Linux Gaming: Is SDL The Answer? May 01, 2002 Paul Sullivan

Introduction

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The Little Engine That Could

I'm a big fan of Linux. Even though now and again I criticize it, I really like the operating system and want it to succeed. I think that all the releases of Mandrake since version 7.0 have been good, and the 8.x releases are particularly worthy of praise. Linux has so much going for it. It is free in almost all basic distributions, is not reliant on the Microsoft juggernaut and is heralded as being faster and more stable than any version of Windows except for Windows 2000. It is far more secure than Windows XP and is much less oppressive too. It does not try to shove a specific media player or instant messaging client down your throat. It does not try to force you to sign up for Passport or .Net services and no distribution I'm aware of spies on your activities and reports it back to the home base. On top of all that, there is no such thing as Product Activation and Forced Registration.

So with all of these things going for it, what is holding Linux back, particularly in the consumer market? It has a lot of applications, like Gimp, Star Office, Koffice, Mozilla, My-SQL and a whole lot more. It is getting much improved in the area of peripheral support as the kernel adds functions dealing with USB, for instance. It also has impressive video driver support thanks to the Xfree86 movement and improving support from companies like ATI , Nvidia and Matrox. Even printer support is getting substantially better. Now, if they can just get those fonts figured out...

Back on topic. So, what do I think may be the biggest area of opportunity for the consumer market? Why, gaming of course.

It's Time To Play The Game...

Why do I put up with Windows, even though I am totally angered at Microsoft corporate policies? Games. That is the primary reason. I think Windows XP is bloated spyware that shoves all things "Microsoft" down your gullet. I think that Windows 2000 Professional is pretty close to awesome, but it still does not have all the peripheral and gaming performance I would like. I stick with Windows 98 SE for simplicity and compatibility, not to mention raw speed. Almost all of my games play great on 98 SE, and I'm not about to upgrade if I have to leave my games behind.

I've talked before about DirectX and how nice it finally is to have a functional, all encompassing API for interfacing with gaming hardware. OpenGL is great for a lot of things, but DirectX is a broad, well-supported umbrella that helps fend off a lot of the annoying raindrops when a downpour hits you on the development front. It is not perfect, but it is there, and it is being widely used.

So what does Linux have? Well, as a follow up to my previous Linux Gaming article, I want to explore one of these alternatives called the Simple DirectMedia Layer, or SDL. This library is to Linux what DirectX is to Windows, and what started as a grass-roots movement from a dedicated group of programmers is expanding into an incredibly useful tool for creating games for, and porting games to, the Linux platform.

I was able to get in touch with Sam Lantinga, the originator of the SDL initiative, and he was kind enough to agree to an interview. I had some nice back-and-forth discussions via Email and later created a list of long-winded questions that he was gracious enough to answer. He is an extremely patient man, it would seem...

The following pages contain the unedited questions and answers from one of the pioneers in Linux gaming. Hopefully you will find them as helpful and informative as I have.


SIDEBAR: It is so refreshing to find leaders in the field who are so accessible and willing to assist. There are times when you seek interviews and are very rudely dismissed, but Homey don't play that here...

Interview Page One

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Here We Go

These questions were sent to Sam Lantinga in March, 2002 and he responded quickly to the entire lot of them. Perhaps I did not put enough effort in. Maybe I'll have to bug him for a follow-up. Regardless, here is the interview for your wandering eyes to read:

1. FiringSquad: Did you initially envision SDL as a direct competitor to Direct X?

Sam Lantinga: No, SDL was originally designed as an API to provide the services that multimedia applications need across many different platforms. This is still the intent, it just happens that it works very well for developing games on Linux where there isn't a DirectX equivalent.

2. FS: Were you able to use Open GL and Open AL “as is” and then develop the rest of the SDL API around them?

SL: SDL doesn't really use OpenAL at all, although games have been written that use both. As for OpenGL, SDL just acts as a sort of cross-platform glx, setting up the window and GL context, but letting you do all your own work, and introducing no overhead. As such, the SDL API doesn't really interact with the OpenGL API.

3. FS: Was the development of SDL more of a solitary or team effort?

SL: I would call it more of a team effort. I wrote most of the core code, but over the years it has been improved upon by so many different people that it literally would not be the API it is now without everybody's help and suggestions.

