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OpenGL 2.0

Discussão em 'Novidades Hardware PC' iniciada por Korben_Dallas, 13 de Novembro de 2002. (Respostas: 4; Visualizações: 1062)

  1. Korben_Dallas

    Korben_Dallas Zwame Advisor

    OpenGL has been a primary component of three dimensional rendering technology since its inception in 1991. OpenGL is implemented in a wide variety of applications, ranging from professional design software to multimedia presentations to interactive games. Currently available as version 1.4, OpenGL has proven to adapt with the evolution of graphics hardware, though it's age is becoming starkly apparent as compared to Microsoft's latest DirectX D3D technology. In hopes of revitalizing the decade old standard, 3Dlabs recently offers a new approach outlining the features of a possible OpenGL 2.0 revision.

    The concept of a proposal as compared to a standard needs to be clearly defined for the purposes of this preview article. The OpenGL 2.0 topicalities presented here are based upon a discussion text and early developmental engineering from 3Dlabs. Many vendors usually submit discussion texts and/or proposals during the OpenGL ratification process, then an appointed governing committee will analyze the various aspects of the given information before reaching an agreement about the final published standard. Since the OpenGL 2.0 development process is still in finalization stages, the information presented within this text will likely undergo multiple changes before a final OpenGL 2.0 specification is adopted for widespread industry use.

    About 3Dlabs

    3Dlabs has been a long-time contributor to the OpenGL community by providing advanced 3D hardware solutions to the professional marketplace. 3Dlabs graphics accelerators are commonly utilized for computer-aided design, multimedia development, and special effects rendering. 3Dlabs technology can also be found in many non-PC devices like military aircraft and personal cell phones. 3Dlabs is a wide market corporation with operations currently in Alabama, California, Massachusetts, Texas, Washington, Germany, Japan, and the United Kingdom.

    OpenGL 1.x Limitations

    The bulk of graphics development was centered on 2D rendering until 1997. The only areas of computing utilizing 3D technologies before this time were generally in the extremely high-end professional markets, such as CAD or virtual reality. The mid-90's release of desktop-oriented 3D accelerators like 3dfx's Voodoo or Rendition's Verite ushered in the concept of affordable 3D graphics for most mainstream PC users. Nearly a half decade later, desktop 3D video cards now include options like cube mapping, hardware transform/lighting, and programmable vertex/pixel shading. The OpenGL interface has evolved along with these new rendering features, but today's OGL 1.x does have substantial room for improvement as the next generation of video chipsets could finally outpace the capabilities of this venerable standard.

    For example, the popular OpenGL 1.3 API suffers from several major limitations, especially in regards to extending the base programming interface to include additional rendering options. The base OGL 1.3 specification documentation is approximately 284 pages of programming conventions and theory, while nVidia's extension documentation needed to implement options like per-pixel shading is well over 500 pages in length. The concern over efficient programming is clearly apparent once one factors in proprietary extensions from other corporations like ATI, Matrox, STMicro, and the vast number of other companies currently offering OpenGL compliant drivers.

    The age of OpenGL 1.x is the primary contributor to these limitations, as hardware has evolved at such a rapid pace over the past few years. System that were once considered to offer high performance only a couple of years ago are now entry-level configurations at best. The rapid development of hardware plays a significant role, as many manufacturers are adding OpenGL extensions without any real inter-corporate centralization in order to release products by usually grossly misrepresented retail availability deadlines.

    Worst yet, it appears OpenGL is following nearly the same development paradigm as DirectX. DX7 was the last fixed-function D3D interface, with the current DX8 standard being devised around poorly coordinated implementations of programmable rendering options. DX8 offers v1.2 programmable options, while DX8.1 offers a slightly improved v1.4 programmable feature set. This development schedule can wreak havoc on developers and hardware engineers. For example, the GeForce-3 supports v1.2, but the Radeon 8500 supports v1.4. In can be expected that programmers will likely opt for the lowest common denominator when coding, thus it is suspect whether some of these staggered options will ever be included in software released in the near future. Only with the release of DirectX 9 does Microsoft plan to offer a hardware independent programmable interface.

    Some developers have proposed extensions to OpenGL 1.x to add programmable rendering options including various extensions which may not be compatible with hardware from another manufacturer. Efforts are also being established to institute a generalized extension set for programmable shading, though these are still largely hardware dependant, thus they will not work with all OpenGL implementations. The goal of 3Dlabs' OpenGL 2.0 initiative is to create an uniform standard with a hardware independent shading language that functions with nearly all OpenGL compliant graphics accelerators.

    OpenGL 2.0 Envisioned

    3Dlabs hopes to address several key issues with its OpenGL 2.0 approach. OpenGL needs to evolve into an easier to code interface format with optimizations for memory management and timing control for increased performance potential. Another issue to be addressed is how to deploy generalized programmable shading routines which are hardware independent. The overall predominate concern is maintaining complete backwards compatibility with OGL 1.x standards while retaining the functionality of the new standard's advanced rendering options.

    3Dlabs has received positive support from many facets of the graphics engineering community. Universities like Stanford are already hard at work on extended OpenGL rendering routines which support some of the v2.0 conventions. Most hardware manufacturers and software vendors are also expressing overwhelming support, as an improved OpenGL standard could lead to better graphics and performance with less development overheard and greater product turnaround times. Regardless of those involved, 3Dlabs is working towards a future OpenGL 2 interface without any imposed royalties or operating system limitations in hopes of establishing a wider market base.

