Possession (formerly Possession 2) - Release Date: July 18th!

[Bear]

Kobold protesters who are blaming you for their troubles so that other protesters will attack you?  If you think the player can take the awful pun-ishment.... Please, PLEASE let them be attacking with Blamethrowers.   

I also really like the rainbow death lasers. 

[Rickton]

Thanks!

And wow...Blamethrower...that's horrible...but also too good to pass up.

[Rickton]

Crossposted from my site.

This post is a little more technical, but hopefully someone out there will find it useful if they're wondering how to face a similar issue.

Possession 2 features two basic types of creature behavior, dumb and smart (though there are a lot of complications that can go into them to make them act differently within the two categories, as touched on in a previous post).

Dumb creatures are fairly simple, as you might expect. If they see an enemy, they move towards them in a straight line, if they can. If there are any obstacles blocking the way, they go around them using basic pathfinding. They will move through dangers that don't block movement (fire, lava, poison gas) without caring.

Intelligent creatures, like dumb ones, move in a straight line to their target if possible. The difference is that they pay attention to whether or not there are hazards in the way. Now, just avoiding hazards would be easy enough, I'd just have to set tiles with dangers on them to be "impassable" on their pathfinder, and they'd path around them like other obstacles. But I don't want them to avoid dangers all the time. If it's impossible (or extremely impractical) for them to move around a danger to get to their target, they should be able to go through them.

What I ended up doing was implementing what this article calls "Djikstra maps."

Basically, the way it works, is that it takes a section of the map, and creates a grid on it. Each square on the grid is set to 10, except impassible squares like walls, which are ignored, and "target" squares (usually enemies), which are set to 0.



(In this situation, the drunk tourist would actually just move in a semi-straight line -- depending on how drunk he is -- towards the ghost and wouldn't bother making a map, but I'm doing it as an easy example.)

Then, it loops through all the tiles, until each tile is one greater than the lowest tile it borders (ie all the tiles next to the ghost are 1, all the ones next to those are 2...)


(Just realized I made a mistake, the tile in the upper-left should be 4, not 3.)

Then, the creature picks the tile it's touching with the lowest number (randomly choosing between them if there's a few it's touching).

This method is also used for creatures running away. Instead, they just pick the highest number they're touching. Fo example, imagine the image above stretches to the right a little. All those tiles to the right would be 4, and the drunk tourist would move to them if it was running away.

Things get a little more complicated if there are hazards involved. In that case, the hazard adds a number to the tile's value, depending on how dangerous the hazard itself is (which is set on a hazard-by-hazard basis when I make them). For example, the hazard value of fire is 10. Let's set a few fires next to the ghost:



Those tiles, which would normally be 1, are now 11. Notice that this changes the values of the tiles next to them, too. The tourist now has fewer options to get to the ghost, plus its route is going to be a little longer.

It's all well and good to draw numbers on pictures, but how does it work in action? Let's take a look at another situation, and do the numbers by hand to see where the drunk adventurer should walk, sans any drunken stumbles into the fire (these pictures are all from the tavern level, and if you can't tell, there's a lot of drinking going on there):



And what path does it take in the game?



Nice!

As I mentioned before, different hazards have different danger values. Fire's is 10, which means it's super dangerous, but what if it was only 1?



Now, it's possible the drunk adventurer will still take the same path...its values haven't changed. But, it could step into one of the fires marked 6, because they have the same value as the empty tile, and the creature randomly chooses between equal values. This would actually save it some time, but it doesn't actually know that because it only looks at the tiles next to it, it doesn't actually plan the whole path in advance (it only looks smart, it's not actually that smart).

Last theoretical situation in this longer-than-normal post...what if there's a fire in the doorway next to the ghost (setting fires back to 10)?



The numbers are all higher, but it'll follow the same path as originally, even stepping into the fire at the end. This is what I was talking about way back in the beginning of the post...if they just can't avoid it, they will still walk through hazards.

And actually, right now, once it is next to the ghost, it won't even care that it's getting burned. It'll try to attack the ghost because attacking things has a higher priority than moving. I should probably change that if you're in a dangerous place like the middle of a raging inferno.

[Zireael]

That's a really neat explanation of Djikstra maps, thanks!

[Rickton]

Glad you found it informative. But apparently I'm an idiot and it's actually "Dijkstra" (I switched the I and J).