4. FS: Can you describe some of the challenges you faced during the development process, from beginning to current day?

SL: The biggest challenge I face during SDL development is balancing the needs of the general application with the services available on different platforms. For example, when designing the audio API, the most common way to access the sound card on Linux is to open the audio device and write a sequence of audio samples to it to play at some point in the future. However on most other platforms, you can't queue audio in that way, you have to keep the audio ready and feed it to the DSP as the DMA buffer is emptied. The audio API I ended up writing reflected this real-time approach.

5. FS: The next version of SDL is said to be a major re-write. Can you go into detail as to why such a re-write is needed, and also what it will entail?

SL: There are a lot of things that would be nice to have in the SDL API that it was never really designed for. Two examples off the top of my head are multi-monitor support and support for hardware audio buffers. These two features alone would require a complete rewrite of the video drivers and a complete redesign of the audio API. There are many other places in the API that could use revisiting, and so the idea has been to start fresh with these concepts in mind.

Interview Page Two

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6. FS: I have been an admirer of the direction that Loki took in the Linux game area, as I prefer native applications to emulations. Can you describe the thought process behind the big decision not to cut corners and to strike out on your own in support of native applications?

SL: Loki always took the viewpoint that it was better to implement game subsystems natively rather than using emulation layers which could add significant overhead. It turns out that aside from major subsystems such as audio and video, calls to emulation layers don't end up adding very much overhead since the bulk of the work a game does involves its game logic and rendering, and not system interfaces. However, implementing the subsystems from the ground up as native code gives the developers opportunities to take advantage of patterns in the way the game accesses the system services to make them as fast as possible and often result in a game that is more stable on Linux than on Windows.

7. FS: How do you feel about projects such as Wine and WineX? Do you feel that they are a discredit to Linux because they “windowize” the experience, or do you think they help broaden the appeal of Linux to Windows users, for example?

SL: They are a great boon to people who, for one reason or another, must have certain Windows applications on their Linux box. On the other hand, I dual boot, and have no problem actually running Windows to run a Windows game.

In the long run, companies that care about supporting Linux are more likely to develop ports of their applications if they don't run on emulation layers. For companies that don't care, well, it doesn't matter at all, and it's nice to be able to run their applications on Linux if that is what you want to do.

8. FS: It seems that while the server side of Linux looks strong, the desktop side of Linux is struggling, what with Corel Linux being all but gone and Red Hat stating they are pretty much giving up on the desktop. Can you give us an idea of the current state of the Linux market and maybe let us know which direction you would like to see it move?

SL: The Linux desktop is caught in the classic chicken and egg problem. Which come first, the applications or the customers? I think overall, the Linux desktop is making great strides in making Linux a comfortable place for end users to compute, and that will only improve as time goes by. Whether or not this will translate into Linux as a desktop market force remains to be seen. It really is more up to corporate policy than anything else. If large organizations decide to switch over to Linux on the desktop, then more organizations will do it, and there will suddenly be real customers for large scale desktop applications.

9. FS: What are your impressions of Mandrake’s new “Gaming Edition”? Is it a good first step in targeting gamers, or do you feel there are better ways to approach that market segment?

SL: It's too bad that the one of the most popular games to come out on Linux is one that is emulated, but I hear good things about the distribution.

Interview Endgame

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10. FS: Which distributions do you feel best represent Linux, and why?

SL: Every distribution represents Linux. Linux is almost by definition a great teeming mass of coordinated development and distribution. Each company and individual that takes part in this process is a part of Linux.

11. FS: What are your feelings regarding the movement by some Linux vendors towards product update subscriptions? Does it fly in the face of the “free software” movement? Given the dot.com fallout, is it a necessary process in order for Linux to survive and prosper, or is there another way?

SL: Product update subscriptions smacks of .NET to me, but what can I say.

12. FS: Is the Linux market about where you expected it would be, or has it grown at a different rate, in a different direction than you anticipated when you first got into the community?

SL: I'm disappointed in the reception that commercial Linux games have received, ranging from excitement in the beginning to more recently fuck it, just give me the game. My feelings are strongly tainted by the demise of Loki, so I should probably not make a stance on this.

