Hi all,
>You can try OvelayNode::setOverlayTextureSizeHint() to increase the
size of the texture to 2048 or 4096 or whatever your gfx card >can
handle, and see if the results are acceptable. -gw
Thanks Glenn. This did help. I had set it at 1024. Unfortunately, it
still wasn't quite what I was hoping for. I will look at the osgGIS
code a little more as it appears that you (and the community) are doing
something similar there (at least as shown in the screen captures on the
Wiki) -- unless you don't think it would be too helpful in my case.
> I think one thing that may alleviate the blending a bit is to set your
> texture filters to nearest neighbour ( but you will never remove this
type
> of issue with textures and lines due to mip-maping among other things)
Thanks Gordon. Would I do this in the osgSim::OverlayNode code or can I
set a StateSet or something to do this?
> The fuzziness you see is under sampling due to the texture being
> captured in objects space rather than in screen space - one texel on
> the overlay texture is being sampled by many screen pixels. Ideally
> you want a 1:1 mapping, but this is very hard to achieve and different
> algorithms are supported by OverlayNode to help address it. See the
> enum:
>
> enum OverlayTechnique
> {
> OBJECT_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY,
> VIEW_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY,
> VIEW_DEPENDENT_WITH_PERSPECTIVE_OVERLAY
> };
>
> VIEW_DEPENDENT_WITH_PERSPECTIVE_OVERLAY is the one with most
> sophisticated support trying to better map overlay texture with the
> requirements of view.
>
> Robert.
Thanks Robert. I had a feeling that it was just an artifact of how
things work. In the screen capture, I had been using
OBJECT_DEPENDENT_WITH_ORTHOGRAPHIC_OVERLAY. When I set it to
VIEW_DEPENDENT_WITH_PERSPECTIVE_OVERLAY, I don't get anything -- no
gridlines are shown. Is there something else that I need to set/change?
Judging by the responses, it appears that I may not be able to get what
I want through the OverlayNode. Is there another way to do what I'm
interested in doing (i.e., overlaying a grid onto a terrain surface)? I
have thought about looking at some of the intersect code examples, but
my first thought was that this would be too expensive in the way of
render speed, startup time, etc. to explore.
Thanks to all.
chuck
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