bob's blog

In part #2 I looked at the built in atomic operations in QNX, Windows, Max OS X, and Linux. I found that they are all different. Some, especially QNX, are more different than others. Part #2 did a much more complete comparison of the different sets of atomic operations than I did when I designed the atomic ops for SDL 1.3. Sad, but true, I do a better job when I am writing for others than when I know no one will question my thought process. That is why public review is so important.

Well, this isn't what I thought I was going to be writing as part #2, but the replies I got to part #1 were all from people who wanted to help, but who did not feel they knew enough to help. So, part #2 is going to be a very basic introduction to atomic operations that builds up to a pretty detailed discussion of intrinsic atomic operations in GCC, Windows, and Mac OS X. Lets start with a glossary. You can argue with me about the definitions, please do, but this is the way I define these terms.

We, the folks on the libSDL.org mailing list, have been talking for years about adding atomic operations to SDL. One user even went so far as to post code for a set of atomic operations. I have been wanting to write some articles about atomic operations and I wanted to use a set that was not tied to any one operating system or processor, so an SDL atomic operations library was exactly what I wanted. But, it wasn't there yet.

Using SDL (the Simple Direct Media Layer) you can write multimedia and game programs that work with only a recompile on Linux, Windows, and Mac OSX. It supports many other platforms including most versions of UNIX, many new and old game machines, and several cell phones including iPhone. Not to mention that you can use it with a very long list of programming languages. SDL is at least 12 years old, has an active community, and is actively being developed.

Last night I was going through my mail and found my electric bill. I never read my electric bill. Why? Because I have it set up so that TXU Energy, my electric company, automatically drafts my bank account at the start of each month. I also have what they call "budget billing" so I pay an amount equal to my average usage for the last 12 months. Yeah, I'm a sucker, "budget billing" really means they always have some of my money and they get to earn interest on it.

When I teach, on my mailing list (gameprogrammer.com), at parties... I get the question "how do you get into the game business" or "Will this class get me a job in the game business". They are pretty much the same question. The person asking the question wants to get a job working for a game developer/publisher and they want to know how to do it.

Computer Graphics uses numbers in the range [0, 1]... a lot. The red, green, and blue color values in a pixel are always described as having values in the range [0, 1]. The alpha value of a pixel is also always in the range [0, 1]. The depth value in the Z buffer is also always in the range [0, 1]. The values in a normalized direction vector are also always in the range [0, 1]. This range shows up a lot. It also shows up in the values of coordinates before they are translated and scaled for display on the screen.

It should happen this year, if it hasn't already happened and I missed it. According to Moore's law 2009 is the year when you should be able to walk into a store and buy a chip with a billion transistors on it.

OK, of course what I am talking about is a violation of the T&C of every ISP I have ever used, but really...

What am I talking about? One of the greatest, yet least used, ideas for wireless networking is the idea of the wireless mesh network. The idea is that if my WiFi device can talk to your WiFi device they can create a network that includes those two devices. If any one of those devices has an Internet connection, then all of them can share the connection and all access the Internet.

OK, yeah, you've seen that, done that, know someone who does that...

First off, let me admit my biases. I worked for AT&T back when it went by the name of SBC. Yep, SBC, the baby bell that grew up to buy its mother and take its name. I did multimedia and network research at what was then called TRI. So, I am well aware of the strengths and weaknesses of the company.