ShaderX

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Like the title says, GPU Pro3, the next installment of the GPU Pro series, is now available for order. The publication date is realsoonnow (January 17th). The extended table of contents is a great way to get a sense of what it contains.

The GPU Pro series is essentially a continuation of the ShaderX series, just with a different publisher. I was given a look at the draft of this latest volume, and it appears in line with the others: some eminently practical and battle-tested approaches mixed with some pie-in-the-sky out-of-the-box done-with-the-metaphors ideas – having a mix keeps things lively. Articles such as the one covering the CryENGINE 3 is a fine combination of both, with solid algorithms alongside “this doesn’t always work but looks great when it does” concepts. Some of the material (including a fair bit of the CryENGINE 3 article) can be gleaned from presentations online from GDC and SIGGRAPH, but here it’s all polished and put in one place. Other articles are entirely fresh and new. Priced reasonably for a full-color book, it’s a volume that most graphics developers will find of interest.

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Visual Stuff

After all the heavy lifting Naty’s been doing in covering conferences, I thought I’d make a light posting of fun visual stuff.

The first one’s not particularly visual, I include it just because the cover and book description was put on the web just a few days ago:

GPU Pro cover

In short, the ShaderX series has moved publishers, from Charles River Media to A.K. Peters. Unfortunately for everyone else in the world, CRM retains the rights to the ShaderX name, hence the confusing rename. This book is ShaderX8, under a new title.

This resource is possibly handy: a map of game studios and educational institutions, searchable by state, city, etc. That said, it’s a bit funky: search by “Massachusetts” and you get a few reasonable hits, plus the Bermuda Triangle. Search on “MA” for State and you get lots of additional hits, mostly mall stores. But, major developers like Harmonix (in Cambridge) don’t show up. So, take it with a grain of salt, but it might be handy in turning up a place or two you might not have found otherwise.

A few weeks back I passed on a link from Morgan McGuire’s worthwhile Twitter blog (the only good use I’ve seen for Twitter so far) for a business-card sized ray tracer created by Andrew Kensler. In case you were too busy to actually compile and run this tiny piece of code, here’s the answer, computed in about a minute, sent on to me by Mauricio Vives. Note the depth of field and soft shadows:

Andrew Kensler's ray tracer

Speaking of ray tracing, I noticed some GPU-side ray tracers are available for iPhone 3GS from Angisoft:

Julia Set ray traced

With the recent posting on Morphological Antialiasing, Matt Pharr pointed me at this cool Wikipedia page on scaling up pixel art. To whet your appetite, here’s an example from that page, the left side being the original image used to generate the right:

Wikipedia pixel art scaling example

In a similar vein, I was highly impressed by the examples created by Potrace, a free, GPL’ed package for deriving Bézier curves from raster images. Here’s an example:

Original, raster head Smoothed head with Potrace

See more examples on Peter Selinger’s Potrace examples page. Doubly impressive is that Peter also carefully describes the algorithms used in the process.

I enjoy collecting images of reality that look like they have rendering artifacts. Here’s one from photos by Morgan McGuire, from the Seattle public library. The ground shadow look undersampled and banded, like someone was trying to get soft shadows by just adding a bunch of point light sources. What’s great is that reality is allowed to get away with artifacts – if this effect was seen in a synthetic image it would come across as unconvincing.

Seattle Public Library by Morgan McGuire

The best thing about reality is that it’s real, not photoshopped. I also enjoy photos where reality looks like computer graphics. Here’s a fine example by Benedict Radcliffe from this entertaining collection:

Wireframe Toyota by Benedict Radcliffe

My one non-visual link for this posting is to Jos Stam’s essay on how photography and photorealism is not necessarily the best way to portray reality.

There are tons of visual toys on the web, a few in true 3D. Some (sent on by John McCormack) I played with for up to a whole minute or more: ECO ZOO – click on everything and know it’s all 3D, don’t forget to rotate around; the author’s bio and info is at ROXIK – needs more polygons, but click and drag on the face. In the end, give your eyes a rest with this instant screen saver (actually, it’s also a bit interactive). This last was done using Papervision3D, an open source library which controls 3D in Flash. More demos here. Maybe there’s actually something to this idea of 3D on the web after all… nah, crazy dream.

OK, I’m done with things that are in some way vaguely, almost educational. Here’s a video, 8 Bit Trip, that’s been making the rounds; a little more info here. Not fantastically entertaining, but I admire the amazing dedication to stop motion animation. 1500 hours?!

Art: Xia Xiaowan makes sculptures by a method reminiscent of volume rendering techniques:

Xia Xiaowan sculpture

More at Google Images.

The Mighty Optical Illusions blog is a great place to get a feed of new illusions. Here are two posts I particularly liked: spinning man (sorry, you’ll actually have to click that link to see it) and more from Kitaoka, e.g.

