Monday, November 13, 2006

Back in service

Sorry to all my thousands of readers... I moved a week ago, and only now got the server back up.

Because of the move, work (and when I say work, I mean thought) on MMORF has been minimal, but it should once again pick up as I ease into my new digs.

Monday, August 21, 2006

Parallel Universes and Design Patterns

I just finished reading the article The Theory of Parallel Game Universes: A Paradigm Shift in Multiplayer Gaming and Game Accessibility, over at Gamasutra. It talks about presenting a game to different players in different ways; that is, providing a mapping of the game experience to those that might have limitations in the way they can interact with the game, be it a physical disability, a skill gap, or a hardware limitation.

The article talked about the idea of a transition function that would take the viewpoint of one player and convert it to that of another, and vice versa. While I'm not specifically looking to design a system (and in this case, it's a client-side problem and not server-side anyway) to work around a player's disabilities, whether reduced motor functions, poor vision or deafness, I believe I have mentioned my intent to implement various levels of client before.

On the grand scale of things, a MMO is a large-scale simulation, running innumerable things at any given time, into which players have an interface, a viewport, through which they can watch and, we hope, interact with the simulation.

On the top end of the scale, we'd expect a lavish 3D environment, with lighting and shading and textures, something taxing the latest-and-greatest video cards. You can look all around you, interact with the world using the mouse as an extension of your arm, and generally feel fully immersed in your surroundings.

For less powerful machines, we might provide a simpler, 2D interface, perhaps with a top-down or isometric point-of-view, in which we can still see all of the scenery, residents and objects of our world, albeit in lesser detail, fewer colors, a from the "front" only. We have this version because the graphics are bitmaps, not rendered meshes, and so aging hardware can still display it with a sense of immediacy, or perhaps because players just prefer this view-from-above (perhaps to avoid motion sickness when playing in a first-person 3D view).

For specialized devices, such as PocketPCs or cellphones, with very limited resolution, and reduced memory, CPU and GPU availability, we can perhaps provide a very low-res 2D- or 3D-view, flipping menus and text information overtop of our graphics to get non-visual information about our world. Without a mouse, we might have a stylus (for our PocketPC) or a simple control button on our cellphone, each with which we must be able to interact with the world as well as well as with the mouse.

And then we have the lowest level of interface, a text-only interface. Whether this is used because of a lack of video card, because of physical disabilities, or because of a preference for the simple, the ability for the world to be described in text, and interacted with from a keyboard can and should exist. In the case of such an interface on a portable device, a menu-driven or shortcut-driven interface might be used, to obviate the need for a keyboard.

I feel that any virtual world should be represented to the client in such a way that any of the above interfaces can be supported. For testing purposes, the text-only interface is by far the easiest to whip up, to interact with, and even to automate. Proof of concept for a world might be implemented in simple, 2D tiled graphics, where the game's content can still be seen in full, if not in full graphical glory. And time permitting, the 3D eye-candy version can eventually be written to make the game what it was truly meant to be for the player.

But how is this done? By separating out the system into parts conducive to this manner of design. In the world of design patterns, this is the Model/View/Controller pattern. The idea is that you separate the software (in this case, our MMO) into these three different "ideas", and keep them separate, providing an interface between the three. The Model is the simulation itself; the world running the physics, holding the database, and communicating with the other two about what's going on. The View is our world's representation on the client, whether a 2D or 3D graphical display or or a bunch of lines of text. The Controller, in this case tied very closely to the View (because they're both in the client), is our source of input from the user to the simulation, through mouse, keyboard, stylus or joystick.

The work for the designer and programmer is to decide what the communication between Model/View and Model/Controller is going to look like -- to design a proper transition function, as talked about in the article. If something moves in the world, we need to tell the View that this has happened, possibly with the path taken, the speed done, the direction the object faced, etc. In the 3D world, the mesh will be animated smoothly on the client; in the 2D world, it may hop from "tile" to "tile", or may "slide" from one to another; and in the text world, a sentential description of the move would be provided.

