What os? What drivers are you using - nvidia, or the ones shipped with the os. If linux, you can type glxinfo to get that information.<br>-J<br><br><div><span class="gmail_quote">On 11/28/07, <b class="gmail_sendername">
Peter Clifton</b> <<a href="mailto:pcjc2@cam.ac.uk">pcjc2@cam.ac.uk</a>> wrote:</span><blockquote class="gmail_quote" style="border-left: 1px solid rgb(204, 204, 204); margin: 0pt 0pt 0pt 0.8ex; padding-left: 1ex;">
<br>On Wed, 2007-11-28 at 00:49 -0800, David Thompson wrote:<br>> > Do any developers hang out here?<br>> Yes.<br>><br>> > I appreciate that having no reply to a question (in what is arguably a<br>> > short time so far), can indicate many things..
<br>> ><br>> > * Question asked in wrong place<br>> > * Question missing information<br>> > * Question containing too much information<br>> ><br>> > If anyone is familiar with the rendering code, perhaps they will be
<br>> > able<br>> > to point me in the right direction.<br>> Depth peeling does not appear to be in VTK 5.0.x. It is present in the<br>> CVS trunk. See <a href="http://www.vtk.org/Wiki/VTK/Depth_Peeling">
http://www.vtk.org/Wiki/VTK/Depth_Peeling</a> for some<br>> information on how to use it (note the list of GL extensions you need<br>> in order for it to work). Shy of depth peeling,<br>><br>> > I doubt this is a VTK bug in the strictest sense (as MESA software
<br>> > rendering seemed to "fix" it), but without knowing what underlying<br>> > cause<br>> > is, or having a simple gl / glut test case, reporting a MESA bug isn't<br>> > yet going to get much attention either.
<br>> It is not a bug. Without depth peeling, geometry primitives must be<br>> depth-sorted each time the camera changes. This is not a trivial<br>> amount of work for large datasets and many people don't have
<br>> transparent geometry to render, so depth sorting is something you must<br>> set up in your pipeline if you want it to be done (see<br>> vtkDepthSortPolyData). Without depth sorting, you will see some<br>> triangles blended into the color buffer in the wrong order. Without a
<br>> screen capture or more details, I would guess that is what you are<br>> reporting.<br><br>It does sound like it, however I "think" I'm seeing this with<br>non-translucent objects too (although not in the
TextureThreshold.py<br>example). I can post some screen-shots, and simple Python + VTK example<br>code when I'm at the lab later.<br><br>I'll do some tests based on your suggestions, and get back to you. What<br>is strange, is MESA software rendering clears up the bug for me in the
<br>case I tested (not TextureThreshold.py).<br><br>This also manifests with viewer, if I toggle on the coordinate mark<br>(x,y,z lines with cones pointing in their directions). The coordinate<br>arrows end up drawn in the wrong Z order. (Would I need to sort the poly
<br>data for these to draw correctly too?)<br><br>I'm also trying to build the CVS head of VTK, as if depth peeling solves<br>the issue, I'll be sorted.<br><br>As its a complex piece of software, I'm trying to build it as a debian
<br>package so I can just dpkg --install it to replace the current version<br>I've got installed without fear of breaking my system. The package<br>building process makes any build failures much more time-consuming to
<br>fix though!<br><br>Many thanks,<br><br>--<br>Peter Clifton<br><br>Electrical Engineering Division,<br>Engineering Department,<br>University of Cambridge,<br>9, JJ Thomson Avenue,<br>Cambridge<br>CB3 0FA<br><br>Tel: +44 (0)7729 980173 - (No signal in the lab!)
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