into some strange behavior debuging an app: It appears that compute shader are executed at each pcp.useprogram() call...
> > I don't think it's a correct behavior since uniforms requires the po to be bound before to be set...
> > It yield an undefined behavior in GLObjectVisitor when compute prog are executed whithout their uniforms setted  (and the same problem should also appears in State::apply)
> > 
> > I'm gonna pr a patch in order remove dispatchprogram from useprogram and add a if(computeshader)dispatch at the end of state::apply but would like Robert insight about it
> > 
> > Thank you!
> > 
> > Cheers,
> > Julien
> > 
> > ------------------
> > Read this topic online here:
> > http://forum.openscenegraph.org/viewtopic.php?p=72404#72404
> > 
> > 
> > 
> > 
> > 
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Read this topic online here:
http://forum.openscenegraph.org/viewtopic.php?p=72457#72457