Exploring the Tech and Design of Noita

[Music] we're going to be talking about exploring the tech and design of noitan because the game is not out yet i'm just going to show you a trailer and hopefully it'll explain a little bit about the game we had some trouble getting the audio working so it's not again this is the curse of mine [Music] [Music] so uh thank you this is essentially us uh there's three of us and then this is our uh audio department here and uh so the talk is going to be divided into two parts and the first part we're going to talk about the tech stuff and then it's going to be the design stuff and i'm just going to say right now that the design part is there's not probably going to be enough time to go into too much detail about it so it's going to be a bit more rambly but for the tech so we have a custom engine that's called falling everything and you can kind of see from the trailer we can do sand and we can do liquids of all kinds and then we can do gases as well and and for the last thing is like we also have like rigid bodies in there and essentially i'm going to talk to how we've sort of done all of that and how that is sort of being accomplished and we're going to start at the basics by traveling back into a much better time period into the 90s when you could type into a text editor and characters would appear immediately so back back in the 90s i got started in quick basic and i discovered in quick basic that you can do this thing where you can put a pixel under the screen by pset and you can ask for a color of a pixel by point by so you point at something and you ask what the color of that is and with this amazing technology i was able to essentially write a sand simulation so what's what's happening here is uh it's testing that if there's a sand pixel here it's looking at the line below it if that's empty then move down and then if that's occupied it looks uh to the left and the right to the down left and the right and it moves in that direction and with that you essentially get this which is a rudimentary sand simulation and this is like 95 percent of our tech is this then i really quickly discovered that you can also do water and it's essentially the same algorithm but at the very end of that you also like check to the left and to the right and if they're empty you move in that direction so with that all of it sort of settles down and now you've got water and sand and then the gases are just like inverse of this so that it's not that complicated it's now you all know if you've been wondering um but we're travel forward in time uh about 12 years and i'm using visual c plus plus 6.0 and i do not know how good my life is and i ended up making this game called bloody zombies and this was made in 2008 and it was made for gamma 256 and it was a competition where you had to make a game that used resolution 256 times 256 or lower so while i was working on this this is essentially using the same algorithm as in the quick basic one but what i discovered is you can also like make it a bit more liquid-like i'll show you more gifs of or gifs so you can make it more liquid-like by adding another sort of a simulation which is like this particle simulation and so the thing that's happening in in this like when the player jumps into the blood and it splatters all around what's happening is taking one of those pixels out of that falling sand simulation and it's putting it into a separate particle simulation and it's tracking its velocity and gravity in there and it's traveling in that until it hits another pixel in the world and then it gets put back into the falling sand simulation right so with this you can make things a lot more liquid-like and not just like this blobby thing that's falling down and we're using this technique still to this day in noita so after i was done with bloody zombies which was kind of like a quick game i made crayon physics and then after that i was interested in like can i add rigid bodies to the simulation i was using visual studio c plus plus 2008 and it turns out you can add rigid bodies to this but it's a bit more complicated and essentially the way this works is i'm using box 2d for the rigid body stuff and it's sort of like integrated with this falling sand simulation so the way it works is you have all the pixels that belong to a rigid body they know their material and they know they want to be one sort of rigid body and what you do with all those pixels is you apply a marching square algorithm to it and that marching squares algorithm essentially produces this outline of all where all the pixels are and that's a lot of vertices so what you do then is you give it a document specker algorithm and that's essentially the smooths that out so you get a lot less vertices and once you haven't like to smooth it out mesh you give it into a triangulation algorithm and you get a bunch of triangles and at this point you're at a stage where you can just give those triangles into box 2d and in box 2d can sort of simulate those bodies and the sort of final step to this is that every pixel that's here it knows its uv coordinates inside of that triangle and it knows which body it belongs to so that's the way it can kind of like figure out its new position and and the way you put these two simulations together so you have two different simulations at this stage the way you put them together is at the very beginning of the frame you take your rigid body pixels out of the world then you run your falling science simulation one step and you run your box 2d one step and then you put your pixels rigid body pixels back into the world and they get their updated positions from box 2d right and there might be this case where there's a pixel now in the way of a rigid body and what you do in that case you just take that pixel out and you put it into that bloody zombies particle system and you throw it into the air so what ends up happening with that is is you get these you know splashes like well that's not a good example let me give you a better example here so like when this this body hits the water all those water pixels get thrown into the world so that's pretty