Drape method performance when zoom in

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JD JD
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Drape method performance when zoom in

Hi,

I have a strange behaviour i don't really understand.

Using the shape file attached to this topic.
If I display it using drape method, the GPU is very more solicitated when it is very zoomed in (like for example zoom in france polygon until there are boundaries visible) than when it is very zoom out (full globe view). I would expect the opposite as very less triangles need to be drawn when zoomed in.

The differences are from 3 to 11 ms for GPU time. Any ideas about what is causing this behaviour?
Note also that the map technique has also this issue but very very less important (from 3 to 4 ms).

OsgEarth 2.10.2 with REX engine.

ne_10m_land.zip
Lands zoom out
Lands zoom in
JD JD
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Re: Drape method performance when zoom in

Note that, It makes me think of a not efficient culling so i tried to remove the geometry merges in order to have a splited geometry which should make possible to completly cull some polygons. But without improvements so far...
JD JD
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Re: Drape method performance when zoom in

In fact, there is no need of using the shape file provided.
Only with this in-line geometry the problem appears:

<geometry>POLYGON ((170 -40 0,170 -30 0,190 -30 0, 190 -40 0))</geometry>

It goes from 2ms to 10ms of GPU.
gwaldron gwaldron
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Re: Drape method performance when zoom in

JD,
There's no reason it should slow down that much; I am not able to reproduce it on OE master. Don't have 2.x handy but I can't think of any reason it would matter. Sorry for not being much help..
Glenn Waldron / Pelican Mapping
JD JD
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Re: Drape method performance when zoom in

It seems to be a very low level issue. Using a nVidia graphic card the difference between zoom in and out is very low (nearly inexistant) while using an embeded Intel HD the issue is very important.

Did the drape method change between 2.10 and 3 ?
gwaldron gwaldron
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Re: Drape method performance when zoom in

No, it didn't change.
Maybe you need an updated driver for the HD?
Glenn Waldron / Pelican Mapping