Hi again on this topic. here is the issue. When I have the camera static, no matter how close to the obstacles, all is rendered it should, no artifacts. When I move the camera, it shows artifact. I have set the camera to not compute znear and zfar. What can affect this change when moving and not moving?
Nick http://www.linkedin.com/in/tnick On Sat, Jan 16, 2010 at 1:48 PM, Trajce Nikolov <[email protected]>wrote: > Hi Wojtech, > > thanks for the links. I will do some research. > > I think I have fixed that. It turned out is the order of updating entities > in the scene. The "lightlobe" camera was updated before updating the light > itself, thats why different behavior based on the direction of movement. > > I think I will go further with this, to implement something for number of > lights. > > Thanks again ! > > Nick > > http://www.linkedin.com/in/tnick > > > On Sat, Jan 16, 2010 at 9:59 AM, Wojciech Lewandowski < > [email protected]> wrote: > >> Google for Shadow Maps. You will come up with a number of >> techniques. Few of them: >> >> http://www.punkuser.net/vsm/ >> >> http://gamma.cs.unc.edu/LOGPSM/ >> >> >> http://developer.download.nvidia.com/presentations/2008/GDC/GDC08_SoftShadowMapping.pdf >> >> Most of these belong to the family of soft shadow algorithms. Soft shadows >> usually oversample depth texel and produce some average shadow term. >> Clamping this term to 0 if value is below certain threshold (for example >> <0.25) usually removes some of self shadowing artifacts. >> >> I will have the second look on the code but not today. >> >> Wojtek >> >> *From:* Trajce Nikolov <[email protected]> >> *Sent:* Friday, January 15, 2010 10:16 PM >> *To:* OpenSceneGraph Users <[email protected]> >> *Subject:* Re: [osg-users] light lobes and shadow maps >> >> do you have some pointers, papers to the work of this guys? I am >> interested in learning what is that about >> Nick >> >> http://www.linkedin.com/in/tnick >> Sent from Ünalan, İstanbul, Turkey >> >> On Fri, Jan 15, 2010 at 11:01 PM, Wojciech Lewandowski < >> [email protected]> wrote: >> >>> Nick, >>> >>> I may look into the code but don't expect much this time. You need to >>> attach the code first, though ;-). Few academy guys wrote >>> couple dissertations on rasterization and aliasing errors in shadow >>> mapping. Unless you try to do some exotic stuff like variance or logarithmic >>> map you will have to use polygon offset. I guess you will end up to >>> cranking up PolygonOfset even more if current values fail at some distance. >>> I don't really have other tricks in my sleeve. >>> >>> Wojtek >>> >>> >>> *From:* Trajce Nikolov <[email protected]> >>> *Sent:* Friday, January 15, 2010 9:08 PM >>> *To:* OpenSceneGraph Users <[email protected]> >>> *Subject:* Re: [osg-users] light lobes and shadow maps >>> >>> That is exactly what I did. Please have a look at the updated code. The >>> uniform is updated thru a callback and it multiplies the matrices, still >>> there is a visual artifact.I dont have compute_near_far. The projection >>> matrix is fixed with very small far plane (100 units, with the znear of >>> 0.01). >>> >>> Nick >>> >>> http://www.linkedin.com/in/tnick >>> >>> >>> On Fri, Jan 15, 2010 at 9:47 PM, Wojciech Lewandowski < >>> [email protected]> wrote: >>> >>>> Hi, >>>> >>>> Light close to obstacles ? If you have COMPUTE_NEAR_FAR it