much pretty much it we have to do a bit more to it so like one thing is like if one of these pixels gets destroyed you have to recalculate all of the marching squares and the box 2d body stuff and whatnot and for the rest of the world wherever there's like study static i'm using static and air quotes because you know there's nothing really static in our game uh static stuff uses two the first two steps of that algorithm so you do marching squares and douglas picker and then you just make these hollow bodies of the world and you only have to do that in places where there are rigid bodies or places where they're going to be rigid bodies and that saves you a lot of so that's pretty much the tech there is one more step to it and this is well there's two more steps to it so we're getting to visual studio 2013 and i have here a video of it taking eight minutes to boot up and i'm making all of you suffer through this because i've had to suffer through it so sort of the last step of this process of making the tech of noita was that i had it running in this 256 times 256 area but it's really hard to make good gameplay in like 256 times 256. so the last step was like figuring out how to make like a really big world we can sort of have everything sort of simulated and the problem was that it was just like taking so much cpu time to test all the pixels that it was getting really complicated to do that so the solution to this was to figure out how to multi-tread the sort of falling science simulation and essentially the way it's done is the sort of world is divided into these 64 times 64 chunks and each of those chunks keeps a dirty rect of things that it needs to update so you can see here the dirty wrecks that are getting updated and what this alone like even if you don't multithread this what this alone does is like it removes like so many of the pixels that you have to test because very often the world ends up in some sort of semi-stable state so then you don't have to update that much stuff but you can also multithread this pretty easily and the problem with multithreading a simulation like this is because it's using the same buffer so there's no not like two buffers uh you have to make sure that another tread is not updating the same pixel as you're updating because if there's like two threads trying to update the same pixel all hell breaks loose and everything is destroyed so the way to do this is you or the way we did it is uh we update the world in this sort of a checker pattern fashion so at the we do four update rounds of the world so at the very beginning you gather all the things that have to be updated and then you pick like in this case we're picking these white ones here and what it allows things to do is this guarantees that any pixel that's getting updated in this can go 32 pixels in any direction and it's guaranteed that another tread won't update it so like you can see here this green area are all the pixels where it can kind of like travel to and so the multitrading is essentially like you take sort of every fourth chunk and you throw them into a tread pool then you wait for all of those to be calculated then you do the next set of four 64 64 areas you throw those into a thread pool you wait until they're done uh you do it once more and then you do it once more and then you've essentially managed to multithread the simulation and get a lot more out of your cpus uh the real final bit because like we have a sort of a continuous big world it's probably the most standard technique of this which is essentially just streaming so in this this yellow rectangle bit here represents the screen and all of these other rectangulars are uh 512 512 areas of the world so as you sort of travel around in the world the procedural generation system is generating new worlds as you're going and we try to keep 12 of these in there at the same time and then we just like take the furthest one and we write it to the disk and then you read it back if you ever go there and this all of this sort of creates this uh very nice uh feeling that the sort of whole world is being simulated all the time even though we're kind of like cleverly figuring out what needs to be updated so that was the tech and now we're off into the design i just want to say that the tech part is for for us it was or for me it's been the sort of easier thing to work on and it's a game design that has been more complicated and difficult and the reason for that is that for the tech stuff you can ask these falsifiable questions like you can ask does this look like water is it running at 60 frames a second yes it's kind of done but when you come to game design you have all these questions like is this game fun and it's like well depends who's asking the question who's who's answering like i enjoy kicking ragdolls around for like eight hours a day but like i don't know if anyone else is going to do that enjoy that so for us the real question is like hopefully the tech was kind of cool and impressive but does it produce interesting gameplay and the answer to that is i mean the game's not out so we don't quite know but the answer to this is very complicated uh so the naive answer to this question does it produce interesting gameplay and this is the position i had when i sort of started this is that of course this is going to produce all this interesting gameplay it's going to work as like this perpetual motion machine of emerging gameplay and i was kind of right this physics engine works in that way that there's a lot of emergent stuff that happens but what i did not realize is that emerging gameplay comes in two colors you've got the cool and interesting thing that everyone is always hyped about and you think when you hear the words emerging gameplay but it also comes in this game breaking fashion that can just like completely devastate your game so this is the early prototype i did and it's the idea is that you have like this 2d building and what i didn't realize is like if you simulate all of that it's going to end up as like this pile of rubble at the bottom of the screen and it was this is kind of cool in a way but like how are you going