Author Archives: Eric

C++, Baby

I was catching up on the Communications of the ACM, and noticed this article, Computer Science in the Conceptual Age. The “catch your eye” text on one page was: “Programming interns/job seekers from our program Spring 2009 (35 interviewed in the game industry) found no companies administering programming tests in Java.”

There are other chewy bits, such as: “The USC experience is that 100% of its students interviewed for programming positions are given three-to-four-hour-long programming tests, with almost all companies administering the tests in C++.”

Also, this: “The game industry will also tell you that it wants the first four programming classes in C++, not Java, according to M.M. McGill and my own private communications with directors of human resources in major game-development companies.”

One final morsel: “Many game companies say they will not interview or hire someone whose first programming language is Java.”

Wow, that last one’s harsh, especially since my experience with two teenage sons (one in high school, the other a freshman computer science major) is that Java is the norm for the first “real” language taught (I don’t count Scheme as a real, “you’ll get paid programming in it” type of language). I don’t think I’d rule someone out for knowing Java first, though having gone from C++ to Java and then back, the transition from Java to C++ is like being thrown out of the promised land: you suddenly again spend half your time messing with memory in one form or another. C# and Java are darn productive in that way. And, no, for me at least, those auto-pointer classes in C++ never quite seem to work—they need a different sort of discipline I don’t appear to have. I also love that my first Java program, from 1997, still works on the web; some of my C++ programs from back then won’t run on Vista or Windows 7 because the WinG DLLs are not a part of those operating systems (thanks, Microsoft).

Nonetheless, the article’s right: at Autodesk we’ve dabbled with Java and C#, I’ve seen Python used for UI control around the fringes of a program, but the heart of client-side graphical programs is almost always C++ (or isn’t, with regrets and cancellation often soon following—been there myself, though Java was only a little bit to blame, to be fair). Also, XNA, which uses C#, does not have a 64 bit version. In addition, Microsoft’s managed code support usually lags behind the “real” DirectX, i.e., the one for C++.

Looking around, I did find an open-source project, SlimDX, that does support 64-bit assemblies for interfacing with DirectX. Interestingly, they claim one AAA game title shipped using SlimDX, but no mention of which. So I asked. They’re keeping the information confidential, which is fine, but the other comment sounds about right: “The large majority of professional commercial PC/console games are still developed in C++ because of the sheer amount of legacy code the studios developing those games have that is already in C++ (and because of the generally poor support from major console vendors for languages other than C or C++, which contributes to lock-in).”

Long and short: it’s C++, baby.

Tools for Teaching

Today’s question: what tools are there for teaching about computer graphics and/or computer games? I don’t have a definitive answer, but I have a little experience with a few resources and know of others. That said, I haven’t sat down with more than two of them for any serious amount of time. Comments are most welcome, especially for pointers to better overviews than this!

I’ll list these roughly from the more basic to those for budding programmers and indies. That said, I think some languages, e.g. Processing, are easier to get into than the UI-driven systems, but some understanding of programming is needed. I’ve also ignored some famous examples like Logo, as it feels a bit crusty and limited to me. But, that’s me—let me know if you have a great counterexample.

Game Maker: My experience with this one is trying it with my younger son, and later Cornell using it in a 20 hour digital game design workshop for high-school students. It’s much more about games than graphics, graphical elements are 2D sprites and backdrops. Most of the focus is on events and constraints, as you might guess. Very UI oriented, no programming language involved per se – the UI controls are essentially a programming language of a sort. I have The Game Maker’s Apprentice, which is good in that it gets the person involved quickly, but bad in that little understanding gets transmitted early on (“now set this UI control to do this, now load that file there, now hit ‘run’; if it doesn’t run, walk through all the instructions carefully again”). From Amazon reviews, the book Getting Started in Game Maker might be better. There’s lots of example games and web support. Cost: free Lite version and trial Pro version, cost for Pro version (which you want) is $20.

