---
title: [Livestream] building a sand pile visualization with p5.js
slug: livestream-building-a-sand-pile-visualization-with-p5-js
published_at: 2021-11-29 10:29:39 +0000
updated_at: 2026-03-04 20:13:51 +0000
summary: 
description: https://editor.p5js.org/cjavilla/sketches/T5vvy8w93
tags: []
views: 200
author: CJ Avilla
url: https://www.cjav.dev/videos/livestream-building-a-sand-pile-visualization-with-p5-js
youtube_url: https://www.youtube.com/watch?v=iJ_dbJlj42A
youtube_id: iJ_dbJlj42A
embed_url: https://www.youtube.com/embed/iJ_dbJlj42A
thumbnail_url: https://i.ytimg.com/vi/iJ_dbJlj42A/hqdefault.jpg
type: video
---

# [Livestream] building a sand pile visualization with p5.js

*Published: November 29, 2021*
*Views: 200*

## Watch

[Watch on YouTube](https://www.youtube.com/watch?v=iJ_dbJlj42A)

[![[Livestream] building a sand pile visualization with p5.js](https://i.ytimg.com/vi/iJ_dbJlj42A/hqdefault.jpg)](https://www.youtube.com/watch?v=iJ_dbJlj42A)

## Description

https://editor.p5js.org/cjavilla/sketches/T5vvy8w93

## Transcript

what's up welcome back everyone in this episode we're going to chat about the uh the visualization for a sand pile and i'm joined today by kevin who is uh going to help us understand what this sand pile visualization is we're going to write a little bit of javascript look at just look at the the visualization it's really cool kevin uh spoke at a recent devrino meetup about this sandpile visualization i thought it was super super neat interesting and kind of trippy and i thought it'd be super fun to go through it uh so kevin uh do you want to like introduce yourself and kind of like maybe say what's up absolutely i am kevin fredericks i'm from marina nevada and i am a programmer and web developer here and i've run a bunch of camps for kids i've done minecraft camps and more strictly programming camps through scratch and through processing that's where i've uh developed develop some tools to make um really simple algorithms look fun nice is so all in in all of the camps did you use processing or like p5.js for every single camp or were there other tools you used actually the most camps i ever did were in mind test which is an open source copy of minecraft that's just very well maintained and so we did it in voxels it's a very logical thing to do in voxels because it um relies on three dimensions to kind of make sense since everything's spread out we'll get into it but it's spread out on a 2d plane but it has depth the main thing that you're mutating as the algorithm runs is the depth so okay cool you want to share your screen and we'll we'll jump into uh some visualization stuff please do i'll show some some versions of the uh completely warped and twisted versions of the sand pile we'll jump we'll jump ahead okay i bet the first one that i have here so let's open up a really we're not actually seeing your screen though hold on a second not yet we'll pull it up oh yeah am i sharing it might need to go into stream yard and share it again let's see sure i will pull it up once i get this loaded cool cool yeah processing and oh so like yeah like while we're uh hanging out and waiting on that one thing we can take a look at is like this uh oh actually no there's there's your uh there's your screen yeah we'll get into that if we really want to get into the math yes full recursion all right yeah so here's the version one this should be a very simple one oh so simple that it's uh aired so we'll do this one instead okay so this is um what's happening here is we have a 2d matrix and every single pixel on the screen has a value between zero and four here okay and every time the frame runs which this is running really slowly uh just because we're screen sharing but it's actually kind of nice because you can see it grow what's happening is that pink represents a pile that's three high and i believe white is if it's too high and black is if it has one high okay and so as the algorithm runs it spreads the sand outward uh in the north south east and west so left right up and down and this one's just a showing the sand slowly moving away from the center because there's a really tall tower of sand in the very center so yeah like could you walk us through maybe like from the beginning how this this whole thing works with the piles and toppling and avalanches and all that stuff yeah yeah this so if we look over and we run it from the very beginning and just see those first few frames imagine that there's a really tall tower of sand in the very center and it's all just void in every direction that's what black is and every single frame four pieces of sand fall to the sides and then this gets repeated on every single pixel so topple and then they build up and if they're four tall or more they topple again so that toppling will just repeat and repeat until the center pile of sand has just distributed all of these well we're calling them sand they're integers until that center one just topples all the way out until it's less than four and then there's nothing more to spread out i usually make this with a ludicrous number in the center something like well well more than a hundred thousand so it just runs and i can stare at it nice okay so this one here looks like maybe in your setup it started at like uh a million like yeah i think i threw a million on there cool and that doesn't really affect performance anymore because that only gets calculated once okay um so looking at the topple algorithm which is this is almost exactly the version of the algorithm that was used by um daniel schiffman on his coding train series okay where he covered this and um the only slightly confusing naming convention here is next piles which is just it's referring to the next version of the screen that we're going to render this is a really nice and clear way to show it even though performance wise it's a little bit slow because we're calculating every single pixel maybe we can when we build it we can do it in a way where we put in a guard clause or something like that to only calculate for the piles that we know are going to topple that would probably be a lot better okay interesting interesting yeah and so in this first chunk we basically go through the whole two-dimensional array and right here we have a few constants or one really important constant which is the max height the maximum of the of each pile and so we say if it's less than go ahead and just cruise on by it still has to calculate something for every pixel though so it's just saying right here it's underneath the topple threshold so just render what's already there just put that into the next the next render but here if it's greater than or equal than the max number we do this very straightforward set of if statements just distribute those those uh um pile that whole pile outward okay that pile gets reduced down to zero because see right here it's just getting getting that subtracted out which i could i think this could just be max num right there to be better to be more consistent okay and then every so the the matrix is just like a 2d array where it stores integer values at every single position and if the pile goes above maximum then you are you're just you're incrementing um the neighboring cells yeah by one and up to the edges of the okay cool and and like how do you determine the color like where is that you're sort of so that's in the draw in the actual rendering so you have i've used uh this this was for some kids and so um normally i wouldn't use a switch statement like this because it just doesn't this isn't so easy to reason about but for kids this is great they love seeing that repetition um so here we get a color set up and this is going through the sand pile uh the entire or 2d array and saying if that value is 0 use this color