13. FS: What are your thoughts regarding the perception that Linux is a fractionalized community? There are different distributions and the KDE vs Gnome debate, for example, and there are critics who simply feel that Open Source is not as efficient as a dedicated commercial team. Do you feel these concerns are valid?

SL: I think that if anything, these are the strengths of Linux. Linux is software evolution on a rabid scale. :)

14. FS: What, if anything, do you think is holding Linux back?

SL: The lack of rapid widespread adoption by large organizations.

15. FS: If you could guide the Linux community forward, what are the two most important areas that you think it should concentrate on to help ensure that Linux thrives?

SL: Make sure that there is a place for commercial companies to sell software. Make sure that the underlying operating system and development APIs remain stable enough for everybody to thrive.

16. FS: Are there any other comments or concerns about Linux and the gaming communities that you wish to communicate to people involved in and considering the use of Linux as an alternative OS?

SL: Nope, just remember that it's not a holy war, we're here to have fun. :)

Conclusions

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Walk Like An Egyptian...

We live in a world of dwindling choices. Microsoft has made Windows a workable gaming platform, and with the Xbox is set to push its lead even farther. The DirectX implementation has matured significantly, and with the exception of OpenGL on the graphics end, it has had little hardcore competition.

However, the rise of SDL may stem the tide and provide users with their first legitimate alternative in terms of a unified API. It has the advantage of being cross-platform in design and as evidenced by native Linux releases from Loki and other high-level production groups, can be quite effective when used properly.

Perhaps it is a personal preference, but initiatives like WineX, at least to me, are counter-productive to the native Linux movement. I know many people moan and complain that WINE is not an emulator, but frankly, I just don't buy it. If you are intercepting Direct X calls and acting on them, then it is emulation, no doubt about it. You are setting up an environment designed to "Mimic" Windows and DirectX, and no matter how you try to spin it, if it walks like a duck and quacks like a duck, it's a duck, ok?

The Real Deal

To me, SDL is a much cleaner way of doing things, and it doesn't shortchange Linux in the process. Linux needs to find its own identity in the hearts and minds of gamers, and it won't be able to do so as long as people are taking shortcuts and avoiding development of native Linux games. Linux needs to have dedicated groups of programmers willing to put it on the line for the belief that Windows is not the only solution. Application development in Linux has surged over the last few years, but unfortunately, the gaming market hasn't taken off with the same speed.

SDL is the best chance yet to change that reality. It is simple but comprehensive enough to take on large mainstream titles. It is not driven by a single company with an agenda to dominate a single platform. While I focus on Linux a lot, it really is a multi-platform solution and that should not be forgotten.

My hope is that programmers get behind SDL in a very big way and start pushing great titles out the door so that we will have dozens more titles sitting on the shelf. It would be great if distributions could bundle some of these native Linux titles with them instead of having to rely on WineX and The Sims For Windows to make the sale.

For some, the whole point of choosing Linux is because it is NOT Windows. They want apps that don't have any ties to Windows whatsoever, and I think I am starting to see myself in that category. It is not a bad idea to borrow some of the concepts that Windows has, such as auto-mounting devices and assigned drive letters, but at the same time, it feels good to fire up KDE and Koffice knowing that I don't have to rely on any Windows applications at all. GIMP looks nothing like Paint Shop Pro, and I like that. Konquerer is nothing like Internet Explorer, and I like that too. I don't want to have to rely on Windows for gaming under Linux either.

To some, Linux is about independence and freedom. It's about being unique and singular. SDL is designed to help continue that tradition, and I truly hope that it succeeds. I hope that game developers realize that using WineX is only a first step, and that the real success will come when they transition over to native Linux games. I also hope that Linux supporters fork over the cash to help show developers that they are willing to support native releases. Loki may not have been able to make things work in their particular case, but that does not mean that the community should give up on the concept. If anything, the troops should band together and circle the wagons so they can fight off the single platform behemoth and spread the word that flexibility is where it's at. The more options, the more progress and the more consumers will benefit. Do your part and let the makers of your favorite distribution know that you don't want emulated apps, but native games bundled with their products. Maybe someone will listen and help push this stone a little farther uphill...


SIDEBAR: Is Linux Gaming even on your radar? Or have consoles captured your heart? If you had a viable alternative to Windows, would you jump at the chance, or are you pretty happy with the way things are? Spill the beans and let us know in the Comments Section.