X@COM

"Nine meters. Seven. Six."
"That can't be! That's inside the room!"

Yes, this will probably happen to you, too.

Actually, the short range of X-COM motion scanners makes it all that much more likely. Of course, with about five seconds of modding you could expand their effect to cover the entire map. Not that you'd want to, but it's *very* easy now that they're a part of the special abilities system, too.

Since returning from vacation I've been pushing forward on that same system, adding yet more triggers and effects, most notably object spawning which means triggers can now create terrain, items, and units. But everything so far is internal stuff that doesn't make for interesting posts with something visual to show for it, so I sidetracked myself in order to bring you a simple implementation of the motion scanner interface.

Motion scanners are nice, and you are definitely going to want one on the new scenario that will come with the next release, but that's all I'll say about that for now...

Check out this video showing the scanner in action as it gets some relatively heavy use in the urban Exodus map: A spotter locates an enemy hiding in a building and his buddy blows through the wall with his gatling laser. Then we put up a smoke screen before moving into an open area, and find another building swarming with aliens and send a rocket through the door...



Now back to chipping away at the trigger/effect list.

The special abilities framework is hands down the single most complex and expansive component of the code so far. It wasn't too much trouble to get the framework up and running, but adding all the moving parts that make it useful takes a while because so much can fit in there. The framework can currently process 21 triggers (at least 20 more planned), 11 conditions (dozens more planned), and 11 categories of effects (at least 17 more planned).

I'd be further along by now if not for a hard drive failure that siphoned away many hours of free time as I tried to recover everything. (X@COM is, and always will be, safe--unless all three of my redundant backups are simultaneously abducted by aliens, in which case no promises. If it makes you feel better, though, know that I would try to get them back :)

I'm eager to finish this system and continue chipping away at the R7 feature list, but I'll be disappearing for several weeks now--on the road without any coding time... It'll at least be a good opportunity to organize the design docs, which have become rather bloated with ideas and lists.

Because I needed at least SOME image for this post, here's a shot of the new "terminal" font set which will come with the next release for those commanders who want to give their console a more traditional look. It's only available at 1280x960 or greater, as the font doesn't scale down very well:
The scene above is an automated first turn on the Exodus map as the rescue mission is beset by a pack of shredders that surges out from behind the surrounding buildings under cover of darkness.

Okay, maybe not the silacoids. Who really cares about them? They're fun and all, but certainly not dangerous.

Chryssalids are of course a completely different story. These bad boys are now out there seeking panicking civilians to zombify. Then there's the zombie spawn out for some fresh soldier meat. You'll be up against the undead hordes in a new scenario planned for the next release (which is still quite a ways off, btw). Bring your Molotovs!

Here are some log excerpts from one of my tests. Louis spots a zombie shambling toward him and uses his quick soldier reflexes to try and mow it down before it can get in close. Unfortunately Igor decides to join in with his rocket launcher and while he does manage to blast the zombie, he also takes out his nearby squadmate in the process. Of course there's now a chryssalid on the lose. Good luck guys.


Then Paul shows up and, apparently having forgotten to prime his alien grenade, uses it instead to bash the chryssalid in the face. Not smart Paul.


You'll make a good zombie, Paul--they don't need brains.

Note that because the silacoid ability is set to deal incendiary damage, as it moves it naturally sets flammable terrain on fire, instead of just burning that area of the ground. I can't recall whether they actually set fire to the ground in the original (I don't think they did), but it would be a simple change in the ability script to turn that off. I rather like it.

Speaking of the ability scripts, here's a shot of the new specialabilities.xt file as it appears in notepad++ (click for full size):

As for modifying the silacoid's abilities as mentioned above, all you'd have to do change the "IN" (incendiary) in the "DMG_TYPE=IN" effect data string to some other kind of damage that wouldn't cause fires, like "PL" (plasma).

