>May I ask re your usage of osgShadow and osgEphemeris, which shadow 
technique you were using?

VDSM (View Dependant Shadow Map), with custom shaders for multi-texturing, 
transparency, fog, etc...
I exclude the skydome of osgephemeris from culling (cf thread) and disable 
depth test on it.
VDSM works quite well for non human-like viewpoints (near the ground, 
looking towards horizon).

   Luc 



De :
Garth D <[email protected]>
A :
OpenSceneGraph Users <[email protected]>
Date:
05/04/2012 16:15
Objet :
Re: [osg-users] Using osgShadow with osgEphemeris (or alternatives)
Envoyé par :
[email protected]




Hi Luc,

Thanks for the fast reply on that one. I hadn't considered checking out 
interactions with the clip planes. I've had to manually override their 
calculation in a past project, so this could be worth checking out. 
Incidentally, I did shrink the ephemeris model via setSkyDemoRadius a 
fair bit before starting, but the presence of the geometry is likely 
going to move the clip planes around.

May I ask re your usage of osgShadow and osgEphemeris, which shadow 
technique you were using?

And yes, osgEphemeris is probably overkill ultimately. ;)

Garth

On 05/04/12 23:30, Luc Frauciel wrote:
> Hi Gath,
>
> I use osgShadow (VDSM) and osgEphemeris in conjunction, and they seem to
> work together.
> However, there are known problems related to osgEphemeris which are
> broader :
>
> - The Skydome in osgEphemeris can be very large, causing unwanted
> interaction with culling/ nearfar planes.
> see
> 
http://lists.openscenegraph.org/pipermail/osg-users-openscenegraph.org/2009-April/026772.html

> long thread, but with useful hints towards solutions
> - I remember problems with clearing operation, but probably related to
> solutions to the previous problem.
>
> If the only thing that you want is a skydome, osgEphemeris is an
> overkill for that.
> You probably still have to consider the culling problems introduced by
> skydomes (a scene with a skydome is artificially big).
>
> Luc
>
>
> De :           Garth D <[email protected]>
> A :            OpenSceneGraph Users <[email protected]>
> Date:          05/04/2012 15:34
> Objet :                [osg-users] Using osgShadow with osgEphemeris (or 
alternatives)
> Envoyé par :           [email protected]
>
>
> ------------------------------------------------------------------------
>
>
>
>
> Hi everyone,
>
> In OpenSceneGraph 3.0.1, is there a known fundamental incompatibility
> between osgShadow and osgEphemeris (circa 4/4/12)? I am using osgShadow
> (namely ShadowTexture), with both animated and static models, and
> started to work in osgEphemeris in order to provide a more interesting
> sky than a single static colour.
>
> One thing I noticed is that whenever osgEphemeris is working, the
> location of cast shadows shifted around significantly, and they are
> nowhere near the objects that are casting them (ie. the shadows were
> very clearly incorrect). Depending on the view angle, they also bounced
> around to different locations. I noticed that animated models no longer
> cast shadows, but that may have just been a symptom specific to my
> particular case.
>
> In case the node mask was causing a problem (for osgShadow I am using 1
> to cast, and 2 to receive), I tried different values. Setting it to zero
> caused the EphemerisModel to vanish (is this normal?), and to four left
> it there, but didn't help the shadow situation. In any case, when the
> EphemerisModel was working, the shadows were shifted around and 
incorrect.
>
> I've tried disabling lighting on the model (via state sets and
> GL_LIGHTING), as well as attaching it to different nodes, but I don't
> seem to have struck upon the correct combination.
>
> Interestingly enough, if I use either on their own, they work fine.
> Shadows work fine, without ephemeris models; and ephemeris models seem
> to produce good results if I turn off shadows.
>
> Can anyone suggest any things to try, confirm there are known problems,
> or otherwise?
>
> On a side note, I began to investigate osgEphemeris in the first case as
> I needed a simple sky. My requirements are pretty low, as the sky is
> merely decorative, so I don't necessarily *have* to use osgEphemeris
> specifically. I am wondering what the best approach to sky creation in
> OSG 3.0.1 would be? The potential solutions I ran into were:
>
> - Use the sky code osghangglide as a base/inspiration.
> - Find a spare $1.5k and use SilverLining (a bit overkill for my
> application at present!)
> - Use "skydome.osgt" from the OpenSceneGraph data dir (I gave this a
> shot, but I wasn't able to successfully get it working correctly with
> the rest of my app)
> - Build up my own geometry, customising the texture coordinates as I
> need (the most flexible approach, but the most time consuming, and the
> most pointless if someone has done it already), and grab or buy some
> existing sky textures to match the expected texture.
> - Use osgEphemeris, which is what I'm looking at above.
>
> Are there other solutions that I should be exploring as well, or in
> preference?
>
> Garth
>
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>
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