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<p class=MsoNormal><span style='color:#1F497D'>Hello again,<o:p></o:p></span></p>
<p class=MsoNormal><span style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>In my previous post,
I forgot to mention that the performance leak occurs only for objects with high
number of triangles (about 70,000 triangles). In my first pass of my derived
rendering pass class, no performance leak is noticeable. But turn on the second
rendering pass within the class the performance leak occurs. So it seems that in
my second rendering pass the whole geometry is loaded to the GPU again and this
for every rendering step. Is that the reason and how can I resolve this
circumstance? I think I miss some important understanding of the underlying
rendering pipeline of the multipass framework.<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Thanks in advance ,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'>Rocco<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US style='color:#1F497D'><o:p> </o:p></span></p>
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<p class=MsoNormal><b><span style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'>From:</span></b><span
style='font-size:10.0pt;font-family:"Tahoma","sans-serif"'> vtkusers-bounces@vtk.org
[mailto:vtkusers-bounces@vtk.org] <b>On Behalf Of </b>Rocco Gasteiger<br>
<b>Sent:</b> Wednesday, December 09, 2009 6:13 PM<br>
<b>To:</b> vtkusers@vtk.org<br>
<b>Subject:</b> [vtkusers] Question to performance leak in multipass Rendering
inVTK<o:p></o:p></span></p>
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<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>Dear VTK users,<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>I derived my own render pass class from vtkRenderPass and
want to perform two render passes in it. My scene consists of two objects A and
B. For each object, I want to store its depth values in a depth texture by using
frame buffer objects (fbo). For accomplishing this task, I call two times
“this->DelegatePass->Render(&myRenderState)” within my
derived rendering class. My delegate rendering pass is a vtkDefaultPass. For
rendering A I set opacity of B to zero and for object B I do it the same for A.
Here is a pseudo code snippet of what I have done. <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>void vtkMyRenderPass::Render()<o:p></o:p></p>
<p class=MsoNormal>{<o:p></o:p></p>
<p class=MsoNormal>
// Perform some tests<o:p></o:p></p>
<p class=MsoNormal>
// …<o:p></o:p></p>
<p class=MsoNormal>
// Create fbo and render state<o:p></o:p></p>
<p class=MsoNormal>
// Get actor for object B<o:p></o:p></p>
<p class=MsoNormal>
actorB->SetOpacity(0.0)<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>
// Create first depth texture and assign it to fbo<o:p></o:p></p>
<p class=MsoNormal>
// Perform first render pass<o:p></o:p></p>
<p class=MsoNormal>
this->DelegatePass->Render(&newRenderState);<o:p></o:p></p>
<p class=MsoNormal>
<o:p></o:p></p>
<p class=MsoNormal>
// Reset opacity of
actorB <o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal style='text-indent:35.4pt'><span lang=EN-US>// Get actor for
object A<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>
</span>actorA->SetOpacity(0.0)<o:p></o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal>
// Create second depth texture and assign it to fbo<o:p></o:p></p>
<p class=MsoNormal style='text-indent:35.4pt'><span lang=EN-US>// Perform
second render pass <o:p></o:p></span></p>
<p class=MsoNormal style='text-indent:35.4pt'><span lang=EN-US>this->DelegatePass->Render(&newRenderState);<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal style='text-indent:35.4pt'><span lang=EN-US>// Reset opacity
of actorA <o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>}<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal>It works fine so far. But I notice a strong performance leak
during interaction due to the second offscreen rendering. Can anybody give me a
hint what the reason for this is? <span lang=EN-US>My render window is 300x300 and
I use a GeForce 9800 GT. Do I have to write a separate render pass class for
each render pass and collect them in a vtkRenderPassCollection (e.g.
vtkMyRenderPassA and vtkMyRenderPassB, for object A and B)?<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Many thanks in advance and best regards,<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US>Rocco Gasteiger<o:p></o:p></span></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
<p class=MsoNormal><o:p> </o:p></p>
<p class=MsoNormal><span lang=EN-US><o:p> </o:p></span></p>
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