may clamp >>>> near plane to very small value which may impact depth resolution. Other >>>> issue maybe related to GLSL float precision. The trick with multiplying >>>> view >>>> space coord by inverse view matrix to get world coord is performed on float >>>> values inside GLSL. Precision wise it would be better to multiply light >>>> camera MVP matrix by main camera INVERSE VIEW on the CPU. Osg Matrices use >>>> doubles. Put the result of the multiplication on GLSL matrix Uniform and >>>> use it to multiply gl_Vertex in the shader. Such approach multiplies >>>> matrices with high precision and resulting matrix will be better suited to >>>> be cast on single prec. GLSL matrix. The drawback of this solution is: you >>>> need to update the uniform every frame, because main camera view changes >>>> with each move. >>>> >>>> Wojtek >>>> >>>> >>>> *From:* Trajce Nikolov <[email protected]> >>>> *Sent:* Friday, January 15, 2010 7:37 PM >>>> *To:* OpenSceneGraph Users <[email protected]> >>>> *Subject:* Re: [osg-users] light lobes and shadow maps >>>> >>>> Hi Wojtek, >>>> >>>> now I spent more time exploring this, the polyoffset seam to work, but >>>> there is still a bit of shimmering. Its interesting, I put the light source >>>> in move, when it moves backwards, the obstacles are lighten ok, but >>>> forward, >>>> when the light comes close to the obstacles, the lighting is incorrect with >>>> shimmering . Any clue how to resolve this artifact ? >>>> >>>> Nick >>>> >>>> http://www.linkedin.com/in/tnick >>>> >>>> >>>> On Fri, Jan 15, 2010 at 4:48 PM, Trajce Nikolov < >>>> [email protected]> wrote: >>>> >>>>> ok .. make sense. Here is updated code, if some one wants to benefit >>>>> from. LightLobes with handling of obstacles :). Thanks to Wojiech, Robert >>>>> and the online community >>>>> >>>>> Nick >>>>> >>>>> http://www.linkedin.com/in/tnick >>>>> Sent from Devlet, Ankara, Turkey >>>>> >>>>> On Fri, Jan 15, 2010 at 3:53 PM, Wojciech Lewandowski < >>>>> [email protected]> wrote: >>>>> >>>>>> 0.0 <= shadow2DProj( shadow_texture, projShadow ).r <= 1.0 >>>>>> >>>>>> Shimering is a result of self shadowing. Boosting depths in shadow >>>>>> map with glPolygonOffset usuallly fixes this. There are many schools for >>>>>> PolygonOffset settings. I usually set glPolygonOffset( 1.1, 4.0 ) and >>>>>> draw >>>>>> objects with front face culling (see StandardShadowMap::ViewData::init(0 >>>>>> for >>>>>> details ). But for this setup models need to work correctly with >>>>>> backface >>>>>> culling on. If you do not enforce backface culling PolygonOffset may need >>>>>> different initialization. >>>>>> >>>>>> Wojtek >>>>>> >>>>>> ----- Original Message ----- >>>>>> >>>>>> *From:* Trajce Nikolov <[email protected]> >>>>>> *To:* OpenSceneGraph Users <[email protected]> >>>>>> *Sent:* Friday, January 15, 2010 2:46 PM >>>>>> *Subject:* Re: [osg-users] light lobes and shadow maps >>>>>> >>>>>> one more question. What are the possible values for shadow2DProj( >>>>>> shadow_texture, projShadow ).r ? I am trying to put the light attenuation >>>>>> back ..... and to avoid the shimmering >>>>>> Nick >>>>>> >>>>>> http://www.linkedin.com/in/tnick >>>>>> Sent from Devlet, Ankara, Turkey >>>>>> >>>>>> On Fri, Jan 15, 2010 at 3:35 PM, Trajce Nikolov < >>>>>> [email protected]> wrote: >>>>>> >>>>>>> Hey Wojtek !!!! Thanks a lot. !! I