Two of the most important concepts in software engineering are abstraction and modularity.  Abstraction allows us to categorize problems and write general code to handle all problems within a group, while modularity allows us to combine disparate abstract components to create unique solutions for a particular problem.  These two concepts give us the ability to write elegant, yet powerful systems that can solve many problems at once.

These systems often rely heavily on data, which is the glue that holds the abstract techniques together.  Data is used to configure which components plug into one another and how they behave. 

As programmers, it makes a lot of sense to us to expose the raw data in the tool to the people responsible for making something useful with it.  After all, not only is this the easiest implementation, it’s also difficult to see another implementation that would not constrict the end user’s ability to get the full benefit of the system’s power.

If the tool was in our own hands, or even in the hands of another programmer, this would all be true.  Unfortunately, this is usually not the case.  The end users have to figure our very clever system out for themselves, often with no knowledge of our intention, the underlying data structures, or even basic software engineering or programming concepts.

Instead of empowering the end users with our uber-system that can handle any problem, we’ve saddled them with a system so intricate and burdensome, that they can’t wrap their minds around it, let alone do anything useful with it.

Training can help to a degree, but that turns into one-on-one training with every user for any one person to understand.  Documentation also helps, but often ignored, in reading as well as in writing/updating.  Usually, one person ends up being the expert that everyone relies on, but when only one person can use a tool, you know that it’s doomed to failure.

The answer is simple, yet hard to swallow.  The tool interface can not be designed around the data structures used by the underlying system.  The tool must be designed around the users, and the very specific things they want to do with it. 

That will probably handle about 90% of the problems the system was designed to solve.  Most users will get along happily with that, and even find their own clever ways of getting some of the additional 10%.  They’ll be much happier with a tool that is easy to use than one that is all-powerful.

The properties set by the designers were stored internally as an XML document, since XML in C# is incredibly easy to manipulate, and since the data would be different for each level design pattern.  It was easy enough to save out the raw XML data as it was stored internally, but the problem was how to transform this data into the format that would be read into the game. Enter XSLT.

C# has the functionality to transform data internally with an external XSLT file.  It’s easy enough to associate a XSLT file with a specific pattern, apply it at run time, and then simply write out the result.  At this point, it’s simply a matter of providing the designers with the data files necessary to generate their data.

The advantages here are great.  Putting the complex structure and syntax in an external file, and separating it from the designer’s view, allows them to concentrate on what’s  actually important.  The downside is that someone has to craft these XSLT files, which is a format that is a bit obtuse for someone used to functional languages.  Additionaly, XSLT has little to no debugging capability.

Now, more recently, I’ve had the challenge of writing an exporter from OpenOffice Calc, which also uses XSLT as filters for importing and exporting.  All OpenOffice documents are are stored as XML.  In fact, if you simply rename an .ODS file to a .ZIP file, you can explore the format, which is spread over several files inside the .ZIP, the most interesting of which is called content.xml.  This is the data that needs to be transformed in order to get the information out of OpenOffice into your own format.

What we wanted was a way to store properies of all enemies in a single table, so designers could tweak values easily.  The data then needed to be exported into a proprietary text format (not XML).  This is also relatively easy with XSLT, but as with anything, exporting from Calc with XSLT had its pitfalls.

It’s easy enough to access individual cells in a row in Calc.  Unfortunately, for some reason, they decided that if adjacent cells in a single row have the same value, it would only be stored in the first cell and an attribute on that cell would indicate the value repeats for n-number of cells.

With XSLT, there are no variables that can change their values, only constants within a single template (the XSLT equivalent of a function).  Consequently, there are no “for loops” in the traditional sense.  The way to get around this with XSLT is to use recursion.  In my script, I basically have every cell recursively calling the template on the next cell in the row, or on itself in the case of repeated cells, and track the cell heading (the first row of the table) separately.  Just thinking about it gives me nightmares.

At any rate, more and more data is being stored as XML, and consequently XSLT is probably here to stay.  It’s another tool that should be available in the game developer’s toolbox, but must be used with care.  To learn more, there are tons of resources on the web, but your best bet for a good introduction is the W3 schools site at http://www.w3schools.com/xsl/.

Running games on the cloud is an obvious use of these resources.  Need a game server accessable from anywhere in the world?  Start one up on a virtual server.  The ability to build machine images (AMIs on Amazon), complete with your own software running on operating systems like Linux, OpenSolaris, or even Microsoft Windows Server gives you that possibility for pennies a day.

But, where cloud computing could really come in handy is in game development.  Imagine starting a build distributed across the cloud, in which thousands of virtual machines simultaneously start processing individual bits data.  You might see builds going from minutes or hours to just a few sconds.

