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McBugzz

OpenGL Emulation in OpenGL and Direct3D

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McBugzz    122
Direct3D has the magic HEL driver. Is there anything like emulation for OpenGL? As far as I know there''s none (at least no built-in), but I want to make sure.

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python_regious    929
Well, there''s Mesa, which is a software OpenGL implementation. For more advanced features however, older nvidia cards can use the NV30 emulation driver. It''ll run slow as hell mind.

You have to remember that you''re unique, just like everybody else.

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VolkerG    151
What should the emulation emulate?
OpenGL is part of windows, you have all operations working. So what should an emulation do?

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Woodoo    189
Linux has Mesa...

Windows has a crappy OpenGL 1.1 software implemenation...


btw. today it should be hard to find a computer without a graphic card which can do OpenGL...

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VolkerG    151
Doesn''t the MS implementation of OpenGL work on any decent video card (don''t want to uninstall my nvidia driver to test that).

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Brother Bob    10344
quote:
Original post by VolkerG
Doesn''t the MS implementation of OpenGL work on any decent video card (don''t want to uninstall my nvidia driver to test that).

MS''s implementation is a software implementation and does not depend on the graphics card at all.

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VolkerG    151
quote:
Original post by Brother Bob
quote:
Original post by VolkerG
Doesn''t the MS implementation of OpenGL work on any decent video card (don''t want to uninstall my nvidia driver to test that).

MS''s implementation is a software implementation and does not depend on the graphics card at all.

That''s the point:
- You have software emulation if the driver does not have its own OpenGL implementation.
- If you have an OpenGL enabled driver all functions are supported, too.
So: WHAT should an emulation like the HEL do? You could as well say, there is a HEL for OpenGL.

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C-Junkie    1099
OpenGL is a spec, and as such any driver you use must implement the whole thing. It''s up to the driver to emulate whatever isn''t present in the card.

The whole "HEL" thing is over blown dumbness, it doesn''t do anything special except say that "if the card don''t support it, it''ll be rendered in software..."

There''s also something to be said for OGL extensions... which is where it gets murky. Here''s hoping for a newer OGL spec.

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McBugzz    122
Well it''s all about extensions. When I write a DirectX app I don''t have to worry about real hardware support, but when I''m writing a program that uses, for example ARB_Vertex_Program, won''t I have problems with hardware that is not OpenGL 1.5 compliant? Or who will do the multitexturing if the car''s not familiar with OpenGL 1.3 (or just doesn''t have the ARB_multitexture)?

So the question is, will my app run in full functinality on older hardware like TNT2 (I''m using GF4Ti) with the latest drivers installed, if I use something that is not directly supported by that hardware?

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Brother Bob    10344
If the extension or the version of OpenGL you''re looking for is present, then every feature for that extension or version is available. If the hardware itself does not support it, the driver have to do it in software instead. So if ARB_vertex_program is exposed as an extension for the TNT2 you mention, you can use it.

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VolkerG    151
Even DirectX does not emulate everything. Most prominent example are the pixel shaders.
And I don't think that Direct3D can emulate texture units that are not available in HW.

[edited by - VolkerG on January 26, 2004 7:04:56 AM]

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