Tactical AI Kit: IT NEEDS MORE THINGS

To anyone out there who happens to be closely following my work (I like to pretend to have fans), no, I'm not dead. Just a bit overloaded and possibly inefficient with time. But then again, here you are reading GarageGames blogs. We're all procrastinators here.

So what have I been doing? Apart from being absolutely swamped by my first year of college out of high school, I've been doing some fun Torque work with Max Thomas to redesign game mechanics and bot behavior for OrangeFPS. It's rekindled my love/hate relationship with good 'ole TGE 1.5, but it's been a blast so far.

So what about that Tactical AI Kit update I promised months ago? Well, let's see what I've been up to.

New Features

Here's some exciting new stuff the update will bring!

Grenade Compiling

I already went over this in the last blog, but this is for the new readers. In a lot of games, grenade throwing by AI is either really good or absolutely horrid. Bots blowing themselves up, bots throwing grenades at rooftops instead of on them, bots missing windows by a mile -- this is the kind of thing I intended to leave out of TAIK.

I've gone through several grenade throwing implementations for AI Players. The first one was fairly decent but still pretty poor. As far as the ballistics math went, it was about the best a 7th grade algebra student could figure out at the time. As a result, you'd get grenades that reached their target, but only when the target was within 30-36 meters away. I ended up ditching this completely, and finally coming up with a better algorithm a few years ago, the one currently shipping with TAIK. This would figure out a trajectory that could work for targets above and below, check line of sight along the path, and then send the grenade projectile on its way. For simple throws across wide open spaces, this method was perfect.

I've been wanting to make way for more "tricky" solutions for a while. A live, human player will bounce grenades off walls, throw them through windows, down vent pipes, and just generally be better at using them. Why shouldn't an AI player be able to do that? Lucky for us "intelligent life," we can eyeball things like bounce surfaces and throw trajectories while barely thinking about it.
So, I taught them how.



Tactical AI Players rely on cover to function realistically. The level designer drops cover points behind suitable objects in the mission, and the bots use those to wander and attack. We can also use these as reference for grenade throwing. Each cover point, by looking at its compiled data, knows how to throw to the cover points around it. Thanks to the intellect of the compiler, a bot using cover will know how to throw a grenade down a flight of stairs to a straggler in the room below.

Recast/Detour Pathfinding

This one is also for the new readers. Thanks be to Daniel Buckmaster for his work in getting the Recast libraries seamlessly working with Torque 3D. Thanks to his work, we no longer have to spend an eternity setting up hundreds of nodes like some sort of savage:


BAD!

When we now can calculate it in minutes with the click of a button:

GOOD!

I said new features, you're just telling me stuff I read in your last blog.

People read my blogs? Oh well, on to the new stuff!

Cover animation support

Cover animation is nothing new to TAIK. When an AI Player uses cover, they play an animation depending on what they're using. There's hiding behind tall cover, shooting around the left and right sides of tall cover, hiding behind short cover, and shooting over short cover. This was a good concept, except it looked really rigid. I mean really, unnaturally, horribly robotic.


This guy does not move. At all.

The old cover animation system only supported two-frame animations. No room for a lightly swaying breathing animation or anything of the sort, just the character stuck behind cover in a solid pose. When they'd switch to the next pose, Torque's animation interpolation was the only thing causing them to somewhat smoothly change poses.

I've reworked the logic behind cover poses to allow for something more fluid. Each animation can be a bit more complex and detailed than the old single-frame sequences. We can now include transitions in the beginning of our animations.

Here's what I'm trying to say: we have an animation for shooting around the left side of cover. Before, the animation would use Torque's interpolation, and you'd see the bot slide from the hiding pose to the peek-left pose. Now, the new peek left pose would consist of maybe one second of stepping out of the hiding pose, and five seconds or more of standing in place. Same goes for the other cover positions. The hiding-behind-short-cover sequence would be an animation of the character starting in the firing-over-short-cover pose, and crouching down into cover, where he would hold that pose for five seconds or more.



Another totally new cool thing is the newfound ability for bots to slide in to cover. This is mainly just a visual effect, but it helps take away from that rigidity and make things more lifelike. When a bot is running for cover, they'll use the new setSlideDestination function to glide toward their cover, and play a sliding animation.


Pardon the "BLUEH" and "OH THAT HURTS." Really guys? 12 years and no new pain sounds?

This animation is pretty easy to create. I just animated the character with a bit of velocity, sliding into a point 6 meters ahead of his origin. Once I was done making the animation, I removed the forward velocity while maintaining everything he does with his arms/legs/etc. This allows it to play seamlessly while setSlideDestination sails the bot smoothly into cover.