[Rickton]

Crossposted from the official Possession 2 site.

Boss design in games can be difficult.

In the original Possession, bosses were pretty basic. They were creatures slightly stronger than most of the regular creatures on the level. None of them had any special abilities, except for the fact you couldn't possess them. I made them unpossessable for a few reasons: one, it'd be a pretty anticlimactic fight if you just possessed the boss as soon as it showed up then merrily went on your way. But also, it forces you to change your tactics somewhat. In most other fights in the game, you always have the option of possessing the enemy rather than trying to fight them (either right off the bat, or if you start losing). Making these strong creatures unpossessable meant that you had to actually fight them, hopefully using what you learned about your body's abilities during the rest of the level.

A lot of the bosses in Possession 2 are still pretty much the same: just a stronger enemy you can't possess. But now, some of them do have ranged attacks and special abilities, like regular creatures do (for example, the Bounty Hunter Imp from the first level has pistols it can shoot at you).

Some (but not all) of the special levels will have bosses that are pretty different, though.

Here's The Baron, the boss of the Swamps. He's actually pretty weak, but you have to make it through his zombie and skeleton bodyguards to actually fight him (and just wiping out the zombies beforehand won't work, new ones will sprout up as soon as the old ones are killed).



Here's the Eldritch City's boss room. A single narrow walkway surrounded by pits. Surely it's just for decoration, nothing bad is going to happen here.

When you try to go up the stairs, four tentacles pop out of the pits and start trying to lay the smack down on you. You have to defeat all of them to advance. The good thing is, they're confined to the pits, so you can run away and regroup more easily than most bosses if you need to. Just watch out to make sure they don't smack you into the pit or into a wall.




The tavern doesn't even have any specific bosses. Instead, to leave the level you'll need to fight your way through a massive barroom brawl!

[Rickton]

Crossposted from my site.

Well, still no progress on the "post every week" front.

I started working on Possession 2 in November of last year. I'd hoped to get it out in less than a year, but things aren't looking like that's going to happen. Of course, January through April I was working 50+ hours a week at my "real" jobs, so I can't really be too hard on myself about it. After all, if you look at it like that, it hasn't really been a year, right? (Excuses, excuses...)

Onto some good news, though, I think things are close to being ready for another public alpha release, to play around with some of the new creature and levels. This one will be much more "complete" than the previous ones, with no ASCII stand-ins in graphics mode and more things in their "final" places.


On the "polish" front, I've made the main menu a lot more appealing. Graphical and ASCII versions for comparison. (Click to enlarge)

In the final game, you'll have to go through 10 levels (well, 11 if you count the final level) each time you play. I'd originally planned on adding 16 themed special levels, two each for levels 2-9, and the game would either pick one of the special levels or make it a "generic" level (which still has a lot of variety: each generic level has its own set of monsters, and they're randomly chosen to be wide-open caves or rooms-and-corridors, can have lava, water or chasms running through them, or can be a forest). Levels 1 and 10 will be special levels in their own right, but the same special level each time, though still randomly generated.

Unfortunately, to be able to get the game out sooner, I'm thinking I'm going to have to cut it back to one special level per level at first, for a total of 8. Of course, each level will also have their "generic" version too. Considering I've got five special levels "done" (at least before I get testing and feedback), that puts me significantly closer to that goal. I'd probably release the 8 other special levels later in a free update. The five levels I have finished are the Tombs, the Sewers, the Eldritch City, the Swamp, and the Tavern. They're all pretty different, and all have unique creatures, level features and bosses that go with them.

Images of special levels:
(Click to enlarge)


I've broken it down to the major things I need to do before final beta testing. I'm sure I've forgotten something that I'll add to the list later, but for now I have:

• Final level and ending - There's going to be a different ending in Possession 2 than the first game, and I need to implement it and make the game winnable.
• Saving - Saving broke when I redid how some things are stored on the back end, and I need to fix it. I'd also like to add in support for multiple save games, which the original didn't have.
• Fixed Settings Screen - This screen hasn't been updated since Possession 1. I need to add in new settings and keybindings, and make the screen look better.
• High Score/Stats Screen - Mainly just need to make it look better. The game also tracks more stats across games (total possessions, ability use, etc.), so I need to set this screen up to show those.
• Monsters for all generic levels - Each level has at least 5 different monsters, so I need a total of 50 (there will be more monsters than 50 in the game, of course, since special levels have their own sets of creatures). I've finished enough to fill up 8 levels. This is what I've been focusing on most recently, and shouldn't take too long to knock out. I've got plenty of creature ideas, I just need to implement them.
• 8 special levels - As said before, I've got 5 done, and have started on others, so more than halfway done on this front.
• Sounds - The sound system is in. Abilities can have sounds associated with them, and creatures have death and notice sounds. The issue now is finding sounds to go with them! I've made some progress, but this could end up being pretty time consuming depending on how easy/hard it is to find good sounds that match the tone of the game.