Likewise, if the player wants to move herself forward a few steps, her Controller might have her hold down the up-arrow key on the keyboard for a second or two, or might use left- or right-click on the terrain in front of them on the screen, or perhaps typing walk forward 3, all of which are translated into a "walk forward" or "walk forward 3 steps" or "walk to here" message to the Model.

The "trick", in the case of the View, is finding out all of the information that needs to be sent from the Model, and then figuring out how to represent it in all View implementations. Likewise, every type of Controller needs to be able to communicate the players' needs, completely, all boiled down to the common "language" that Controllers use to make requests in the Model.

In theory, people should have no advantage or disadvantage given any implementation of View or Controller. That is, no View information should be extra to some or lost to others, and actions in the simulation should not be possible in some Controllers and not others. While it's a given that for speed-dependent simulations, certain interfaces will have an advantage, it should only be based on time and not lack of information or ability. The time it takes to read the description of the monster is certainly longer than visually seeing some 3D monstrosity eating your head, and typing "shoot bug-eyed creature" over and over is going to take longer than right-clicking on the screen a bunch of times... but these are all limitations of the player, not the interface.

Since I've never read Design Patterns: Elements of Reusable Object-Oriented Software by Erich Gamma, Richard Helm, Ralph Johnson, and John Vlissides, I don't know for sure whether my description of Model/View/Controller is the same as they present; what I've talked about above is something I came up with independently. I have obviously heard of design patterns, though, and the book I talked about before, Massively Multiplayer Game Development, makes mention of them, so I've started reading Design Patterns to finally see what the fuss is about. I'm sure that there will be other patterns in there that are intuitively obvious (to me, anyway) like the MVC pattern, but perhaps I'll learn some other useful nuggets that might be applicable to the MMORF project.

Monday, July 31, 2006

Additional reading

I picked up and started reading Massively Multiplayer Game Development and Massively Multiplayer Game Development 2, both edited by Thor Alexander. I'm halfway through the first one, and am quite disappointed that I didn't know about these books before.

Not that I've found a lot that I hadn't known or determined, but it's good to see that others, especially those that actually do this for a living, have hit the same hurdles and come to the same conclusions that I have about various stages in MMO design.

The first section is about game design, which, if you've read previous postings, is something that I say will come much later for me. After all, MMORF is the foundation for building the games, not the act of making the game itself. Still, that doesn't stop the designer side of me considering all sorts of issues (and telling the developer side to make sure functionality is there to solve them).

The second section is about system architecture, with the first two articles titled Building a Massively Multiplayer Game Simulation Framework. Yeah, that's what I thought. There were interesting articles on open-source platforms out there for game development, and really, the whole section almost made me abandon this project.

But again, the point is to see if *I* can do it, not to have one done, so I kept reading and learned a few tidbits here and there.

Section three, which I've just started, is about server-side development. I've only just finished reading the first article, Seamless Servers: The Case For and Against. As my previous posts have indicated, I'm all for the seamless servers, and this article does a good job verbalizing the pros and cons that I had already determined. I did find his conclusion interesting, where he stated "the author's opinion is that seamless servers are not worth the effort involved."

I find that an interesting statement, because to me, the decision is one that would or should cause contention between the game designer and the game developer. I would imagine that, for the most part, game designers would want the world seamless, so their grand dreams are realized in an epic scape of whatever fits the genre. The developer, for reasons mentioned in the article, is likely to push towards instanced or segmented worlds, where events cannot cross over the boundaries, and thus programming required to handle this crossing (again, very well described in the article) can be avoided.

There are reasons, of course, that a developer might want an instanced world; in DDO, the dungeons are instanced so you and your party are allowed to explore without interference from others. Ultima Online added a similar idea with the Mondain's Legacy expansion, where a group leader can "tag" a group of others that are allowed to cross over and fight the end boss with him or her.

But generally, I wouldn't expect that it's up to the developer. With luck, the developer can point out all of the hurdles, and convince the designer that for time reasons, budgetary reasons, and reasons of sanity, the game needs to be designed around the segmented world. And if he can't convince the designer? I guess this is where the producer comes in, telling one side or the other what's going to happen, or how to compromise, or who gets to find a new job.