if it's 1 use this color these are rgb values okay i'm not sure yeah base color is just 255 to be maxed out 2 three and then finally four like cool for example if we really wanted to make this adaptive and we wanted to be able to topple at a height of eight or nine this would be a really terrible solution but um in the case where we're gonna lock it at four this is terse enough to be to work yep cool all right so we got number equals three it looks like i did something goofy here to probably hack something into place yeah like dimensional or like it's a two it's a 2d array but you're like reaching into it yes as if it was 1d or something yeah yeah that's what i'm doing there uh that's because of the way processing renders okay it renders the screen the pixels array is all the pixels on the screen and so you have to actually do this in processing because it just takes every line and makes that a number from say so you had a 10 by 10 array or a 10 by 10 screen it would be 100 pixels with breakpoints at all the rows got it got it got it okay that's kind of old school but it's uh it's probably the simplest way because it is how scan lines have always worked so it's pretty accurate cool and at the end we update the pixels and then there's not that much more and when we run we just topple and i take something into this topple this is me hacking stuff where i can change that max number every frame okay so here's something crazy this is just a little primer for like when you can really have fun what if every frame we do the ceiling of a random number between two and six yeah yeah that's i think that's like where it gets really exciting is when you're just like throwing in randomness to make it kind of like be more sort of mushy this is this is going to be extremely slow but yeah look at how different that is this is every single frame it's calculating a new random number and then creating more of a mandala effect out of it yeah but it's still symmetrical so that's cool because you're toppling like this even though it's random it's like the same amount in every direction like the other thing i was thinking was like you could topple randomly in every like also random per direction or something like yeah yeah you definitely you do that that would definitely violate our solid principles here but um given that there are none in this particular code um yeah you could do that right up here when you were deciding what number to put in yeah i'm not gonna do that right now because it that would be a fun discovery to make later okay should we so processing i thought processing was javascript but that does not this is this is the java flavor the java flav okay yeah it was originally java um based processing is from 2001 okay so they um just kind of they re-wrapped it because it's more or less a wrapper for java you're not writing i don't think you can use the whole standard library in processing for java okay so as um es6 came out they just rewrapped it and made it so that you could use all the same functions and everything worked the same in this version which is p5.js i have had issues running that in the desktop version like it says you can just switch over but um i just use the web editor and take the performance hit because it's so much simpler got it got it got it okay cool should we uh try to build one let's do it yeah i'll we'll we'll step through it um the steps are one two three there build a 2d array um well a setup is built in an enormously uh large column of sand in the center of a 2d array okay and then on every single frame perform the algorithm where you take one out of anything that's over four a single pixel it's over four and distribute it and then just run that every frame okay so uh how do i i just like click play and then something should show up here okay so yeah if you if you're following along at home and you want to like mess around with this you can go to editor.p5js.org and then you can you can play around i guess we can also drop a link can we drop a link to this specific thing do we have to log in or um you can you can actually go ahead and build it and then and then create an account afterwards and save it okay so let's see if it's just gonna that'll so you see at the top it gave you boatneck lasagna okay that's your that's your name and then once you save it yes it does create a share link okay and how do you save it file save okay imagine that all right so i'm going to drop that in the comments if people want to follow along or play around with us um and then in terms of in okay so going back to your your steps here we're going to like create a pile of sand in the middle and then we're going to write like a topple function or something yeah yeah the the 2d array is such a straightforward step that um you'll do that inside of setup um setup is uh basically like init for for most other game like engines and things like that and then draw is a function that gets run every single frame okay and in the in the draw function like we'll we'll want reference to whatever like matrix we come up with i'm assuming so yeah you could store it um you could mutate it um in the topple function if you want because you'll likely yeah you're like what you're doing is exactly what it will like you to do which is you create that matrix and then the topple function itself will reference that matrix and then [Music] when you put topple into draw all those references will remain correct got it and since this is a 400 by 400 array like maybe we should make a smaller canvas or is 400 yeah i do recommend that for for the web editor all right so let's do maybe 100 by 100 uh and that gives us 10 000 cells right or yeah yeah so then for our matrix we actually want like array or like new array of 100 elements or something i can't remember the syntax yeah go go with what you feel like doing that's kind of the fun of fun of doing these algorithms so yeah and it should look good uh yeah i guess we can just initialize it like the easy way um yeah so this can just be an array and we'll just say like uh matrix and then we will push on a new array of 100 and then they'll be like undefined to start but i think that's probably okay yeah that's fine in javascript that you're totally right that would that would bust um java's chops i'd be pretty upset about that but um we'll be able to coerce that type as we go uh all right so then inside of our setup we want to find like the midpoint right right which is you know 100 yeah um yeah is it going to be the exact middle if it's a hundred by a hundred because it's gonna be yeah it's gonna be a base zero array so 50 should have an equal number on both sides okay i was wondering when it hits the side of the screen if it's going to do it all that's one frame off got it uh and then this is gonna be like width divided by two and height divided by two uh or i guess yeah it's gonna be matrix at width over two and height over two something yeah yeah that'll be good um what what is that or maybe we don't actually need a midpoint there we can just like set this equal to whatever our initial file is or something of like a hundred thousand things i don't know like right right yeah yeah that's perfect yeah that's that's so much easier to reason about that okay um and then i don't like i guess like if we run this is it going to spit out down here okay cool so we've got uh a hundred by a hundred and then like yes so in we think you need to have one at yeah forty nine or fifty forty nine or fifty yeah is uh boom okay we've got our okay so that's like our initial our initial dot right like in the center okay are like incredibly tall but extremely narrow and thin it's like that thing where say you'd fold the paper all the way to the moon it's just like yeah that's the best way to think it's just