Ignore this post. The answer is: DrawElementsUInt is a VectorGLuint. Of course, I had to post and show my ignorance first before I figured that out. :-/ Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com <http://www.skew-matrix.com/> +1 303 859 9466
_____ From: osg-users-boun...@lists.openscenegraph.org [mailto:osg-users-boun...@lists.openscenegraph.org] On Behalf Of Paul Martz Sent: Thursday, March 19, 2009 2:35 PM To: 'OpenSceneGraph Users' Subject: [osg-users] DrawElements* memory management Hi Robert -- I have a question about how the DrawElements* family of PrimitiveSets handles the pointer to the indices. In OpenGL, data is bound/copied at call time, so if I were writing a plain ol' OpenGL app and calling glDrawElements, I'd pass in a pointer to my index data, and when the call returns, I'd know the indices had been copied and I could safely delete the array of indices. In OSG it's a bit different. Even after I create the DrawElements PrimitiveSet, I need to hang on to the index data memory, as the memory will be accessed during subsequent rendering and/or write operations. Unlike other OSG objects, the index array isn't reference counted internally. Indeed, the interface looks a lot like the glDrawElements call in that the index data parameter is a plain pointer, but it does not act like glDrawElements as it doesn't immediately copy the index data. This forces my app to keep the data around and ensure it isn't deleted. This is cumbersome in modular programming situations. Imagine I have a NodeVisitor that converts DrawArrays to DrawElements and therefore allocates memory to hold the index data. The processed scene graph could have a life that extends far beyond the scope of the NodeVisitor, so it doesn't make sense to keep the addresses stored in the NodeVisitor (where the memory was allocated). So who should keep track of the index data memory addresses? Who should own deleting that memory? This isn't the first time I've encountered this situation, and I thought perhaps you had encountered it as well and maybe had a good solution that I was not aware of. If so, please let me know. Thanks in advance. Paul Martz Skew Matrix Software LLC http://www.skew-matrix.com <http://www.skew-matrix.com/> +1 303 859 9466
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