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 > >
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