http://www.youtube.com/watch?v=tgwi0lWgX8w

The demo was coded by the guys who maintain Alternative3D, one of the the few software-rendered 3D engines for Flash that are better suited for 3D game development. The engine has recently been made free of charge for commercial development. The makers only require a back link to their product website in your game now.

I find Alternativa3D quite attractive, in particular after seeing videos and screenshots of War.ru, an online multiplayer Role-playing game that reminds me of RPGs classics like Wizardry, just with better graphics. Unfortunately the whole game is in Russian only for now and so far I haven’t been able to log in, the load procedure is very slow and always gets stuck at some point for me.

Still the game looks very promising with some nice looking 3D environments. The actors (NPC’s and creatures) seem to be inanimate billboard sprites though so they only look impressive on a static screenshot but imagine what would be possible with the newly achieved 3D power! I’m looking forward to create vast 3D environments with autonomous actor AIs a’la Oblivion or Fallout 3! The only bottleneck will – yet again – be the content creation.

Either way, many classes have been updated and improved (and many still need too *ugh*) and what is particularly worth mentioning are the file IO classes which provide a unified way to work with different file formats. Basically the way how files work in hexagonlib is that you can create file objects of any specific file type (like text, binary, image, XML, etc.), give them a path to a physical file and then add them to a loader (BulkLoader, FileLoader, ZipLoader) which then loads the data of the physical files into the file objects.

While you can use the BulkLoader class to load a collection of arbitrary files in one go with all sorts of comfort (priorities, weighted loading, load retries, multi-connections etc.) the newest addition to the library is the ZipLoader class which can be used in AIR development to access a standard zip file using Random Access. What does that mean? It means that you can create a zip file (a very large one if you want), pack all your resource files that can be loaded by your application and then open it with your app and ‘load’ (= extract) files from it without ever needing to load the whole zip file completely into memory. This makes accessing a large zip file very efficient because only the chunk of the requested, zipped file is loaded.

This is especially interesting for us game developers who desire to use large, nicely packed resource files like they are utilized in a similar fashion in most current day commercial games. For a while I was promoting to add such functionality to AIR over at Adobe Labs but that was before I knew that this can actually be done in AIR since 1.0 thanks to the FileStream class and the position property of it (alas, the property is not available in the URLStream class so random access is not possible on web-based Flash). The ZipLoader uses asynchronous loading to open a zip file as well as ‘loading’ files from it because I don’t like the idea of having the application at the mercy of the file system which would be the case with synchronous access (and which is used in way too many examples on the web).

You can download the hexagonlib distribution over at Google Code, which includes the SWCs and documentation and of course the source code is available for access via SVN. I’m updating the library on a irregular basis. There are already some Wiki pages too with code examples showing how to use the BulkLoader and ZipLoader here but I will hopefully get to write some more in-depth tutorials soon.

hexagonlib at Google Code
File API Wiki
Documentaion

I could go on and make this project an oldschool-style game with 2D graphics like some other indie devs are doing but I feel that going 3D would be the best bet to convey atmosphere and tactical gameplay at the same time (you could use switchable first-person and third-person views). This makes me think if ActionScript is actually sufficient for this but the experience of some of my recent coding tests with Away3D which already start to bog down the CPU with a few hundred polygons on the screen tend to say “no!” to my ambitious plans.

Since this is a desktop game my platform choice is AIR which offers more freedom that the Web Player but there are still many let-downs that make you grind your teeth …

Hardware 3D

Without a doubt the biggest problem is the lack of hardware-accelerated 3D rendering. With the current software-rendering engines you could make simple 3D games where you try to always keep down poly-count to an absolute minimum. Basically your game will then look like anno 2000, if not worse. I remember most games of the late nineties to early two-thousands as having these “wood  puppet”-appearing character models, both in terms of look and animation. I must admit that some games achieved quite good quality for the technology they were running on, for example Metal Gear Solid on the first-gen Playstation. Would that be possible in Flash? Probably yes, with a lot of trickery but who wants to make games that look that outdated? As I mentioned in another post, I’d be better off with well designed 2D instead.