The Unstable Compound ability on the list was something I was using to test volatile items. Now if only Paul had smashed the chryssalid with *that* he could've at least gone out like a man! (Volatile items explode pretty easily, including when smashed against something. Oh man this game's gonna be fun once I actually get to designing the content...)

The chryssalid zombify effect was somewhat annoying because it's not supposed to take effect immediately, only on the target's death or once the chryssalid stops attacking it, so it didn't fit very well into the system and ended up requiring a "special case" MUTATE_DELAYED effect. Makes sense from a gameplay perspective, though, since that would mean a group of armored troops would be less likely to fall as quickly to a chryssalid as unarmored troops would (especially since chryssalids zombify their target even if their melee attack *misses*, and the special effect completely disregards the defender's armor!).

About the implementation, I spent a lot of time hesitating over details, trying to design the system so that it's flexible yet not prone to errors and overcomplication, but complex systems have a natural tendency to defy being forced into a simple design...

After days of bouncing back and forth between a smaller and larger scope for the special abilities, I settled on a system somewhere in the middle. In hindsight, there really should've been a lot more planning and testing before putting it to code, but the lack of concrete progress started getting to me after a few days of nothing but brainstorming and taking notes. Besides, no matter how robust it may seem, I'm sure creative modders will be able to break it. I'll just have to resolve to fix issues as they pop up, since I'd probably drive myself insane before managing to account for all the emergent possibilities. The engine does perform a lot of data checks on startup to make sure the abilities don't include any combinations that don't fit internal parameter restrictions, so we can hope the number of problems should be minimal.

Now that it works, I'll continue expanding the number of supported keywords before moving on to special items like the motion scanner. Much later on there will still be some kind of separate map-centric trigger system for terrain- and mission-related scripting; this one was focused on the game's more dynamic objects, especially entities (units).

Just when I thought I'd jump into adding new content, more planning showed that a generic system to implement the chryssalid ability and a few others might as well be expanded into a powerful dynamic system.

Enter "special abilities."

The term is probably not as limited in scope as you might be thinking. Special abilities will enable objects to combine conditional triggers and effects to define unique behavior under the right circumstances, and will probably be applicable to races, entities, armor, items, and/or terrain. They'll make it possible for chryssalids to turn their victims into zombies, zombies to transform into chryssalids on death, silacoids to leaves trails of fire as they move, and many more effects that you didn't see in X-COM. They could enable:

• An alien that absorbs or eats vegetation or objects it passes over/nearby, possibly regenerating itself as a result
• An alien that emits smoke
• An acid beast that corrodes adjacent metallic objects
• Snakemen that lay eggs which can in turn spawn more snakemen (UFO TTS)
• Volatile ammunition for some strange alien device that has a small chance of exploding when loaded
• An alien man-eating plant that chomps on units that pass by it
• A plant that rapidly grows and spreads over time, perhaps with additional side-effects of its own
• etc. (<--very inclusive bullet point ;)

Of course some triggers and effects may not be compatible in all cases or with certain objects, but there will be a pretty wide variety of valid combinations, and new additions should be relatively easy once the system is in place (I'd be happy to add more in the future for modding purposes). All of the parameters will be defined in the text files.

Yesterday I started implementing the necessary data objects, and as a test merged unit death explosions into the system--so now the basic infrastructure is ready. I was considering merging grenade use and light emission (by units, items, and props), but they're already working nicely so I'll leave them alone for now, and maybe migrate those features later. Silacoid fire trails and chryssalid/zombie mechanics are next, and even the upcoming motion scanner, medi-kit, mind probe, and psi-amp functions will fit in nicely. For a single item with multiple manually-triggered abilities (as opposed to the passive kind), there will be a list to choose from when activating/using it (ex: psi-amp, which could then easily be later modified to support a broader spectrum of psionic abilities).

