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<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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