So, all in all, while I haven't made as much progress on the game as I'd have liked, progress is still being made. This is my first project of this scope, so I don't really feel too bad about underestimating how much it would take. From what I understand, everyone underestimates how long software development takes, even people who've done it for years. Cutting back on content is not something I'm terribly happy about, but I think it's what needed to be done at this point.

If you're interested, you can sign up to get exclusive info and news on Possession 2 before anyone else does, including first access to the new build!

[Rickton]

New post, crossposted from my site:

It's been almost five months since the last blog post, I guess we're long past due for another one.

Unfortunately, I haven't gotten nearly enough work done considering the amount of time that's passed. In truth, missing my one-year deadline kind of bummed me out for a while, and then the holidays came to distract.

Still, I have gotten quite a bit done. There's a new special level in, the Mines. It's a pretty dangerous place even aside from the monsters, since it's filled with rocket-powered minecarts, lava and explosive barrels.


Dwarves apparently have no workplace safety laws.

I've also been doing a lot of work that is pretty unexciting (but necessary). Some UI and polish work, like scrollbars in the message log and monsterpedia.


Try to contain your excitement.

The game has rudimentary mod support now, which is kind of exciting, but again, doesn't make for a great screenshot.

There are also sound and music systems implemented. I haven't decided what I want to do for the music yet (ambient noises? regular music? chiptune?) but I have found and implemented a lot of sounds for monsters and spells. They obviously can't show in a screenshot, but I might try and get some video up later.

For those of you who might be in the market for sound effects and are willing to pay a little bit, I really recommend Affordable Audio 4 Everyone. They sell packs of professional-quality sounds for way cheaper than most libraries out there. Plus, a portion of the proceeds go to charity so that's always nice. There are, of course, plenty of free sites with sound effects, but finding high-quality sounds on those can be hard, plus there's always some worry about whether or not the person uploading the sounds really had the rights to do it (I've heard some sounds on some sites tagged as "public domain" that I'm almost certain came from a commercial product).

I have had some good luck on Open Game Art. The quality there seems to be a little better than other free sites, and people who upload sounds they didn't make usually include links to the original so you can check it out and make sure it's legit.

I've also recently found Sweet Sound Effects. It's another free site, but the sounds are all made by one guy, so they should be legit. I haven't tried many of their sounds yet, but it seems like a good resource.

Finally, I've realized I really need to step up my marketing materials. I've put up a website for Possession 2, and I'm working on a trailer. I also need to buckle down and get an acceptable preview version out. Need to start getting the word out a little better so there's people who actually want to play the game once it comes out. I hate doing marketing stuff, but it's a necessary evil I guess.



Anyway, I do have some blog posts already written and ready, so there won't be another four months until the next post this time.

[getter77]

It is thoroughly awesome that 2015 may well see the full release of not one, but two possession-centric Roguelikes or at least get tremendously closer!      You should totally throw some time at the start of the new MidBoss beta that came out fairly recently to kick off the final push---where each project has went in very different directions on some aspects, surely there's some mutually nifty things each can note to bolster the entire lot.

[Rickton]

It is thoroughly awesome that 2015 may well see the full release of not one, but two possession-centric Roguelikes or at least get tremendously closer!      You should totally throw some time at the start of the new MidBoss beta that came out fairly recently to kick off the final push---where each project has went in very different directions on some aspects, surely there's some mutually nifty things each can note to bolster the entire lot.

Yeah, it's kind of funny how that happened. I haven't played MidBoss, and probably won't until I finish Possession 2, but it seems pretty cool and I definitely hope it does well..

[Rickton]

Crossposted from my site.

The most recent feature I've added to the game is (are?) lit areas. They were a planned feature that got cut pretty early on, since it wasn't necessary, and I didn't want to waste time on it. But then I came up with an ability that required it, so I went ahead and put it in. Luckily, it didn't end up taking very long to do.

