Ke-Sen Huang’s paper pages are down, will soon go back up

We have mentioned Ke-Sen Huang’s awesome paper preprint link pages in many previous posts – they’re the best graphics resource on the web by a long shot.

Early last week, many people (including myself) were shocked to see most of the pages replaced by the following:

REMOVED – This page has been removed at the request of the ACM Publications Board

This resulted in an outpouring of anger as well as support for Ke-Sen. Many people in the community contacted the ACM Publications Board to try to convince them to change their position.

Fortunately, the story has a happy ending. Today, Ke-Sen received the following email:

Dear Ke-Sen,

As you are aware, the computer graphics community has expressed dismay and concern about the removal of your web pages. ACM wants to make it possible for you to continue this service that the community clearly values very highly. By this message ACM grants permission for you to repost the pages, with the addition of links to the authoritative versions of the papers in the ACM Digital Library. The author’s home page links may also be included, but should not be links directly to the author’s version of the paper. Please post on the site that the information is being provided with the permission of the ACM. This is the solution you proposed earlier, and it is clear from the community’s comments that it is the right thing to do.

As you know, the concern about your pages was ACM copyright policy with regard to links. As a result of the community discussion, ACM will institute a formal review of this portion of its copyright policy.

Please contact us with any concerns or questions.

Sincerely,

Patricia Ryan
ACM Chief Operating Officer

ACM also offered to help with the work of adding the Digital Library links. So nothing will be removed from Ke-Sen’s pages, and additional useful links will be added.

It will take a little while until the pages are back up, but they will be better than ever. In the meantime, you can go to the Way Back Machine and find his pages from 2007 and earlier.

The graphics community has engaged with the ACM in a much more active manner than usual, which is a good thing. We need to remember that it is our organization, and it is only as good as we make it. So consider volunteering for conferences, paying more attention to ACM elections, etc. – I know I will.

A cool “what if” video – Earth with rings like Saturn

This is a great video, showing what Earth would look like with rings like Saturn, including from various cities, taking latitude and other factors into account. A bit off-topic (well, the visualization uses graphics, if not real-time graphics), but cool nonetheless.

DX9 GPU Hacks

When I transitioned from PC to console programming in 2003, I was struck by the many graphics hardware features I now had access to which are not supported by PC APIs such as Direct3D and OpenGL (the latter is in slightly better shape due to its support of vendor extensions). Some of these features are supported by newer iterations of Direct3D, but for many people Direct3D9 is still the target of choice (it is the newest version supported on XP, and it most closely matches the capabilities of current-gen consoles).

Over the years, graphics hardware vendors have implemented an array of undocumented, semi-official hacks around the Direct3D9 API to allow access to more hardware features. Aras Pranckevičius has recently put up a very useful list of these. I have not seen this information anywhere else – kudos to Aras for doing the work.

Flocking on steroids

Flocking (running a large number of independent agents with simple proximity-based rules and letting interesting behavior emerge) has been a popular graphics technique since the 1987 SIGGRAPH paper by Craig Reynolds. The idea is, of course, inspired by examples from the animal kingdom such as bird flocks and fish schools. Today I saw an internet clip of 300,000 (!) starlings flocking. With such a large number of entities, the flock looks like some kind of bizarre physical fluid or smoke simulation.

Radeon HD 5800 Demos

AMD has posted executables and videos for two new demos for the Radeon HD 5800 series. Both demos require Windows 7 (I guess that means that Vista support for DirectX11 isn’t quite here yet).

One of the demos show order-independent transparency; from the description it sounds like an A-buffer-like approach, which is interesting. The other shows a high-quality depth of field effect.

NVIDIA Optix Clarification

Regarding this somewhat alarmist post, NVIDIA were kind enough to contact me and provide some clarification.

After Fermi ships, NVIDIA plan to extend OptiX support to at least GT200 GeForce cards, and possibly down to G80 as well. So eventually you will indeed be able to run Optix on pretty much all consumer NVIDIA cards.

Halloween

Humus votes for this being the coolest costume ever. Pretty great, I agree, and technically lovely, but I vote for this one since I’ve seen foldy heads before and never saw this idea until today.

NVIDIA Optix ray-tracing API available – kind of

We’ve written about the NVIDIA Optix ray-tracing API (which used to be called NVIRT) once or twice before. Well, today it is finally available – for free. While it’s very nice of NVIDIA to make this available, there are a few caveats.

We already knew Optix would only work on NVIDIA hardware (duh), but the system requirements reveal another unwelcome fact; it does not even run on GeForce cards, only Tesla and Quadro (which are significantly more expensive than GeForce despite being based on exactly the same chips). They say GeForce will be supported on their new Fermi architecture – I call shenanigans.

Do you really display PNGs?

Digging up the luma palette images reminded me of a useful PNG I made back around 1996 or so, back when this file format was quite new. A peculiarity of the PNG file format is that it stores alpha separately, unmultiplied. For 3D work it is the norm for the color stored to be premultiplied by the alpha. I won’t go into the how and why; this topic is covered in our book on pages 139-140 and is discussed on Wikipedia, among many other places.

One nice feature of premultiplied images is that you can just ignore the alpha channel entirely when displaying them for preview. This is equivalent to compositing the image over a black background. With PNG, you are required to examine the alpha channel and multiply the RGB by it in order to get the right color to display. Unmultiplied alpha has a 2D photo sense to it, the RGB image exists everywhere and the alpha is masking some part of it. The alpha is not an integral part of the pixel, as it is in 3D.

On to the image:

alpha_test

I cobbled this together to be able to quickly check if a particular piece of software was respecting the alpha channel in PNG. Back then, most software didn’t, so what would be displayed is “This viewer does not support transparency”. Today, it’s pretty rare to find such flawed PNG readers commercially (I couldn’t find a current example for you to try). Still, I’ve found this image useful as a quick reality check for whether software is using the alpha in a PNG.

Lest we forget, it was the LZW patent in the GIF format that helped popularize PNG as a patent-free alternative for the web. The Unisys patent finally fully expired back in July 2004, so it’s a moot point now, but for awhile this was a patent enforced for tens of millions of dollars, with over 2,000 licensees. My favorite quote on the whole controversy was from a flak at Unisys giving spin about their positive role enforcing a patent on a technology unknowingly used in a file format that they didn’t invent:

But Unisys credited its exertion of the LZW patent with the creation of the PNG format, and whatever improvements the newer technology brought to bear.

“We haven’t evaluated the new recommendation for PNG, and it remains to be seen whether the new version will have an effect on the use of GIF images,” said Unisys representative Kristine Grow. “If so, the patent situation will have achieved its purpose, which is to advance technological innovation. So we applaud that.”

Real-Time Rendering

Tracking the latest developments in interactive rendering techniques