A solid reason for doing your own physics and reinventing the wheel is to build a nice understanding before you throw it all away and use a more functional physics library where we take for granted some of the things that are possible with it.
@Kid420
Ай бұрын
Very well said
@Lakitu1446
Ай бұрын
Fax
@mariovelez578
Ай бұрын
Furthermore, in order to understand how to make a physics engine, I recommend looking at and using pre-existing engines (like Box2D for example) to see how they solve certain problems.
@p5play_js
Ай бұрын
Agreed! It requires a lot of math to even do something simple like a ball rolling down a slope. In most cases it's better to use a physics library and the most popular 2D physics sim, used in games like Limbo and Angry Birds, is called Box2D. p5play uses a JS implementation of it which is superior to matter.js and also easier to use.
@pavloburyanov5842
Ай бұрын
1000%
@jabak1450
Ай бұрын
This guy is more animated than any of the characters I’ve ever made. It makes a video extremely entertaining.
@killermonkey1392
Ай бұрын
Nice one! For your "overlap correction", I think the proper way to go is to get the particles' relative velocities along the impact vector. Based on this relative velocity and the magnitude of the overlap, you can then compute the time dt by which your simulation overshot the actual collision due to finite framerates, backpropagate the particles by this time step, then update the velocities, and move them forward in time by dt again.
@deadrat2003
Ай бұрын
yeah this would be more accurate
@kevnar
Ай бұрын
Now shut off the wall bouncing, make the particles wrap around, and add a spaceship that lets you shoot the particles. Pew Pew Pew! Asteroids, with collision physics!
@MahBor
Ай бұрын
I hope you start doing Coding Challenges regularly again
@revenevan11
Ай бұрын
Very cool and encouraging to see your trial and error steps along the way!
@minijimi
Ай бұрын
Awesome job Dan as usual.
@oldadajbych8123
Ай бұрын
The next step: Adding the elastic bodies! Let's add some deformation upon bouncing! ;-))) As a mechanical engineer and amateur programmer, I have really enjoyed this video.
@AmeeliaK
Ай бұрын
Actually, I thought that's what elastic collision meant before watching the video.
@oldadajbych8123
Ай бұрын
@@AmeeliaK Yeah, that's the silliness of the terminology. Rigid bodies make elastic collisions, while elastic bodies make inelastic collisions. Not to mention the plasticity.
@chitlitlah
Ай бұрын
That's what I thought he was going to do at first. You could get a pretty good approximation by simply having them accelerate away from each other when they overlap, and the amount of acceleration would be a function of the distance between them relative to the sum of their radii. Drawing it would be a bit harder, but you could just remove the curves where they overlap and draw a straight chord to show that they're mashed together.
@mariovelez578
Ай бұрын
@@oldadajbych8123 not quite. Rigid bodies can do elastic and inelastic collisions (and everything in between), and soft bodies can do the same. The elasticity of a collision is the ability for the objects to return to their original shape. For rigid bodies, this happens on the microscopic level and at a very small time interval.
@oldadajbych8123
Ай бұрын
@@chitlitlah But it woild be nice if also modulus of elasticity (aside from a mass) was involved in the accleration and overlapping process.
@nyashachiroro2531
Ай бұрын
As always I love your enthusiasm when teaching ❤
@kevinchopra9111
Ай бұрын
Definitely a book worth reading...
@realcygnus
Ай бұрын
Nifty ! These plain old school challenges are hard to beat IMO. & Of course we're interested, you're a legend to MANY bud.
@davehock7239
Ай бұрын
This was fantastic. Really enjoyed you going through the code and correcting issues as you went along.
@Almethese84
Ай бұрын
Just more, please! Whatever you've got the time and energy for. I love your videos; particularly the live stream VODs, because I enjoy watching the entire process (no pun intended) warts and all. Finally, thank you so much for all your hard work and energy fostering such a wonderfully inclusive instructive community!! ❤
@5dots297
Ай бұрын
Loved this, for cs undergrad that have studied physics thoroughly in his/her high school is quite nice to do
@DipamSen
Ай бұрын
Amazing video! Congrats on the new book!
@TheCodingTrain
Ай бұрын
Thanks for all of your help and support!
@abdulkareemalhamdani3060
Ай бұрын
one of the best videos actually, I tried to do the math like 8 years ago without using linear algebra (I did not know why linear algebra exists back then). I did the simulation using C# GDX library I believe, and that definitely impacted my choice to be an engineer.
@kingnathi9451
Ай бұрын
Awesome video, reason we love coding and programming. Can't wait to get the book.