Basically, everything that can go in a level (features, effects and even creatures themselves) can potentially "cast light."


An effect, feature and creature that cast light.

Any time anything that casts light is added to the map, it also gets added to a list of "light sources." The map now also has a "lightmap," which holds a true/false value for each tile that says whether it's lit or not. Every turn, every tile on the lightmap is set to unlit. The game then loops through all the light sources and checks every tile within each light source's "light distance" to see if it can draw a straight line to the tile without hitting any sight-blocking obstacles like walls (using Bresenham's line algorithm), and if it can, it sets it as lit.

Now, in terms of determining what creatures can see, every creature has a set sight radius. Anything that's within that range of them, they can see as long as there's nothing blocking the way. Now that I've added the lights, all I had to do is check to see if the tile is in range OR it's set as lit on the lightmap (it still also checks to see if anything is blocking the creature's line of sight, of course).

Here's an example. The player (currently possessing the zombie), can see a small radius around themselves. The torch on the left also illuminates a small area around itself, but some of the light is blocked on by the trees.



For the player, every turn I check every tile in the map to see if they can see it. Not very efficient, and if I did this for every single creature it'd probably be pretty slow. The good news is, creatures generally don't care that much about the stuff in the levels. They just need to know about walls and floors, and (for the more intelligent ones), hazards. All this information is actually stored in a preset pathfinding map that all creatures have access to without actually having to have seen the tile (more info on how that works in a previous post). I guess we can assume that they live in the area so they know where everything is. The only thing they actually need to worry if they can "see" or not is other creatures.

So, all in all, it really was a lot less complicated to add than I thought it would be, which is really nice because usually when you add a new feature it turns out to be MORE complicated and take twice as long as you expected to code. And now I can have things that light up the levels like torches or candles, and you can see fire even if it's far away, and even glowing creatures that you can see in the dark.


Forest fires are visible from quite a distance away.

[Rickton]

Crossposted from The Possession 2 devblog

Not all the creatures in the caves are mindless monsters that will attack until one of you is dead -- though some particularly stubborn, foolish or brave ones will. Most creatures in the game have a fear value that can cause them to run away if it gets too high.

When a creature gets damaged, its fear goes up by the % of health it lost compared to its max health. For example, if a creature has 50 max health, and gets hit for 10 damage, that's 20% of its total health, so its fear goes up by 20. Most creatures then have a set bravery value, and if their fear goes above that value, they'll run away. Here I've set the caretaker's bravery to 5 to show how this works:



Certain abilities can increase fear (for example, there are banshees in the game who have a wail ability that causes fear), and having certain conditions (poisoned, cursed, etc.) can increase or decrease fear or bravery. Creatures that like to keep distance between them and their enemies (usually spellcasters or other ranged attackers) also have their fear increase when enemies are too close.

When a creature runs away, it uses the so-called "Dijkstra maps" I talked about earlier, but instead of moving to the tile that's closest to an enemy, they pick a tile that's the farthest away from them.



Imagine this, but in reverse.

Creatures' fear decreases by one every turn, if it's not near any enemies it decreases by two, and if it hasn't seen any enemies in a long time, it decreases by three. So, a creature that is afraid of you and runs away will eventually stop being afraid (even if it doesn't heal).

There are certain other things that increase fear, too, like seeing a nearby creature explode or get possessed. I wanted to implement a generic event system and have creatures react to those events, to have lots of things able to influence creatures' fear. Unfortunately, I've had to cut that feature out, because it's not necessary and it's just something that would add move dev time, which is really not what I need right now, and the things that increase fear are just hard-coded instead.

[Rickton]

Crossposted from the Possession 2 devblog on weirdfellows.com

So much for pre-written posts preventing me from going months without a post. I could make excuses, I could call myself a garbage human being, but whatever. It is what it is. It just worries me, because I know that marketing is really what determines how well your game's going to do, even more than how good the game itself is, and if I can't even do the bare minimum of that...

Well, anyway. I have been working, but as usual, not as quickly as I'd like. Part of that's because what I've been working on recently is probably the least fun part of any project: the settings screen.


Awesome?

I'm actually kind of proud of the work I did (though I hated doing it at the time). The old game had all the settings and their locations hard coded, so moving them or adding new ones was a pain in the ass. This one stores each setting as an object that handles drawing itself, changing and being highlighted, and I can move them around or change them easily. The settings screen itself just has to know the order they're in, not exactly where they are.

