It's especially outrageous since Carmack came up with the technique independently of Creative. If it doesn't show that this is a fundamentally trivial patent that should be thrown out, when pretty much the second person to even look at using depth shadows in performance-critical code independently "invents" the technique, I don't know what it would take.

It really doesn't take John Carmack to figure how the patented shadowing algorithm works. It's a very trivial modification of an older shadowing volume algorithm where you slightly change depth test and stencil test settings to get more robust shadow volumes.

I used this algorithm just the other day in some exercise work for uni studies. We actually had this algorithm as an example on one of the basic 3d graphics courses.

When the d3 source is out, I might take the time to re-write the z-fail shadow volume code to doom3 and push it to a git server hosted in a country with sane patent laws. If I have very much time on my hands, I might try to do the shadow volume extrusion on the GPU with geometry shaders (a post-doom3 addition to GPU pipeline).

No, that doesn't demonstrate that the technique is "trivial", but it does make the requirement that the patent be "non-obvious" much harder to defend. As you note, if the first few people to look at the problem come up with the same solution independently, it is dubious that the solution is non-obvious.

Let's not forget that this is Carmack we're talking about. The fact that one of the best 3D graphics programmers in the industry has invented something independently does not tell us much. This thing happens in science all the time and not seldomly for things that are far from trivial.

Software patents are ridiculous, but not because (or only if) they're trivial.

Triviality is supposed to be a test case for the validity of a patent. I think you can make a reasonable argument that if the first few users of a technology all independently invent a technique, that technique should be considered trivial in the context of that technology.

I don't think it's necessary to deify Carmack, either. He is an extraordinary programmer, but he is not super-human.

Isn't the test 'an engineer sufficiently skilled in the art' ?

Carmack would qualify as 'an engineer sufficiently skilled in the art'. That he's one of the most skilled wouldn't be relevant.

I gotta say, you raise a good point, but I'm not sure using Carmack as an example here is going to work, because patents are supposed to be for things that an ordinary person in that field of work would not be able to come up with. Carmack is far from ordinary.

What about bitcoin? Should Satoshi Nakamoto patent that?

Just because something is badass and awesome doesn't mean it should be patented.

I didn't say anything about whether something _should be_ patented. I was commenting on the eligibility for patenting.

> There was also a lot of discussion about whether the patent was reasonable at the time, including, as stated on Slashdot, a claim that Sim Dietrich from Nvidia had demo'd the technique publicly, months before the patent was filed.

Until recently, the US was "first to invent", not first to file, and public disclosure didn't establish a bar date but rather started a count-down to a bar date. In other words, a public disclosure a few months before a filing can be irrelevant. Whether it actually is irrelevant depends on some other details.