Not sure what Adobe is doing regarding 3D but sure is if if they are sleeping on this, the competition will not sleep and we might see developers wander over to Silverlight or Unity3D.

Full-screen Resolutions

There are several other painfully missing features in Adobe AIR which I hope Adobe will care about. One such feature would be the option to change the screen resolution! As it is currently if you switch your game to full screen it will run at the same resolution in that the player runs the OS in. Screens have become larger and with that screen resolutions have too. If you now switch your Papervision game – which was running fine in a 640 x 480 window – to fullscreen in 1920 x 1200 you can watch how your game is being degraded into a slideshow! Fullscreen games would profit a lot from being able to change screen resolutions.

The fullscreen mode brings me to another bugger: The Escape key! Adobe has the opinion that the Escape key must not be remapped and that it should solely be used to close a full screen mode. I guess they did this for security reasons so that an ill-intended coder cannot hijack your screen. However I disagree with this rationale! Such a coder could use C, Java or Python or any other universal programming platform for that matter in a much more suitable way. Some security restrictions go too far and the Escape key is one of them. It’s more of a blocker than a help!

Resource Files

Most modern commercial games use what is called Resource Files; large compressed archive files which contain all of the game’s media and data files. These files are often in the hundreds of megabytes up to several gigabytes. While I doubt that I will make a game anytime soon that has an assets library of several gigabytes I can imagine that my current project could go easily up into several hundred megabytes of assets.
The commercial developers use resource file formats to organize their asset files into nicely compact files. These resource files house many advantages over just simply having your naked files on the harddisk. Among the advantages are compactness, protection, easy file distribution and better structural organization.

With ActionScript you could load compressed Zip files that store all your games’ assets but there’s a tiny but important catch to this: Most of those commercial games which are written in C++ and which utilize the file system have the ability to access any of the packed files quickly and right at their position in the resource archive without the need to load the whole resource archive into memory first. In fact you wouldn’t want to load a 4Gb file into memory completely but how about a 200Mb file? While that’s possible it’s not a best-practice.

ActionScript currently provides the URLStream class that can be used to stream a file in but it still does so only in a linear way. You could start loading your Zip file, check which assets from it is available, abort loading and use the asset but this is sub-optimal! Imagine your file is somewhere at the end of the Zip file you’d still have to load the whole Zip file first. ActionScript (or in particular AIR) would go nicely with a URLStream class, or even a completely new API that could make optimal use of a Resource File format which houses compressed media and data files. Maybe Adobe could even introduce a specific new file format for this purpose. That would be ultimately nice!

I have no idea where Adobe stands with the future plans for Flash and whether some or all of the above mentioned points are resolved at some time or if they are never resolved in which case I’d get the impression that the Flash platform is a sinking ship for me – which I do not hope for!

Currently we as Flash game developers (I hate that name!) are standing at the fence which borders on that green and juicy meadow of professional game development and we can only hope that things improve in our favor so we too can graze on that green grass where the big cows are reveling.

I’ve been designing on a rather ambitious Role-Playing game project since a while now (in fact quite a long while but I’m not in hurry to finish it anytime soon) and while I’m in the process of working out the story, technical details like the combat mechanics, skill system etc. and creating interesting characters I still haven’t made a decision on the type of graphical projection for the game so far. I’ve been thinking about five kinds of projection from the most basic one (2D orthographic) up to full dynamic 3D which would be quite an effort. As my development platform of choice happens to be Flash, the resources in terms of 3D are limited.

So with that in mind I thought it would be good opportunity to introduce some of the most-used projections in computer and video role-playing games to get to know them a little better. This is by no means a complete list of all sorts of projection used in games but I believe these the ones most commonly used for role-playing games.

Orthographic Projection (Top-down View)

Orthographic is pretty much a collective term for all projections that lack perspective (i.e. all 3 axes have the same length) but I’d like to use it here to describe the typical top-down view – often called birds-eye view – used in RPGs.

