OK, I've tested now different cases and found out that the best way is to change the double into float in the osg::Viewport. I think the precision given by floats is big enough for any viewport computation. Using of float will also reduce the run overhead required for handling with doubles on a 32bit system. Even more; cuda compiled applications doesn't read out any nonsense values out of viewports anymore. Hence I propose to use floats there instead of doubles. Or maybe use doubles only if compiled for 64 bits.
What do you think about that, Robert? Art --- Art Tevs <[EMAIL PROTECTED]> schrieb am So, 30.11.2008: > Von: Art Tevs <[EMAIL PROTECTED]> > Betreff: Re: [osg-users] osg::Viewport doubles??? > An: "OpenSceneGraph Users" <[email protected]> > Datum: Sonntag, 30. November 2008, 18:06 > Hi Robert, > > OK, I see, however I ran into troubles using CUDA together > with doubles in viewports. The problem is that CUDA compiler > invokes gcc with -malign-double parameter, which isn't > the same as for osg. Hence whenever I want to access the > values of a viewport in a CUDA code (actually C-code > compiled with gcc by cuda compiler) I am not able to get > proper values out of it. Hence one of the applications > (either CUDA compiler ;) ) or OSG has to go in the direction > of the other by either removing -malign-doubles (which I > think wouldn't be done so easyly) or by adding this > parameter to OSG compilation. However the second case > isn't also a good solution, I think. > > I tried to implement the viewport with int and it works > fine. I think also using floats instead of doubles would be > also fine (because no alignment is needed). Currently I am > checking the case with float and also want to try to compile > osg with -malign-doubles. Let see if it does help. I would > let you know more soon... > > Art > > --- Robert Osfield <[EMAIL PROTECTED]> schrieb > am So, 30.11.2008: > > > Von: Robert Osfield <[EMAIL PROTECTED]> > > Betreff: Re: [osg-users] osg::Viewport doubles??? > > An: [EMAIL PROTECTED], "OpenSceneGraph > Users" <[email protected]> > > Datum: Sonntag, 30. November 2008, 17:17 > > Hi Art, > > > > On Sun, Nov 30, 2008 at 3:59 PM, Art Tevs > > <[EMAIL PROTECTED]> wrote: > > > Shouldn't then the method, which scales the > > viewport, take care of casting? > > > Because based on OpenGL Specification viewport is > per > > definition an integer value. > > > > Not quite, it's not about passing data to OpenGL, > > it's about handling > > resizing down and back up again of viewports, if you > do > > this with > > int's then you can never recover the original size > of > > the viewport > > because of rounding. > > > > Robert. > > > > _______________________________________________ > 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