The way this will work:
Abilities specify an initial trigger, and all abilities with a given trigger are checked for whenever the trigger situation occurs. A sample list of possible triggers:

• "Use" an item
• Move
• Attack
• Hit by an attack
• Fall
• Death
• New turn

Abilities may qualify their triggers using one or more conditions, for example:

• Standing in or adjacent to burning/smoking terrain
• Standing next to a unit
• Holding a certain item
• Some stat has a relative value
• Random chance

Finally, once triggered there are a number of effects an ability could have, including:

• Explode
• Spawn an object (many variations)
• Assimilate a unit (switch faction--could be for psi-amp mind control)
• Panic unit (psi-amp effect)
• Mutate one unit into another
• Transmogrify an item

All of the above lists are just what I currently have enumerated in the code for eventual implementation. Many more will be added (ideas welcome).

As a part of the new system, objects will be able to list their traits (or properties, e.g., organic, sentient, metallic, etc.), where the list of possible traits also comes from an external script. So you could pretty easily add new traits and define abilities that may only (or cannot) affect objects which possess a given trait. I'm adding that feature now because it's better than hard-coding the restriction preventing chryssalids from zombifying tanks. Can't have tanks roaming around trying to bite your soldiers, now can we...

For you, not me, that is.

The game is starting to get rather complex, and that complexity will jump yet again in the near future with the addition of more special items and their UI elements, so I decided to go ahead and add context help before going any further.

The first time a new help topic is available (one that hasn't already been seen before), the game will pop up some text to give an overview of how to use a particular function or window. Here's what you'd see when opening the inventory window for the first time (click for full-size image):


The entire system is very dynamic and ready to simply drop in new text (it comes from an external file) and give it a target area or console. That said, the help I've got in there now is limited mostly to UI elements, not gameplay. Eventually there should be more tutorial-style help as well to help new players understand the X-COM mechanics, but for now the majority of players probably know what they're getting into, so I'm holding off on that.

Hitting F1 or '?' on any window will also bring up the list of commands associated with that window. Here's the command list for the map/HUD screen:


A command list screen did exist before, but it was a temporary solution hacked together for the first release as part of last year's ARRP. Now it's mouse accessible, is properly animated, and has been integrated into the primary UI control system. The inventory and log windows have their own command list, as will all future windows. (For now mouse access for the main command list is through a tiny button found near the bottom-right corner of the HUD, since the that part of the UI has yet to be designed.)

So with another good chunk of the [somewhat boring yet essential] internal stuff behind me, up next are probably special items and Chryssalids/spawning. As with the other mechanics, the latter will be implemented using a pretty dynamic overarching system that will enable creative modding while still being capable of modeling the original X-COM mechanics. Weapon attacks (e.g., Chryssalid bite) will become capable of special effects on the target, one of which will be to cause the target to die and spawn another unit (e.g., zombie) of a specified faction. A greater variety of spawning will also be possible, so instead of just spawning a single unit, you could have the effect be to spawn multiple units nearby (xenojelly/ooze?), or even have a unit that naturally spawns duplicates of itself, or some other specified unit, at certain intervals. Think of all the possibilities! (No, really, think of possibilities you might like to see and tell me about them, so I can make sure they'll be supported.)

Morale is in, and works how you remember/expect it to. So now you can shoot your friend in the foot when he (and you) least expect it!

Check out the results of a total berserk rage as described in the log:

There you can also get a glimpse of the log coloring (which is available in the current release, R6, but I never put up a screenshot showing how it looks, for those of you who aren't downloading the intermittent dev builds).

