Re: [osg-users] Modify Object After Picking
I have done this before, and the results are interesting but not high quality due to differences in line/polygon rasterization. Still a good trick nonetheless. -Paul glPolygonOffset()? Yes. This is actually what I used to do (not exactly as the original poster described it): 1. Render front faces in GL_FILL mode. 2. Disable lighting and texture mapping, and set primary color to white. 3. Enable polygon offset for lines, set to something like (-1, -1) to pull the wireframe towards the viewer in depth buffer window space. 3. Render backfaces in GL_LINE mode. With this approach, there is no need to tinker with depth test. The results were good but somewhat rough. I was using this back in the OpenGL 1.1 days, so there was no multisampling available, which (I imagine) might improve the appearance somewhat. I believe there are ways to get silhouette outline effects these days using shaders, which don't require multipass and produce better results. Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com 303 859 9466 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
-Original Message- From: [EMAIL PROTECTED] [mailto:osg-users- [EMAIL PROTECTED] On Behalf Of Paul Martz Sent: Friday, February 15, 2008 8:20 AM To: 'OpenSceneGraph Users' Subject: Re: [osg-users] Modify Object After Picking An extension to this, which I've read about but never implemented is, after rendering your object, set ztest to equal, switch to wireframe, set line thickness to 2 or 3 pixels, and render the backfaces of your object. You'll get a rather funky, and fairly cheap, silhouette of your object. AFAIK, this is how Modo does it's highlighting. I have done this before, and the results are interesting but not high quality due to differences in line/polygon rasterization. Still a good trick nonetheless. -Paul glPolygonOffset()? -- mew ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
You will have to write code to do this One way I have done this in thee past is to (once you have the node) , calculate the picked nodes bounding box, create a simple wire frame box 1x1x1 add under a transformation node then scale that node to min and max of the bounding box you calculated and then add the transformation node to the node you selected. It works, then you can simply remove the transformation node when your done, Another old school Performer way, would be to double draw your node once in normal mode and then a second time in wire frame mode _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Romain Blanchais Sent: Friday, February 15, 2008 8:28 AM To: OpenSceneGraph Users Subject: [osg-users] Modify Object After Picking Hello, I would like to know if there is a simple way to show if an object is selected ? When I load a mesh from a osg file I use readNodeFile. When I pick the object I get this osgNode return by thefunction readNodeFile but I don't know really how to modify the mesh (colour or something else) to show that this mesh is selected. Regards __ Romain ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
Ah... Anyone remember PHIGS? Built-in pick highlighting that was almost guaranteed to not be what your app wanted? :-) And a PITA to implement too. You could take a look at the Scribe decorator node in osgFX. Just insert it into your scene graph above the picked object, then the object will render with a wireframe overlay. Hope that helps, Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com http://www.skew-matrix.com/ 303 859 9466 _ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Romain Blanchais Sent: Friday, February 15, 2008 6:28 AM To: OpenSceneGraph Users Subject: [osg-users] Modify Object After Picking Hello, I would like to know if there is a simple way to show if an object is selected ? When I load a mesh from a osg file I use readNodeFile. When I pick the object I get this osgNode return by thefunction readNodeFile but I don't know really how to modify the mesh (colour or something else) to show that this mesh is selected. Regards __ Romain ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
Gordon Tomlinson wrote: Another old school Performer way, would be to double draw your node once in normal mode and then a second time in wire frame mode An extension to this, which I've read about but never implemented is, after rendering your object, set ztest to equal, switch to wireframe, set line thickness to 2 or 3 pixels, and render the backfaces of your object. You'll get a rather funky, and fairly cheap, silhouette of your object. AFAIK, this is how Modo does it's highlighting. -JD __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
Paul Martz wrote: I have done this before, and the results are interesting but not high quality due to differences in line/polygon rasterization. Still a good trick nonetheless. -Paul Yeah, I've seen line rasterization on different graphics cards produce different results, and sometimes it's completely broken. Wasn't there a Linux ATI driver issue that made wireframes in OSG useless? I guess a lot of the issues also depend on the geometry and the depth precision of the scene. -JD __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
An extension to this, which I've read about but never implemented is, after rendering your object, set ztest to equal, switch to wireframe, set line thickness to 2 or 3 pixels, and render the backfaces of your object. You'll get a rather funky, and fairly cheap, silhouette of your object. AFAIK, this is how Modo does it's highlighting. I have done this before, and the results are interesting but not high quality due to differences in line/polygon rasterization. Still a good trick nonetheless. -Paul ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
Thank you for your answers, About the osgFX Scribe effect, I found a problem in the archive mail list that when you apply this effect the object disappear few frames. Do you know if it's still the case ? http://archive.netbsd.se/?ml=openscenegraph-usersa=2006-11m=2558289 Regards __ Romain On Fri, Feb 15, 2008 at 2:28 PM, John Donovan [EMAIL PROTECTED] wrote: Paul Martz wrote: I have done this before, and the results are interesting but not high quality due to differences in line/polygon rasterization. Still a good trick nonetheless. -Paul Yeah, I've seen line rasterization on different graphics cards produce different results, and sometimes it's completely broken. Wasn't there a Linux ATI driver issue that made wireframes in OSG useless? I guess a lot of the issues also depend on the geometry and the depth precision of the scene. -JD __ This email has been scanned by the MessageLabs Email Security System. For more information please visit http://www.messagelabs.com/email __ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Modify Object After Picking
Hello Romain, I use the Scribe effect all the time (both at work and in my Masters project) and I've never seen that particular issue. But do you add the scribe effect in real time ? Yes. Just be sure to do it in the update thread and make sure you don't do it while traversing (to not invalidate iterators) and you should be fine. J-S -- __ Jean-Sebastien Guay[EMAIL PROTECTED] http://www.cm-labs.com/ http://whitestar02.webhop.org/ ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