    OpenGL 2.0 Explained

    The 3DLabs approach is to first extend software through utilization and public promotion of certain OpenGL 2 standards, then gradually move code towards a "pure" OpenGL 2.0 environment. However, unlike DirectX 8, all OpenGL rendering conventions should be available for those seeking a pure OGL implementation at release, instead of staggering the releases in various subset revisions. As stressed earlier, the ultimate final goal is to reach a streamlined programming interface which offers hardware independency.

    Each of the programmable processor pipelines (software and/or hardware) essentially eliminate and/or replace a significant portion of current OpenGL conventions. The programmable vertex processor replaces the current options for transform, lighting, normalization, texture coordinate generation, and fog rendering. The fragment processor replaces the current operations for smooth shading, texture access, texture application, alpha testing, and pixel transfers. The pack/unpack processor included capabilities for flexible pixel formatting during memory move operations to create a coherent and consistent stream of pixel data to the rendering pipeline. The clear benefits of these programmable options are increased performance and image quality by removing the dependence upon fixed functions of static T&L pipeline routines. The associated rendering conventions for each of these advanced routines are unified through a comprehensive C-based programming language with special detail added for vector and matrix processing operations.

    3Dlabs also implements a new data buffer mechanism to be utilized for enhancement of the programmable rendering interface. The buffer is used to enable multiple-pass fragment programs with full stream processing support. Usage examples include multiple outputs from a single fragment routine, intermediate result storage, multi-spectral imaging, and acceleration of back-end rendering by reducing the time needed for read-back of floating-point images by the host bus. Additionally, the buffer space is accessible through either spatial or FIFO memory operations.

    Today's OpenGL 1.x provides no real direct control over when or where objects are stored or deleted within the memory address range. OGL 1.x also provides no direct control over memory copies or address fragmentation. 3Dlabs plans to implement a new management routine to allow for improved timing control over memory operations. The OGL 2.0 proposal sets policies and priorities for all datasets with timing estimates provided for each task. Additionally, all pinned policy operations allow the application to control memory store/delete and packing operations.

    John Carmack's Opinion

    "Given the good first impression, I was willing to go ahead and write a new back end that would let the card do the entire Doom interaction rendering in a single pass. The most expedient sounding option was to just use the Nvidia extensions that they implement, NV_vertex_program and NV_register_combiners, with seven texture units instead of the four available on GF3/GF4. Instead, I decided to try using the prototype OpenGL 2.0 extensions they provide.

    The implementation went very smoothly, but I did run into the limits of their current prototype compiler before the full feature set could be implemented. I like it a lot. I am really looking forward to doing research work with this programming model after the compiler matures a bit. While the shading languages are the most critical aspects, and can be broken out as extensions to current OpenGL, there are a lot of other subtle-but-important things that are addressed in the full OpenGL 2.0 proposal.

    I am now committed to supporting an OpenGL 2.0 renderer for Doom through all the spec evolutions. If anything, I have been somewhat remiss in not pushing the issues as hard as I could with all the vendors. Now really is the critical time to start nailing things down, and the decisions may stay with us for ten years.

    A GL2 driver won't give any theoretical advantage over the current back ends optimized for cards with 7+ texture capability, but future research work will almost certainly be moving away from the lower level coding practices, and if some new vendor pops up (say, Rendition back from the dead) with a next-gen card, I would strongly urge them to implement GL2 instead of proprietary extensions."

    John Carmack
    Lead Programmer
    ID Software

    Final Thoughts

    OpenGL 2.0 is still in its development stages, though 3Dlabs does offer some insight into the new features needed for this aging standards to maintain acceptance within the graphics marketplace. As noted earlier, the concepts and ideas presented here are only preliminary at best. The information gathered for this article was obtained through various discussion overviews published by 3DLabs and associated companies. It appears 3DLabs and other developers are steadily moving forward with development of a new and exciting OpenGL standard that strives to offer the best compatibility with sustained performance across the widest variety of hardware configurations available.
    fonte: xtremepccentral.com

    artigo original e com pics

    Por acaso tenho saudades do OpenGL... os jogos bufavam suave que era uma maravilha... hoje em dia parece que qq placa sofre para corre um jogo... o Half-Life qd saiu bufou logo a 1024 na TNT e com uma frame rate brutal... nostalgia :'(
    Última edição: 13 de Novembro de 2002
  2. Tecnoboy

    Tecnoboy Power Member

    E o Half Life era prai o jogo mais "realista" em termos de gráficos da altura e corria fx num Pentium 166MHZ com uma Banshee de 16MB PCI ! ;)
  3. SoundSurfer

    SoundSurfer Power Member

    Saudades do OpenGL??


    jogo que é "JOGO" tem de ter opção de OpenGlRendering :P (o UT2K3 tem..)

    Eu pessoalmente só tenho usado o OpenGL para programar coisas muito "basicas" como introdução ao 3D...

    Mas vamos lá ver se o "gurus" do jogos gostam deste novo OpenGl...
  4. chight

    chight Power Member

    Eu jogo o Unreal 2003 no portátil com a radeon 7500 em linux, através de OpenGL, e só noto diferenças a nivel de alguns efeitos e cores de resto tá igual, e muy rapido :)
  5. NeoToPower

    NeoToPower 1st Folding then Sex

    ya, em OGL o UT2k3 corre muito, mas muito mais rápido! Basta dizer que na minha actual maquina era praticamnete intragavel mesmo a 800x600! Agora corre fino com os drivers beta da ati pra dx9 e em OpenGL a 1024x768!

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