Turn Animations

Nothing all that special, but it still goes a long way in eliminating how robotic Torque AI tends to look. Think about something as simple as turning to the right. How do you turn right? You turn your head, step with your right foot, and then with your left foot. How do bots in modern AAA games turn right? You guessed it -- by using their feet, arms, and head in a way that looks fluid and realistic.

How does Torque AI turn right? By rotating while frozen in place. Something's wrong here.

To combat this, TAIK now supports turning animations. Whenever a bot's aim location is set, it runs a script callback to check the angle of its turn. If the angle is high enough in either direction, he will play either a turn right or turn left animation.



At the moment, it's only working with two turn animations, but there's a lot of room for improvement for those willing to take their time animating. For example, turning while running would be a nice animation to have.

Improvements

Among the sea of dozens of bugfixes, here are some things that have been reworked.

Reaction

The "react" state was absolutely horrid. You'd see bots moving to cover, then backing up and moving torward it again. Bots staring at walls. Bots not knowing when it's appropriate to run. Bots picking cover and staying behind it for eternity. I did a lazy job ironing those out before release.

That state behavior has been almost completely revised. The code's been changed to be more readable, and to more accurately figure out the state of things. Let's consider how a Tactical AI Player would behave when a bullet lands nearby.

He first needs to figure out where the round came from. If he heard the shot, he'll go by that. If not, he'll figure out where the shooter might possibly be based on his position, the position of the bullet impact, and the surfaces around him.

The next step is to run for cover. The bot will react if they take damage, if their threat position changes (i.e. another bullet lands by their current hiding spot), or randomly if the threat is not determined to be a sniper. As time passes, they'll move from cover to cover, eventually moving toward the assumed enemy position.

Other bots who may have heard the gunshot will enter a different reaction condition: "ShotsFired." They will move slowly toward the position, searching the area upon arrival. After sixty seconds of no new gunfire or other stimuli, they will start searching a wider area. Bots will react to explosions in a similar way, with the exception being that they will do whatever it takes to get away from the explosion during the first few moments of it. If a body is found, bots search the area. I take extreme care to make sure that everything an AI might need to react to is built in and ready to go.

Shooting Around Cover

One crippling bug that I somehow missed was that bots shooting around a thin wall might sometimes have to aim farther than the wall allows to shoot a target. In other words, they'll end up shooting the edge of the wall while they get picked off by someone else.


Bots will now notice this as it happens and shift further out to attack the target. Upon attacking a new target, they'll move back into cover, and adjust their required exposure again to keep them from leaning too far out of cover.

Maintaining Cover and Dying Less

Previously, bots would take cover to attack threats. That's a great thing, except for the fact that they'd leave cover upon killing a single target. That's right, after one kill, they ditch their cover and run out in the open, finding another cover for the next target. This got them killed pretty quickly, and was no fun in a firefight with dozens of bulletsponges. Bots using cover at a good vantage point would waste it by running away from it after a single kill, and that's no longer a thing. After making a kill from cover, bots will now spend 15 think ticks (7.5 seconds by default) behind their same cover looking for a new enemy to attack. They'll still move up to better cover when it's available, but now they won't be leaving their cover right away.

Also, you'll now find them hiding behind cover a bit more than they used to. Previously their only conditions for popping back behind cover were to reload, and to hide from a slough of incoming gunfire. Now, I've added a simple random hide/unhide condition that makes them hide to avoid an attack that might happen. Simply by being hidden and unhidden half the time, we're now decreasing their chance of death behind cover by 50%.

You said something about a weapon pack last time, didn't you?

Sure did! Every so often I'd get an email from someone wanting the code and artwork for the weapons found in my TAIK demos. I never understood the want for the awful Milkshape 3D artwork, but the code and functionality is something I'd be happy to see in a game.

Like I mentioned before: the TAIK update will include a weapon pack. It contains sounds, weapon/arm models, and functionality for 28 unique weapons:

Weapon list

ACR
AK47
AKS-74u
AUG
F2000
FAL
Five-seveN
Glock-18
G36C
M110
M14 EBR
M16A4
M24 SWS
M249 SAW
M4A1
MP5A2
MP7
P228
P3AT
P90
PDW
PX4 Storm
RPG-7
SCAR-H
SIG550
Spas-12
UMP-45
USP-45


Here's a video of me erratically hitting the random loadout function and shooting at things. Enjoy!

Weapon Pack Functionality

I took a lot of care to ensure that firing these weapons looks, sounds, and feels as realistically as possible.

Bullet Penetration - Bullets fired through thin surfaces will punch through them with lower velocity and lower damage, leaving an entrance and exit decal.

Reloading - Auto-reloading occurs when the magazine is empty, or the weapon can be reloaded by pressing the universal "R" key. It uses a backpacked-reload system in which unused magazine rounds are pooled, similar to many shooters nowadays.