an impossibly tall thing okay so is that all that we do in the setup is just like like create the first pile like yeah i think you'll be all right with all those undefined that is like the worst sounding javascript statement ever um but yeah i think we'll do it yeah as you do the topple um yeah if you really need to you can go and put a bunch of zeros in there is that i i think that's how you spell topple i'm probably wrong well it'll do proper topple all right so then as part of topple this is where the magic happens right we have to like uh so if i'm remembering correctly we've got our 100 000 we want to just take four off the top right yes if it's four or greater okay so and maybe to start off we can just topple uh the middle one and just to like think through what happens next right um so we're gonna like take four away from some pile and this just happens to be the initial pile like right at the center and then we want to like increase um stuff around it so like i guess there's gonna be four of these that are like plus plus right or it'll be like o to the midpoint and then minus one and then go to the i guess here we can do like yeah okay uh hmm that's pretty good you're gonna save a bunch of lines since you're probably never gonna look at that ever again once you build it yeah okay and then this is also minus one and then you've got to do like plus one yeah if we're from the upper left we're now we're at the north western one minus one and minus one got it and a plus one minus when we're now to the yeah the x is the first well we haven't decided that but yeah it should be um now we're on the yeah so the first one was just oh wait no you're going on a diagonal are we yeah okay uh oh i see yeah yeah we're going down it should just be like directly north south east west yeah that's actually easier um okay uh yeah because then you only have to change one direction right yeah you could do it i mean you have it now you can try running it all right so then yeah so then i guess this would only topple this only topples one one down right um and if we made if we make this like 10 by 10 maybe that'll help us even further reason about it like uh yeah that's actually probably going to save on uh the performance as well okay and then how frequently does draw run like do we have to tell it you can't you can set your frame rate and set up uh with um camel case frame rate as a function that's pretty useful uh yeah if you like set it to frame rate 10 in setup um you can actually do that it's a it's a built-in function oh you okay you call it just calling inside your setup yeah i like just set frame rate to something yeah the browser will be a little more relaxed about i would really this has been one of my inspirations for uh learning uh webassembly is just being able to run sand files in the browser at this like native desktop speed yeah because i just haven't been able to share the really crazy looking ones that are um that and that without even adding motion blur or anything like that or lighting yeah and okay so i saw that p5.js did have some webassembly something something like is that just out of the box like it lets you i think it's just leaning on that to do make the editor work okay i'm pretty sure that it's kind of like um how uh what is figma figma like doesn't use webassembly for everything it just uses it for the really complicated math parts like drawing vectors and things like that yeah so we've got we've got an interest our first like interesting issue so our pile is going down in the middle but when we look at the neighbors we've got nan because because you're subtracting from undefined of course yes so uh i guess we should maybe we should like actually try to like iterate over the whole matrix in setup or something or maybe just a little hygiene just a little array hygiene yeah yeah uh okay so then yeah yeah yeah like i guess 4j hey it's still it's still um only a complexity of n if you do it in two steps so oh no no now it's n squared there it is so then uh i guess but it's set up it's in setup you're not running it so you can actually just yeah just make it easy in the setup function exactly uh const or like let inner and then in here we'll say like inner at j equals zero open and then push enter good yeah let's see all right stop and take a look our middle one is going down and then a diagonal we've got three and three so i think it's working now yeah it's it's toppling what is it doing there it's it's why is it going up to three so it's incrementing oh i paused it but it ran a couple times ah okay good good yeah yeah yeah i think you've got it um i think it's running now cool so now for rendering which is yeah you got the hard part out now which is the um yeah algorithmic part so this is where processing shines you can do this couple different ways okay uh well the first way is to do that pixel trick where you you run on the pixels array which represents all the pixels on the screen you'll have to do a little medjulo math or something like that to figure out where the rows are or you could draw a pixel you could run through the array take the figure out the x and y coordinates that that point in the uh two dimensional array represents so it'd be what i uh i would probably be x and i think your j would be y in this case or the other way and then use the function pixel which is draw a pixel at x y and you can then change the color of that pixel using um stroke okay so what we want to do is we want to do something like uh draw matrix or something right and this is going to say like um uh which one do you think would be i i uh it depends you're probably do you how did you do it that's that's the thing you did the array where um that that first layer of your array those are rows right yeah good so if that's the case i think you should be able to use the index of like as you're iterating through it you'll be able to use your index to tell it what its y position is and then use the index of that array within there as the um x and that's that's probably going to be way that will open it up to be a little easier to mess with okay hack and goof around with the pixels array in the medulla thing it is very old school and it does like once you try to start doing that stuff and like um chopping it up according to your width that means you then have to have a constant for how long your rows are and yeah yeah so like you're like i guess set like uh this looks like it's kind of what we're looking for maybe right like yeah pretty much i mean it what it's doing there is it's um the first number is the exposition uh the second one is the y and and you can in that case you can also it'll save you some trouble probably because you can overflow the screen and draw off the screen in case you do something that's like out of bounds okay okay okay um and but now you need to take the value that's there and use that to adjust the uh the color that color that gets put as the third argument to pixel got it got it got it got it got it okay so if we just initially start off trying to draw black on like i and j uh this is like if matrix at i a is like greater than zero or something to start right like then we should at least see like some black dots end up on the screen maybe it's a good sanity to check yeah yeah uh okay cannot access black before initialization um set i think set needs to be how does that work in the function so it seemed like it was just called just called set uh but maybe black needs to be or like color needs to be set inside of here or something here i'm going to look at i think there's actually a function just called pixel or maybe point maybe that's what it's called this point let's see okay is there a way to make the the preview bigger or is this um it's gonna be um uh no unless you zoom in