Re: [osg-users] Trilinear vs Bilinear
Guy Volckaert wrote: Ok. I have a little more information for you guys. Just to recap the situation: When I run using Bilinear, I get 30 Hz. When I run using Trilinear, I get 60Hz. During my investigation, I noticed that their are actually 2 bilinear modes: LINEAR and LINEAR_MIPMAP_NEAREST. LINEAR does not include any mipmaps, whereas LINEAR_MIPMAP_NEAREST will include mipmaps. As a test, I modified my texture attribute visitor to replace LINEAR by LINEAR_MIPMAP_NEAREST. Now, the performance is similar to using Trilinear. It seems that the graphics card does not like using Bilinear textures without the mipmaps. Does anyone know why? How big is the base level of your texture, and how big is the on-screen rendering? If you use LINEAR but you're minifying, this will produce poorer cache results than if you used a mipmap filter (and thus loaded a smaller texture into the cache). -Paul ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Trilinear vs Bilinear
Ok. I have a little more information for you guys. Just to recap the situation: When I run using Bilinear, I get 30 Hz. When I run using Trilinear, I get 60Hz. During my investigation, I noticed that their are actually 2 bilinear modes: LINEAR and LINEAR_MIPMAP_NEAREST. LINEAR does not include any mipmaps, whereas LINEAR_MIPMAP_NEAREST will include mipmaps. As a test, I modified my texture attribute visitor to replace LINEAR by LINEAR_MIPMAP_NEAREST. Now, the performance is similar to using Trilinear. It seems that the graphics card does not like using Bilinear textures without the mipmaps. Does anyone know why? Regards, Cheers, Guy -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=24243#24243 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
Re: [osg-users] Trilinear vs Bilinear
Hi Guy, This sounds rather odd. Going from bilinear to trilinear should not have a significant effect on performance, as it would suggest that the texture filtering is a bottleneck to a massive degree, something I wouldn't expect any card made in the last decade to show. So what is going on? Well you can start by telling us what performance you are getting and what other settings you are using that may effect texture filtering performance. Robert. On Sat, Feb 13, 2010 at 12:04 AM, Guy Volckaert wrote: > Hi, > > I was wondering was experiencing the same odd behavior I am. I created a > visitor that essentially iterates through all the textures of a terrain scene > graph to change their texture filtering from bilinear to trilinear. > > When I replace the filtering from bilinear to trilinear, I get a boost of 50% > in performance. If I completely bypass my texture visitor then I get a bad > performance. > > This is contrary to what I've been told. I was under the impression tha > bilinear filtering was essentially free (as far as performance goes), and > that trilinear was a little more expensive (but fairly negligeable). > > This is not was I am observing. I've tried this on several different graphic > cards (9500 GT, 8800 GTX, 260, etc). The driver version I am using is v195.x > but it also happens on 185.x. > > Can someone explain this to me? Someone told me that the new GPUs are built > with trilinear in mind, and therefore would perform better is trilinear. Is > this true? > > Regards, > > > > > > > > > Cheers, > Guy > > -- > Read this topic online here: > http://forum.openscenegraph.org/viewtopic.php?p=24104#24104 > > > > > > ___ > 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] Trilinear vs Bilinear
Hi, I was wondering was experiencing the same odd behavior I am. I created a visitor that essentially iterates through all the textures of a terrain scene graph to change their texture filtering from bilinear to trilinear. When I replace the filtering from bilinear to trilinear, I get a boost of 50% in performance. If I completely bypass my texture visitor then I get a bad performance. This is contrary to what I've been told. I was under the impression tha bilinear filtering was essentially free (as far as performance goes), and that trilinear was a little more expensive (but fairly negligeable). This is not was I am observing. I've tried this on several different graphic cards (9500 GT, 8800 GTX, 260, etc). The driver version I am using is v195.x but it also happens on 185.x. Can someone explain this to me? Someone told me that the new GPUs are built with trilinear in mind, and therefore would perform better is trilinear. Is this true? Regards, Cheers, Guy -- Read this topic online here: http://forum.openscenegraph.org/viewtopic.php?p=24104#24104 ___ osg-users mailing list osg-users@lists.openscenegraph.org http://lists.openscenegraph.org/listinfo.cgi/osg-users-openscenegraph.org
