When will DirectX 10 matter for SL ?

I get confused about OpenGL and DirectX. Will DirectX 10 matter for SL at some point ? TIA.

Doubtful. Highly doubtful. Not anytime remotely soon, anyways.

Direct X and Open GL are two competing APIs (programming instructions) for communicating with graphics cards, allowing you to render graphics.

Direct X is made by Microsoft and is Windows only, I believe it also requires the programmer to know more about the graphics cards they want to support, which can make supporting different cards more difficult.
Open GL relies on graphics cards manufacturers to develop good drivers for their cards, but is overall a simpler interface to use.

In terms of capabilities, Open GL is still competitive compared with Direct X 10, and there is a new standard on it's way (Open GL 3.0) which will hopefully be even better.

However the main point is the cross-platform capability, you can use Open GL on almost any platform, using almost any programming language, so long as the graphics cards your users have support Open GL on your platform (most do).

Direct X would require SL's rendering engine to be completely re-written, and most likely require chunks of SL to be written in C# (programming language) which is also Windows only.

Open GL is also open-source, which is another bonus =)

OpenGL and Direct3D (part of the DirectX spec) are 2 different graphics APIs, serving a similar purpose but incompatible with each other. Both ATI and Nvidia support both in their drivers for Windows.

OpenGL benefits from being cross platform. Interestingly, Microsoft were one of the founding members of the OpenGL Architecture Review Board, which standardises extensions, but then left. SGI (who created OpenGL) and Microsoft also had a joint project to unify OpenGL and Direct 3D, which fell by the wayside.

DX10 will never matter for SL. Vista is the only platform that will run it. So it is somewhat pointless at the moment... unless you want a client for xbox 360 or something?

DirectX 10, per se, will never matter for Second Life, as it is an OpenGL application. (A port of the SL viewer to DirectX has to be considered Highly Unlikely; the only likely reason such a thing would ever happen would be as a side effect of an XBox360 port, which also isn't very likely.) However, the new shader capabilities that are part of the DX10 specification will likely also be in OpenGL 3.0, and the SL viewer may someday use them. Using the additional capabilities might allow a future viewer to offer better graphics, or to run faster while offering the current visual quality.

If you are buying a new video card, you might as well buy one with DX10 capability (nVidia 8000 series or Radeon 2000HD or 3000HD series), as they only slightly, if at all, more expensive than older cards offering the same performance. But if you already have a good card with full DX9 capability (nVidia 6000 or 7000 series, Radeon X or X1000 series) and you are satisfied with its performance, there is no compelling reason to upgrade right now -- well, not for SL anyway.

Err.. Might want to double-check that bit.

Well, it would require a rewrite of SL rendering code but DirectX is very much _not_ C# only - where'd you hear that???

Linden Lab wants to be able to use Linux and other operating systems also so I think they will stick with OpenGL.

well the direct X serie is pretty much another attempt of Microsoft to lock users AND programmers into the windows platform, and sadly, the PR work pretty well.

But directx10 is pretty much equal to the latest opengl specs. And both api have similar performances in the end.

For what i know opengl is easier to code with, and is cross platform.