[osg-users] ShadowMap problem...

Wojciech Lewandowski lewandowski at ai.com.pl
Wed Nov 11 11:47:45 PST 2009

Hi Guys,

could be useful too sometimes, they take advantage of the same shadow volume 
optimization methods as LispSM flavours, but not use skewed projection like 
LispSM. This skewed projection is sometimes a problem when used with non 
directional lights. It may also bring trouble when one wants to mix smooth 
shadows with ViewDependentShadowMap techniques.  So in the end all the 
techniques stemming from ViewDependentShadowTechnique have their advantages 
and are definitely not abstract (excluding maybe DebugShadowMap which 
provides a bottom layer with debuging methods).

Wojtek Lewandowski

From: "Jean-Sébastien Guay" <jean-sebastien.guay at cm-labs.com>
Sent: Wednesday, November 11, 2009 5:26 PM
To: "OpenSceneGraph Users" <osg-users at lists.openscenegraph.org>
Subject: Re: [osg-users] ShadowMap problem...

> Hi Wyatt,
>> 1.  Is there a way I can query the number of texture units available on 
>> my
>> GPU via an OSG call?
> A Google search turned up glGetIntegerv(GL_MAX_TEXTURE_UNITS_ARB). Also 
> searching the OSG headers, I found 
> osg::Texture::Extensions::numTextureUnits() which returns a GLint (int). 
> Look at the source to find out where the value will be initialized or how 
> to initialize it yourself.
> I generally don't bother to query and use 8 (0-7) as a number that's 
> supported pretty much everywhere.
>> 2.  Is there a list, other than the osgShadow programming guide of 
>> shadowmap
>> techniques, specifically ViewDependentShadow techniques?
> The source/headers... And the mailing list archives.
> The three usable types are:
> class  LightSpacePerspectiveShadowMapDB /*...*/ {};
> class  LightSpacePerspectiveShadowMapCB /*...*/ {};
> class  LightSpacePerspectiveShadowMapVB /*...*/ {};
> And LightSpacePerspectiveShadowMap is an alias for 
> LightSpacePerspectiveShadowMapDB :
> typedef LightSpacePerspectiveShadowMapDB LightSpacePerspectiveShadowMap;
> And also StandardShadowMap is usable, but it's not view-dependent, so it's 
> pretty much a direct replacement for osgShadow::ShadowMap but in the same 
> class hierarchy as the LightSpace* classes.
> Hope this helps,
> J-S
> -- 
> ______________________________________________________
> Jean-Sebastien Guay    jean-sebastien.guay at cm-labs.com
>                                http://www.cm-labs.com/
>                         http://whitestar02.webhop.org/
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