Kitaoka's rotating snake planets

I love that new illusions are being developed all the time nowadays. I found this next one here; unfortunately, to quote Tom Parmenter, “digital technology is the universal solvent of intellectual property rights” (Copyright 1995). No credit is given at that site, so I don’t know who actually made this one, but it’s lovely:

4 perfectly round circles

One last illusion, from here (again, author unknown), included since it’s such a retina-burner:

Flying City

If you hanker for something real and physical after all these, you might consider making a pseudoscope (instructions here). To be honest, I tried, and I’ll tell you that mirrors from the local craft store are truly bad for this project. So, I can’t say I’ve seen the effect desired yet. Next step for me is finding a good, cheap store for front surface mirrors (the link in the article is broken) – if anyone has suggestions, please let me know.

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With Wolfgang Engel’s blessing, I’ve added the ShaderX2 books’ (both of them) CD-ROM code samples as zip files and put links in the ShaderX guide. The code is hardly bleeding edge at this point, of course, but code doesn’t rot – there are many bits that are still useful. I’ve also folded in most of the code addenda into the distributions themselves. The only exception at this point is Thomas Rued’s stereographic rendering shaders; in reality, more up-to-date information (and SDK) is available from the company he works with, ColorCode 3-D.

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I love the movie sequel title “2 Fast 2 Furious”. How clever, and a great way to guarantee there will never be a third movie. Well, there was, but they had to go the colon route, “… : Tokyo Drift”.

Which is indicative of nothing, as I don’t think I’ve ever actually seen any of these movies. I was reminded of the title as my goal today is to whip through the backlog of 72 potential blog resource links I’ve been gathering on del.icio.us. [Well, as it turns out, I got through 39 of them (the fresher ones), 33 to go...]

ShaderX^7 has been published. We hope to give it an overview sometime soon (mine’s on backorder from Amazon.com).

From various source I heard that OnLive got a bit of notice at GDC. Think: pure server-side computation of all graphics for a game, i.e., a cloud computing model. Now even your grandma’s computer or even a rigged-out TV can play Crysis, assuming the net bandwidth is there. Which of course makes me think: what about latency? Lag for how other players see your action is always there, and causes mismatches (“how did I instantly die?”). But increasing lag for you seeing the consequences of your own actions seems like a non-starter for shooters, at least.

Mark DeLoura has a great two-part article on what game engines are licensed for titles. First part is a general survey, second is about the technology involved. I found it interesting to see what people cared about, e.g. multicore is on people’s minds. Nothing too shocking here, but it’s fantastic to see what is getting used, and why, in this marketplace.

Related to this, I happened across a list of game engines on wikipedia. Not massively useful (e.g. no sense of what’s popular), but a starting place.

John Ratcliff has a graphics math library available for download with an unrestrictive reuse license. He recently added best fit methods for AABB’s and OBB’s.

I was interested to look at the open source, cross-platform (!) model viewer GLC. I’ve wanted something like this for doing some experiments with mesh manipulation. Not a bad viewer, but that’s all it is at this point, unfortunately: you can’t even export to a different 3D format. The search continues… If you know a reasonable open source 3D file viewer/converter out there, please tell me. I should probably bite the bullet and just use Blender, but this application is way overkill.

CUDA voxel rendering – pretty impressive!

I liked this post on optimization mainly because of the line “I went in and found out that some title bar was getting rendered 140 times every time you refreshed the screen”. I can entirely relate (though 140 must be some kind of record): too many times I’ve put output debugging statements showing updates, only to see 2,3,6 updates happening. I once started on a project and in the first few weeks increased performance by 100%, simply by noting the main draw path was being executed twice each frame.

Speaking of performance, there’s an article on volume rendering optimizations when using a ray-casting approach on the GPU.

Wolfenstein source code for the free iPhone version, along with Carmack’s documentation on the project, is available.

Software patents are only slightly dumber than business method patents, which are patently absurd. I hadn’t noticed until now, but there was recently a ruling on a business method patent, In re Bilski, which has been used to strike down software patents.

A detailed data and execution flow diagram for the new DirectX 11 pipeline front-end is available from Jolly Jeffers.

People are still making ray-tracing specific hardware; witness Caustic Graphics. They have a rather amazing claim: “The CausticOne, however, thrives in incoherent raytracing situations: encouraging the use of multiple secondary rays per pixel. Its level of performance is not affected by the degree of incoherence.” Good trick. That said, I can’t say I see any large customer base for such a product. This seems like a company designed for acquisition, similar to Ageia. Fine by me, best of luck to them.

I’m happy to learn that the Humus site now has a news blog. This is a great site for demos of advanced techniques, and for honest comments about strengths and limitations of various approaches.

Another blog: The Geeks of 3D. Tracks demos, APIs, SDKs, and graphics card releases. Handy – some of the links here I found there.

There was a nice little article on data alignment on Gamasutra. Proper alignment is a key element in getting high performance.

I was trying to find the name of the projection of equidistant latitude and longitude lines for a surrounding spherical environment. From this interesting page (click on the “Wall Maps of the World” text) I found it: Plate Carrée.

Predicting the future is so much more interesting than predicting the past. I love this: MIPS per $1000. It’s entertaining to equate raw computing power with structured processing. By the same equivalence, I should be able to hook up 1700 mice in parallel to get a human brain.

