2.10.2 GeodeticGraticule disappears at certain zoom

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krzysief krzysief
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2.10.2 GeodeticGraticule disappears at certain zoom

Hello,
I am using osg 3.6.4 ubuntu 20 and osgearth 2.10.2 At this version the GeodeticGraticule always disappears at a certain zoom level no matter how precise i set the resolutions option. Is there a way to at least make it not disappear? Or maybe force the wanted resolutions?

Cheers, Kris
gwaldron gwaldron
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Re: 2.10.2 GeodeticGraticule disappears at certain zoom

Kris,
Well.. good question. If memory serves, the shader (GeodeticGraticule.glsl) uses an obscure fragment quantization technique to render the lines. This technique starts to fail (due to precision problems) and produce artifacts when you get too close to the ground. For this reason we put in a maximum height in the shader. A lazy solution :)

Anyway, you can see for yourself my going into GeodeticGraticule.glsl and changing the maxHAE (maximum height above ellipsoid) value to something smaller, or by removing it from the alpha calculation altogether. (The precision issue is very likely due to the use of osg_ViewMatrixInverse[3].xyz.)
Glenn Waldron / Pelican Mapping