And the cloud isn’t just for processing either.  Some companies offer services for managing data that would traditionally reside in a relational database, and as well as file storage services.  You could even use your own machine image running some flavor of SQL.  With that capability, why not store assets in the cloud?  An asset control vendor could use the software as service (SAS) model for asset control, supplying developers with web and client based views into an asset database on the cloud itself.

The big problem here is that we’re trading bandwidth for processing power and flexibility.  The build process may take a few seconds, but retrieving the results to local machines may eat up every bit of build-time savings and then some.  We may see overnight builds turn into overnight downloads, and that’s no savings at all. 

Bittorrent file serving (available on AWS) may be useful as a build distribution model, but with most users on a single network, it doesn’t seem likely to make a difference.  Limiting the download process to necessary files only is simply the flipside of building necessary files only, so may also offer little in the way of savings.  Doing a bit by bit comparrison of files built on the cloud, and downloading just the file differences, may be a way to reduce the download time, assuming there are chunks of data in a binary file that remain constant between builds.  Other optimiztions almost certainly exist.

All in all, it could be a big win, but until someone proves it, we can’t know for sure.

First, you can have the tools and the game depend on a shared library of resources. The tools have their own UI, tick or don’t tick at their own rate, and may or may not use the same renderer as the actual game. By creating tools this way, you have tools automatically update their own behaviors as new features are added to the game, or even automatically generate their own UIs if you’re using a dlls and a reasonably robust reflection system. The problem here is that if you’re not using the game’s update and render loops, you still have to boot the game to see everything in action. This can create long turnaround time for assets, especially if your game takes a long time to boot and / or load. That said, this allows you to keep your tools slightly smaller, it reduces dependencies on what are often unnecessary game libraries (like threaded sound and in game UI), and can make the tools less prone to break due to game changes.

Your second option is to either make the tools dependant on the entire game, or make the tools embedded in the game. Now, I think every studio has a small amount of “on the fly editing” capabilities in their engine, but there are very few that are willing to take the full plunge and make their game the editor. In some cases, this is because they can’t afford the extra memory or processor time to fit an editor on a console dev kit. That said, in game editors, or editors that can run the full engine stack, can reduce asset turnaround time significantly. Given a properly designed tool, artists, designers, and scripters can actually edit objects on the fly, and see their changes affect the environment immediately. Once given a tool like this, few would want it taken away. However, these tools can also get cumbersome as well. Because you’re working in the game engine directly, few tools developers in this scenario will take the time to develop good user interfaces, as it tends to clutter up the screen quickly, instead relying on weird key or button combinations to achieve the desired result.

In both cases of dependency, the one thing you need to avoid is the dreaded #IFDEF EDITOR block, and I know you’ve all seen them, and they almost always defeat the purpose of having shared code in the first place. The idea behind shared code is to make sure the editor behaves the same way the game would under the same circumstances. #IFDEF EDITOR blocks, by definition, create inconsistencies between editor and game. But these blocks almost always become a necessity at some point, which is why some studios prefer to forgo the dependency question entirely, and instead opt for a tool that outputs a platform independent format (XML or JSON for example) then has various versions of the game decide what to do with them. The game can ignore blocks it doesn’t understand, and fill in missing blocks with default values if needed. This keeps game and editor independent, so that mismatches can be safely dealt with. However, it still incurs the wrath of the slow turnaround time, and the necessity to maintain two separate code bases.

In my opinion, dependency is a requirement. The idea here is to protect against game changes, include the ability to preview your game, and shorten turnaround time to the game whenever possible. Toward this end, you should limit yourself to dynamically linking in only the libraries you need, which is usually your rendering libraries and your game object libraries. Try using reflection where possible to generate your UI against game objects so that changes in game objects don’t require complete editor recompiles. Save and load objects to a text format (XML is my favorite, but you can choose whatever you like) at least during development so that you can protect against mismatched resource bugs, and, lastly, use a robust shared command system to transmit changes to a running game to shorten turn around time.

Many game companies struggle with delivering tools quickly and cheaply.  Money is always an issue wherever you go.  After all, the bottom line is what keeps a company afloat and it’s employees employed.  No one wants their company to fail, to lose their jobs, or to lay off their workers.

Game companies are in an especially difficult position.  Attempting to balance a workforce spread over multiple disciplines — art, design, programming and production — is hard enough, but when you consider that those disciplines have their own specialties within each one, the task is even more difficult.