Despite the thoroughness of UFOpaedia.org, some questions remain as to how the system works, which I resolved using what I guess are the most likely and appropriate methods:

• How much morale is lost by an individual unit when it is only injured? (I have it set to use half the value of an ally death.)
• How do non-X-COM, non-alien factions (e.g. civilians) fit in? (I have this handled on a per-faction basis, whereby it affects only the individual shooter, and X-COM soldiers lose morale for killing civilians, while aliens gain it. This behavior is easily moddable, of course.)
• What are the precise alien equivalents for the human ranks where morale calculation purposes are concerned? (The data I've got now sets alien "leaders" equivalent to colonel, and "commanders" equivalent to X-COM commanders, and all the remaining applicable aliens are squaddies, except where N/A.)
• How much stamina is drained for fleeing units, if any? (I left it as normal, though I believe the original doesn't actually deduct TU/stamina for panic movement.)
• Do fleeing units trigger reaction fire before they reach their destination?
• Exactly how many TUs do berserking soldiers get? (I've got it set at 125% their normal TU, which makes some sense--UFOPaedia says they get an absolute 255, but that can't be right since it would enable units to fire a ridiculous number shots..., and no one has confirmed that value for certain. From what I remember, I think they are only restored to full (100%) TU before berserking, but I would have to go back and play the game [yet] again to confirm it. Still have yet to do that, but I'll definitely need to set aside some time for it eventually to make sure I get everything right.)

Some of the strangeness in the original has not been carried over, of course:

• Fleeing units will not always head southeast
• Fleeing units behave according to normal movement blocking rules (i.e., no walking through other units)

I'm not going to put these extended options in the game yet, but some ideas for the future of panicking:

• Out of ammo? Charge up to an alien and repeatedly bash it in the face with a rifle butt. That would be great...
• Could also have different actions based on varying degree of panic
• Civilians jumping out of high windows to escape aliens (not unlikely), most likely plummeting to their death (for anyone who didn't already know, units jumping through windows and other fragile terrain has been possible for a while now, but civilians won't normally do it yet)

Morale effects are optional and can be turned off, like just about everything else. By necessity/extension, unit rank was also coded and actually means something now.

Below are a few more log screenshots of a game played in Area 51. Nothing exceptional, really, and these excerpts don't show much of the possible unique text and interesting events, but I haven't had enough time to gather a collection of fun logs yet.

This isn't the big release I intended it to be, but I figured it'd be nice to get a playable demo back out there so anyone new to the game can try their hand at perforating some aliens.

There's no new scenario this time around, or any new gameplay at all--R6 is mostly a batch of UI changes.

As described in the previous post, the engine was refactored to support multiple fonts simultaneously, which will play a big part in future UI design. Using multiple fonts of different sizes isn't very true to the console tradition, but square fonts aren't very readable, and readable non-square fonts aren't all that great for a tactical map since they distort space, so X@COM should benefit greatly from mixing the two--square fonts for maps, and narrow fonts for text. (The R6 HUD still uses the wide text font, but will eventually be narrowed once it's redesigned.)

The temporary message feedback system was replaced by a more proper version which can be easily expanded and modified through the data files.

A new Combat Log window is now available, where you can read all about your squad's glorious exploits. The log is still in its infancy, but already includes more than 80 different message types. On completing a mission, your score and log are output to an html file (it'll show you the file name and path). I originally had it writing to a text file, but decided it'd be nicer to retain the log message colors, hence the html.

If you played Cogmind, you'll recognize the text animation effects and sounds, which were from this previously unreleased version of X@COM to begin with (I've been sitting on most of it for a while now). If the message sounds annoy you, you can mute the game with F6. (Don't forget to check F1 help for new commands.) It won't be so annoying later when it's accompanied by a wider variety of console bleeps and bloops as you give commands and watch the battle.

Although it doesn't affect current gameplay, R6 comes with the refactored anatomy system. Future modders will be happy to know that they can create new body parts, then combine those parts into completely new beings where the body part parameters do actually have a number of gameplay implications. This system was already described in an earlier post.

There's also a set of new larger fonts available which can be activated for a 1280x960 window, along with somewhat improved fullscreen support. The larger fonts were a quick job--I just blew up and the normal fonts and tidied them up enough to prevent graphical artifacts, so they don't look nearly as good as the official fonts will when I get around to dedicating more time to them. Here's a shot of one of the font sets available at the higher resolution (click for full size):


The next release will bring some new gameplay and yet more UI windows.