Multimedia Fusion 2: this is an expanded and rebranded version of the company’s “Games Factory 2” product that includes all its functionality. It looks similar to Game Maker, but targeted for a somewhat more professional audience (and at a higher cost) overall. That said, there is a book for it, Game Creation for Teens. Cost: free trial download from 2008, lowest street price I saw for Multimedia Fusion 2 was $83.

Flash: Adobe’s popular animation & game programming system, famously unsupported by the iPad. Back some years ago the local science center used Macromedia Flash to teach grade-school kids about basic Flash animation. Now Adobe Flash Professional CS4 is used to create Flash. From what little I’ve read, the interface is daunting, but it’s actually pretty easy for beginners to get going. Animation is something that can be done purely with graphical tools, Actionscript 3 is a language for serious interactive applications. There’s of course a huge number of books, forums, and other online support. Cost: as low as $200.

Flixel: I’ve heard this mentioned twice as a worthwhile development resource for Flash. It provides some useful base classes in Actionscript 3 for making games, along with tutorials, a forum, etc. Cost: free.

Pygame: This is the first of a few language-oriented resources. Pygame is a bunch of modules to help in writing games in Python. One friend said he got a simple game running in less than two hours from download (but that’s him…), another acquaintance wasn’t so wild about it as he hit its limitations. 2D oriented, though there’s a few 3D experiments. This sounds like a pretty good, and super-cheap (free!), way to introduce kids to programming. I recall an article in CACM or IEEE Computer a year or so ago about Python, and it made an excellent point: Python is one of those great languages that is made for people who have never programmed before. Like Perl, it provides the ability to program and get something done quick without a lot of clutter, and so is a better candidate for the first programming language taught, not Java. Let the programmer have fun getting things done, then teach them about more elaborate computer science concepts and why these are useful. Python is pretty easy to learn: Andrew Glassner has a great introductory page – in a few hours you’ll know the basics. But I digress… Anyway, Pygame has lots of users, many of the projects are open source, there’s even a second edition of a free professionally-produced book about Pygame. Cost: free.

Processing: OK, if you’re sick of hearing about game programming resources, here you go. This is a little language suited for making cool 2D images. Key basic graphics concepts—transforms, curves, image manipulation—are encapsulated. Basic interaction is also a snap. It has a 3D component, but that part is fairly weak. I’ve played with it, it’s fun. Not meant for games; nonetheless, it’s possible. Much online support, and there are two popular books, here and here (the second has lots of additional material online). Cost: free.

Blitz Basic: I’ve heard of this one from a few people but have no direct experience. Definitely about programming, it uses BASIC, but enhanced with functions and types. It looks pretty full-featured, e.g. there’s joystick and networking support. BlitzPlus is the Windows 2D version, BlitzMax also runs on Macs and Linux, Blitz3D adds 3D support: camera, lighting, texturing (including bumps), CLOD terrain, etc. There’s an SDK for interfacing the 3D engine with C++, C#, etc.  Manuals are online, and there looks to be a healthy user community. There’s a German version of the website. Cost: free trials of all, prices range from $60 to $100 per product, with more for add-ons.

XNA: This is something of the 800-pound gorilla for programming-related graphics education. As an example, some teen programmers in the Cornell workshop were using XNA as the next step beyond Game Maker. A Microsoft initiative, it’s partially aimed at students and hobbyists. The base language is C# (Java on steroids, if you haven’t used it). There are lots of element and audiences for XNA, Wikipedia also covers the area well. There are many XNA resource sites and books out there (though I was sad to see Ziggyware is no more). Cost: free for the most part, depending on what you’re doing.

Ogre: Begun about a decade ago, this is from all reports a pretty nice graphics engine. It supports a huge number of effects and areas (I know developers who have consulted the codebase for ideas). There are lots of add-on libraries. It’s great for deep-down serious graphics education; Ogre is entirely open source (MIT license), so everything can be examined. Cost: free, and free licensing.

Unity: You’ve now definitely entered the Indie game developer zone. A 3D games development system I’ve heard mentioned by others as a way of learning. Multiplatform, now including the iPhone. Cost: free base version and trial of Pro version, which costs $1499; other pricing for iPhone version. There’s a book. Licensing for Indies has become free.