The obvious solution is to cut corners wherever possible, and that oftentimes falls squarely on the shoulders of  the tools team.  Why?  Because most game companies don’t make money selling tools.  Tools programmers serve in a support role, and therefore (in the minds of most game execs) are less valuable than those working directly on the games.

Tools teams very rarely get the full support of management, and game teams can’t be stalled waiting for tools to be completed.  The unfortunate sentiment among those in power is that there’s no time for tool design.  Get it done and get it done now.

There is no time for design, so the thinking seems to go, but what does that really mean?  Does that mean that the programmer implementing the tool charge blindly into development without thinking about how the tool needs to function?  Of course not. 

The programmer has a vague idea of what to do, and without ever writing it down or validating his thoughts with the end users in any formal way, begins to implement the design from his own mind.   He still thinks about it a great deal.  Perhaps 75% of his time is spent thinking and only 25% is spent typing.  There are probably still many  unanswered questions, but as the tool begins to take shape, some answers may start to become more obvious one by one.  The tool seems to practically design itself, but in reality, design is going on quite informally.

But wait!  What if one of those unanswered questions causes a serious problem?  What if the best answer to that question requires a rewrite of major portions of current code-base?   What if the other possible answers are so undesirable, that the rewrite actually appears to be the best option.  Because the design had been postponed until the code was in the process of being written, redesign is now very expensive.  Code that has been written will go to waste, and new effort must be exerted to replace it.

If the programmer takes this problem to a (non-technical) manager, concerned with cost and speed of developing the tool, the manager may come to the very justifiable conclusion that a rewrite is not the way to go.  Instead, just make a work-around for this one problem, in other words, a hack. 

As long as that’s the end of the story, then that’s probably okay.  Unfortunately, more issues may arise, with similar outcomes.  Also, once delivered, the end users will likely have feedback.  After all, without any formal design process, many of their needs/wants/concerns went unheard.  And now the real fun begins.

It’s already been established that the quickest solution is more desirable than better architecture and code, and so as feature requests are delivered to the programmer from the users, more and more workarounds are put into place to deliver a new tool quickly.  This leads to code that is difficult to maintain and potentially very buggy.

The end users are now saddled with a tool that does basically what they want but perhaps has stability or performance problems.  The difficulty  to fix those issues increases as time goes on as the code becomes more brittle and spaghetti-like.  Fixing one thing breaks something else, leading to a never-ending maintenance cycle that really makes no net improvement whatsoever.

Team sizes are increasing.  So are the assets, themselves.  The more users stressing the system, the more fragile it becomes.

NxN had the right idea with Alienbrain but never really got anywhere due to serious technical issues with their back-end.   It’s been a few years since I used it last, so they may have fixed a lot of those problems.   Anyway, it also had some very nice features you don’t get in other source control solutions.  You could easily redesign the whole interface (it was mostly html and javascript as I recall), and they included a feature that was very art-centric.  Previews.

You could generate previews of assets and view them right in the Alienbrain interface.  It was a very slick feature and a selling point of the software.  Finally, a user could see a preview of a model or texture (and many other asset types) without doing a get and opening the files in Maya or Photoshop, etc.  That’s a real time-saver if you don’t remember the filename that was used for a specific asset.  You have the chance to browse all the assets of that type and find the one you want pretty easily.

Like I said, though, NxN had its share of troubles.  Still, I believe we can do better than the source control status-quo.  I imagine an asset database solution that integrates with every asset generating tool, as well as the build process, generates a preview for each asset (even if it’s a bitmap that says “Preview Not Available”), and is searchable by its meta-data, including tags, creator, last modified, and so on. 

The classic view of assets as a collection of files inside of folders, with users having to know exactly what files need to be checked in and out of source control when changes are made seems a little antiquated.  Instead of searching through folders ten layers deep, how about using a tag cloud to find assets instead?

I imagine being able to open a web-based interface, searching for an animated character from an old project and clicking a button to copy it to a new project, including all of it’s vertex, texture and animation data and using it as the starting point for a brand new character, or maybe just as a placeholder until a new character is created.  How many walk cycles does one studio need to recreate every time a new project is started, anyway?  Why not take something you have and modify it to fit a new character in a completely different game?

I really beieve that asset databases are the wave of the future for game development.  When the Xbox360 and PS3 came along, team sizes doubled, and assets got bigger and more complex.  What’ll happen next time there’s a hardware revolution?  We need to streamline the way we manage assets, or else, it’s going to bite us in the ass… even more.

Luckily, there is a lot of great software out there that is either open source or very cheap, and the very best solutions have risen to the top.  Most of us have heard of Blender, Gimp, the Torque Engine and Unity (which includes a $200 “indie” version), and there are a great deal more.  Check out IndieGameTools.com for a good list of the best stuff.

