Today there was a bug. A bad one. I was trying to use a 4-byte RGBA color value as a vertex attribute to tint the particles in my new particle system. It worked if I set the value manually, I tried a bunch of different colors: red, green, blue, black, white. Those colors worked perfectly. The real color values were supposed to lerp from one keyframe to the next. That totally did not work. If I didn't set the color, the particles were magenta, or sometimes cyan. I checked the lerp calculation, that was good. I checked the conversion from 64-bit color to 32-bit, that had a bug so I fixed that. I looked at the vertex and pixel shaders. They were super-simple so nothing there to be messed up. I checked the color data in the game versus the data in the VBO on the video card with GDebugger and Windows Calculator. The data was identical. I was at a loss.

Really interesting talk on the graphics in Battlefield 3 by Johan Andersson, the Rendering Architect at DICE. Parts 2, 3, 4 have the most "meat". There are sections on lighting, post processing, terrain, particle effects and more. For those not entirely into rendering, he breaks down all the passes that go into a single frame in part 4 (there are a lot.)

Parts: 1 2 3 4 5

To get things ready to add the new particle system, I've been adding support for additional fields in my vertices. Previously all my vertices were the same Position/Normal/UV format. I've also been removing the use of deprecated functionality when I have the opportunity.

As part of the vertex upgrade, I wanted to replace my existing calls to the deprecated glVertexPointer/glNormalPointer/glTexCoordPointer functions with the more up-to-date glVertexAttribPointer. While reading about glVertexAttribPointer, I discovered Vertex Array Objects (VAO's.) A VAO combines all the calls you would normally have to do to set up your vertices, VBO's and IBO's into one call. I read about VAO's in the OpenGL SuperBible, but there is some hand-wavey stuff in their code that worried me. Looking into it more, I discovered glGetAttribLocation.

Vertex attributes (position, normal, colors etc) are passed to the shader via an array of integers. You can specify the integers yourself which is what the OpenGL SuperBible does - YUK! Or you can just declare your vertex attributes in the shader code and use glGetAttribLocation to find out where the shader compiler put them for you. Much nicer.

Getting the rendering to actually work however, was a huge pain. I spent a lot of time staring at a black screen in GLDebugger. There is a lot of misinformation on VAO's and I couldn't find a single example of how to use glGetAttribLocation like I wanted. So to save anyone else the pain, here's how it goes.

I've been following the launch of Guild Wars 2 with some interest. I've played the original Guild Wars quite a bit, and have been seriously considering picking up Guild Wars 2. But not anymore. At least until they work the bugs out.

When I read the reddit thread where people could ask ArenaNet Customer Service the reason they got an account suspension, that was pretty funny - even though the language is pretty colourful.

But today ArenaNet went too far. An in-game vendor was offering one particularly good item for significantly below market value. Apparently a mistake on ArenaNet's part, (given that everything that vendor was selling cost exactly 21 Karma.) Some players bought this item from the in-game merchant. The result, from reddit.com:

We permanently banned 3,000 accounts of players who substantially exploited it, and applied 72-hours bans to another 1,000 accounts of players who mildly exploited it.

People bought items from an in-game vendor and got a permanent ban from their brand new $60 game for it? I'm sorry ArenaNet, that's just wrong. I don't care how many times they did it.

If it was going to mess up the economy, then roll it back, but you can't call buying something from a vendor an Exploit and punish people for it. Take some responsibility for your mistake.

I suspect someone at ArenaNet realized that they'd made a public relations gaffe banning all those players, because they have relented. They're still not taking any responsibility, but if banned players go through customer service and beg for their account back and then delete anything they got from the vendor, then ArenaNet will let them keep their account. You can read the announcement here.

I've been integrating Variance Shadow Mapping shadows into my full game engine. As expected, that took longer than expected. I have the feeling that I'm going to be tweaking the shadows until the game comes out. There are a lot of adjustments. Shadows are not an exact science by any means.

My first question was "where do I put the sun?" I looked at a bunch of screenshots of other games. It turns out, most games put the sun in the same place - where the shadows are most visible. So behind and to one side of the shadowcasters.

Once the sun was to one side of the camera, I found an issue - looking at the shadow map in GDebugger, the entire visible portion of the scene was rendering at one end of the shadow map with "up" towards the center of the texture - wasting about 3/4 of my shadow map memory. There was however, a surpisingly simple solution!

I needed to have a way to take a color and change its brightness but to be sure that the color would remain true as I adjusted the brightness. I've used RGB a lot over the years so I was familiar with scaling the color components by a value, but I wasn't sure that technique would retain the color properly or that it would let me use the full brightness range available.

Researching the problem, I quickly found this Wikipedia article with a description of the HSL (Hue, Saturation and Lightness) representation of color and an algorithm for how to convert to and from RGB. The HSL color space looks like this:



You'll note that one of the axes is lightness -- just what I wanted. And it works like a charm.

One of the things I've always liked about computer programming is that if something works, you really don't need to know how it works. Libraries work like this, quite often code samples do as well. I've been working on getting soft shadows to work, and when I started, armed with a great code example of soft shadows using Variance Shadow Mapping I was totally optimistic I wouldn't need to really understand how shadow mapping works.

Well that's out the window. I understand.

Wow, been a while. I've been on vacation, playing with my daughter, going out with the wife. First time since my daughter was born that I can say I've seen 5 of the top 8 movies on Metacritic (or any of them actually.) Dark Knight was fun, Prometheus was fantastic, The Amazing Spiderman I saw in 2002 - it was called "Spider-Man".

There has been some small amount of progress on the game, but I tried to take my own advice this year.

I was looking into consumer internet offerings this week and I was shocked to find there are still internet services with as little as 15GB/month and with punitive $1.50/GB overage fees. 15GB/month is about enough for email and web browsing, not much more. For someone with this type of account to give some of the popular MMO's a try, check out the cost:



There's your business case for building a streaming MMO client right there. If you can get players started with a couple hundred megabyte client they'll save money, be able to get playing way sooner, and you'll save the cost of having them download Gigs of files they may never need.

I struggle a lot with wanting to share my excitement over how things are going with all the cool things I'm building, and with my internal quality bar which says which parts of the game aren't ready to have people judge them.

Indie games don't get any sort of pass on presentation just because they're put together by small teams. Like it or not, you're competing with AAA. If your product isn't immediately visually appealing you are putting yourself at a huge disadvantage. People won't even give it a chance. Sure you can put out an ugly game and slowly build a following with amazing gameplay, but you're putting up a significant barrier to casual interest. Look at all the big indie game successes of the last few years - can you think of any that weren't pretty in their own way?