Re: [osg-users] [forum] How to acquire the current location information of a drawable object? And how to calculate the distance between an object and the viewpoint?
在 2012-7-2，22:48，Fan ZHANG oceane...@gmail.com 写道： Hi all, I'm quite new to OSG and have no OPENGL background. I want to know how to acquire the current location information of a drawable object? Actually the initial position of the geometry is set by me. But when I move the objects with mouse, the spatial information changes, right? So I want to acquire such information. the world coordinate of a drawable is determined by scene graph. So it's world coordinate never change before you change the scene graph, logically. What you see after mouse action is probably controlled by view matrix and projection matrix. The pipeline looks like: object coordinate -- world coordinate -- eye coordinate -- device coordinate -- window coordinate. View matrix affects the eye coordinate and projection matrix affects the device coordinate. Mouse action will change the two matrixes. osg::Camera maintains these matrixes. For the second question, how to calculate the distance between an object and the viewpoint? Because I want to differentiate the 'stateset' when objects are far away from the viewpoint and when they are close to the camera. And I don't even know where the camera viewpoint is! viewpoint can be accessed in CullVisitor, so you should get it in cull traversal, by defining a cull callback and adding it to a Node. Regards and thank you! Cheers, Fan -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=48628#48628 ___ 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] Ho to change slave cameras offset matrix later on?
osg::View::getSlave(index) Get slave and do everything you want, Viewer will update their matrixs each frame. 在 2012-7-1，22:03，Torben Dannhauer tor...@dannhauer.info 写道： Hi, I would like to change a slave cameras viewOffset and projectionOffset matrix _after_ I added the camera via viewer-addSlavecamera(camera, viewoffset,projOffset). Is there a interface to set the offsets later on? I haven't found anything. What would you recommend to achieve the desired functionality? Maybe I should add some functions to allow later changes and submit it to Robert. Thank you! Cheers, Torben -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=48621#48621 ___ 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] Clipping planes for slave camera
Slave camera relies on main camera matrix and matrix offset, so it's meaningless to set their matrix. By contrast, view camera is independent of other view. 在 2011-9-27，23:05，He, Yefei yefei...@uiowa.edu 写道： Thanks, Robert, I'll take a look at the examples. Another question: in a composite viewer, if I set the view and projection matrices directly on the slave camera, what are the internal differences between doing this and simply creating another view and setting the view and projection matrices of its camera? I'm trying to set up a composite viewer with multiple views of the same scenegraph. I noticed that the main view (the first view added to the composite viewer) and its slave cameras all render properly, but in the contents of the other views, the depth sorting is incorrect, most noticeably the skydome obscures a lot of faces that should be in front of the skydome. Yefei -Original Message- From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Robert Osfield Sent: Tuesday, September 27, 2011 3:16 AM To: OpenSceneGraph Users Subject: Re: [osg-users] Clipping planes for slave camera Hi Yefei, On Mon, Sep 26, 2011 at 9:20 PM, He, Yefei yefei...@uiowa.edu wrote: Is it possible for a slave camera to have different near and far clipping planes from the master camera? Are there examples for it? I figure it will be more complicated than changing the angle of view or adding a shear to the view frustum. You have assign different projection matrices to the slave camera either by setting the projection offset matrix for the slave and keeping the slave Camera's ReferenceFrame set to RELATIVE_RF (relative the master Camera) or by setting the view and projection matrices directly on the slave Camera and setting the ReferenceFrame to ABSOLUTE_RF. There isn't a specific example that illustrates what you want but the osghud and osgdistortion examples should give you an idea of the different things you can. Robert. ___ 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 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Parallel Rendering Problems using NVidia GPU cards in Windows
how about 2 same GPUs? 在 2012-6-29，21:18，Stefan Eilemann eilem...@gmail.com 写道： On 26. Jun 2012, at 8:57, GeeKer Wang wrote: In fact, Windows NVidia driver will try to send OpenGL cammands to all GPU when SLI model disabled. NVidia drivers =256.0 send the commands to the most powerful GPU and then blit the result to the display GPU. You can override the GPU on a per-application base in the control panel, afaik. On Linux this is a non-issue, as you address the GPUs through X screens. Cheers, Stefan. ___ 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