While some of these tools are really great, there will always be a need for custom tools, that aren’t very useful to other developers.  Smaller developers should consider partnering with a small tools development company or individual contractor.  there are a few people out there who are doing this sort of work and banding together can be mutually beneficial.  Getting someone experience to help out in this area can give a leg up on the competition, after all, the better the tools, the easier it is to make a great game.

There are a lot of approaches to this problem, but I’m going to narrow down the solutions to three that tend to be more efficient and should be used when developing a mature tools pipeline: Using in game editors as opposed to stand alone tools, implementing dynamic resource loading and unloading (through something like a developer console), and improved communication between game and stand alone tools.

Right now, I’m going to focus on the third possibility. The use of a game-embedded editor versus a standalone tool set is an ongoing argument in the tools community, and each side has its positive and negatives, but regardless of which way you go, some of your tools are not going to be game-embedded, and it is important that any “stand-alone” tools be able to communicate with your game. By creating even a simple a communication library, you’ll be able to issue commands to the game remotely, grab and analyze information without using game resources, and smartly organize, load and save diagnostics information, which might otherwise create large amounts of special case code in your game. By creating a slightly more complicated communication system, you can dynamically run scripts, save and load resources, and even set up a system that communicates changes in seconds to running games. Talk about turnaround time.

The key to creating a good communications library is understanding the limitations of each console, and when the console (or running game) can initiate communications with a PC, and visa versa. For things other than debug output (the topic of another article), you can assume that a running tool can communicate with a running game, but not the other way around. This means that the tool must initiate the communication before the console can send the necessary information back. In addition, most communication libraries perform this communication in a background thread and, if they don’t you should design them to do so. The last thing to keep in mind is that some commands may require a lot of data be sent back and forth from the tool and the game, and it is advantageous to split these commands into multiple sends of packet data, both from the tool and back from the game. A well defined command system will be able to specify just how much data will be sent, and how many packets it intends to split the data across.

So how do we go about doing this? First, consult your console’s documentation on communication. For PC, your best bet is to used named pipes. From there, the diagram at left offers a very high view of things, using command factories to create defined commands and issue responses. Here’s the basic rundown.

1. Have your game open a well known named pipe, either public (if you want to communicate across PCs) or private (if you don’t). The game can then sit in a wait state on the pipe, looking for commands from your tool. Remember, this is in a separate thread, so having it in a wait state shouldn’t impact your game.
2. Have your tool connect to the same named pipe, and issue a command string and parameters.
3. Have the game, on receiving input, look up the command in a command map. This should point to either a command factory class or command factory method (I prefer the later for memory reasons, and a class is usually overkill). The factory should return a class that inherits from a base command.
4. Run the returned command with parameters. The command should always generate some sort of simple response, be as simple as Succeeded / Failed or as complex as Need More Data, Ready To Send Data, or Ready To Initiate Communication.
5. Send this response back to your tool, which should display the result to the user.

From here, the amount and type of communication is up to you, though this can become very complicated very quickly, as you’re essentially creating your own network protocol.  However, there are a few things you should keep in mind. First, as I said before, you’ll want to design your protocol to be able to push multiple packets of information, usually of fixed size. This will dramatically reduce your memory requirements game side and will improve response on your tool side, as you’ll be able to offer more information to your users faster than if you were waiting for one large response. Second, develop a system for communicating with persistent items, such as pieces of debug information or your AI. This way you don’t have to go searching for the AI or object you’re watching or manipulating on every command, it will just always be there.

While at GDC this year, the idea of usability came up at the Tools Round Table.  Now, I’m pretty sure John had included the topic at the round table, in part because he had gotten a very early preview (and several revisions) of my article before it went up on Gamasutra.  I appreciated the effort on his part, but I was a little surprised at the total lack of response from the group.  When asked who was using what techniques for usability, the room was completely silent.  I expected that if anyone in the industry was doing anything at all with usability, surely this was the group.

Although it was a bit disheartening, it illuminated a real issue in game development that most of us have known in our hearts for quite a while.  Very few people are serious about making game development tools accessible to their users.  Artists, designers and even programmers spend a great deal of time dealing with tool issues for the length of every new project.  The tools developers wonder why they have so much trouble, without ever realizing that there are techniques in existence that could answer that very question and could help them make better tools that got fewer complaints and more work done.

I recommend every tool developer out there take a look at these resources:

The Usability Professionals’ Association website

 Jeff Sauro’s Measuring Usability website

Also, read Alan Cooper’s excellent books on usability:

About Face 

and

The Inmates Are Running the Asylum