OpenGL++

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OpenGL++ was intended to be a powerful layer above the OpenGL 3D graphics system written in C++ that supported object-oriented data structures. The project started as the result of a partnership between SGI, IBM and Intel (and later Digital Equipment Corporation as well) to provide a higher level API than the "bare metal" support of OpenGL. Work on OpenGL++ ended when SGI decided to partner with Microsoft instead, leading to the Fahrenheit project, which also died.

[edit] Development

OpenGL++ (OGL++) was intended to offer a selection of routines and standardized data structures to dramatically simplify writing "real" programs using OpenGL. Instead of the programmer having to keep track of the objects in the 3D world and make sure they were culled properly, OpenGL++ would include its own scene graph system and handle many of the basic manipulation duties for the programmer. In addition, OGL++ included a system for modifying the scene graph on the fly, re-arranging it for added performance.

Much of OGL++ was a combination of ideas from earlier SGI projects in the same vein, namely Open Inventor which offered ease-of-use, and OpenGL Performer which was written separately from Inventor to deliver a system that optimized scene graphs for increased performance and exploited scalable architectures. It was later intended that a new design could get the best of both worlds while forming the underlying framework for several projects including CAD, image processing, visual simulation, scientific visualization and user interfaces or 3D manipulators allowing them to interoperate, thereby offering both rapid development and high performance.

SGI has recently been involved in a similar effort in partnership with Sun Microsystems that was intended to produce a scene graph for the Java programming language. This project eventually failed, and led to the separation of Sun and SGI's efforts, Sun releasing theirs as Java3D. SGI packaged some of their developments into the Cosmo3D produce suite, which as a sort of marketing name for a wide variety of semi-related products. By then a CAD/"Large Model Visualization" layer of functionality called OpenGL Optimizer had already been implemented on Cosmo3D and then released as a product. Other "front end" packages like, Cosmo Code, a VRML authoring tool, were produced by a different division, it ran on OpenGL directly. OGL++ was intended to be a cleaned up and more flexible version of Cosmo3D, most of the Cosmo3D team started work on OGL++ and a lot of the effort was aimed at a specification and implementation that could deliver on the promise of a truly powerful yet generic scene graph.

[edit] At the end

In the end, there is little to show for any of these efforts. Partnerships with Sun, Intel and IBM and Microsoft all led to nothing as SGI jumped from project to project. In retrospect, SGI reacted badly to a rapidly changing environment. An internal desire to create a generic but extensible scene graph was constantly sidetracked by a belief that SGI couldn't go it alone. Partnerships were formed and later abandoned due to irreconcilable differences or simply as priorities and internal pressures shifted. OGL++ was the most nacent of these efforts and its failure forced an unholy alliance between Microsoft and SGI in the form of Fahrenheit. Ancillary issues like powerful CAD APIs running on Cosmo3D complicated the picture. In the final analysis the new unified scene graph concept was bounced from project to project, and eventually died in 2000 when Fahrenheit was killed.

Today, no such standardized scene graph exists, and SGI has all but exited the API world. SGI has released the earlier Open Inventor code into open source, but the source to OGL++ was never completed to any satisfactory degree. No specification exists and as with OpenGL the spec and idea behind such an open platform would have been what lent it it's lasting value, not a single implementation of a scene graph idea.