Repeat that title three times, then “and I feel fine.” This R.E.M. song has been going through my mind much of the week, as the Ray Tracing Gems book was released last Saturday as a free PDF. With Open Access, the publisher agreed to put the book up for free, even before the physical book was available. Apress has 27 other Open Access titles free to download, so they’re somewhat used to the idea.

The bragging number is that the official Ray Tracing Gems PDF has been downloaded 102K times as of today. I suspect there are a lot of pack rats out there who will download any book that’s free, or someone’s trying to make Tomas and me feel good by setting up an auto-download bot farm (if so, thanks, good job!).

But wait, there’s more. Stephen Hill spotted some typos in the preview copy and sent them on to me Saturday. Monday I made an unofficial PDF for distribution, identical to the official PDF but with his and other errata fixed. Doing so is fine under the license, which allows reasonable changes that are properly noted. The publisher and I worked on the wording on the front page to clearly label this version as unofficial, then I released it on Tuesday. It’s of course the one I recommend grabbing. Being more “hidden,” this one’s been downloaded a more believable 499 times as of last night.

“Supplies are limited” is my favorite ridiculous marketing phrase, always true since there’s a large but finite amount of material in the universe. For GDC and GTC, it’s actually true. The publisher is rush printing and shipping a few hundred copies for these conferences, and they should arrive at onsite booksellers and to NVIDIA next week, fingers crossed, knock wood, rub lucky rabbit’s foot. The hardcover book will not be available for online purchase until mid to late May, though on slightly-higher quality paper (coated glossy vs. coated matte; I believe “coated matte” is what the GPU Gems series used).

Me, I like having both the physical and the electronic forms: electronic is great for searching and for travel, physical is nicer to read (at least for me), use stickies on, add notes in the margins, and for getting signed. Speaking of which, see our page for authors’ signings and talks at the conferences.

So, this is all an odd sequence: NVIDIA released free preprints of the book during February, as did EA; the publisher released the PDF for free in March; I (or anyone) can then make a slightly improved version for distribution; the physical book will be available at conferences in 10 days but not for online purchase until May. Releasing preprints of a whole book, fixing errors in the released version – this is not something we’re used to. Personally, I know I’ve had any number of emails along the way where we each reassure the other, “no, it’s OK, this is how it works under Open Access.”

Short version: the first book on ray tracing, An Introduction to Ray Tracing, from 1989, is now free to download. You can get the PDF or DJVU version. Note that the PDF has been updated with one erratum fix (so far), and currently is at version 1.1.

Longer version: with Pete Shirley releasing for free his three introductory mini-books on ray tracing this summer, then Matt Pharr releasing the book Physically Based Rendering for free, I asked Andrew Glassner if he could get the rights to release the classic An Introduction to Ray Tracing. He was game, clearing it with the authors, tracing down the right person at Elsevier to ask, going through the paperwork, and – freed! He just wrote me:

I’ve just now received the countersigned rights release for An Introduction to Ray Tracing. I guess the contract was in my name, because I now own the rights! I hereby grant you permission to publicly share the aforementioned book, or the manuscript thereof, or an electronified version of the manuscript thereof, electrically encoded and presented using one or more typefaces of human design, upon a website for the general reading pleasure of the general reading public. Go for it!

So going for it I am. Enjoy! Yes, it’s ancient. But, surprisingly, it’s still a fine introduction in a bunch of ways – math doesn’t rot, and many of the bits from back then are still used today – stochastic sampling, bounding volumes, adaptive supersampling, etc. (Matt Pharr agrees). Andrew’s page about the book (and some history about the cover) is here.

Me, I expect this will cut into my yearly royalties – I earned $6.22 last year on the book – but, ah, the giant sacrifices I make for The Greater Good, and so humble, too. If you consider free books a travesty, you can always buy a copy off this insane page on Amazon – a steal (on someone’s part) at $588.23. The normal Amazon book page is not so bonkers.

Update: Andrew was asked what sort of license the book is under. We discussed it and he chose the Attribution 4.0 International (CC BY 4.0) license, the most liberal of the CC licenses. To quote the main bits:

You are free to:

• Share — copy and redistribute the material in any medium or format
• Adapt — remix, transform, and build upon the material for any purpose, even commercially.

If by some miracle you use the first printing of the book, I’ve made an errata page. All these errors are fixed in the PDF and DJVU versions, except as noted.

It clearly takes a village to write the book Real-Time Rendering. Ola Olsson pointed out this entertaining bit on Google Scholar:

The fourth edition appears to be Volume 19 Issue 2. The article mentioned does exist, but is the very last reference in the book (#1978). The number of authors on the paper is impressive, quite an increase from the original three for this article. Ansel Adams, among others, gets listed three times as an author – excellent CV padding. My favorite, though, is the description of the article, a quote by Billy Zelsnack used at the beginning of our chapter “The Future.”

I poked around a bit more and found some alternate reality listings, such as this:

In both 4th editions our new three authors don’t show up. More disturbing is that in one universe’s edition Tomas Akenine-Möller also no longer exists (sad, since he’s listed six times as an author in the first image). And a strange universe it is, where the book has 40 citations, despite being out for less than 6 weeks. The prescience of some authors citing it is impressive, with one article published in the year 2000 referencing this fourth edition. Research must be wonderfully accelerated there, with developers being able to read about future breakthroughs that they can then write up.

Now that I’m back from SIGGRAPH, I can catch up on all the things. So here’s one: win a free copy of Real-Time Rendering, 4th Edition. Our publisher is giving away three copies, deadline to enter is August 31.

As far as actually receiving a copy of the book, well, if it’s any consolation, none of us authors have a physical copy at this point, either. Our publisher wrote on August 8th:

This reprint should be in the warehouse within the next 3 weeks.  I assume the fulfillment dept will give customer orders priority over author copies.

So it’s a case of the shoemaker’s children go barefoot. Amazon says the book’s back in stock on August 27th.

I do like that the first three chapters are free on Amazon, for Kindle, and Google Play, so I hope that will tide people over until these ship. That this much content was made free was unexpected, a happy decision on the publisher’s part. If you’re done with those chapters and still waiting, don’t forget to read Pete’s now-free books on ray tracing.

I got to see a physical copy of our book at SIGGRAPH, so know such things exist. I also bought the book on Kindle (which at first had some download problem on my iPhone and PC, but downloaded fine the next day) and Google Play (surprised to find it there; same price as Kindle, by some amazing coincidence), as I wanted to see if a layout problem in my local copy was present in the book (happily, it wasn’t – ahhh, the mysteries of LaTeX).

One of the best parts of SIGGRAPH was actually meeting my coauthors. The wild party on the yacht that night in Vancouver Harbor was really something, too, but then I realized I made that up.

Eric, Angelo, Naty, Seb, Tomas, and Michal; photo courtesy of Mauricio Vives