ImageOverlay question

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Vladd Vladd
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ImageOverlay question

Hello there,

I'm using osgEarth::Annotation::ImageOverlay to create multiple images overlay on terrian.

Everything looks fine with orthocamera - images are sharp and clear


While perspective camera makes overlayed images blurry.


What can cause blurring?
Any thoughts are welcome.
boy2melo boy2melo
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Re: ImageOverlay question

Hi,

this problem has already been stated here: http://forum.osgearth.org/Image-overlay-blurry-with-tilt-td7581805.html

Unfortunately no solution has been found yet. We have the same problem. What we realized lately is that if one only adds images which are in close vicinity to each other everything works fine. No blurring. But if one adds couple of images which are distant to the current view (e.g. USA <-> Europe), the blurring occurs when the camera is tilted too far.

With that in mind my suggestion would be to add a culling to the images dependent on the distance to the camera. But I didn't have the chance to test it yet.

\Boy2melo
gwaldron gwaldron
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Re: ImageOverlay question

The draping of an image uses projective texturing, and it has stretch the image over the entire projected area. It can only approximate the extent of the terrain in view, and so you get this blurring artifact. A long-term solution might be to use cascading (as with shadow maps) but that's not on the roadmap at the moment (i.e., not funded).
Glenn Waldron / Pelican Mapping