[osg-users] how to zoom in and out in orthographic projection

[Paul Melis]

Posting your question just once and waiting a bit for an answer would be 
nice...

santosh wrote:
> how to do zoom in and out in orthographic projection?
> As I zoom in  the detailed geometry should be loaded .
> 
> Right now I am scaling the  geometry but in this method the details are 
> not getting loaded.

How did you implement the zoom in your projection, just by changing the 
viewport to be smaller? In that case the distance from the viewpoint to 
your objects doesn't change and therefore the same LOD-level will 
continue to be selected, as the default RangeMode for an osg::LOD is 
DISTANCE_FROM_EYE_POINT. Changing it to PIXEL_SIZE_ON_SCREEN should make 
your LODs switch to more detailed models if you zoom in.

Paul