Archive for the ‘Books’ tag

Performance vs Error Checking

Hi everyone, Vlad here!

Seems like on a thing versus some other thing rampage with Application Design vs Game Design shortly followed by this post. I guess that’s a good thing, it means there are challenges and doubts and that we need to research.

This post is also inspired by some books I’ve been reading lately and that I highly recommend: The Productive Programmer that was influenced by The Pragmatic Programmer.

Problem #1

We are writing code and there’s not such thing as writing code without bugs. Sometimes our oldest, most used code, that code that we trust each of our games with gets into a specific spot where a hidden bug appears and we spend hours and hours figuring out what’s happening.

Solution #1 is Problem #2

There are several solutions to this. Writing code that includes testing is in my opinion the best. The problem with this, game development wise and specifically in scripted languages such as AS3, is that this makes the code much slower. The solution was checking for inconsistencies and not performing operations instead of throwing errors and exceptions.

I ended up creating conditions for use. For instance our blit package uses three different types: the core, the object and the texture. The core keeps the state of the whole system, the object keeps the state of what and where to render and the texture keeps the state of BitmapData. If the object did not have a texture it would simply not render. Sounds pretty cool, right?

To be honest… wrong…

Problem #2.1

First problem was the times where the position had NaN value instead of a Number. This rarely happened but every time it did it was a huge headache to identify why and then track the source of the bug down. While this seems unrelated, the fact was the it looked like the texture did not exist. So I had to check if the texture was created, if it was passed, if it was there at all and the worst part was that if the texture was there as it should, where the hell was the problem?

Problem #2.2

Performance wise checking if there is a texture is absolutely dumb! 99% of the times there is a texture present. More, the object class has a visible variable. If the object does not have a texture why is it visible in the first place?

So while apparently I solved a problem by checking if the texture was present and not performing any blit operation if it wasn’t, the truth is that both performance wise (not that serious by the way, it’s just a if statement) and the unwanted problems it induced in the code backfired from time to time.

I spread this type of behavior through the code. While one if statement does not have a large impact in performance, a lot of checking piles up and I had a lot!

Solution #2

A short story and a riddle both taken from those books that explain my thoughts on the ‘final’ (we’ll see about that!) solution for these problems.

The first one was when one of the authors was hired as a consultant for a development project where the coders sent broken code to the version control system. What he did was to create a routine where the version control server would compile the code that was pushed. Every time the compilation didn’t work the server would send an email with the error. With the amount of mail with errors constantly piling up on mailboxes, one of the coders asked if there was a way of not getting that much email. The consultant replied: “Sure, don’t push code with errors!”

The riddle is… what code takes not time to be executed? The one that is not compiled.

So the solution is to write code that allows zero error tolerance while not compiling it. The way to achieve this is with conditional compilation which can be used in several way but these are the ones I believe the most useful is to use code blocks, like this:

Inside the same function, different code is compiled depending on the current configuration. We can have several checks with exceptions and errors being thrown and then have a ‘don’t check at all’ version in the release configuration.

This is a two stage solution really. On one hand every time I do something stupid, I get errors so my code has to be perfectly implemented at least when it comes to our framework. On the other hand the same code that make me code as best as I can is also the code that does not run in the final version.

Flash Multiplayer Virtual Worlds Review

Like I mentioned sometime ago, we will be reviewing some books published by Packt Publishing. So and since there aren’t news or articles about Bruce Ali that are ready to go, nothing like keeping the good momentum with a good book.

I read Flash Multiplayer Virtual Worlds mostly because it is an area that interests me a lot and crosses many aspects that are part of my daily work from a design point of view. The name could not be more obvious regarding the intentions of the book: to create a virtual world using flash technology, so what’s in it?

The good

There are many good things about this book, but probably the one that doesn’t stand out immediately is that it will get you up and running with SmartFox Server in no time! From installation to technicalities to server-side implementation, the amount of examples surrounding SmartFox Server should make this book interesting for anyone that wants to pick up this server-side software even before considering MMOs and virtual worlds.

One of the really good things about this book is that it covers every standard implementation that is present on a virtual world. Starting on architecture and going through in-game systems such as avatars and messaging up to the social aspects like Facebook integration and even some quite smart details that I personally would not remember or know. I admit that in such a wide area, maybe something is missing, but I can’t really remember any.

Another good aspect is that it seems written to a lone wolf kind of developer given the detail of some particular aspects (such as extracting 3D renders) that most coders working in teams or companies would not care because it would not be their work, but it doesn’t really get in the way.

The bad

The last paragraph brings me to what I didn’t like in the book. I can look at this book from two perspectives: the game programmer or the game designer. From a game programming point of view there’s too much game design in different depths of detail and even some stuff about handling graphics that I admit is important but should be as important as the assumption of AS3 programming of the book. From a game designer point of view, not only the code is not my core work, but the design is not in depth enough. I sometimes felt that the level of detail was not constant, when comparing how to integrate tiles in isometric perspective (extremely well explained and detailed) and the implications of designing a solid online economy (well explained but no detail).

Conclusions

So, is this book for you? Like any book, it depends on who you are. Are you a AS3 coder that wants to work with SmartFox Server or create virtual worlds? Are you a lone developer that wants the overall knowledge about this topic? Or even a designer that codes a bit and wants to try it out?

Then yes, this book is for you and I do recommend it!

Packt Publishing and Book Reviews

Hi everyone

I really like books. My biggest flaw is not owning a e-reader, but it will arrive mid-September, don’t worry! While I read some non-technical books occasionally, like most of you (our dear friends and blog readers) I mostly read technical books. One of the issues with technical books is to find those that match your needs. Like me, I bet that you will not buy a book that doesn’t pack the the promise of growing your knowledge considerably. I also bet that you, again, like me, have bought a book or more that was less than what you expected.

On occasion I’ve read books that seem awesome and has time goes by prove themselves wrong… so is life…

The best books I bought were through word of mouth. People I trust having a opinion on a specific book that would meet my needs. Reviews help also, naturally. Bringing the two of them together on our blog sounds fantastic to me!

Packt Publishing released two new books that sound amazingly interesting for todays flash market space. Flash Multiplayer Virtual Worlds and Flash 10 Multiplayer Game Essentials. The book titles are self-explanatory are they not?

I’ll read the books in the near future and review their content from flash developer to flash developer. All that is left is to say thank you to Packt Publishing wish them a lot of success and hope for more books that are interesting for the flash gamedev community.