@GuildOfCalamity
Ай бұрын
I wish Daniel would have been around when I started to learn coding. Would love to see you do a follow up with inelastic collisions (including some coefficient of friction/heat).
@tzisorey
Ай бұрын
I remember doing this for 'fun' in the late 90's, with *_NO_* idea of the math beforehand. I did rather well, in my own opinion, but could only really handle velocities where objects couldnt pass 'through' each other between frames.
@nagualdesign
Ай бұрын
Objects passing through each other sounds like a fascinating problem to solve. Assuming that there was a good solution, it makes me wonder how far you could raise ∆t before it breaks. I mean, you might have had more than one collision between frames. It's a real head scratcher.
@tzisorey
Ай бұрын
@@nagualdesign Never ended up solving it, but I considered checking whether they were moving towards each other both before and after adding their velocity vectors - if they were getting closer before, and further away after, then the closest point wouldve been somewhere 'during' the frame, but trying to figure out exactly where and when..... and then I got a new job, and significantly less free time.
@pesterenan
Ай бұрын
Hey Daniel! I finally watched all the coding challenges! Feels so good to finally catch up! Hahaha Keep up the AWESOME work that you do!
@TheCodingTrain
Ай бұрын
Wow…. all of them?!?!?!
@pesterenan
Ай бұрын
@TheCodingTrain Yes it took a long time, and it was so fun to see how JavaScript was before ES6, you struggling with if/else statements and arrow functions hahaha I didn't know that it was you that made the first Nature of Code book! I read that while I was learning about JS a few years ago, and today I'm a web developer!
@nopetuber
Ай бұрын
4:30 Daniel?? We will *always* stick with you
@Yazan_Majdalawi
Ай бұрын
Something about this comment makes me uncomfortable
@iminvisibl2u
Ай бұрын
As I tried to make a breakout game, I could never figure out how the ball should bounce after it hits something. You have solved my several decade old question. Thank you. Love the show!
@michaelbare911
Ай бұрын
Thanks for this ! The optimized version is fully functionnal and will help me in my class.
@p5play_js
Ай бұрын
It requires a lot of math to even do something simple like a ball rolling down a slope. In most cases it's better to use a physics library and the most popular 2D physics sim, used in games like Limbo and Angry Birds, is called Box2D. p5play uses a JS implementation of it which is superior to matter.js and also easier to use.
@lukasaudir8
Ай бұрын
One of the things I love the most about the code train is exactly solving problems with pure vanilla js, It's most important to learn the strategies, calculations and ideas behind the simulations so to make good and confident usage of ready solutions, you'll have a much deeper and better understanding allowing you to use the libraries more effectively, and when you face a problem that the library doesn't solve, you're equipped with the base knowledge to explore the solution yourself... Video with no special library are the best ones
@FreeCourseGuru
Ай бұрын
This is simply amazing. I'm definitely impressed by how you developed the entire collision detection from scratch. The explanations were clear, and the walk around the code was pretty detailed. Good job!
@plastikbeau3695
Ай бұрын
Can't wait for part 2 with quadtree for collision check optimization 😁
@SYNAPSEdwl
Ай бұрын
You have created a beautiful book. Thanks. Take care
@ramlongcat
Ай бұрын
bought the book immediately -- you manage to explain complex problems with fun and humility like nobody else, truly refreshing! you make it look easy/approachable and this requires a deep understanding of the problem and a lot of talent & work. TL;DR = thank you!
@panadefluture1988
Ай бұрын
I was working on EXACTLY this, and I got stuck about 1 week ago. Decided to take a break, cause I didn't really want to go over elastic and plastic (non-elastic) high school theory. LOL. now this is here, so I guess it's time go get back to the project... Thank you, Daniel!
@munzeralseed
Ай бұрын
Congrats on your new book Dan!
@mariovelez578
Ай бұрын
Watching this after I made a 3D rigid body physics engine. I remember the days when I first made this, glad to see you're making it easy and fun for beginners!
@JoaoVictorCavalcanteMiranda
Ай бұрын
Dude, I've never seen you my entire life. How? I'was quite worried about start working and go numb, but you showed me a better way. Thank you!!
@Danielle-ew1el
Ай бұрын
your depth of knowledge is impressive, well done!
@bonesai-dev
Ай бұрын
Can't wait for the new book to come out :)
@thehappycoder3760
Ай бұрын
Brilliant as per usual. More coding challenges. Unpacking the optimisation would be really interesting.