UDK: The Unreal Development Kit is the most popular game engine used for game development. Cost: free to download full version, 530 Mb of fun. Licensing cost: if you have to ask, you can’t afford it.

Torque: Torque is the second most popular development platform for game creators. For Torque, two versions exist, 2D and 3D. Three books are available on this engine. Cost: $250 for 2D, $1000 for 3D version, but educational pricing can be arranged.

Whew! OK, what did I forget? (Make sure to read the comments—some excellent additions there.)

Update 2/6/2010: Kodu, from Microsoft. For grade schoolers, it uses a visual language. Surprisingly, it’s in 3D, with a funky chiclet terrain system. Another interesting graphics programming tool is NodeBox 2, now in beta. It uses a node graph-based approached, see some examples here.

You May Want to Own Your Own Images

Now that the SIGGRAPH 2010 paper deadline is over, I thought it worth mentioning ways in which you can retain full use of your own images, should you be fortunate enough to have your work accepted for publication. This isn’t meant as an “ACM’s copyright policy is bad” article, rather it presents some possible workarounds while waiting for the policy to be improved. Think of these ideas as code patches.

A number of graphics people were talking about the ACM’s copyright policy. James O’Brien wrote:

I also am bothered by the fact that ACM claims to own images used in a publication. For example, if I render an image and use it to illustrate a paper, ACM now claims to own the copyright on the image and I am limited in what I can use that image for in the future. I’d like included images and other non-text content to be treated similarly to how 3rd party images are currently treated so that the authors retain copyright to the images and only grant ACM unlimited permission to use.

Larry Gritz replied:

James, why are you more bothered by “I painted the image, now they claim ownership” than “I wrote the words, now they claim ownership”? Aren’t they essentially the same situation?

James responded:

Not really, at least not to me. The images often represent a huge amount of work to demonstrate some algorithm. The words I wrote in an afternoon and I can always write some more words that say roughly the same thing if I had to. The images also have uses beyond the paper. For example, if “Time” magazine writes an article about me, they will want to run the images, or if a textbook author decides to talk about my algorithms s/he may want the images to illustrate the book. I also don’t see the argument for why ACM would benefit by owning the images. It’s a case where it costs the author something but gains ACM nothing, so why not change the policy to maximize everyone’s benefit?

—

In further discussions, we identified a few different ways to be able to use your own images. Mine is one that was first mentioned in the Ray Tracing News in 2005:

My advice (worth exactly nothing in court) to anyone publishing nowadays is to make two images of any image to be published, one from a fairly different view, etc. In this way you can reuse and grant rights to the second, unpublished image as you wish. That said, there’s an area of law where you compare one photo with another and if they match by 80% (by some eyeballing metric), then they’re considered the same photo for purposes of copyright. Usually this is meant to protect one photographer’s composition from being reused by another. What it means to 3D computer graphics, where it’s easy to change the view, etc., remains to be seen. Still, ACM’s rights to your work are less clear for a new, different image. This sort of thing is small potatoes, but taking action so that you have images and videos you fully own then removes the hassle-factor of granting permission to others wanting to use your work.

James O’Brien said the following:

I’ve bumped into this copyright issue with images a few times. The first was when a book author wanted to use an image of mine in her text. I said yes, but she was subsequently told by ACM that she needed ACM’s permissions and she had to pay a fee and include a notice crediting ACM rather than me.

If you are willing to be persistent, you can keep ownership of your copyright for your whole paper and just grant ACM unlimited permission. I did this in 2005 and if you download “Animating Gases with Hybrid Meshes,” SIGGRAPH 2005, from the DL you will see the copyright notice says “copyright held by author”. That was inserted by them instead of the regular notice after several days of discussion on the phone. It was very unclear what the motivation was for the ACM to insist on owning the images.

If the images are owned by a 3rd party they can only ask you to get permission. After 2005, I did a few papers where I included a note that the images were all copyright by UC Berkeley and used with permission. It’s not clear if that sort of note means anything.

