[vtk-developers] Performance slow down

[Francois Bertel]

I'm gonna revert back the order of painters for now.

[LONG PART starts here]

The problem is the current implementation of the display list painter
makes some assumptions about what kind of delegate it can have.
Hence this 8-line conditional statement to decide to rebuild the
display list or not.

A long term solution I can think of to address this issue would be to
add a new method in vtkPainter called "virtual bool
NeedUpdate(...)=0;"
This pure virtual method (with the same arguments of RenderInternal )
will tell if the painter (and recursively its own delegates) needs to
be re-rendered in the case of the use of display lists.

At the end, part of the implementation of RenderInternal() of the
display list painter would look like:

if(this->NeedUpdate(...)))
 {
  // rebuild the list.
  // ...
 this->Superclass::RenderInternal(renderer, actor, typeflags, true);
// true for forceCompileOnly
  // ...
 }
if(!forceCompileOnly)
{
 // call the list
}
...

its NeedUpdate() will look like:
{
return this->DisplayListId==0 || (this->Delegate!=0 &&
this->Delegate->NeedUpdate(...));
}

and for each other sub-class of vtkPainter, NeedUpdate() would be the following:

bool NeedUpdate(...)
{
 bool result;

 // figure out if I need to rerender (assuming this painter need the
property on the actor)
 result=actor->GetProperty()->GetMTime() > this->BuildTime;

// what about my own delegate?
 if(!result)
  {
  result=this->Delegate!=0 && this->Delegate->NeedUpdate(...);
  }
 return result;
}

On Thu, Jul 24, 2008 at 12:46 PM, Francois Bertel
<francois.bertel at kitware.com> wrote:
> The problem is there is no modification time specific to a part of the
> actor (in this case, the transform and ivar modifiying it are part of
> the vtkProp3D (superclass of vtkActor)).
>
> On Thu, Jul 24, 2008 at 12:38 PM, Jeff Baumes <jeff.baumes at kitware.com> wrote:
>> I've seen this issue before where textures were being reloaded every
>> frame because someone had added a
>>
>> || this->Renderer->MTime() > blah
>>
>> to the if statement for reloading the texture, and the renderer was
>> actually being modified every frame. It looks like in this case it is
>> really just a specific part of the vtkActor that Francios is checking
>> for modification. Something in the actor is changing in your program
>> every frame, but not the part of the actor that should really make
>> that "if" pass. The condition should probably be more restrictive and
>> only pass if certain parts of the actor are modified.
>>
>> Jeff
>>
>>
>> On Thu, Jul 24, 2008 at 12:22 PM, Mathieu Coursolle
>> <mcoursolle at rogue-research.com> wrote:
>>> Hi,
>>>
>>> I've track down the source of the problem to this change:
>>>
>>> http://public.kitware.com/cgi-bin/viewcvs.cgi/Rendering/vtkOpenGLDisplayListPainter.cxx?r1=1.7&r2=1.8
>>>
>>> For some reason, if I undo this single change, it is rendering as fast as
>>> before.
>>>
>>> Anybody knows what the problem might be?
>>>
>>> Thanks!
>>>
>>> Mathieu
>>>
>>>
>>>
>>> On 24-Jul-08, at 11:07 AM, Mathieu Coursolle wrote:
>>>
>>>> Hi vtk-dev,
>>>>
>>>> I am developing a Cocoa application on Mac OSX 10.5 based on VTK.
>>>> I usually update from CVS once in a while to have the recent fixes
>>>> and features.
>>>>
>>>> I updated yesterday and rendering a vtkPolyData is now very slow.
>>>> It use to be quite fast with my 2 weeks old version.
>>>>
>>>> I used the Shark tool to check in which part of the code it was spending
>>>> all
>>>> this time, and it resulted in the OpenGL API.
>>>>
>>>> Any idea of which last days commit might have cause this?
>>>>
>>>> Thanks!
>>>>
>>>> Mathieu
>>>> _______________________________________________
>>>> vtk-developers mailing list
>>>> vtk-developers at vtk.org
>>>> http://www.vtk.org/mailman/listinfo/vtk-developers
>>>>
>>>
>>> _______________________________________________
>>> vtk-developers mailing list
>>> vtk-developers at vtk.org
>>> http://www.vtk.org/mailman/listinfo/vtk-developers
>>>
>>
>>
>>
>> --
>> Jeff Baumes, Ph.D.
>> R&D Engineer, Kitware Inc.
>> (518) 371-3971 x132
>> jeff.baumes at kitware.com
>> _______________________________________________
>> vtk-developers mailing list
>> vtk-developers at vtk.org
>> http://www.vtk.org/mailman/listinfo/vtk-developers
>>
>
>
>
> --
> François Bertel, PhD | Kitware Inc. Suite 204
> 1 (518) 371 3971 x113 | 28 Corporate Drive
>  | Clifton Park NY 12065, USA
>



-- 
François Bertel, PhD | Kitware Inc. Suite 204
1 (518) 371 3971 x113 | 28 Corporate Drive
 | Clifton Park NY 12065, USA