Switching - The player gets three weapon slots: two primary weapons, and one pistol slot. As you might have guessed, the primary slots are only for non-pistols, and the pistol slot is for pistols.

Swapping - Weapons on the ground can be touched to show an on-screen prompt, telling the player what weapon they are on, its attachments, and to press F to swap their current weapon for it.

Grenade Throwing - Pressing G will toss a frag grenade which explodes after four seconds.

Aiming Down the Sights - Right-clicking will shift the weapon image up to bring the sights up to the player's eye. Its main purpose is to increase the player's accuracy.

Attachments - Weapons can support many attachments to alter their functionality. Red dot and ACOG sights will change the sight picture and provide different levels of zoom. A sound suppressor will change the firing sound and make the weapon less audible to all players, human or otherwise. A grenade launcher can be toggled by pressing 4, firing an explosive round at high speed. More than one attachment is supported per gun; feel free to attach any combination of sights, suppressors, and grenade launchers to a weapon.

Full Hud - I added a GUI showing an icon of your current weapon, its name, the fullness of your current magazine, the exact number of rounds in it, and the amount of "backpacked" ammo you have.

Weapon Sway - Instead of being stuck to the screen, the first person weapon will realistically bob with the movement of the player, sway as the player turns, and slowly float as the player remains idle.

Support for Takedown Cinematics -- A little over a year ago, I experimented with getting two characters to animate cooperatively. In other words, the idea was to have melee takedown sequences, where both actors would animate in such a way that it appeared the two actors were fighting one another. When the sequence was over, the winner would leave the fight constraints, and the victim would be killed off. I got a lot of requests for a system like that as well.

This requires a dedicated animator if you don't want to use my stock character, but all the code support is implemented and ready. Pressing T while facing a nearby enemy will initiate a takedown cinematic, killing that enemy. It works by locking your controls, switching the camera to render the third person model from first-person perspective, and having that camera follow your eye node. At the end of the sequence, control is restored, and the player is in awe. This works in both first and third person.

There are 4 parts to a fight sequence:

1) The "win" player initiates the fight with the "lose" player. Both the win and lose players are locked out of their controls and prepped to view the sequence. The winner plays the winning animation, the loser plays the losing animation.

2) disarmTime - The moment that the loser's gun is taken from him. If a disarm is part of the animation, this is the moment to remove the weapon.

3) noReturnTime - The moment that the loser cannot be saved; the exact moment he dies. Up until this point, if the winner of the fight is killed, the fight ends and the loser walks away. After the loser dies, killing the winner will not make a difference. This works both ways, too. Someone can also kill the loser before he dies from the fight (though the winner might be a bit angry at the stolen kill).

4) The end of the fight. The winner gets his gun back, and he's free to move around to his heart's desire. Picking up the loser's weapon is also encouraged as a trophy for the humiliating kill.

I should also mention that this works between both human and AI players: humans can takedown humans, humans can takedown AI, AI can takedown humans, and AI can takedown AI. I'm altering the dodgy "melee" AI code to allow for this system.

How many fight sequences can there be? As many as you want. I included four unnecessarily flashy fights that depend on the direction of attack: attacking from the right, left, front, and from behind. You might want to make more simple, less time consuming animations, a la Far Cry 3 and Battlefield 3 that just include a knife plunge. The heavy lifting is done for you already.

Oh, right. Video.



Just a quick note: When you see the player get attacked from the right while he's shooting his gun, it's not just shooting straight ahead. I've altered it to send bullets in the true muzzle vector during fight sequences, so bullets are actually being sprayed everywhere. Ain't that somethin'?

I WANT THIS STUFF

After reading all that, I sure hope so.

The update is almost there, guys. I'm working on it pretty much non-stop whenever I can, and I absolutely cannot wait to get it out the door. It's being developed for Torque 3D MIT.

Pricing

You can buy the Tactical AI Kit here for $74.95!

Email me if you buy it and it doesn't give you a download link. This is a problem from time to time.

If you are an owner of the Tactical AI Kit, the update including all of the features I just spewed on and on about will be completely free. When the update is released, I'm raising the price of the kit+update to $89.95 for those who don't have it by then.

Look at it this way:

Get TAIK now for $74.95, get the free update when it comes out,

or...

Buy them both later for an extra $15. I don't know about you, but I like that other option a lot. Either way, it'll help me hammer away at student loans and I'll love you forever.

Can I try it out first?

You can play the ancient demo from two years ago, running the old, rusty TGE 1.5 by clicking the picture:



It's not showing the bots at the level of intelligence they show today, but it'll give you a pretty good idea of how the AI behaves in response to combat and stealth play-styles. I'll have a new, shiny, updated T3D demo released alongside with the update fairly soon.

Thanks for reading, folks! Let me know what you think. I always like me some feature requests!