And of course, that's something that I'm hoping to avoid with MMORF. I don't want to have to tell a designer that they can't have their wide open plains of Saskatchewan in the Colonizing Canada Online game. I suppose that's one advantage to not having any money or backing from anyone to get this done -- I don't yet have a definitive target to develop for.

As for the rest of the book, we've got sections on Client-Side Development, Database Techniques and Game Systems coming up, which all promise to be as interesting as the first half. I haven't cracked open book two, but I'm sure it's going to be as good a read as this one has been.

Monday, March 13, 2006


I started playing Dungeons and Dragons Online: Stormreach (DDO) a few weeks ago. I've been looking forward to this for a while, as I'm a big fan of the D&D franchise, and felt it would make a fine concept for a virtual world.

Before the game's release, there was a lot of talk on the forums about how the game was going to be strongly instanced -- that is, that adventures would be isolated to a party of players (which is limited to six), and their adventure would be separate from another party that happened to be doing the same task. This is an idea that many games are now using, to prevent griefers (players that just wish to annoy other players) and to better handle server resources.

The rest of the world, I was to understand, was not instanced, so if you weren't on an adventure, you could mingle with the other people in the world. This is partially true; you can certainly mingle with others (in the taverns, on the street, or at the various trainers or quest-givers), but even the outside world is instanced -- there are four different "The Harbor" areas, and which one you end up in is based on the load in them all.

Now the game does supply a fiction-breaking method to hop between these four instances, which means you're not forced away from your friends, but this really puts a cap on the "multi" part of "multiplayer".

But is mingling with people what makes a massively multiplayer game or virtual world work? Should DDO be considered one at all?

I've been struggling to like this game. Part of that is because I'd like to play on my own if I wished, but the developers were pretty clear that the game was designed with party adventure in mind. It can certainly be fun when you have others with you (because you aren't dying all the time), but I don't care for the idea of having to find someone to go adventuring with every time I wish to leave the tavern.

I'll admit that the interface for finding others with which to adventure is a good one (although again it breaks fiction -- what's wrong with bellowing out in the tavern, "who wants to clear the sewers of their infestation?" But it does do a good job of helping you find a certain level cleric to heal the group or a rogue to disarm the traps.

But the party is still limited to six. This means you are sharing a common goal, a world event, with at most five other people. It's fun for small adventures, but what about the grand scheme?

And these adventures... I was under the impression, early in the development stage, that the missions had an underlying theme, but that the dungeon or forest or crypt would be different each time, so while you may have heard from others what the gist of the adventure might be, you couldn't know what was coming. I've yet to see this, and it is again fiction-breaking that you can simply redo the same adventure over and over again -- how many times can you save that girl, find the lost badge, or recover that darned healing potion cask?

It finally occurred to me the other day: DDO is not a massively multiplayer game. It's not a persistent world. A better way to define the game is to relate it to a game such as Diablo 2. You could go online, there were other people with which to adventure, you could trade items ... but there was nothing persistent. The only think that changes on the server when I finish saving that girl yet again is that I have a few more experience points, a few more copper pieces, and a damaged mace. But Stormreach is no better off for it; I haven't made things better or worse for other players; and that damned girl is just going to get kidnapped again.

There's no housing with which the players can litter the land. You can't even drop items on the ground -- a good idea from a resource management point-of-view, to be sure, but a bit immersion breaking. And there will be no epic battles as the world's fiction progresses, where dozens or hundreds of players from numerous guilds will come together for a lag-inducing grandiose battle against some great evil.

But perhaps I'm to blame for the misconception, because the game *is* exactly the way they said it was going to be. Perhaps it's my fault that I expected the experience to be more in line with previous entries in the field. Or perhaps they're culpable, because it's not truly a massively multiplayer game. But did they ever claim it was?

As I said, I enjoy the game, and now that I've gotten it out of my head that it's a virtual world, I won't be so critical. It's just an online game where you can see the other players walking around instead of in a roster (like,, Steam, etc.), and I can enjoy it more now that I'm conscious of that. But I suppose I'm a bit disappointed that we still don't have a D&D virtual world.

Perhaps MMORF can offer that possibility?

Wednesday, March 01, 2006

Any chance?

I've recently discovered two other projects, Multiverse ( and BigWorld ( Both of these purport to be "Complete MMOG" solutions.

