OpenGL++: Difference between revisions

Revision as of 17:13, 18 June 2008

Revision as of 16:34, 21 September 2008

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Scene graphs were generally left to the developer to implement, and it was all too common to see poor examples that led to poor performance. SGI had worked on a number of projects that were intended to help the developer produce a high-quality scene graph, but none of these had become widely used for a variety of reasons. [[Open Inventor]] was one such example, and was intended to simplify building the scene graph, but the results were not necessarily very high performance. [[OpenGL Performer]] was a similar project that was intended to produce high-speed scenes and support very large numbers of objects in the "world", but was not particularly easy to use. Both teams had already realized that there was no particular reason the two systems could not be combined into one, offering both ease-of-development and high-performance.<ref name=ARB>[http://www.cg.tuwien.ac.at/~wimmer/apis/opengl++_summary.html Scene Graph Standard for OpenGL], ARB Meeting Notes</ref>

During this period SGI started work on their [[Cosmo3D]] suite, which was a marketing name for a wide variety of semi-related products. Much of the effort revolved around the [[VRML]] standard, which would live on beyond the Cosmo3D project. In order to make VMRLVRML something more than a paper standard, SGI also provided the Cosmo products that use VRML natively, including a scene graph system that read and wrote VMRLVRML and rendered it using a custom OpenGL stack, CosmoGL. A CAD/"Large Model Visualization" layer of functionality called OpenGL Optimizer was implemented on Cosmo3D and released as a product. Other "front end" packages like, Cosmo Code, a VRML authoring tool, were produced by a different division and did not use the Cosmo scene graph at all.

Cosmo's scene graph was by no means a unique solution at the time, and a number of other graphics companies were working on similar ideas at about this time. At the August 20-21, 1996 meeting of the [[OpenGL Architecture Review Board]] (ARB) SGI floated the idea of a new standardized scene graph similar to Cosmo3D but with the express intent of being based on "standard" OpenGL. There was some interest in the concept, so at the December 9-10, 1996 meeting the group presented the first draft of the OpenGL++ concept.<ref name=ARB/> A follow-up meeting in February 1997 demonstrated that there was considerable interest from most parties, with the exception of Microsoft and Sun, although there were concerns as to whether or not the ARB was the right body to support such an effort without diluting their primary job of supporting OpenGL.<ref>[http://www.mrpowers.com/Papers/OpenGLPlus/OGLARB.htm Meeting Notes, February 17-19, 1997]</ref> Development continued throughout 1997 including several distributions of the [[API]]. However, the ARB notes "There's been lots of work, but relatively little communication."<ref>[http://www.opengl.org/about/arb/meeting_notes/notes/OpenGL++_notes_6-3-97.html OpenGL ++ ARB Interest Subcomittee Meeting Notes]</ref>