[osg-users] osgdem --terrain vs polygon count?
jean-sebastien.guay at cm-labs.com
Mon Sep 29 08:20:53 PDT 2008
> The main speed up with using --terrain in the osgdem/vpbmaster build
> is that the tile geometry doesn't need to simplified - it can just be
> aquired from the source DEM's as grids and then output as grids.
> The key thing to remember with --terrain databases is that since the
> triangulation is done dynamically on load you do load balancing - you
> can set the Terrain::setSampleRatio() according to the hardware that
> you have
Ok, so in order to get --terrain databases to work optimally on all
machines I would have to expose this setting in my software's config
files (for example) so that it can be tweaked according to each
machine's hardware, is that right?
I would suspect that on relatively flat terrain, the terrain database
using simplified geometry might run fast enough on all machines (or all
reasonably fast machines) without losing any relevant detail, whereas
the --terrain database would be too slow on older machines, which would
require that we lower the sampleRatio, and thus lose some detail? Is
In that case, if we need to support a large number of different hardware
configurations, we might be willing to accept the longer build times of
not using --terrain in exchange for not needing to tweak sampleRatio and
not losing any detail.
Jean-Sebastien Guay jean-sebastien.guay at cm-labs.com
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