I heard of Multiverse from its relationship to James Cameron, the director, mentioned I believe in a Wired article. According to their press, they support the .mesh format (though I don't know graphic formats) and have a converter to get you from other popular formats, such as Maya and 3dMax. They have a tool for designing the world. They have support for a product called SpeedTree ( for providing scenery.

They provide a client, based on the Axiom 3D engine (, and the client can be customized using Python or C#.

The server is written in Java. Their target platform is Linux, but it also runs on Windows XP. They support multiple servers, splitting the world into a quad tree, and passing off quad trees to other servers. Objects are stored as either XML or binary data. Extensions to the server code are either written in Java, for low-level changes, or Java or Python to add features to their MARS (Multiverse Agnostic Rules System). The server does not currently support instanced areas. It uses TCP and UDP for communication.

The game world Kothuria ( has been built on the Multiverse engine. They do not charge licensing fees provided you do not charge for use of your world.

BigWorld I heard about on the Multiverse forums. I'm not sure what mesh format it uses, but it has a plug-in for 3dMax. They have a BigWorld World Editor to design to world.

They provide a client, the BigWorld Technology Client engine, which is customizable with Python, HTTP and XML. It runs on Windows.

Their server supports multiple machines, and re-aligns server load based on CPU usage. They don't say what language it's written in, but it can be modified with Python. They support dynamic world updates, dynamic manipulation, climate and day/night.

So what does this mean for MMORF? Well, it sure crushes the novelty of it all... I suppose I shouldn't be so surprised -- did I really think no one else would do this?

Both projects talks about being able to distribute the load across multiple servers, which is something that I, too, planned. They both support adding in customizations (I should hope so!) as I did, but I'm again astounded by the popularity for Python in this.

I've got a personal peeve against Python, which is probably clouding my view of it as the be-all end-all of scripting languages. Though I haven't looked too deeply into it, I'm under the impression that the Python runtime allows for some nice on-the-fly interpretation, which can be seen here on the BigWorld site, in the Kill Striff video near the bottom. That kind of interactivity is exactly what I want to be able to provide; not only having a console on which you can change the running world, but to be able to add, change and remove logic to the running server. If these two projects are using Python, I'm starting to ... worry ... that I might have to look into using it too.

I've mentioned before that I've wanted to use C# for this, because that is my current plan for the implementation language. I don't know what kind of interactive solutions are available for C#, or what kind of Python-on-C# solutions are available. I've also mentioned that it would be an interesting exercise to design a stripped-down scripting language, to help the non-programmers still work with the world. Python is a touch too involved for that, and C# would likely be as well.

Both systems provide clients, which is really beyond the scope of MMORF. While I plan to develop clients alongside the server for testing purposes, I hadn't planned on providing a client framework that would be used -- that's something that I would have left to my "customers" to supply.

The World Editor is something I never considered. I suppose providing a world editor would sure make world building a hell-of-a-lot easier than requiring world builders to use their god client to hand-place every item into the world, using the client's interface. Honestly, I hadn't considered it because the purpose of MMORF is to prove the theory that I could write the system, and never to use the actual system for anything concrete. Or populated.

One thing that I haven't found discussed in either project is the interface between client and server (cluster). That is, is there a separate login server, or does each server also act as a login server? If so, is there any rotation of this, or is that done through round-robin methods at the router? BigWorld talks about "[t]he maximum size depends on the number of machines and the switching fabric of the main switch", so this could be exactly what they intend (unless this "main switch" is something they provide.)

I envision MMORF separating the servers that the users connect to (portals to the servers) from the servers themselves -- from a logical view anyway. That is, to reduce the latency (lag) between the user's machine and the world's first point of contact, we might have these points nearer to the user ("near" being a networking idea, not a physical one) than the world servers themselves. The routing and communication between these portal servers and the world servers would then be separately analyzed and configured for optimal communication internally. Of course, they could be the same machine, for the cost-efficient worlds, but I want to provide the ability to separate them.

I'm not abandoning MMORF yet, but it's becoming less of a "wow" thing now. I still want to know, though, that I can write one myself... whether that ever gets done, we'll have to see.