Dev Log: Space Warfare Infinite – New AI tricks, missiles for everyone! and Unity3D Bloom findings

screen_78.26921Over the past week I’ve been having a lot of fun with Space Wars, while also researching and reading about AI. (I also got a little sidetracked by trying to perfect the bloom image effect….)

AI

AI can make a game like Space Warfare pretty exciting. I plan on having some multiplayer aspects once I get the major systems together, but the focus of the game is really a single player experience at this point. Since that is the case, cool AI pilots who behave in interesting manners is important. My actual AI code at this point needs to be refactored because it is a big mess, but the things its doing already even without a really nice organized OO state machine are pretty fun. I plan in the future to build out more of a Playmaker-esque state machine for these guys but it’ll take some focus. Because of the behaviors of the AI, the game is becoming pretty fun to watch. It has the enemies turn and loop and barrel roll to escape or ambush each other.

Current states include Chase, Attack, Reposition / Flee. Within those states the ships are able to barrel roll in reaction to being hit as well as change target focus. My idea is that I want to have some base states like Attack and then have a bunch of maneuvers that can be employed by the pilots depending on their style/personality/status. I am looking into multiple temporary short range ‘waypoints’ to create maneuvers so that AI can do looks or spiral at another ship instead of go in a straight line.

Some of my research to me to the above really cool video from Star Citizen (disclaimer: I am one man, Star Citizen will always be cooler than my game…). It hints how they are thinking about AI and displays some quick shots of the Ai engine. I can’t afford to hire that Ai company but I like some of their approaches. One of the things they really focus on is collision avoidance which made me think – oh man I don’t have anything to collide with yet other than really small ships better get to work on that! Unity’s Nav Mesh seems out because its a 2D plane and not a big open space. I’m heading towards a raycasting set up for individual ships. I forsee it being a little costly so I might have to add some collision radius objects that trigger the raycast steering only when necessary. One video that seems to explain the basics is here: http://vimeo.com/9304844. Sadly the author seems to have disappeared from the internet and never continued the series.

Missiles

I’ve also implemented missiles into the game. They are basically have perfect tracting to the only way to not get hit is to accelerate long enough that they can’t catch up or have them hit or get hit by something. I am working on a few countermeasures like a ‘chaff’ like drop and perhaps flares. I know chaff is for radar, but I might make it a dual purpose item in this game. It just drops a bunch of chunks of metal behind the ship that can clog an enemy radar with blips or set off a guided missile if a chunk collides with it. The other balancing option I will add is the length of time the guidance system works. This will give the player the ability to outrun then dodge a missile over a range if the guidance cuts out early, but is still a threat if the ship remains on the same course.

When I have add the ability to upgrade, ships could by better missiles with longer range guidance systems to make them harder to shake. As it stands now, unless your opponent launches a missile from too far away, the likely outcome is an explosion. Its so likely that for the above video I needed to disable missiles just to show you the Ai fighting without immediately creaming each other with missiles. Also I wouldn’t be able to stay in one place and film for my that 10 seconds before getting hit myself.

Missiles are a powerful weapon. But I always feel they are underpowered in games. Perhaps I should make it a little more random – 10% chance of surviving a missile? Perhaps its time to add shields!? Also individual parts of ships might mean less instant kills if its not a direct hit.

Bloom

On the Bloom front… well the game is shiny now! Look at the before and after!

 

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Before…

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After…

Things I’ve learned so far… some Unity image effects may be added after every camera is rendered. This means that no matter what camera you add an effect to, everything is gonna get the effect. The bloom happened on all my cameras no matter what my order was or culling set ups were. I’ve tried it all…. If someone out there reads this and finds out a way to make my findings untrue, I would love to see the solution! Comment, twitter, email me!

The main problem I’ve had is that the really nice Space for Unity scenes were getting over exposed and washed out so that you couldn’t enjoy the scenery. Since the main thing I wanted blooming were the trails and lasers, I ended up really brightening the particle materials they were using and then turning up the ‘threshold’ setting on bloom so that everything doesn’t wash out. It sort of works. I like more glowing than less so I am happy where I am with the look. Sometimes I feel like almost Bloom alone makes the Unity Pro license worth it — just the cool factor.

Dev Log: Space Warfare Infinite Updates -Bloom and Ai

I know I should be working on my November game, but the prospect of being able to devote more time to Space Wars (As well as finding a real game name for it – Space Warfare Infinite?) has been too tempting! I will get back to my monthly project soon, but  in the mean time lets talk updates to Spacewars.

Bloom –

Bloom is all the rage. It’s the main reason to get Unity Pro from what I can tell. That and the profiler. But lighting effects take your game and put it in the pro category – at least with the looks. I’ve been trying a bunch of different post-processing effects, but standard bloom seems to be the best for making space object look interesting and making laser flash and glow. The battle now just seems more alive! The downside is that brighter backgrounds glow too much and look too bright. At the moment I am just letting it slide. I fooled around with the camera render orders and such but could never get the bloom to only effect lasers. So far it doesn’t seem possible for me. (I did see someone wrote a shader that keeps bloom from rendering on something. I might do something like that someday to fix the nebulas and other stuff I don’t want to glow).

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Ai –

I’ve also been futzing with the Ai. I really want to write behaviors and more decision making. The current Ai chooses a random target from a list of enemies and then blindly charges. When in range they start firing. The other behaviors include: if they get hit a couple time in rapid succession, they will find a random waypoint to run off to; if they are attacking for more than a few seconds they will find a new way point to back off and then go back to it; if they get hit by a ship that is not their target a few times, they will switch targets and defend themselves.

Last night I changed a few things that annoyed me. First I added a lead object to each ship so that ai will aim just before the target thus leading their shots. Works well for moving objects.

I want to build a behavior where the Ai does flybys or other maneuvers that make sense. As I step towards that, I removed their ability to stop. It looked super dumb to see ships just floating in space taking shots. I just have them thrust at all times now. I also dropped their rotation speed from 20 to 1 which makes them curve a little more when flying – looks more natural. No more turning to the player in a blink! I also want to add a behavior when they are too close for more than a few seconds, find a nearby waypoint to go to before attacking again — the ai seems to get in close and then circle the target without being able to aim shots. They need to be able to get a new attack vector. The movement makes the game much cooler looking. Everything circling around with trails.

Ai Behaviors I am hoping to put in:

  • Rush pass / loop: Ship flies by target attacking as they pass then pulls up and executes loops to do another run on same strike vector
  • Flanking loop to hit target from side Circle to get around and behind target Go to waypoint
  • Patrol series of waypoints
  • Follow / Protect target
  • Follow / Copy target (attack its targets) Stand still – cap ships will prob do this alot Kamakazi ramming
  • Strafe side – get up to speed then rotate to aim guns at target let inertia carry ship along side target while unloading weapons… (currently not possible in way game handles ship flight… but this might be an effective attack for fighters against a cap ships PDS)
  • Preferred targets – weakest, injured, toughest, untouched, ranged, fighter, cap, midrange, auxilery, stationary, slowest, low shields, low armor, high shields, high armor, no ‘type’ gun, specific ship
  • Scanning / Sight Range- how far should awareness go? Should be increased by auxiliary scanning ships in fleet.
  • Use specialized component – Scanner Jammer, EMP, Cloaking,