OpenGL 2.0: Chasing DirectX

MJ writes "Is OpenGL 2.0 All That? Hopefully you will be able to answer that yourself after reading this article from XtremePcCentral. They have cool looking leap frog graphics with lots of arrows and a quote from John Carmack, what else could you ask for? Robert Richmond does a great job of delving into this subject. Carmack says, '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.'"

Comments

OpenGL is vital for Linux

[bsharitt]

The contiued success of OpenGL is vital for the survival of Linux on the desktop. Without it, making games for Linux is impractical. I don't think WineX can be counted on to keep up.

All in the name

[prisen]

OpenGL..I think that says it all. DirectX is a great platform, don't get me wrong. It does its job. But what happens when DirectX doesn't do what the programmer wants/needs it to do? Too bad, gotta wait for DirectX (current version + 1.0). What happens when you want to release your software for more than one platform? Out of luck here. I think there are quite clear advantages.

Re:All in the name

[CoolVibe]

I wouldn't put down the Mac as of yet, since they are picking up pace at the moment. Same goes for the free *nixes. If those platforms weren't ebcoming interesting, companies like Nvidea wouldn't have made accelerated drivers for FreeBSD and Linux.

I realize that Direct3D has gotten better, but still, it's going to be a tough job for MS to totally finish off OpenGL. It's well rooted into spaces other than gaming, like CAD/CAM and VR research. And if MS tries to patent it away, that will never work, because of prior art.

I think MS's stance toward OpenGL is neutral. I'd say that if somehow Direct3D would die off, MS would embrace (and probably extend) the OpenGL standard.

What 3D library does, say the PS2 and the Nintendo console use? Their own in-house one? I'd guess OpenGL, because it's available on many platforms, and it's portable. And don't forget the wealth of documentation and example code that's out there for OpenGL. It'd save a lot of time training-wise. It's a wise choice if you do console development on a workstation and if you can just cross-compile so it'll work on the console. Other than the X-box (which is just a IA32 machine on funny hardware), DirectX is indeed only available on 2 platforms.

I'm not a console-developer though, maybe someone who develops 3D-action games for consoles that are not X-boxes could comment?

Re:All in the name

[Chris Burke]

You can't add more stuff to the API if you find that it's lacking. The reason is that you can't add your new functionality to the hardware, which is the whole point in using OpenGL in the first place.

Ah, but what if you can add new functionality to the hardware, because you are the manufacturer? With DirectX, nothing changes -- if the API doesn't support what you want, it won't until MS says so. With OpenGL, you can expose new hardware functionality through an extension. Programmers can use your hardware's new features immediately, unlike with DirectX.

So, you still have to wait for the next version of OpenGL to come out, and graphics-cards manufacturers to build cards with it in mind.

This is the exact opposite of what actually happens. In reality, manufacturers build cards with new features and expose them through extensions. Then, in the next revision, the new functionality may be folded into the standard API. The hardware leads the API, rather than trails, without sacrificing the ability to use the hardware immediately.

This is one spot were DirectX has a big advantage over OpenGL. DirectX is designed by only one party, rather than a big committee of different companies who want different features. As such, DirectX has a much faster development cycle, and gets improvements quite often.

OpenGL gets an improvement whenever a vendor has an idea for what new trick they'd like their hardware to pull. Yes, it takes them some time to agree on what the next official version of the API should look like, but that doesn't slow the development and acceptance of new features a bit. Vendors can innovate as much as they want, without waiting for a central body to approve and support their innovation -- that is a big advantage.

As opposed to DirectX... I just can't see how being dependent on a single outside vendor to support your hardware's features is an advantage.

Four years is a long time in the world of 3D graphics.