on it um let's see this is a good check though okay and we're yeah all right i don't know like the anti-aliasing is gonna make it look really smooth got it that's good okay so console um setting i j mac okay so yeah i looked it up um pixel and set is doing something slightly different it's it is actually accessing the pixel at the location i think you'll get a clearer result if you use the point function point point is a function that takes two arguments it's your x and your y and it takes the stroke that you've defined prior to calling it to decide the color okay so that's um that seems a lot easier okay so we want to say something like stroke stroke purple sure yeah you want to call that stroke at the beginning okay um do we need to call it like or like clear it out or anything after we no that looks good yeah okay huh oh i think maybe it needs to be inside there let's see awfully close yeah a lot of things in processing uh work globally like that especially when it comes to rendering got it okay uh where did we go here the stroke weight i yeah i'm hoping oh that's an issue yeah that's got to be one because we're just drawing a pixel got it and it does not seem like it's showing up on here um we need to call update pixels or no we should be able to just call oh wait background is being written on top oh so yeah that'll do it yeah actually i get background out of draw that's like that's a classic processing uh optimization it's like all of the boilerplate always starts with it in dropper that means you're repainting the background and we can do that later you wanna do that in setup oh and set up okay yeah and you're gonna instead of figure out like where you're allowed to call certain functions that that is um kind of it's java lineage got it yeah uh it's it's not a terrible thing but yeah yeah so in order to create um animation we'll then call background at the beginning and then we'll update because that that array we have is like a full global state of our of what we want to render we're not like saving the stuff that we already did and then adding more so in that case once we get our colors figured out then you can put background back into draw i see okay uh all right so like because we would be uh resetting it here or something or uh you can just do at the top of draw like okay basically the first thing you do is repaint the screen um yeah like like a sort of a typical game engine thing i shouldn't have told you to take it out right away since i think i think it's working yeah okay all right so that that does seem to work okay so now like our topple yeah to get this like going right we want to make the topple actually like topple not just the middle pile so yeah you now have to iterate that uh so every frame we have to run through our entire array and then do that guard clause ask if the value is higher than four okay or four or higher and if if that guard clause doesn't get checked then we run topple on that item of the array okay all right so um so i'm thinking maybe we can refactor topple to take in like an x and y or something or like an example yeah okay so maybe like uh x and y or something and then here right we can do do structured assignments in there maybe yeah i think okay and then here we can just use this as x and this is y and all of these become x x uh x and then this becomes y i know all this clicking must be really painful for you has there been mode on this yet let's see oh geez uh yeah anytime i like move to a web editor or like any of these things it always throws me off all right so then inside of i guess we could make this one like topple uh like a single pile and then we can make another function called topple which like iterates over the whole matrix yeah that's that's pretty clean that's easy to because yeah the more um we isolate these functions the the more we can break them later that sounds good cool um so then in order to figure out which ones we need to topple what you were suggesting was like we uh as we're iterating over the matrix we figure out like um we're going to pass i and j as like the position to topple but only if matrix at i and matrix at j is greater than mat or like what what did you call it like i called it yeah to be more descriptive i guess we'd call it max height or actually that's confusing because of height um like topple height maybe or something depth maybe uh yeah it's it's the it's a hard-coded value because the whole thing breaks if the number of grains that we topple is like not equal to the maximum that we choose to do it at um so like it'll just stop right away if you just toppled too too quickly okay it'll just topple the sides and then they'll say hey i haven't reached my threshold so i'm just going to sit still so we've chosen four like if we wanted to do five you could actually do north south east west and northwest then you'd have five grains of sand to topple from okay so it looks like it is doing something it's so hard to see because it's super hard to see yeah i don't know oh yeah y'all can't i think it's time to kick up our numbers i think you can kick up to 100 by 100 okay and then maybe can we make our point um our point size bigger like set this to 10 and let's see if we get it like okay okay it's just a blob now okay yeah yeah well the problem there is uh 10 it's still drawing in that little like 10 by 10 space but then it's making gigantic strokes so you'd have to multiply by a scale across where you're going i think if if you make it 100 by 100 and basically run it the same way uh where you're still gonna calculate by pixel okay that's uh it takes a little bit longer and if you want to cheat you could like call topple 10 times every frame to speed it up that's a got it but it's going it's definitely going uh so two bros youtube says would it be faster to only render one quarter of the array and then rotate 90 degrees the pile would have to be centered i can't figure out if that actually optimizes anything that's super interesting yeah that's an interesting solution i think that would totally work right because like every right now everything is symmetrical but i think the fun thing about having it not be or not not rotating it is that later on i think we can grow in like weird ways that go in like different directions and things absolutely yeah i could i could pull up more on mine i love that suggestion actually that's um because this will naturally be a symmetrical uh problem that arises that's uh very practical but since we're in like renegade mode right now yeah we keep on thinking ahead to how we're gonna destroy it yeah um the trick that i would suggest there is to topple a bunch of times every frame so okay you can run a loop inside a draw and just run topple ten times okay um this is fine don't understand that part hold on yeah yeah so um you're going to recalculate 10 times the calculation happens so fast it's the rendering that takes forever oh i see okay um uh oh my gosh like i don't know why for loops everywhere well yeah welcome it's kind of cool to go back to procedural stuff like i use a functional i i can see this being done functionally but um it'd be kind of hard to reason about at this speed yeah there you go that's super cool okay so now you need to grade the color by the height of the pile yes let's do that sounds like fun uh i keep like wanting to zoom in i wonder if there's a way to zoom from stream yard no all right whatever uh no no no okay so okay now we want to grade or we want to we want to change the color based on how tall the pile is right yeah okay while you're working on that i will see if there's a way to if there's just like some built-in function to scale the screen okay so then maybe we have like one is purple two is red three is blue four is yellow or i don't know whatever all