open gl

[Skiracing108]

what exactly is this??? my friend wants to know because im trying to talk him into buying a xfx 6800gt

[dsio]

OpenGL is a 3d API. The API is kind of like a layer between the 3D driver, and the 3D program, that takes what the program wants to produce, and then tells the 3D driver what it should look like. I think thats the best way to describe it.

Some other APIs are GLIDE (a 3DFX invented API from the early days of 3D) and Direct 3D (note direct x is a bundle of APIs rather than an idividual one, and Direct 3D is to OpenGL as Directsound is to OpenAL.

OpenGL is Open graphics language, and OpenAL is open Audio Language.

OpenGL games include Chronicles of Riddick, Doom 3, Quake 3, all of the games that are based on Quake 3, including all of the Jedi Knight games, Quake 2, and all of the games that are based on it, including Daikatana (if you like games that suck), and Quake, which is what Half Life, and Counter-Strike (non-source) is based on.

OpenGL is also used in Unreal and Unreal Tournament based games.

The major advantage of OpenGL is its portability. OpenGL can run on any windows platform. But so can Direct X. On Linux however, Direct X is unusable as its a Microsoft API, however OpenGL is in its element. It also runs on MAC OS, BSD Unix, Solaris, and any other flavour of Unix you could choose to run it on (within reason).

Aside from that, the new GLSL is much more flexable than the Direct X equivilant, so is preferable to use for high quality graphics.

OpenGL is currently at version 2.0.

No games are made for OpenGL 2.0 yet, but many top games, including Doom 3, and Chronicles of Riddick are OpenGL 1.5.

Nvidia has had a massive advantage over ATI in OpenGL since before the Radeon series was invented, mainly due to inferior ATI drivers rather than inferior hardware. These days, ATI is much better with OpenGL, but still nowhere near as good as Nvidia.

[calgar]

mmm, the earth series of games (earth 2140, earth 2150, earth 2150: the moon project ect) can use open GL as well, but it doesnt support weather effects when using it, why?

[dsio]

Likely because the weather effects that they chose to use in the game were very easy to do under direct X, but they couldnt be bothered spending time working out how to do it in OpenGL. The same thing often happens in reverse as well. Many of the special effects in the original Half Life, and its expansion packs, only work under OpenGL, and are not properly represented in Direct X. Unreal (the original) also falls into this category.

[calgar]

so fog is hard to do in open gl? how odd....

[dsio]

More than likely its that they were too lazy to do it, than it was too hard. There is more to it than just fog though, and even with fog, due to the various implementations of the effect, its hard to tell exactly how thick, dense, dark etc to make it. Fog is harder to produce accurately than you would imagine.

[cadaveca]

DSIO, the 6xxx line only supports OGL 1.5, right?

[dsio]

No, it fully supports OpenGL 2.0. 2.0 was not around when the 6 series was launched, and was not supported in official drivers, however it is supported in the latest drivers, 75.90 onwards.

[GrahamGarside]

but if you have these installed then you need to use the opengl version overide in rivatuner to get OpenGL 1.5 games working