Yes, and in those four years we've seen the development of hardware T&L, texture compression, pixel and vertex shaders... And OpenGL has not wanted for one of them.

problem with opengl

[SystematicPsycho]

The problem with opengl is that vendors decide to add there own extension to it, and too many vendors do such a thing. If opengl is going to outperform the rest cooperation between vendors and the opengl commitee needs to take place more often.

vs. DirectX

[wray]

MS will of course continue to press DirectX, but, the more Linux, and FreeBSD, and "alternative" platforms become used, and viable, (Thanks to NVIDIA for their drivers for FreeBSD AND Linux) the more appealing it is for developers to create cross-platform games. This is why it is essential for OpenGL to progress, and why I am so excited for version 2.0.

BTW: what is the status on the MS patent issues? Anyone know?

DirectX

[be-fan]

I'm vehemently anti-Microsoft, but for a long time, I've loved DirectX. Of course, the DirectX team has always been something of a rebel element within Microsoft, so I don't feel too bad :) Hungarian notation aside, it's a wonderful API to use. I didn't start using it until it was around 6.0, which explains why I didn't get put off by the stinky earlier versions. From what I've seen of OpenGL 2.0, it's a worthy competitor to Direct 3D. It's comparable in terms of features, and has a nice clean design that's much more straightforward than Direct3D, which is admitedly complex. However, OpenGL is a replacement for D3D only. OpenAL is probably comparable to DirectSound, but there is nothing comparable to DirectShow, DirectPlay, or DirectMusic on Linux. A breakdown:

DirectShow - Gives you a unified media framework. Allows plugins to be written independent of program, and allows programs to use any installed plugins. The code for something like this exists (or soon will) in the Linux world, in the form of gstreamer, aRts, mplayer, and xine, but unfortunately, the latter are not one framework, but several. In particular, it infuriates me that there are codecs that mplayer has support for that xine doesn't, since Xine has KDE interface and mplayer doesn't.

DirectPlay - A high level networking API. DirectPlay is independent of the underlying protocol, and encapsulates high level networking concepts like meeting places and session management.

DirectMusic - This is something that Linux really doesn't have, to my knowledge. DirectMusic allows the composition of dynamic soundtracks using a powerful MIDI engine. I know MIDI sounds like a throwback to the past, but several modern console games have taken to using it to allow in game music to reflect in game events.

Re:DirectX

[Graff]

OpenGL is a replacement for D3D only. OpenAL is probably comparable to DirectSound, but there is nothing comparable to DirectShow, DirectPlay, or DirectMusic

I'm not sure about some of those, but I do know that there is OpenPlay, an alternative networking API. Here's a quote from the site:

What is OpenPlay? OpenPlay is a cross-platform network abstraction layer designed to simplify the task of creating programs which communicate across multiple computers.

While originally designed for multiplayer games, it is useful for any developer who wants an easy, platform-independent way to send messages to programs running on other machines. It completely abstracts both OpenTransport and Winsock, and its plug-in architecture makes it easy for you to support new transport protocols.

Games are good but...

[ikekrull]

Where are the new 'Pro' features.

To me, OpenGL lacks really good object-picking algorithms, has problems with coplanar geometry (lines on top of polygons, for example), and poor typography support.

Personally, i would like to see OpenGL move towards being more suitable for general purpose displays, which would allow easier implementation of things like Apple's OpenGL accelerated windowing system.

I know that programmable pixel shaders etc. are useful, but why does OpenGL not specify things like raytraced and radiosity lighting models, along with voxel primitives, and features for window and page oriented output of arbitary geometry (including support for true curves/surfaces etc.) ala Postscript

Many of these things can be implemented at a low level by pixelshaders, but whats the point of a high-level API that simply exposes a lower-level API?

Even though these things can't easily be accelerated by current consumer hardware, neither could gouraud-shaded polygons a few years back.

OpenGL does not seem to be moving forward in defining new and easy ways to define computer imagery, and is chasing the tail of DirectX, seemingly to avoid losing relevance as a gaming platform.

This, to me, is not the right approach - I don't want to see OpenGL discarded by games programmers, but I also want to see OpenGL become a more powerful API across-the-board that makes my life as graphics programmer easier, not harder.