Hard Nova uses a very simple (but nevertheless charming) top-down view for it's interiors.

The top-down view can either be completely flat which is obviously the most easy way to draw graphics or it can give the impression of depth by using an oblique style. Many of the older J-RPGs like Zelda and Final Fantasy are using this method. You see buildings, characters and other objects that point into one direction (usually to the top of the screen) to give the illusion of depth. Often this style is used in a very simple form so that characters are not being able to ‘step behind a wall’, i.e. the collision detection that checks where the characters are allowed to walk adheres directly to the graphic tiles used in the game. Some other games of this style might involve some trickery to offset the line used for collision detection so that characters can walk behind walls and are half-covered by them to add some more dynamic.

Jagged Alliance: Deadly Games is a good example of an oblique top-down view.

The advantages of this projection are clear: it’s the easiest to draw and the easiest to implement. Also the nature of this style makes it easy to use for RPGs that use a character party which needs to be guided around the screen. Selecting party members and using them tactically (positioning, line-of-sight, etc.) is more easily done here.

The disadvantages are that this projection is the most simple looking and most overused one (but then again these are not necessarily disadvantages)  and in particular that this projection type can ruin potential immersive atmosphere, i.e. unless you’re using some sort of Fog-of-War the player can see what lies around the next corner. Even if you don’t draw any opponents until they are in the line-of-sight of the player in my opinion this doesn’t convey the same level of immersion as 3D or Flip3D (see below) projection would.

Isometric Projection (Tiled)

Isometric view and (although not technically isometric) it’s cousins trimetric and dimetric are projections that were (and still are) used in a long list of games, mostly strategy-, management- and of course role-playing games. Highly regarded by many as the finest-ever invented graphics style, isometric projection has the advantage over basic top-down view that is adds more depth and at the same time often more dynamic and clarity to the layout of the play field.

Fallout 2 - one of the better known tile-based isometric RPGs.

I must admit not many RPG titles that are using a tile-based isometric projection are coming to my mind but some good examples from this domain are Fallout 1 & 2 which use trimetric projection (all three angles are different) and the Indie RPG  series Avernum.

Advantages of the tiled isometric projection include the easiness of implementation and a big favor for tactical gameplay. It’s easy to see tactical elements in relation to each other and so it comes to no surprise that many strategy games used this style.

The disadvantage I see with isometric graphics is the same as with top-down view projection, the lack of immersive atmosphere (see above) and that isometric graphics (tiles, sprites) are more difficult to design (but assets rendered with a 3D package can help a lot here).

Isometric Projection (Full Backgrounds)

The big contender among isometric engines that used pre-rendered backgrounds instead of tiled graphics was without a doubt the Infinity Engine and with it such classics like Baldur’s Gate, Icewind Dale and Planescape: Torment.

Baldur's Gate II: Excellent use of pre-rendered backgrounds and light-effects all around!

Instead of using tiles, larger backgrounds were modeled, textured and pre-rendered with a 3D graphics application and then used … well, as sort-of large-scale tiles in the game. This technique allowed for a lot more visual detail and variation. Environments that were difficult to draw with a tile-based approach such as for instance a deep, rocky abyss or other intricate landscape were made possible much easier with fully rendered backgrounds. Also many other items like furniture and interior walls could suddenly have a lot more detail. Another advantage that the Infinity Engine introduced was the use of dynamic lighting and acceleration of visual effects by use of DirectX. Full-screen rain or snowstorm? No problem here!

Collision detection and path-finding was solved by using a special bitmap for every background that defined the walk-able areas using different colors.

The big advantage for this technique is of course the gain in graphical detail and that it eliminates some of the problems of a tile-based engine, namely intricacies when dealing with dynamic lighting, path-finding etc.

The disadvantage here is the extra-work of complexity required to implement such a full background rendering engine, the additional task to design pre-rendered background graphics using  3D modeling and that such an engine requires more system resources than a tile-based engine, RAM and CPU-wise.

