You may find some benefit in going OpenGL due to the extra overhead that may occur with using osg::Geometry, however, I suspect that it would be very small. That said, I currently do a similar operation as you present in that I draw flightplans overlaying a scene. For this, I use straight OpenGL to draw the flightplan versus any OSG methods (there is a long history on why I do it this way that doesn't relate at all to the performance question you raise, but I digress). But, I had to "tweak" the code such as to balance the number of points (i.e., vertices) in the drawing to achieve acceptable framerate and performance as well as a smooth, accurate depiction of the flightplan. For instance, I didn't need to define a vertex to draw the flightplan at every 1-second interval along the path when the aircraft was moving at 140-knots.
So, I would suggest looking at an algorithm for determining how many points you really need to define the lines whilst balancing performance and accurate depiction. chuck ________________________________ From: [EMAIL PROTECTED] [mailto:[EMAIL PROTECTED] On Behalf Of Jason Sent: Friday, May 18, 2007 9:55 AM To: osg users Subject: [osg-users] OpenGL Vertex Arrays Hey everyone, Will using direct OpenGL calls to make vertex arrays buy me any performance increases over using osg::Geometry vertex arrays, or are they one in the same? I am drawing lines that represent flight paths, and when an aircraft flies over a particular part of the path it changes color to show its path history. This has a noticeable effect on framerate and performance, and right now I'm currently using straight OpenGL to draw the lines (no vertex arrays). Should I just try osg::Geometry for my dynamic data or is there a better solution? Thanks, Jason
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