A great line from a GPU review: “Nvidia’s new line of unbelievably expensive cards will block out the sun, and ray-trace its own shadow in real time.”

Faber College’s motto is “Knowledge is Good”. Learning about the idea of metamers would have saved this article from confusion. Coming back to this article now, I see all the comments have been removed, and an apologia trying to convert confusion into enlightenment added, but I think this still misses the point. Sure, there is a color associated with a single wavelength of light. But, my guess is that 99.99% of the colors we perceive arrive at any location on the eye as light with a spectral mix of wavelengths, not a single wavelength (Naty will correct me if I’m wrong). Unless you’re Dr. Evil and deal with sharks with frickin’ laser beams on their heads on a daily basis. Hmmm, I’m probably forgetting some other single-wavelength phenomena, like fluorescence. Anyway, the article did lead me to look up more information on metamers on Wikipedia, where I learnt about metameric failure, a term I hadn’t heard before. One more reason a simple RGB representation of color isn’t sufficient.

Cute thing: Snapily lets you turn some set of images or video into lenticular prints.

I don’t have a lot to say about what I do at Autodesk. Here’s a tidbit.

Art for the day, crayons as pixels.

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Will there be a GPU Gems 4? I don’t know. But I do know there will be a ShaderX^7 and, with your help, a ShaderX^8. The timeline and information about this next volume is at the ShaderX^8 site. If you’re interested in submitting, one detail (currently) missing from this site is that an example ShaderX proposal, writing guidelines, and a FAQ can be downloaded from here. The key bit: proposals are due May 17th. I’m not currently associated with this series (though I was for volumes 3 & 4), I just like to see them get good submissions.

The existence of these book series – Game Programming Gems, ShaderX, GPU Gems – is a fascinating phenomenon. Conferences like SIGGRAPH are heavy on theory and cutting-edge research, light on practical advice. Books like ours can be more applied, but are survey-oriented by their nature, not spending a lot of time on any given topic. Code samples and white papers on the web from NVIDIA, AMD/ATI, etc., and independents such as Humus, they’re great stuff, but are produced by particular groups of people with specific interests. Also, sometimes just finding relevant code samples on these sites can be a serious challenge (“search” sometimes works less well than I would like).

These book series fill the gap: they go through a review and editing process, improving quality and presentation. This in turn makes them of higher average interest to the reader, vs. a random article on the web of unknown quality. They won’t disappear if someone’s domain expires or interest wanes. They can be easily accessed years later, unlike material published in ephemeral venues such as Game Developer Magazine or GDC proceedings. The titles, at least, can be surveyed in one place by sites such as IntroGameDev (though this one appears to no longer receiving updates, unfortunately, e.g. ShaderX^6 is not listed).

The major downside of these books is that they’re only available on paper, not as searchable PDFs (except the first few ShaderX books). Well, almost the entire GPU Gems series is, wonderfully, online for free, but is still not easily searchable. Now if someone could just figure out a Steam-like system that let people buy books in electronic form while protecting publishers’ monetary interests. Hmmm, maybe eye-implanted bar-code readers that check if you have access to a given piece of digital content, that’ll be non-intrusive… Anyway, this is the challenge ahead for publishers. Maybe the Kindle is the best solution, but I like the Steam games model better, where something you’ve purchased is available on any computer attached to the Internet.

Best of all for consumers is free & digital, of course, but this does trim back the pool of authors pretty drastically, as a royalty percentage of 0% is not much of an incentive (I’ve been reading too many popularized economics books late, e.g. Naked Economics, so have been thinking more in economics-speak, like “incentives”). We wrote our book for the love of the subject, but I can’t complain about also, to my surprise, earning a bit of money (enough to allow me to, what else, upgrade my computer and graphics card on a regular basis). Enough rambling, but the subject of electronic publication is one that’s been on my mind for a few decades now. I expect a solution from you all by the end of the week, then let’s create a startup and we’ll sell out by next March and make a mint.

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More Free Books

GPU Gems 3NVIDIA’s done it again, they’re releasing GPU Gems 3 to the web. It’s being done in the installment plan, I expect so that there’s something to announce every few weeks, which is fine. Eventually the whole book will be available, so much better to have this “section a month” scheme than not at all. NVIDIA’s to be complimented on their progressive attitude. GPU Gems 3 is less than a year and a half old, so could still make a few dollars, but NVIDIA’s goal is to get the information out there.


ShaderXThis summer Wolfgang Engel and I tracked down authors of the ShaderX and ShaderX^2 books and secured releases. The ShaderX^2 books quickly found a home at gamedev.net, but Wolfgang had to dig around for the PDF for the first ShaderX book, then find a place to host it, plus the dog ate my homework, etc. Long and short, the original ShaderX book is now free for download here: http://tog.acm.org/resources/shaderx/ - I decided to host it on the ACM TOG site, as it’s a valuable resource, despite its hoary old age. Just ignore the first chunk about using 1.x shaders and enjoy the rest.

I do wish the GPU Gems books were available as PDFs (hint, hint, NVIDIA), as they would be much easier to search for those “I know I saw this in one of these books” moments.

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