[vtk-developers] Why is BuildShaders() continuously being called?

[Ken Martin]

Thanks. I need to make that test more conservative. I'll try making a topic
soon to update it. Probably what it needs is

(actor->GetProperty() && actor->GetProperty()->GetMTime() > ...) ||
(actor->GetTexture() && actor->GetTexture()->GetMTime() > ...) ||

as opposed to the

actor->GetMTime() > ...

line

Thanks
Ken

On Fri, Sep 9, 2016 at 6:20 PM, Milef, Nicholas Boris <milefn at rpi.edu>
wrote:

> Thanks Ken. I was moving a few cone sources around (about 50) with
> SetPosition() and I see that they called Modified() which I'm guessing
> changes MTime? It was mostly for debugging because I can actually get
> around some of this in shaders to avoid going through the rendering
> pipeline. But, there are times when I need to move actors in real time, so
> this can sometimes be a bottleneck for me.
>
> Thanks,
> Nick
> ------------------------------
> *From:* Ken Martin [ken.martin at kitware.com]
> *Sent:* Friday, September 09, 2016 5:58 PM
> *To:* Milef, Nicholas Boris
> *Cc:* vtk-developers at vtk.org
> *Subject:* Re: [vtk-developers] Why is BuildShaders() continuously being
> called?
>
> When  GetNeedToRebuildShaders returns true. Which roughly is
>
>   if (cellBO.Program == 0 ||
>       cellBO.ShaderSourceTime < this->GetMTime() ||
>       cellBO.ShaderSourceTime < actor->GetMTime() ||
>       cellBO.ShaderSourceTime < this->CurrentInput->GetMTime() ||
>       cellBO.ShaderSourceTime < this->SelectionStateChanged ||
>       cellBO.ShaderSourceTime < renderPassMTime ||
>       cellBO.ShaderSourceTime < this->LightComplexityChanged[&cellBO])
>     {
>     return true;
>     }
>
> So if the main points are if you are modifying the actor, mapper, or your
> data. If one of those is being modified every frame then let me know the
> use case and we can see if the current test is being too aggressive etc.
>
> Thanks
> Ken
>
>
>
>
> On Fri, Sep 9, 2016 at 5:47 PM, Milef, Nicholas Boris <milefn at rpi.edu
> <http://redir.aspx?REF=ONPFOfU2bpzpsrcIgt2m7hhEWUJNJohZBPDsZ_BG4gPOQ7kY_tjTCAFtYWlsdG86bWlsZWZuQHJwaS5lZHU.>
> > wrote:
>
>> Under what conditions are shaders actually rebuilt? This seems to be the
>> source of my performance issues and I need to know how to avoid this. The
>> function I'm referring to is in vtkOpenGLPolyDataMapper(). It seems that
>> they get rebuilt when an object gets modified, is this true?
>>
>> Thanks,
>> Nick
>>
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>
> --
> Ken Martin PhD
> Chairman & CFO
> Kitware Inc.
> 28 Corporate Drive
> Clifton Park NY 12065
> 518 371 3971
>
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-- 
Ken Martin PhD
Chairman & CFO
Kitware Inc.
28 Corporate Drive
Clifton Park NY 12065
518 371 3971

This communication, including all attachments, contains confidential and
legally privileged information, and it is intended only for the use of the
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