Hi Robert, Sorry ;) I need the results (distance map) back to the cpu.
Roland -----Ursprüngliche Nachricht----- Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Robert Osfield Gesendet: Dienstag, 7. Oktober 2008 13:44 An: OpenSceneGraph Users Betreff: Re: [osg-users] Linesegment, shader Hi Roland, Thanks for the extra details, but alas still missing important bits - answered parts from my first set of questions. The key is what do you want to do with gain function, you do need this result for all the rays back on the CPU, or can it be used in shader to compute a pixel value that will be seen on screen or used as a texture for later rendering? Robert. On Tue, Oct 7, 2008 at 12:11 PM, Leitner, Roland <[EMAIL PROTECTED]> wrote: > Hi Robert, > > I have simulated a ray (line segment) which has a given position and > orientation in the scene. Then I compute the distance between the start point > of the ray and the first object which is intersected by this ray. This > distance value is then a gain in a function. > > Now I would meassure the distances of up to 4000 rays. The start points of > these rays are concentrated in one point and divergent like the rays of a > pinhole camera. I need the distances use it as gains in a function that is > computed every frame step in the same code. > > If you have any questions, please let me know. > > Regards, Roland > > > > > > > > -----Ursprüngliche Nachricht----- > Von: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] Im Auftrag von Robert Osfield > Gesendet: Montag, 6. Oktober 2008 18:08 > An: OpenSceneGraph Users > Betreff: Re: [osg-users] Linesegment, shader > > Hi Roland, > > You'll need to be a be more specific about the nature of your problem, > as this make a huge difference about what solutions you could possibly > pursue. For instance if you don't need any results on the CPU and you > want the results to be screen space then using shaders is a very good > way tackle the problem, but if you need to results back on the CPU > then using a GPU to do this would only work effectively in cases were > you can wait for a CPU to GPU back to CPU round trip which is very > expensive. > > Robert. > > On Mon, Oct 6, 2008 at 4:23 PM, Leitner, Roland <[EMAIL PROTECTED]> wrote: >> >> Dear all osg users, >> >> I meassure the distance of a ray (linesegment) from a given point (start >> point of the ray) to the first intersection of this ray with any object >> in the scene. Now I need more than one ray (up to 4000 rays) to simulate >> a sensor. I have read that it could be done with a fragment shader, to >> meassure the distances from any view pose to the object in sight. So, >> maybe you have any ideas to solve this problem. >> >> Best regards, >> >> R. Leitner >> _______________________________________________ >> osg-users mailing list >> [email protected] >> http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org >> > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ > osg-users mailing list > [email protected] > http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org > _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org _______________________________________________ osg-users mailing list [email protected] http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