Anyway, on more interesting note, this is the last big thing that needed to be done before I get a preview version out. I just need to semi-balance the levels that are going to be in the preview and make sure their creatures all have sounds and there aren't any major bugs. Then I'll be able to get a preview version out, hopefully along with a trailer, and I'll get the game up on Steam Greenlight. Then we'll see how bad my marketing skills really are...

[Rickton]

Crossposted from the Possession 2 Devblog

In roguelikes, almost everything is usually trying to kill the player. It makes sense from a gameplay perspective, of course. Monsters are there to be obstacles standing between you and your goal. In the Possession games, you can even make an argument that makes sense from a narrative standpoint: people and animals can tell something's not right with something that's possessed.

That said, it can be interesting from a gameplay point of view (as well as making the game world feel more alive) by making some creatures hostile to each other, and some creatures not immediately try to kill the player as soon as they see them.

I've talked a little before about the fact that creatures have different "aggression" values, that some will attack on sight, while some will hang back unless you get too close.

In Possession 2, creatures can also have a "faction" assigned to them, as well as a list of enemy factions. If they see a creature that belongs to an enemy faction, they'll treat them like an enemy, exactly like they would if the creature was the player.


The miners don't take kindly to protestors in their mines...

Players can use this to their advantage, though. If they possess a creature that belongs to a faction, other creatures in that faction won't be hostile to them! Well, unless they saw the possession happen...

There are three special factions: Chaos, which means they'll attack anyone, Passive, which means they won't attack anyone except creatures who attack them first, and Player Ally. If a creature is a player ally, they're treated like the player, and are hostile to everyone except other player allies (including the player themselves, of course), and members of their own faction.

Aside from the factions, there are some other things that can change the way creatures behave towards each other.

The first one is the fact that creatures can have "masters," who they will follow around and attack the enemies of. Creatures won't attack their master or their master's other followers, and will attack their master's enemies, regardless of their own faction.


A bunch of cultists beat up their mummy master's enemy: the archeologist.

Creatures also maintain something that I call in the code a "shitlist." It's basically a list of known individual enemies. If they notice and become hostile to someone, they go on the shitlist. But even creatures to whom they'd normally be friendly can end up on the shitlist if they accidentally hit them with a ranged attack that missed its intended target, an attack that damages an area, or if they hit them while confused/drunk/mind controlled/getting knocked backwards/whatever. Players can use this to their advantage by causing enemies' attacks to hit each other, making them attack each other while the player sneaks past or waits until they're weaker to pick them off.

So, this is all well and good, but it does present a problem. If creatures on the other side of the map are attacking each other, then by the time the player gets there, they'll probably all have killed each other off, maybe leaving a few almost-dead stragglers. And while it's kind of cool to walk into a room and see the aftermath of recent fighting, it's not very challenging or fun if there's nothing left for you to fight.


I bet there's a challenging room full of enemies to fight through this door! Oh...

The first thing I do is also a bonus for performance. Creatures far enough away (currently defined as "more than twice as far as the player's sight distance") don't run through their whole AI code. They just move randomly to a square they're touching. If they do happen to take damage (say they wander into lava, or step in a trap or in front of a moving mine cart), they only take 10% of the damage, rounded up. Of course, if something happens that would instakill them (getting knocked into a pit, for example), they'll die.

So this works well for far away creatures, but maybe a creature is physically near the player but the player would still have to travel a long distance to actually see them...they might be on the other side of a wall, but the nearest opening in the wall is halfway across the level. Or maybe they're just in the next room, but the player's hanging out in this room for a while, so we run into the same problem.

For creatures near the player, but that the player can't see, they'll only take half damage from everything. This could be exploitable (position yourself so a friendly creature can't be seen, but their enemy can...enemy takes full damage and ally only takes half!), so it actually only kicks in if you can't see the creature or their attacker.

[Gornova]

Really interesting series of post, thank you about sharing!

About world simulation: seems boring to find a room full of dead bodies (a joke for a ghost with possession power ? lol), but could be a great plot twist for player. Wait forever and everyone will die eventually! To me seems a good enough motivation to keep exploring and make choices.

For example explore a maze in a certain order could resolve in a different encounters because in other part of the same maze all creatures are dead