Flip3D

Now what in the hell is Flip3D? You might hear this term for the first time ever here but Flip3D is what I like to call (for the lack of a better word) the projection style used by many games from the Golden Age of RPGs era that use pseudo 3D images which are drawn with perspective in mind and if you turn in-game to the left or right the whole view is flipped turned by 90° hence the name, uhh, Flip3D (if you know the technically correct term for this type of graphics display technique I’d like to learn it but until then let’s just call it Flip3D).

Countless RPGs utilized this projection, most notably titles like Dungeon Master, Eye of the Beholder, the Ishar series, the Might and Magic series and – although not really a RPG – one of my all-time favorites, Hired Guns. All these games used pre-rendered graphic parts like floors, walls and ceilings that are composed together on the screen to create a room or corridor or even an outside environment.

Wizardry 7: VGA never looked better (and RPGs never were harder).

The advantage is that these graphic parts could be re-used, making it easier to quickly build whole maps. The disadvantage to this was often that in many of the games the maps looked monotonous. In my opinion Hired Guns nailed this problem quite well which is one of the reasons that made it stand out from the others for me.  The maps looked detailed and very different from level to level, in the background they’ve used a gradient to represent the dawn on the firmament and there was usually a dark backdrop used for a horizon to give the impression of mountains, landscape or buildings in the far distance. It’s exactly these details that are one of the features that filled the game with atmosphere. What could be there in the far distance? The distance that you were never able to reach because it was not a part of the map but, alas, only a backdrop.

The lack of clear detail opens a lot of freedom to the player’s own imagination and this is one of the points why I highly regard some older games that use simplified graphics where modern games with tons of detailed real-time 3D choke the last bit of imagination from the players mind (not that I’m saying that this is necessarily bad but for me it is gaming on a different mental level).

Ahh Hired Guns! Flip3D at it's finest!

And with that we have the main advantage of this projection type … used with well-drawn graphics it can add a nice deal of ‘hidden’ atmosphere to the game because you never really see what lies (or lurks) in the distance.

The main disadvantage of this projection from my point of view is that it’s not much in favor for tactical gameplay as long as you want to involve your party into the action. Games with Flip3D projection are necessarily first-person so you don’t see your own character and your other party members are either behind or sideways of you or standing in front, covering a big part of the view field. Guiding and commanding all your party members can become quite a chore here.

3D Projection

3D projection is the current state-of-the-art in computer game graphics and will probably not be replaced so soon (until somebody invents some sort of 4D virtual reality device). This projection allows the highest degree of freedom meaning that any object can be viewed from any angle, at any distance and with arbitrary FOV.

SWKotoR 2: Can we haz it in Flash please?

There is virtually no quality loss when zooming in and you can re-use 3D objects for all kinds of displays, for example you could have your once-designed character 3D objects walk around in the game world and at the same time use them on a special inventory window where you drag and drop equipment onto the same used 3D object of their bodies. This allows for ‘create-once, use everywhere’ unlike with 2D assets where you often have to create variations of the same object for use in different views.

You could also use 3D with a fixed camera to simulate a certain type of 2D view and the advantage of 3D objects would still be obvious.

The disadvantage of choosing this projection is that the creation of assets, i.e. 3D models of characters, items and environments is a lot more involved as with 2D graphics. Unless you are some sort of super-developer-designer-machine with 300 years of time up your sleeve you probably need a small team of professional 3D designers who can do this work for you. Ok, I’d say nobody died of trying but recent 3D game graphics have become so professional that it’s not an easy feat to try catching up with it. And who wants to design a game with 3D graphics that look like anno 1996? I’d probably be better off with nice-looking 2D graphics instead!

Then, as you want to create a large world for a RPG you’d have to design many interior/exterior maps that are used for the game world. If you use 3D I doubt you want to design this all manually. What you need is a map editor to create the environments more comfortably and re-use assets quickly etc. Writing such a map editor is already a whole job unto itself and takes a lot of time.