right and then we can do like colors there we go that's starting to look like some some javascript now we've got an object finally yeah okay all right clears at uh uh no at matrix of i and j that'll give us like the value of i and j and we reach into this object we get out actually this could just be like an array right with uh undefined and uh or no i guess maybe we want that to be the background color honestly these days i've i don't think you can use it inside there i would love to use a map i love the javascript map function for these things to avoid so many problems but if you're doing an object yeah it'll go uh it's yeah and you've used one two three four to make it yeah yeah actually zero zero is a value there yeah but yeah so zero is going to be like in the array right zero black is good for zero because it gives you the impression of an unaltered sand pile got it okay okay and uh let's see how it looks ooh uh something crashed all right call from draw draw matrix blah blah blah not a valid color representation okay so yeah what is the value um oh you know what i bet it's for like the hundred thousand one or something probably yeah yeah uh oh also we only have to set the stroke if it's greater than zero nice yeah that's a that's a shave off a bunch of function calls there yeah and then um but and then we can do like and uh matrix at i and j is less than max or like less than or equal to depth because we don't want it to do it for the center one oh super cool nice flashing all kinds of crazy colors ah so trippy i love it cool yeah you've got a good one going it's it's bouncing back and forth i find that it does that uh usually on these i think it has something to do with that matter of what's in the center yeah like because it's also i guess like when you're toppling something like if you topple a pile and then some of that topples back right yeah yeah yeah okay yeah there's there's a trick there's a trick to i can't remember if there's some trick to preventing that exact behavior but this is very neat because now you're still you've got that um like feedback loop going where it weighs back so if you topple a few less times per draw let's see let's see what we can maybe cut it in half here okay the other idea that i had was like what if we um when we're increasing these we can we only increase them if they are less than depth or something like i think that would cause it to just go out in all directions um but i think you're the other thing is that we we don't have any bounds right now so like i think it's toppling potentially outside of it or something oh yeah you have a bunch of zeros and and i guess you're not going through yeah you're only going through the points in the array that are gonna topple that's why we're not getting all of our black void space yeah okay so maybe that guard clause is a little too conservative but it's pretty helpful considering we're running this in the browser yeah the other thing i wonder if we can move this on here too so that's only going once oh it's getting better it's getting faster uh run stroke weight in the up and the setup okay okay cool like generally when you're building visualizations like this like how do you think about what goes in setup versus what goes in draw uh it's i mean it's classic like immutable versus mutable state but because hacking is so much more fun things migrate in between the two draw should be pretty lean because it's just it has to like rendering is very intensive yeah in the way that it draws its thing it's it's the rendering that really hurts performance like it's it's running javascript i think pretty much just in the way using the same engine that's always used so it does the calculation very quickly got it got it got it okay trying to move as much as we can up and out uh nice so that it moves faster oh nice oh cool it's very good it's so fast nice i love it yeah you're getting that that that waving but you know that's just another version of the sand pile it's having it emerge from the center is is is mathematically kind of like where it comes from but now you can start doing like playing with the color and making the colors a little bit more subtle and actually having them sort of feel like representations yeah is a nice trick um if you use hue saturation lightness and use hsl for as your color mode that would make that really easy okay so [Music] like not rgb but hsl where is that um you do that in setup you can you can define hsl as your color mode got it it's a it's a built-in constant so yeah color mode camel case in the setup function and you pass it the argument of uh hsl as a global constant so no no quotes okay it's actually a variable and then let's let me double check it's in this one it's it's huge saturation brightness so hsb okay and then the second argument is your range so 100 is a good number for that okay uh and then for for the actual colors here when we have that set we can just call call color like this and then it'll use like h s and l for the yeah yeah then you can do like say you want it all to be monochromatic and just be different shades of green so like dark green would be very tall and light green would be not tall then you just set up and you say every one of those colors is just a little bit darker so the the brightness would come down like 100 90 80 70 60. cool awesome all right there yeah that's that's definitely way way easier than going through rgb and setting those up okay let's see what happens whoop right now there's a setup color being defined in the current scope ah okay so then yeah let colors uh oh yeah that's actually good that's just a good good way to keep it in a readable yeah oh my gosh it's so cool yes yes beautiful look at that that's so neat it looks like a firework or something i don't know yeah um cool yeah you got it working um if you want to you could take one more step to to see how big you could make your your canvas before it starts to really hurt okay i think that might be a good thing to do is it all just gonna read off of that i think it might you're good yeah so um for being able to see this better if anyone's uh going along um once i reach this point where where the thing's running and it's going well the if you have a really powerful language at your disposal so you're doing this like a game engine and you're not worrying so much as we are about the constraints then you can start uh scaling your picks your your actual sand piles so you're making them 10 pixels wide and then scaling your grid to be where each one is 10 pixels apart that's that can help with this a lot but in our case we can just topple really quickly and jump ahead maybe we can increase our frame rate now too since you got it running smoothly okay i was trying to increase the stroke rate again but let's see uh 30 30 yes right that's okay let's be chugging along yeah so the the thing that i was trying to mess around with was how far were how far we are oh you know what okay so i did that wrong so what i wanted to do was so like the topple distance i guess i was trying to make it so that like instead of just going to the the direct neighbors go like further out oh bigger dots that is like that is kind of the weird abstraction with this right yeah it's it's it's where when you have a pile of sand on a beach it it rolls down the sides it doesn't just like straight yeah in a very discreet way yeah so like if we made the topple distance also four and then we change all of these to topple distance nice yeah and then run it yeah getting all those magic numbers out of there look at that okay so it's spreading pretty far i want to try to oh now if you oh now you can draw rectangles instead of points yeah or yeah we can make the stroke weight 10 or something that is really clean yeah oh huh that