[osg-users] Dynamic terrains, DatabasePager + PagedLODs

Robert Osfield robert.osfield at gmail.com
Wed Jan 6 01:04:58 PST 2016

On 5 January 2016 at 18:52, Nickolai Medvedev <raizel.dev at yandex.ru> wrote:
> Hello, Robert.
> In VirtualPlanetBuilder there is no "manual" control, to be exact - it is impossible to specify the fixed quantity of triangles or vertices, or the landscape size. Why so?

VirtualPlanetBuilder by default generates tiles as
osgTerrain::TerrainTile, the TerrainTile has a user definable
TerrainTechnique that builds the final geometry data from the
heightfiled+texture data provided by the TerrainTile.  There are now
two TerrainTechnique implementations in OSG-3.4, GeometryTechnique and
DisplacementMappingTechnique.  Currently GeometryTechnique honours the
Terrain::SampleRatio and will downsample to fit with the target
SampleRatio, DisplacementMappingTechnique doesn't yet have this

In general though one builds a VPB database with the appropriate
resolution in mind so downsampling isn't required.  It's all LOD'd and
paged with it so load balancing is done automatically for you,  It's
not a "fixed quantity of triangles or vertices" but it such a metric
is a misleading one to use in most applications including games, the
bottom line is hitting a solid framerate, this is what VPB and the
osgDB::DatabasePager are all about.

I can't help but feel that you are a bit blinkered by preconceptions
how one to solve problems rather than setting the goals in a more
objective way relative to the game deliverables.


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