The latest version of the ACM copyright form I’ve seen requires you to fill out an addendum listing 3rd-party-owned components and you have to get a separate permission form for them. My paper in SCA this summer required this form (images owned by Lucas Arts). It was a hassle to get Lucas to sign off on the permissions. But that’s not ACM’s fault… in fact Stephen Spencer was very flexible.

An anonymous person wrote:

Another option would be for people concerned about this to set up an organization, call it Digital Images LLC, that you assign the copyright to as soon as you generate the image. (That will likely require the permission of your university or employer, since the image is arguably a work-made-for-hire under the copyright law and therefore owned by the employer.)

Digital Images LLC then licenses its copyright in the images so that you can use it in papers, books, or other works. As far as ACM is concerned, it’s just like if you used a figure from another source with permission. The ACM policy makes that clear:

The author’s copyright transfer applies only to the work as a whole, and not to any embedded objects owned by third parties. An author who embeds an object, such as an art image that is copyrighted by a third party, must obtain that party’s permission to include the object, with the understanding that the entire work may be distributed as a unit in any medium.

—

So, there are at least three ways where you can retain full rights to your own images. Mine is “make another”, James’ is “request an exception”, and there’s finally “create an LLC”. If you have another, have information about the use of any of these, or just plain have an opinion, please comment.

7 things for January 22

There’s been some great stuff lately:

  • Gustavo Oliveira has an article in Gamasutra about writing an efficient cross-platform SIMD vector library and the tradeoffs involved. The last page was of particular interest, as I had wondered how effective the Intel C++ Compiler (ICC) was vs. Microsoft’s. He also provides downloadable source code and in-depth statistics.
  • NVIDIA has given some information abour Fermi, their next GPU. Warning: their page will automatically start some audio – annoying. You could just skip to the white paper. One big deal about Fermi is its support of doubles, which means it can be used for more science & engineering number-crunching. The Tech Report has a good overview article of other interesting features, and also presents benchmarking results.
  • Tests of OpenCL, the platform-independent parallel programming standard, have started to appear for AMD and NVIDIA GPUs.
  • Speaking of NVIDIA, their PhysX engine is getting some attention. The first video clip in this article gives a sense of the sorts of effects it can add. Pretty stuff, but the funny thing about PhysX is that it must accelerate computations that do not actually affect gameplay (i.e. it should not move around any objects in the scene differently than non-PhysX machines). This limits its use to particle systems and other eye candy. Not a diss—heck, most game graphics are about eye candy—but something to keep in mind.
  • Naty pointed out an article about how increasing the number of megapixels in a camera is just salesmanship and gains no actual benefit. The author later gives more explanation of his argument, which is that diffraction puts a physical limit on the useful size of a pixel for a given camera size.
  • Sony Pictures Imageworks has released a draft describing their Open Shading Language (OSL). While aimed at high-end rendering for films, it’s interesting to see what is built-in (e.g. deferred ray tracing) and what they consider important. Read the introduction for more information, or the draft itself.
  • My favorite infographic of the week: Avatar vs. Modern Warfare 2. Ignore the weird chartjunk concentric circles, focus on the numbers. The most amazing stat to me is the $200M advertising budget for MW2.

… and that’s seven; more later.

Some Actual Larrabee Information

Tom Forsyth, one of the many programmers and engineers on Larrabee, passed on this link to a lecture he gave at Stanford on January 6 for their weekly Computer System Colloquium class. At the beginning he gives a bit about Intel’s view of Larrabee and the effect of “cancellation”, i.e., it’s not cancelled, just the first hardware release is off. He notes the day-to-day work of most Larrabee developers is unaffected. I appreciating him walking through the Intel position, as I haven’t been able to find any hard information (press releases, etc.) on their site. In retrospect, rumor-mill articles like this one (which we passed on earlier, lacking any sound data) appear to have extremely little resemblance to reality.

The rest of his lecture is about Larrabee itself. Early on he talks about the new instructions in Larrabee, something like Abrash’s article but more entertaining. Around minute 37 he gets more into graphics rendering per se. I’ve been listening to it in bits, in the background.