to build a game out of this when all your level design is just gonna it's gonna end up as a rubble and you can imagine like building a game on top of a system like this it's gonna be like nightmare uh so really the process of making noita has really been a process of sort of trial and error and a process of sort of trying to tame this emergent chaos beast that is our physics engine and to find the game that sort of like maximizes the good emergence stuff while sort of minimizing the bad ones and the way we've approached this is just testing a lot of things so we've tested a bunch of different games we've tested a lot of different things and it's because it's so hard to know like if you put something in there is it the coolest thing or the thing that's going to break the game [Music] uh so besides testing a bunch of different games uh what's ended up happening often is we've made changes and then we've sort of ended at a sort of local maxima so local maximum is sort of a place where the game was kind of fun but we felt that there could be something much better out there and we didn't but we didn't know what what we should be doing to get there so as an example of that sort of a thing this is our earlier version of of the game and the player had this tool where they could like dig through everything this drill and it was kind of fun you'd get this at the very beginning of the game and it was kind of fun and interesting to go around the world using this this tool but the problem with it was that it essentially broke all the combat gameplay because like what you would do is you drill this hole into a wall and you shoot all the enemies through that tiny hole and then it was it was kind of fun but it was also kind of like breaking the whole game uh combat gameplay so what we ended up doing at some point was just like taking the drill out completely and what ended up happening there for a while was that the game got a lot worse because like the whole procedural generation system was built with that in mind that he would go through everything and it was kind of worse for a while until we actually fixed everything and then we were actually at a better position than we started [Music] and sort of besides being stuck at these sort of local maximas which happens very often we few times sort of managed to push the game forward in a big splash into something better and one of those things was when we decided to sort of make it roguelike which means it's a permadeath game with procedural generation uh what really happened when we sort of made a rope light was that we managed to sort of shift this sort of like we have this emerging chaos beast that is our physics engine we're sort of shifting uh dealing with it first into the player and then b to the sort of random nature of the game so like because the world's out there to kill you you as a player have to pay attention to it and sort of be because of the random nature of the game uh we we got to put back some stuff so for example the drill that i mentioned earlier that broke our previous game that wasn't roguelike it has made its comeback in in noita and because the game is random you as a player you can't like build all your strategies around just like finding this one tool and beating the game with it because it's not that good it can sort of go back into the game and be there and it's actually kind of fun as a player like now as a player like finding this drill and then figuring out how to use it and then figuring out that you can kind of break a bit of the combat if you use that that's like an exciting thing like you think you're really clever and you found something that the designers don't know and it's kind of like an exciting moment but we've gotten away with a lot of that stuff because because of the random nature uh another thing making it permanent really fixed us for us is uh you can essentially get a new world every time you play so previously it used to be uh it used to be sort of a similar game but you it would be like like in terraria that when you died your stuff would remain in the world and you could go pick that up but the problem with that was because we have such a highly dynamic world he's a player you could like let's say you have to get into this portal and you fill out this place with lava and it's a persistent world then you sort of essentially screw to yourself you can't never make it there anymore but because we we have a permadeath game we don't really care about that that much so like you if you as a player you're kind of like dumb enough to block your progress in the game that's that's on you you get a new chance when you die and hopefully you'll die very quickly or very likely you're gonna uh so i'm going to talk about a few more things hopefully we have time so the this is probably the thing that's most obvious to people is like when we made it a roguelite we managed to make it like we can make it a challenging game and the benefit of that for us is in a moment the benefit of that for us is [Music] you as a player you really have to pay attention to the world and the physics and how it works because the physics are there out to kill you and related note to this was one of the prototypes we did you played as a sort of god like entity and you could like spam lightning everywhere and kill everyone and it was really fun for about 20 minutes like being the super powerful entity but the problem with this was that you wouldn't essentially pay that much attention to the physics of the world like the physics simulation turned into sort of a visual effect for you instead of being a thing that you had to pay attention to but now making this a roguelite has sort of allowed us to uh have our cake and eat it too so at the very beginning of the game you sort of as a player have to pay a lot of attention to the world but if you make it far enough there you can become like super powerful and you just like destroy everything in this one uh and the reason we did not like figure out that we should make this a roguelite and permanent game at the very beginning actually i think we had a very good reason for that and the idea behind