[osg-users] Using OsgSim Overlay

J.P. Delport jpdelport at csir.co.za
Thu Nov 19 02:16:40 PST 2009


Vaibhav Bansal wrote:
> Hello jp,
> Thanks for the quick reply.
> How do I check if the 'resolution' of ovelay geometry is changing.

imagine the following:
You want to overlay a 1024x1024 checkerboard onto the earth and you have 
a 512x512 overlay texture. If you view the whole earth it obviously 
would not look good - too much detail to fit into the texture. What the 
view dependent modes try to do is this: When you zoom in, you only see a 
piece of the checkerboard, so now the 512x512 texture can contain only a 
piece of the checkerboard and so you see "more detail" of the overlayed 

I think this is the effect you are seeing when you are moving the view 


> Regards
> Vaibhav Bansal
> -----Original Message-----
> From: osg-users-bounces at lists.openscenegraph.org
> [mailto:osg-users-bounces at lists.openscenegraph.org] On Behalf Of J.P.
> Delport
> Sent: Thursday, November 19, 2009 2:41 PM
> To: OpenSceneGraph Users
> Subject: Re: [osg-users] Using OsgSim Overlay
> Hi Vaibhav,
> Vaibhav Bansal wrote:
>> Hello,
>> I have added a geometry as an overlay over another geometry.
>> The overlay texture seems to distort(stretch) under certain viewing
> angles.
>> It seems the projected texture is generating incorrect texture
> coordinates.
> The texture coordinates might be OK, but the resolution of your 
> overlayed geometry might change in the generated overlayed texture. What 
> resolution/stretch stay the same?
> jp
>> The white area is the overlaySubgraph geometry, and the colored area is
> the
>> Overlay Node (base) geometry.
>> Can anyone suggest where should I start troubleshooting.
>> Thanks
>> Vaibhav Bansal
>> ------------------------------------------------------------------------
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