@roccov3614
Ай бұрын
I am now interested in the Nature of Code book. Especially since you love to tackle so diverse challenges, the book must be very interesting.
@tugamer89
Ай бұрын
Now I NEED the inelastic collision simulation!
@tsarprince
Ай бұрын
28:42 Demn the animator really took an extra mile to cutely draw that out! So impresive!!!!!
@DenisovichDev
Ай бұрын
Haven't been keeping up with the community for a bit because of studies. It's good to see a coding challenge after a bit! I'm excited about the Nature of Code launch. Hopefully it becomes available in India soon. Cheers Dan!
@TheCodingTrain
Ай бұрын
Nice to hear from you!! The book should be available in India if not please message me on Discord!
@francoisgantier4207
Ай бұрын
your videos are always amazing ! I remember doing an event driven 2D collision in perl back in college. that was... something XD
@MrBadSmash
Ай бұрын
Very cool that you did this video! A few months ago, inspired by some of your other videos, I tried to solve exactly this problem. Without the math education, I never quite got it right. I ended up with some very odd results. I'm five minutes into the video, I've got my old attempt that I wrote in Lua opened up, and I'm excited to see where I went wrong! Also I pre-ordered your book months ago! I'm a big fan!
@kevinbatdorf
2 күн бұрын
preordered the book after watching this. Cant wait!
@robotbobby9
Ай бұрын
(4:27) "This is a very important moment in your life" 😂😂😂 So good!
@Endelin
Ай бұрын
Erin Catto, the guy behind the Box2d physics library, posted a cool video "Solver2d Results" where he puts 8 different solvers through a variety of physics simulation tests.
@quintonashley5745
Ай бұрын
Trying using p5play, it makes it easy to use Box2D physics simulation with p5.js!
@marcasrealaccount
Ай бұрын
The better solution to collision detection of moving circles is to extend the circle into a 3D sheared cylinder and then you solve for the time when the two cylinders touch. A hint is find the distance function between the two circles in motion, then find a solution for when the distance equals the two radii added together, another hint is you can use the squared distance and the sum of the radii squared (r1+r2)², an equation for the diatance could be d(t) = ||(p1 + v1t) - (p2 + v2t)||
@luisdss
Ай бұрын
Awesome! Do cover more of this (whether its the optimization or the other sort of collision)
@Haagimus
Ай бұрын
Your end result immediately made me think of Brownian Motion. I know it's not the same thing but, adding a little random walking to the particles might be cool. 🤙🏻
@boemioofworld
Ай бұрын
Hey Dan, nice vídeo as always. I am glad you are back, I love your videos and they make me happy! I am looking forward for the new The Nature of Code. I did all chapters of the old one, it was a great experience! I also have the "Learning Processing" book, another great book!
@reik2006
Ай бұрын
27:00 I agree the correction has to be done. The system can enter physically invalid states because of finite time steps and the overlap correction resets the system to the last valid state which was traversed during the last state transition
@egonde5895
Ай бұрын
Mr. Shiffman we want to see you more. You are an amazing person!!!
@frumbert
Ай бұрын
Game of life with particle collision ;) Thanks for the great explainer book!
@luizieu
Ай бұрын
Great video as always, i love to see the way you are always optimizing your code.
@andradegilmar
Ай бұрын
Very cool! I like implement things from the ground to understand better how it works. Even if later I decide to use a library
@christerpherhunter930
Ай бұрын
Your videos are fascinating to me. Your on-video energy is spectacular! Personally, all my personal and work projects are in Rust as opposed to the JS you use. No matter, your videos are ultra interesting. Thank you!
@TheCodingTrain
Ай бұрын
If you make Rust versions please share them in the passenger showcase!
@funkyb6598
Ай бұрын
Great video! Looking forward to the book.
@TheIndolence
Ай бұрын
I'd love to see the histogram of speeds and do some thermodynamics! Add other interactions (with radial potentials) and even spin for magnetism models... Physics are your oyster!
@erichlof
Ай бұрын
Awesome video! As you mentioned, I would like to see how you got the simulation of many particles to run at 60 FPS using a quadtree. A supplemental video like that would allow us to take this to the next level. Thank you!
@TheCodingTrain
Ай бұрын
You can find the source code on the webpage linked in the description!
@dimBulb5
Ай бұрын
Fun and brilliant as always! Thanks!
@chrisjames278
Ай бұрын
awesome video, thanks! Just pre-ordered the nature of code book!
