openscenegraph

hai,
i am using openscenegraph for rendering .flt files.Using osgviewer i can walk thru .flt file. my model(.flt) is forest terrain.
my problem is, i am seeing white line between two trees.what may be the problem?
is it problem of visual database? i have a image showing the problem.i have marked the problem in red. Please help me to find out the solution.
Thanks in advance.

Link to the image
file

Dude. Please don’t cross post!

Any follow-ups please post to this thread. (cross-post thread collapse)

This has nothing to do with Advanced OpenGL Coding.