I3D 2010 Registration Open

I3D 2010 is located just north of Washington, DC this year, during the weekend of February 19-21 (Friday through Sunday). It will be at the Bethesda Hyatt Regency, which is conveniently located right on the Metro Red Line.

The early registration deadline for I3D itself is January 20th; hotel registration at the conference discount rate of $115 is available until January 19th.

Ke-Sen Huang has added a few paper links since we last mentioned his page, though the majority are still not available from authors’ pages. Somewhat surprising, given that December 14 was the camera-ready deadline, but perhaps some people are still returning back to their universities & colleges and haven’t gotten around to putting theirs up. That said, conferences like I3D are only partly about the papers and posters themselves. They also offer a unique and wonderful opportunity to meet and talk with leading and up-and-coming researchers and practitioners. It’s a fantastic feeling to be in an area for a few days where just about everyone there is working on ideas that are of interest to you. Anyone you meet knows something you don’t, and vice versa, and most people talk freely about what works and what doesn’t. Energizing and useful. Plus, they’re just fun people to be around, at least for this nerd.

7 things for January 4th

First day of work, so here are a few from coworkers and others:

  • Naty passed on this blog post about RGBD, a compact way of storing HDR environment map colors.
  • Gamasutra has an excerpt from Game Engine Architecture, a book we’ve mentioned before. Added bonus info on the author, Jason Gregory: he was a lead programmer on Uncharted 2 (which my older son loves, as do many others).
  • Manny Ko mentioned the free program Mendeley, which he swears by for organizing his PDF collection of graphics papers. I’ll look into it once I’ve reloaded everything after my Windows 7 upgrade.
  • Physics in graphics? Here’s one person’s extensive collection of abstracts through 2005.
  • From Nicholas Wilt, interesting to hear how one brokerage firm is now using GPUs to run complex simulations for bond prices. That GPU Gems chapter on options pricing was prescient.
  • Speaking of brokers and lots of GPUs, there’s this article. I’m a little skeptical of a GPU cloud for graphics (vs. running OpenCL), since graphics cards are not quite interchangeable parts at this point. Also, CPUs don’t normally need driver updates, GPUs do. OTOY I’m super-skeptical about, I have to admit, though I’d love to see them pull it off. Anyway, fun to think about situations where network bandwidth > graphics compute power and cloud cost < local cost.
  • One more from the demoscene, Farbrausch’s The Cube – interesting effects, what looks like procedural clips and procedural surfaces using interior mapping. At least, that’s my guess. I wish they would spend a little time explaining what they did, though maybe that would ruin the magic.

7 things for December 25

A schedule for Christmas:

7 things for December 24

Here are 7 for the day:

7 things for December 23

Here come seven more, until I run out:

  • The game Saboteur on the PS3 appears to be performing antialiasing by using MLAA. This is great to know that some form of MLAA is both fast enough and high enough quality to be usable in a commercial product. I found it interesting that it is used only in the PS3 version of the game.
  • The free glslDevil OpenGL shader debugger has recently been updated. Pretty cool (though maybe not so happy for content providers): you don’t even need the source code to debug into the shaders.
  • There is a new site dedicated to OpenCL and CUDA programming: gpucomputing.net. It is focused on university research efforts, and has some heavy-hitters in the research community involved. Just begun, not a lot there yet, but you could always subscribe to the blog.
  • Here’s a short little article on texture atlassing. If you want a bit more information, read Ivanov’s article on this topic on Gamasutra, published some years ago. For even more detail, NVIDIA’s white paper is helpful. My point: if you don’t know about texture atlassing, you should. Read one of these three and check it off your list.
  • Getting the X,Y coordinates of a pixel for a post-processing pass is typically done one of two ways: texture coordinates or using VPOS. This short article gives the details.
  • You’ll note the previous two entries came from the new blog/site gamerendering.com. There are plenty of other short articles here, most with code snippets or links to other sites. That said, I’ve asked the admin for a little more attribution of sources, e.g., the figure from our book here. Hopefully fixed by the time you see it…
  • This shader code is truly amazing (from easily my favorite graphics blog).