did not work as expected it doesn't seem like points taking the stroke weight it was when you got that muddy affected a couple of minutes ago yeah is stroke is stroke like resetting the stroke weight when i call stroke i don't think so i i think it i think it takes that okay stroke stroke weight okay huh yeah the the only argument to stroke is color got it um okay and then point yeah maybe point is the one let's see i feel like another thing we can do with point in terms of oh no stroke weight 10 and it's supposed to make bigger dots right make the points they would be circular um so you get kind of a an interesting effect out of that and it should be i don't see any reason why that shouldn't be taking that stroke away that you've defined and set up yeah maybe try throwing it and draw see if it works okay let's see oh nice work okay this is so cool i don't know why i don't know why it didn't take another setup but hey there you go oh my gosh i love it it's so crazy yeah that's cool that's like uh if you say had a led matrix at home this would be so rad if you could put that up on your wall yes okay so what i want to try now is like we've got our topple distance and yeah we're going uniformly out in that direction but yeah let's see so hmm i was trying to you're jumping your dots are jumping that's that's the effect you're getting now um you could change you can maybe make the colors a little bit more yeah okay dramatic because it is kind of hard to see right now yeah maybe like changing that hue as well as the brightness let's see oh it's a muddy color yeah maybe they're going up because you're flying into the red range oh go go up oh yeah yeah well uh 40 30 20. if anyone's playing around with this and they have some some cool color combinations that's that's like a nice nice thing to throw out there yeah we are in hsl mode so right okay i guess are these i'm assuming they're between i think did you did you pass 100 as a second argument to color mode um i did oh so that's like the max that's the range yeah got it okay so then yeah okay so we can make all of these 100 and then we can make uh this if this is 100 that should be black or white or something uh no that's a rotation around the color wheel got it got it got it so yeah 100 you're at red if you if you go like 180 degrees away from that you'll be at roy g biv like blue got it see there we go oh cool yeah gosh it's so trippy okay so then yeah i really want to try to figure out how to make it so that it doesn't come back up the hill right and so i think we want to do something like if the value that's already at this location is um is uh zero or like do we only want to increase it if it's yeah i see what you're doing yeah yeah um so when we decide i think you have to do this for every spread like for every directional spread which man that's a lot of i think uh yeah because the that is that is tricky the way we're doing it because the um the agent like the it's mutating the state directly of its neighbor yeah like we're not doing this with objects so the neighbor isn't like taking a receive pile method if we were doing that it would just be simple as dirt it would just be like if i am greater than four don't pile me right if you can do that just from the math like it shouldn't happen wait okay so okay so we're only incrementing if the if it's less than or equal to the depth and oh you know what no i copied and pasted but i didn't yeah i didn't update my signs here that's important and then these should both be pluses okay dude this is i gosh i had to think through that in like oop sort of thinking and you did that in like the most visual basic way ever that's awesome like i would have just been sitting there like fuming over this that's great it's patterns all of these are just patterns it's good that's good okay so then yeah it's interesting right how it grows okay uh cool so then maybe that's right yeah it's it's searching on the outside edge and it takes a little while for it to move out from the end and it propagates through and then it hits the edge and it puts one more on the edge yes okay i like it i like it uh and then um the other thing that we can get crazy with is for topple distance um like we could define topple distance inside of here as like let topple distance equal ceiling of math or is it what is it again random it's just like random oh yeah um so yeah i ran this this is a built-in a processing function that behaves just like math.random in javascript got it so then there we go that's more like nature right there nice yeah yeah yeah we're getting some like spore some sporulation yeah and then that's not right or like different for every direction now right like i mean this is probably adding a lot of expensive stuff but whatever yeah you've been keeping up pretty well like working on that 100 by 100 area yeah okay so then it almost feels like we need to go further than two like maybe four to eight or something because um because the size of our dot is now three so we need like at least some gap between um or something oh gosh it's so cool that's neat yeah you got those diagonals that form so quickly yeah it's like it is your is like four green is green very high is it um let's see i don't know okay so this is zero zero one two three four yeah we really should use this is the only problem i have with hsl in this case like i love the way css does hsl because the um the hue value is 360. the range is 360. so it's actually like a logical color wheel setting it to 100 i have no idea anymore i don't have a mental map for where purple is between 0 and 100 right yeah what if we yeah let's go back to just rgb yeah um and see is this gonna this will just work right because they're just yeah okay there's all green uh okay so then if we do [Music] actually instead of using colors directly we could like calculate the color here right like instead of having like a fixed thing we could use the depth as like a input into some color thing like uh point color and it takes like the value and then we return like color and it's rgb so it'll be like value times something i don't know uh 50 value times 50 value times 50 and then uh here we can say stroke of like point color of matrix at i and j um but i don't know like when it's generating these oh wow look at that it's just like different colors of gray uh that's cool uh and [Music] okay so if the height maybe we just fixed one of these our no hmm trying to figure out how to get like a gradient and also like maybe change the change the depth so that like you have to you can have like taller piles or something what do you think oh okay i'm back okay i was i've been watching you this whole time and i've just been ghosting um my internet came in and out but uh no worries no worries yeah what do we got here uh color value value tensors so the problem is that you're yeah um with rgb if your r g and b are all equal it will be a shade of gray so uh one trick for that would be to set a constant for rg or b whichever one you want to be the base color okay yeah let's see yeah there you go that that's all blue or what do you think is this that'll do something like looking at a regex i have no idea what's going on good uh neat those are good colors purples and blues and the light blue like it yeah so two bros youtube says probably out of scope but would it be faster to initialize a circular 2d array and then only calculate the inner ring and push the inner values into an outer ray outer array instead i'm not sure i understand i think i get it um but would be faster to initialize a circular 2d array so a circular 2d array would be one with variable length to the rows um maybe this is just me like basing this off of a strictly typed view of it but um a circular array is like makes my brain hurt i think i