will tune it to fix the shimmering >>>>>>> >>>>>>> >>>>>>> >>>>>>> Nick >>>>>>> >>>>>>> http://www.linkedin.com/in/tnick >>>>>>> >>>>>>> >>>>>>> On Fri, Jan 15, 2010 at 3:08 PM, Wojciech Lewandowski < >>>>>>> [email protected]> wrote: >>>>>>> >>>>>>>> Trajce, >>>>>>>> >>>>>>>> Attached is a fixed source code. There is a lots of shadow >>>>>>>> shimmering on my GF8800. You will have to add some depth bias while >>>>>>>> rendering shadow map. Selection proper PolygonOffset values is usually >>>>>>>> a >>>>>>>> matter of trial and error so leave this for you. >>>>>>>> >>>>>>>> Wojtek >>>>>>>> >>>>>>>> ----- Original Message ----- >>>>>>>> >>>>>>>> *From:* Trajce Nikolov <[email protected]> >>>>>>>> *To:* OpenSceneGraph Users <[email protected]> >>>>>>>> *Sent:* Friday, January 15, 2010 9:58 AM >>>>>>>> *Subject:* Re: [osg-users] light lobes and shadow maps >>>>>>>> >>>>>>>> ABout the code. I use shader to simulate lght lobes thru phong >>>>>>>> lighting in the shader. Then I use shadow maps to detect the area >>>>>>>> behind the >>>>>>>> obstacles that need not to be lighten. Most is mixture of shadow maps >>>>>>>> technique with lighting scheme. Code snippets borrowed from all around >>>>>>>> >>>>>>>> Nick >>>>>>>> >>>>>>>> http://www.linkedin.com/in/tnick >>>>>>>> Sent from Devlet, Ankara, Turkey >>>>>>>> >>>>>>>> On Fri, Jan 15, 2010 at 10:54 AM, Trajce Nikolov < >>>>>>>> [email protected]> wrote: >>>>>>>> >>>>>>>>> Hi Guys, >>>>>>>>> >>>>>>>>> here is the code. >>>>>>>>> >>>>>>>>> Nick >>>>>>>>> >>>>>>>>> http://www.linkedin.com/in/tnick >>>>>>>>> Sent from Devlet, Ankara, Turkey >>>>>>>>> >>>>>>>>> On Thu, Jan 14, 2010 at 11:42 PM, Wojciech Lewandowski < >>>>>>>>> [email protected]> wrote: >>>>>>>>> >>>>>>>>>> Hi Nick, >>>>>>>>>> >>>>>>>>>> Post the troublesome code and elaborate a bit more about the >>>>>>>>>> problem. If its really a minute or two I am sure someone will be >>>>>>>>>> able to >>>>>>>>>> help. >>>>>>>>>> >>>>>>>>>> Wojtek Lewandowski >>>>>>>>>> >>>>>>>>>> *From:* Trajce Nikolov <[email protected]> >>>>>>>>>> *Sent:* Thursday, January 14, 2010 8:58 PM >>>>>>>>>> *To:* OpenSceneGraph Users <[email protected]> >>>>>>>>>> *Subject:* [osg-users] light lobes and shadow maps >>>>>>>>>> >>>>>>>>>> Hi community, >>>>>>>>>> >>>>>>>>>> I have some shader that does some lighting in the scene. Now >>>>>>>>>> studying osgShadow and the techniques. I want to a shadow map >>>>>>>>>> technique to >>>>>>>>>> disable the lightening of the scene behind obstacles. I have some >>>>>>>>>> code done, >>>>>>>>>> but not working. I need some help, someone experienced with GLSL to >>>>>>>>>> spend a >>>>>>>>>> minute or to to have a look and if possible to spot the problem. >>>>>>>>>> Anyone? >>>>>>>>>> >>>>>>>>>> Thanks a lot >>>>>>>>>> >>>>>>>>>> Nick >>>>>>>>>> >>>>>>>>>> http://www.linkedin.com/in/tnick >>>>>>>>>> Sent from Izmit, 41, Turkey >>>>>>>>>> >>>>>>>>>> ------------------------------ >>>>>>>>>> >>>>>>>>>> _______________________________________________ >>>>>>>>>> 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 >>>>>> >>>>>> >>>>>> _______________________________________________ >>>>>> 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 >>> >>> >> ------------------------------ >> >> _______________________________________________ >> 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