that was that it's going to be super annoying playing this game and you're going to get killed because of like a physics glitch or some sort of physics thing that's going to kill you and you don't understand what's happening and and sort of our fix to that has been to try and fix as many of the glitches as possible or make it so that if there's a glitch that we haven't figured out how to fix that it's not going to kill you so like right now the rigid bodies don't damage the player but they damage the enemies in there and the reason for that is we haven't like figured out that maybe sometimes the rigid bodies can get kind of like wobbly in a place and there's going to be huge forces that would kill the player immediately so we're just like let's just disable that that seems to work decently it'll probably make its comeback later [Music] but the other part of that which which i have realized during this process is that it's really about communication to the player so if the player dies because of something like there's lava that drops out of nowhere they're going to be super they might be super pissed at the game if they think that's like a glitch or some random thing but if the player notices that there's like a wooden plank here and there's lava on top of that and they walk underneath there and then the wooden blank sets on fire and the lava drops on them then if the player sees that they're going to blame themselves for it they're going to be like oh i wasn't careful enough like there was this thing and really the difference between someone like hating your primitive game and sort of blaming themselves for it really is almost i think communication of like of these emerging systems and if you look at some classic games like if you look at net hack net hack is actually really good at communicating what's happening in in there like it stops the game stops and there's a line on top of the screen that says that actually says what's happening in the world and there's a funny thing like when you add the sort of communication thing there that happens is you as a player sort of attribute more to the emergent system than actually might even be in there so we had a sort of a thing where you would get stained by the liquids that you walk through so for example uh if you got covered in blood you'd be red and whatnot and it was purely visual at some point and then we added like let's make it so that if you're covered in oil you're more likely to ignite and that was kind of confusing to people like they didn't realize that okay they're going to get get ignited so the last thing we just did was we added these ui icons on top of you as a player that indicate which liquid you're covered in so the blue one here indicates you're wet and as soon as that went in it went from being like this obscure thing that no one got into a thing where people started attributing things to this so like they said oh i'm wet now so i'll probably take more damage from being electrocuted and that wasn't implemented in there but everyone sort of assumed that that's the case and to demonstrate like as an anecdote how powerful this thing was we had like when you're wet now i think you take more damage from being electrocuted but when you're wet you're not as easily you don't ignite as easily and that was actually implemented in there and then we broke it at some point and for like two months it was not working but we all sort of assumed that it's working there and we're just like avoiding it because it's like it's communicating this thing and i think like some games like dwarf fortress and the sims for example managed to like rise above to a certain level where players actually attribute more to the emerging systems that actually are in there but okay that's that's about all the things that i have i think we have like few minutes for questions we have one question or two two minutes okay thank you [Applause] hello hey um i'm curious uh you mentioned that uh the simulation was single buffered everything happened on the same buffer yes is there a reason or did you try double buffering uh well originally it was just that's the way it got going uh but later on i realized like you can't like if you do a double buffer then you have to actually update everything right unless you sort of double buffer every junk separately but then you have to sort of maintain two different buffers and and for i don't think there's different kinds of simulations that you can do if you do double buffered uh falling sand stuff is much more harder i think because then you have to figure out where does this pixel have to go because right now pixels can only occupy one place cool thanks great talk thank you um thank you i wanted to ask about uh the procedural level generation like how did you get that part going for you okay uh as would so i forgot to mention that we've been working on this game for like seven six years now so we've tried a lot of things and for procedural generation we've tried a few different things and there are a few different things in the game right now but the main part of it is using sean barrett's herringbone wang tile set so essentially the what it is is like if everyone here knows how spelunky does procedural generation so spelunky does like four times four uh squares and those squares can be connected with certain rules uh the herringbone wang tile set is essentially uh do we have anything happen how can i i'll demonstrate it with these things so it's it's like this sort of like a brick shape and then you put another brick shape that goes down like this and then one that goes like this and one that goes like this and there are certain rules like how those can be connected and the benefit of that to like the splunky style which is like squares is that you don't see the seam as easily because like there's not a seam that goes throughout the whole world where you see like oh this is the part where we are on this grid and this is the part where around the screen do we have are we done okay if there are more questions i think there's some sort of a place out there and i can and hopefully answer those thank you so much for everyone

