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typos suck

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I've had a largely unproductive weekend, but this evening I finished off my implementation of the Ashikhmin-Shirley anisotropic model.

It turned out to be the hardest model to get correct, and I'm not even sure that my final version is actually correct. Y'see, the Wolfgang Engel book I was originally using was hopeless - you'd get less typo's per page if you allowed a monkey to re-type that chapter [flaming]

In what I can only describe as a sick joke, I go to Wolfgang Engel's website, follow the link to the errata page to which is states:

Chapter 15
There are numerous typos in the equations in chapter 15. Please download the following PDF file with the correct equations in it (Chapter15.pdf).

(Chapter 15 being the one covering Ashikhmin-Shirley). Clicking on the provided link give me... a 404 not found.

An error with the errata page - how funny [rolleyes]

As a side note; the pacing, layout and coverage in Engel's book is great. I just wish he'd consider a 2nd edition where it had actually been given to a proof reader. It's not just Chapter 15 - the whole damn book is full of stupid mistakes that really should not have made it into a final print run.

So I went to the original research paper (linked at the start) and went through implementing it from there. Seems to be quite different to Engel's implementation in a few places. But still, there are a couple of terms in the equations that seem to magically appear from nowhere. That combined with a few general typo's in the main text doesn't inspire me with confidence that even the original source was any good.

It's such a shame when great resources are ruined by such pointless mistakes [sad]
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Don't be sad.. I'll give you a hug!

Now go on and do your best! I'll be here waiting for your screenshots! [wink]

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haha, thanks [smile]

I'll see about posting some screenshots tomorrow. I've got a few things to tweak and them I'm working on a comparison shot with the original research paper [grin]


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yes I am sorry. This chapter went terribly wrong. Send me your e-mail and I e-mail you the version.
I assume the source code helped nevertheless.

- Wolf

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oh just read your comment regarding the quality of the Ashikhmin Shirley implementation. I think my implementation is now used in at least one game here at Rockstar.
The problem with the original version in the paper is, that you will get some problems with it ... it is such a long time ago, I can not remember the reason. So I think I changed it and the version that is used now.
You can look forward to an updated version for DX10. This time a couple of people will work on it and I hope that the chapter on Ashikhmin Shirley won't have any typos anymore.

- Wolf

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maybe I should post chapter 15 here on ...

- Wolf

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