[osg-users] Dynamic Geometry per frame

[Sebastian Messerschmidt]

HI Adam

Simply configurethe geometry to
     geom->setUseDisplayList(false);
     geom->setUseVertexBufferObjects(true);
in order to deactivate the display list generation

Also, I think you don't have to use setVertexArray, as long as you keep 
the array as a pointer. (@Robert, is the data actually copied?)

Cheers
Sebastian
> I'm looking for ideas/the correct way to implement a vertex array or VBO in OSG that gets updated each frame.
>
> I have a camera that renders to a FBO. It renders a bunch of rain drops to an alpha texture that is applied to a cars windshield. Each frame on the CPU I update the rain drops to move down, and I also spawn new ones and erase ones where the wipers wipe them away.
>
> I created a callback class inherting from osg::Drawable::UpdateCallback, that gets called each frame, I perform my logic and then re-use the same osg::Vec3Array and just update it per frame and then reset the drawable with:
>
> osg::Geometry* geometryNode = drawable->asGeometry();
> geometryNode ->setVertexArray(rainState->vertices);
>
> Unfortunately this setVertexArray is killing my framerate from 98 to 78. All this does is make the Drawable::draw() function make a new display list, do the draw functions and finish.
>
> ------------------
> Read this topic online here:
> http://forum.openscenegraph.org/viewtopic.php?p=63294#63294
>
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>
>
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