understand it though um so yeah oh oh i see it he's got two two of them so you have like a staging array that would be circular that'd be only looking at the things that are only looking at the files that are capable of toppling and then pushing the values of that staging array to uh your you'll actually render it arranged got it okay in some languages that would definitely be fast especially like a if you're in go for c plus plus that would definitely be faster but yeah okay so the other thing that i'm noticing is that uh we are only going like it's not growing beyond this square right here like i was expecting it to grow all the way to the edges but it seems like we're never getting that far and i'm wondering uh well there is the that might have to do with the weirdness of uh why it's not toppling symmetrically up and down and outward i i've seen this before i would have built this it's in there somewhere at some like for some reason it's it's i think this actually happened in daniel shiffman's version of this where he had it doing that wobbly left and right thing huh i think if you can if you hey what did you just do i i removed the randomness from the topple distance so that we could see like if it just keeps pegging at like well you just fixed that and you'd magically fix the symmetry issue yeah so yeah it's almost like it's not uh like when we're iterating right here or something it's not actually going beyond a hundred so um yeah i get the feeling that that two bros would probably be feeling this um because it's been getting oh i can see oh yeah i can see like his thinking or her thinking um in terms of how this circle is sort of the active space where all the mutation is happening and all the important calculations happening yeah and the the way this math works though is that it takes it's like a um it gets more difficult for or yeah it takes longer for a single pile of sand to propagate to the outer edge of the circle as it progresses because the number of piles it has to pass through oh so that's why i iterate on the topple function in draw in order just to kind of you know see some action okay you can sit here and let like topple it even faster i see what you're saying i totally see what you're saying because it's not like in order for us to like as soon as we hit a certain range in order for the pile that's on the very edge to to to topple it needs to stand yeah like all the way out and it looks like oh hey you're getting some great symmetries now but i'd love it frozen i think you ran out of sand oh what no way okay epic epic maybe that was it we're running out of sand by the edge oh yeah let's do 10 million what is that 10 million yeah here we go yeah what is going to be an issue i think i saw that in in javascript in like a new version of javascript they're going to have this thing that we haven't really saw yeah yeah it's okay yeah it does look so you can kind of see the like almost tan there's like circles that are sort of tan that are like kind of are those high brightness there's like the 80 or the 90. yeah it seems like those are the ones that are kind of like starting in the middle and working their way out and then yeah so then this one's blue and we're okay so there we go there we go yeah so it should keep going it should keep going you've made a good sand pile i love the the spacing of the dots and the stroke weight oh it's fun it gives that led array effect to it that makes it just kind of easier easier to to intuit and feel yeah it's cool so okay so let's let's just try messing around with this uh yeah the speed or something like try to make it okay here's one um yeah so uh processing has a very useful um global variable that is a not not a constant and it's the frame count okay so it's just a typical of a game engine or an animation engine it's counting every tick and that increments every single time a frame passes so you could change any number that you're using to calculate your top array by making some kind of calculation on the frame count a frame count goes up really fast in sort of the integer range we're working in so you might want to multiply it by a very small number what i like to do is in that uh like like you saw where i passed the maximum number into topple yeah if you don't just pass a random number every frame but you pass a sign of the frame count then you will get an oscillating change in how how tall it can get before it topples okay so it the at the very beginning and and once again sign on frame count is going to change really fast so uh i usually create a smaller or slower sine function in draw that would be like i like like like a smaller change or like slow sign which is the sign of frame count times a very small uh float okay so the sign okay so frame count yeah that's that's where that's the one to start with okay so frame counter that's just like a global thing okay and then you're saying take the sign of that yeah and then you get oscillation okay so frame count is a nice linear uh increasing number and if you slap oh yeah oh yeah oh it doesn't like that oh maybe seal or something i think so are you what it it it broke it very quickly um maybe it doesn't want to take zero well okay so i passed that yeah okay so depth i passed depth here but topple pile also needs to take in depth i guess and this can take in depth yep there it is the yeah oh man that shows up a lot yeah it's all right okay good yeah you're already already set up for that nice and so for now if we just say yeah let's let's bring her back to basics yeah so then if we do like sign or maybe what if we just did frame count yeah that'll be weird oh it's going to get so yeah after like five frames it's going to lose its mind cannot read property of undefined reading 192 on 56 what is this hmm i think you're out way out of bounds of your array maybe but that's normally not an issue in javascript yeah oh okay so we're out of bounds on the first side and then not anywhere near the second side i think okay can you go above even four with the way it's currently set up oh yeah let's try it let's try that so then if we just say pen or something right like that works what 100 yeah frame count okay i think it said the value is like 156. okay so but either way either way if we uh yeah oh maybe it's because it's a negative number because sine goes between one and negative one got it okay so oh god that makes no sense yeah yeah how can you calculate at a depth of negative right so i think that yeah is abs is that a thing let's see now it's going to be yeah sawtooth wave okay so then now we just multiply this by yeah there you go 10 or something um you want to make it very small okay um oh i love this chaining this is like yeah this is good okay uh there it is yeah it was born into this world yeah in pain okay we weren't actually using that for topple let's see so let's actually use it here oh yeah yeah um oh yeah i got hit with that again so so what's happening here is that you're you're rounding an absolute of a sign so zero is still going to get in there yep well no ceiling it's going to start at one and it's just gonna do a lot of ones make that um [Music] whoa did you see what it did yeah so this yeah it's going so fast yeah and also i don't think we should be toppling 50 times every frame while we're doing this okay okay because you're also running that yeah yeah yeah all right so what do we get with this three two three does it have a default value for that depth in the topic function it does or no it doesn't uh i don't know how that's working but uh okay so we're back to we're back to normal but if we put depth back in here you variable shadowing times okay so that seems like i think it's gonna eat here plus two or something yeah here we go um the big one that's yeah there you go it's