Wizardry 8: Simple 3D graphics & first-person view

Another complication with 3D graphics is the platform used for the game. I use Flash (or AIR) with use of ActionScript. While I’m convinced that ActionScript can handle all the other projection types, with 3D we’re hitting the limits very quickly. PaperVision 3D, Away3D and the Alternativa Platform all have been used sucessfully for game development already but I have yet to see a good example of an extensive RPG made with one of these and the fact that a few thousand triangles bring the framerate to a screeching halt doesn’t help the case.

Still, any of these 3D engines could be utilized in Flash for a simpler form of 3D graphics style, for example the use of mainly simple primitives with a good job in texture detail work and a combination of 2D sprites. I’m definitely looking further into this possibility.

Conclusion

I’m still in the dark about which projection style I’ll eventually use. I might be creating a first prototype with a very simple and flat top-down view (a la Ultima) to test other components of the game and then later change to something  more advanced.

Any of the introduced techniques have their charming sides, for example (as you might have had no troubles noticing) I’m very fond of Hired Guns and it’s dark and futuristic pseudo 3D view. Then again an isometric view could be more suitable for tactical gameplay (which, as I’m planing the game should have quite a few of).

Realtime 3D would be the ultimate thing but I dislike the idea of creating super-simplified 3D objects and Flash currently lacks the rendering power to use higher-end 3D graphics. I might as well be watching if the Flash platform improves in this area and then see what can be done in terms of 3D later.

Was it that? I’m sure I forgot a ton of facts and details here but I would be very interested in what others have to say about this topic or what view styles you’re about to use and why etc.

Further Reading: Significant Bits – A layman’s guide to projection in videogames

“…and a component system which lets you easily package game functionality into reusable modules. The component system draws on nearly a decade of game development history…”

This looks very promising indeed and the component structure makes a lot of sense.

I’ve been working on the hexagonLib on and off but time is sparse currently and so it seems I would never get it into a decent release state. I Might as well see how the pb engine works out for me. Let’s see how this engine fits for my current role-playing game project!

In game development randomness is often necessary for certain tasks, be it the random distribution of graphic tiles, a random factor in NPC AI or random stats in a roleplaying game. Especially for the latter purpose the static Dice class provides a set of methods to roll dice as it is common in a Role-playing game, to be exact four-, six-, eight-, ten-, twelve-, twenty-sided and percentile dice.

The Dice class (and it’s supporting classes) are rather elaborated, using for example the Linear Congruential algorithm in the process of generating ‘true’ random numbers so it might not be the most speed-optimized method for calculating random numbers. For absolute performance the LCA and rounding routines can be removed to speed up calculations.

Using the Dice class is very simple! For example rolling two ten-sided dice can be done with the following call …

var result:int = Dice.tenSided(2);

… rolling the percentile die is even simpler as it does not need any arguments. It always returns a value between 1 and 100 …

var result:int = Dice.percentile();

… the class also provides the roll method with that any x-sided die could be rolled, 3 sixteen-sided dice for instance …

var result:int = Dice.roll(16, 3);

The following small Flex application uses the Dice class and can be used to test dice throw probability according to the bell curve (the more dice are used the lower the probability to roll boundary results).

(Please open the article to see the Flash content.)

Update: The Dice class is now part of the hexagonLib and can be found here.

What are the advantages over using a generic MovieClip? When writing games you might have several animated graphics (also called sprites, but not related to the AS3 Sprite class) that should run with a different framerate than the game’s global framerate. Let’s say your game runs with a global framerate of 99 and you put several animated sprites into your game that were created for playing back with a framerate of 24. With a MovieClip all those sprites would also play with a framerate of 99 which means they play way too fast. However with an AnimatedBitmap you can set every framerate individually. There are a couple of other advantages like that a Bitmap is more lightweight than a MovieClip and it has a isPlaying() method. Also it changes the way of how to embed assets. Instead of embedding many files for one animation only one image for a whole animation sequence is embedded which has positive effects on the file size. The ring sequence used in the demo has 21 frames that use 102Kb as single images but only 44Kb when they are combined to one image.

