Thursday, November 24, 2011

Carmack's Reverse

Just been looking at the stencil shadow code again. What's really annoying about this is that what Creative have patented essentially boils down to this:

-1 + 1 = 0
1 - 1 = 0
0 - 1 = -1
0 + 1 = 1
This really comes through when you see it expressed using glStencilOpSeparate, you just see the lines of code stacked up, and it's so obvious.

6 comments:

Anonymous said...

Since patents are by definition showing their contents and since you say it is rather trivial, surely some port will surface in a country where software patents are not existing.

mhquake said...

Well I'm in the EU so as the EPC excludes this kind of thing from patentability (under 52.2.1 amd 52.2.3) I could in theory get away with it... but I'd need definite confirmation from a legal person with specific reference to this patent before I'd personally feel comfortable.

gb said...

Pretend the software was leaked against your will. Although there are still potential attack vectors toward such a strategy... maybe upload the source somewhere under a pseudonym using TOR. Just to do something that's probably legal in the place you live in.

It would be funny if it wasn't sad.

Anonymous said...

When you get a cease and desist, tell them how happy you are that they pointed you to that nasty bug you were trying to resolve for so long.

Alternatively, write a backwards custom stencil buffer.

Anonymous said...

Yes, do it completely reverse.

And at the end do a "* -1"

Anonymous said...

I remember reading an Ars Technica article where is mentioned the math formulas cannot be patented. Isn't that the case ?