a tr okay whoa this is like a trip because it's yeah it's uh like on the right side yeah um that definitely has to do with the ceiling function oh nice yes you're totally right okay so then what if we uh uh um to get this to evolve a little more slowly that five that you're using that magic five yeah if you make that 0.05 that will then slow the rate of our sine wave the frequency of our sine weight will decrease this one the amplitude will yeah the amplitude will remain the same of going between what we have like two and four i think but um the thing that you multiply by the sine wave is what makes the sine wave longer there you go now you have smoother animation whoa that's great make that smaller and smaller like typically for things that are running at this speed of like 10 frames per second so cool why is this keep getting okay so it keeps getting to 192 and bailing out like is uh yeah there it is 56 like why isn't our matrix why isn't our matrix 400 right here so it'd be 400 by 400 uh this should end up being 400 this should end up being 400. um yeah it shouldn't be able to calculate i mean it is i think when it gets to the edge it tries to find i think you have to subtract this is like oh i think you're in the uh i really it's called the the n plus one issue for your for loops okay where um your when you get to the edge it's looking to one pixel to the right of the array like so it gets the edge of the row and the row is only 100 long and it asks for position 101 got it yep so if you just subtract one off of your uh yours your end clause inside of your for loop i think that'll go away um [Music] like all of these need minus one right um just in the for loop uh when you're selecting which oh wait i see what you mean yeah yeah uh or like i guess the other way we could do it is like um for all of these do like modulo uh width or something or like i guess yeah it needs to be between uh oh man your your your super vb code is hurting now if x is zero or y is zero or x is width nice or y is height and just return i like that that should cut off the limb yeah when it happens we'll see yeah uh gosh it's so cool it's calling that a lot we got to figure out that seal situation because it's yeah like how do we how do we go out uniformly well uh i think it's fair to say that um your your three nested function calls uh might be causing our brains oh it did it again okay okay yeah so who knows mystery bug for the viewer yeah why 192 is such a weird number yeah okay so hmm so instead of seal what if we use like uh parson or something mm-hmm yeah yeah uh you don't necessarily i mean you can use round is that another thing yeah yeah i believe it has a round nice okay perfect i forget does js have a math.round i think it might uh it's a wonder because i i then i have if it doesn't yeah it does yeah it's in it's in the standard javascript so this should be greater than fifth whoa it's still it's like i bet you um like point five one one one one one one is is screwing that up yeah cool thanks for joining too bros uh yeah have a good rest your weekend yeah yeah appreciate i always love hearing people's ideas on this one that was an interesting interesting view yeah cool man why don't we leave it at that i think that's like people are well equipped they can go and build their own sand pile visualization and here i'll share it let me pull up one more since yeah go for it since we uh i'm gonna dig around there i think i think i remembered where the or some of my favorite ones when we'll go to like version 11 here of goo yeah there we go screen again yeah i'll get my screen on there and and so if you are running on a local machine and you have all that freedom uh show just another another type of phenomenon that can happen when you're doing these okay here we go it's running oh there we go so this is one where i've seeded it and i've applied sort of a magic eye effect and it's it's has like random sized piles all over the screen and then they come in and they converge towards the center but because there's all this pattern that's already there for it to emerge from it'll uh it'll it won't be symmetrical it'll just be a brand new thing like this there's just there's just one more let's see if i can find one more that one is like too chaotic and insane cool i think i'm gonna pop off screen for just a sec yeah show your yeah do your do your thing okay all right we'll do one more should have labeled these but that was pretty similar either way that's i think that's good i think uh i think cj's gone so i'm just gonna stay on stay on this and keep on digging around till we find one that that shows a little bit more of a geometrical effect oh yeah i think this one will be good is it working here we go yeah this is taking a little while to check along but this is a good this is a good finale this is showing what can happens if the corners are seated nice at the beginning when those hit the middle i think it's going to start flipping out there we go it looks like the screen chair too popped off do you want to share again oh no oh no it's doing cool stuff we would never watch that let's see the cool this is a good this is good this is kind of the type of thing i was looking for where it's a little easier to read visually what's going on because there's so much math happening okay okay here we go so the contrast between these colors is really low but as long as you are seeing some of the screen sharing are you seeing that yes yeah yeah yeah that's cool so uh after this has been running for a minute there's uh this kind of fuzz happening at the outer edges which is just very interesting this is definitely from a sine wave being affected on a on a topple function and the center just it just starts creating shapes that feel like it's it's drawing like geometry yeah but it's not it's all being generated from each pixel just talking to each other neat all right super cool yep all right well awesome that was fun yeah thank you for watching awesome yeah thanks for thanks for hanging out kevin this is uh this is super cool i know that like uh there's a few other things that we could build with p5.js just like show people like uh yeah it seems like you know it really really well like all the different apis and stuff to call so yeah projects with it it's it's a pretty neat program what they've what they've built is not meant to be very i've actually built industrial software using processing okay uh by running the java version of it on raspberry pi nice so it has that potential where it's very extensible and it's it's been around long enough that people have all these things built for it but uh at the same time it's it's definitely its strength is being able to really quickly prototype things out and see a visual representation of them yep that's so much more valuable totally totally yeah it's super fun to play with so yeah if you're watching uh if you're watching later and you've built something with processing or p5.js drop a link down in the description and we would love to check it out and play around and uh yeah if you have any ideas for future visualization videos or something that you think are would be fun to see let us know and yeah thanks so much for your time and attention really appreciate it and uh yeah until next time cheers kevin actually yeah is there anywhere online that you wanted to plug or people like wait ways that people could find you you could always find me i'm i'm a melodious underscore punk on github um it's going to be easier to take the show through a link yeah okay yeah i'll put up some of the sketches that i have in my p5.js account as well okay awesome awesome thanks again hope everyone has a great weekend and yeah we'll see you next time cheers

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