The following demonstration plays with a global framerate of 99 but all AnimatedBitmap instances play at a framerate of 24 …

(Please open the article to see the Flash content.)

You can download the class including demo source code and demo image here:

Update: The class is now part of the hexagonLib and can be found here. You want this version because it’s the one that is being maintained.

Changes in v1.1
The timer object used to time the frame animation has now been made external. For this purpose a custom FrameRateTimer class has been added. This has the advantage that AnimatedBitmap objects don’t use their own timer objects anymore. Instead you can use one timer for many animated objects if they use the same framerate. This saves memory and CPU cycles. However you are still able to use one FrameRateTimer for every animated object if it is desired.
An IAnimatedDisplayObject interface has been added so that future animated display object types can be integrated more easily.

Also included is a jsx script for Photoshop CS named HDRS- CreateImageSequence that can be used to easily create a ‘single-frames image’ with Photoshop. Simply run the script in Photoshop and choose the images in the file browser that appears. Photoshop will then generate a single image with all the frames laid out horizontally. All images should have the same size to get a correct animation sequence. Also sometimes you need to fine-tune the position of some frames, e.g. for the ring in the demo (which was rendered to single frame images from a 3D modeler) I had to adjust the horizontal alignment on some frames because otherwise the animation would glitch to left/right by some pixels.

So what makes this game so addictive that people are coming back en masse? First and foremost it’s simple and straightforward. No long introduction, no necessity to read instructions, you get into the game quickly. Then there is the addiction factor … Maybe its just me but the reason why it is fun to play is because you try to make your defense perfect to stop the intruding enemies. Another factor is that you can shoot and destroy something. Sounds dumb? I know, but I can imagine that many people’s ‘hunting’ instinct is triggered by that. After all many popular games follow the same scheme. In fact you don’t even need to do the shooting as that is what your towers are doing for you. You just have to place them in a strategically good position and watch how well it works out. The author sure made a good choice by picking a Tower Defense game for this!

Now there are hundreds of other well proven addictive games out there. Make your choice and don’t forget to improve it by adding something that makes it even more fun to play! Meanwhile excuse me … I have to dig through my old games collection and do some searching …

Currently there are AlphaFade, BlurEffect, ColorFade, ModuloEffect, MoveEffect, Pixelizer and TimeDelay who act as effects. The EffectCombiner can be used to combine several of the effects into one (which means that all combined effects use the same Timer) and the EffectChainer can be used to play back effects in sequencial order (including the EffectChainer which acts as an effect on itself). The TimeDelay is a non-visual effect which simply applies a time delay.

The class from where the effects are started has to implement the INotify interface which only contains one method, notify(). The effects (as well as the EffectChainer and EffectCombiner) use this interface to notify the caller and – if necessary – give back a callID that can be used to determine which effect has returned. More detailed info on this will be available in the API docs when the framework is released … soon™.

(Please open the article to see the Flash content.)

You can focus the SWF with the Mouse and press Space to skip through the effects.

A valuable resource for everyone who is thinking/planning to write a roleplaying game … Indie developer Planewalker Games who are currently making their debut RPG The Broken Hourglass are publishing precious bits of insider information about their game engine called WeiNGINE. The Broken Hourglass is a computer roleplaying game with a strong visual relation to late nineties RPG pearls like Baldur’s Gate, Icewind Dale or Planescape: Torment (who all were based on the Infinity Engine).
Some examples of their articles: Inside the Engine – Introduction to Items, Inside the Engine – Introduction to Sprites, Rules and Mechanics – Group Skills … and there’s a whole lot more when navigating through the links at the bottom of the pages. I kind of soak up such detailed information on game/RPG design as such things are sparsely seeded on the web (you will not see such information leaking from commercial developers!)