Channel: GDC

Views: 139,584

Keywords: gdc, talk, panel, game, games, gaming, development, hd, design, noita, procedural generation, steam, particles

Id: prXuyMCgbTc

Length: 31min 0sec (1860 seconds)

Published: Thu Jan 02 2020

Reddit Comments

[u/raiedite]

Noita is great fun with a proper roguelike structure, but as you descend through the floors, the physics take a backseat and the game turns into a full fledged wizard-shmup (with an extensive wand crafting system).

It's harder to properly use physics since most enemies start flying, aim better, and physical objects become scarcer. Kicking rocks around isn't as viable as the early levels and liquids typically pour straight down so your options are limited

[u/camycamera]

This game really makes me excited. It’s the sort of game that I never knew I wanted. Really great talk on how “falling sand” games are made.

[u/HTF1209]

My goal when playing this game is always trying to become as powerful as possible and explore as much as possible. It's amazing what you can do in this game.

And even if you have the spells to obliterate every enemy or barrier in the blink of an eye and a health bar bigger than the screen you can still die.

Like digging into a small water filled cavern with a chest at the bottom. Chests have loot so I shot it. I didn't think about it much because I was starting to tear things apart in this run and felt invincible already. Chest contained a flask of chaotic polymorphin which got destroyed by my spells too and spewed it's content all over the cavern. Little noita got morphed into a giant hell beast. Sounds cool but is also heavily damaged by water, which I'm now stuck in thanks to being so big and scary.

Got noita'd in seconds by water and stupidity. Same end as every run.

[u/Slashermovies]

Noita's fun but I feel it kind of lacks...focus? I don't know how to describe it. I never know if my goal is to get to the bottom of the map to beat the final boss or what.

Is the game a puzzle game of secrets finding all the weird hidden stuff?

Is it a physics based game?

Is it a Magicka Spell crafting kind of game?

Obviously it has all these things but it makes the focus a bit skewed on what a player should be doing.

[u/Baconstrip01]

A lot of posts on here are talking about how insanely powerful you end up getting at the end as if its a detriment... but what I don't see a lot of is the fact that the game is actually EXTREMELY difficult. Getting to that point is -not- easy at all. Maybe I just suck. lol

I agree that something is "off" about the balance of the game, though!

[u/MINIMAN10001]

I always wanted to know why the game had the "You can see the physics tiles" when you have a lot of falling sands. According to the video it comes from the code updating 1/4 of the tiles at a time. A flaw specific to their answer to "How do I multi thread"

The thing I noticed constantly throughout the video when it came to explaining the physics. They chunk the data and only create and monitor physics in areas that physics can happen ( In a vague sense, again they took liberties that work good enough )

But I just can't wrap my mind around how they track where physics are happening.

For some reason I'm puzzled by the idea of "How can you have a whole world exist but know exactly what and where in the world needs to be simulated"

In other words they can and do have an infinite world where you can physically interact with the entire infinite world and it knows exactly what it needs to simulate. It's such a hard concept for me to wrap my head around from a programming standpoint.

To summarize. The largest scope is the monitored regions. 12 512x512 pixel regions are actively simulated dropping off the furthest monitored regions. The world is split into 64x64 squares for physics. Within these zones a rectangle area of where physics needs to be calculated. In order to multithread those 64x64 square are grouped into 128x128 squares and calculated where each of the 4 64x64 squares are calculated sequentially ( You can notice the 64x64 chunk shape because of this ). Where rigid bodies exist you create collision meshes for the terrain.

From what I can tell those 12 512x512 monitored regions is where the magic happens. That is what allows you to have an infinite world but only monitor a part of it. Because outside of that nothing physics related exists.

I mostly just wanted this post to ramble me solving conceptualizing this concept to see if it could be extrapolated to anything else. Honestly I think it can be extrapolated to all AI in any game ( as in braindead mob units in a world ). You only need to update AI if a player is within range to interact with it. I'm pretty sure if I understood the Albion online post that's actually what they did with their mob units ( that game is of course finite )

It's cool to be able to see the problems and solutions to what I consider to be one of the most interesting challenges in games programming. Something that is persistent, simulated, and infinite.

Many games have used infinite but not simulated ( such as Minecraft or No Mans Sky ) But this is the first game I've seen that has something persistent, simulated, and infinite.

On a related note in this video with a nuke and all explosion buffs you can see how the 12 monitored regions limit the blast radius.