@LithiumDeuteride-6
11 күн бұрын
Mathematics and physics are important for a programmer. I had to come up with an algorithm for a grenade with a shock fuse, I came up with it. But usually programmers just use a collision callback and detonate a grenade in this callback. Although this is the wrong decision, it is necessary to track the impact, the grenade can be hit not only by a collision with solid geometry, but also by some external force. In general, I use changes in the velocity vector, subtract the current velocity vector from the past and look at its length, this is the impact velocity, if above the threshold, then the ball inside the UDZ presses on the spring-loaded plate on which the striker is fixed with sufficient force so that this striker initiates a capsule, which causes a grenade explosion. The code turned out to be very simple and reliable, the main thing is that it simulates the real UDZ of the RGO and RGN grenades quite well.
@RichardCyburt
Ай бұрын
There is a different way to work out the equations of the collision that you might find helpful. Transform v1 and v2 into center of mass and relative velocities. COM is same before/after. Vrel(after)=-a×Vrel(before). a=1 for elastic, a=0 for perfect inelastic. 0
@hexcrown2416
Ай бұрын
Might be cool to go over fixes for tunneling (when one object is moving fast enough towards a ting/small object, it can move completely through that object instead of detecting the collision and resolving it correctly)
@bersi3306
28 күн бұрын
Super interesting video! Please do the quadtree version. For gamedev/software design the optimization part is the most important/fun! Thank you very much for the free culture you are providing.
@zrodger2296
Ай бұрын
I can *always* use a refresher on vector math. Thank you!😊
@stephan19912710
Ай бұрын
Love the video and really curious about the book, congrats :)!!
@Sqwince23
Ай бұрын
Let's see that inelastic collision example. I wanna hear a nice crisp *Crack* of a billiard ball, or maybe somehow deform the shape in the axis of collision slightly for animation?
@NowInAus
Ай бұрын
Very nice. Can you colour and simulate diffusion by mass of the particles? And yes please do inelastic and make an annoying sound for each collision! Great work
@brain-freeze7995
Ай бұрын
اخيرا ، تحدي البرمجة هو قلب هذه القناة 😍
@PatrickHoodDaniel
Ай бұрын
Completely not related to the content of this video, but what techniques do you use to remove all of the silent portions of your video. Is it a manual process, or have you found an automatic process? I face this daunting aspect for every video I make. Another question, why did I enjoy this video so much?!? Haha
@SirPhysics
Ай бұрын
Physics professor here with a small gripe. While there are plenty of people who use the word 'conserved' the way you did ("momentum and kinetic energy are conserved in elastic collisions") that is not how I would describe it when communicating this idea. Quantities are either conserved quantities or they are not. What it means to be a conserved quantity is that the total amount in the entire universe remains constant; it cannot be created or destroyed. Momentum is a conserved quantity, so it is always conserved. Kinetic energy (by itself) is not a conserved quantity, and so it is never conserved. There are no collisions in which both momentum and energy aren't conserved. What you're talking about is whether the total amount of a quantity within a specific system will remain constant or not. This is different from conservation because it depends entirely on our choice of systems. If you consider both of the objects in an elastic collision then both total momentum and total kinetic energy remain constant, but if you consider only one of the objects in that same collision neither remains constant. To put this into more coding terms, whether a quantity is conserved or not is a global property while whether it is constant in a particular interaction is local. So I would say that momentum and kinetic energy remain constant in an elastic collision. To use the word "conserved" in this context implies that sometimes momentum isn't conserved (and that kinetic energy is sometimes a conserved quantity, which it is not).
@TheCodingTrain
Ай бұрын
Thank you for this helpful feedback and clarification. Makes a lot of sense to me! I’ll try to be more accurate and clear next time!
@likwidmocean
Ай бұрын
I really enjoy your videos. Do you think tunneling might be worth mentioning? Projectiles going through obstacles rather than bouncing.
@jinitom
Ай бұрын
I enjoy experimenting with problems like this, and watching your process. I especially like the idea of using a quad tree to reduce calculations. How do you handle the case where two objects have passed thru each other during the time between each step of the draw loop, and the collision is not detected?
@bluetheredpanda
Ай бұрын
Hey Dan, thanks for all the amazing videos over the years! I just pre-ordered a copy of the new book, but I wanted to ask a question: will there be a PDF version included so that I can always have it with me? I love physical books and believe they're the best medium for focused reading, but they're not always super handy to move around with and reference quickly. Thanks!
@pietrocestola7856
Ай бұрын
(v2 - v1)•(x2 - x1) and (v1 - v2)•(x1 - x2) are the same, they therefore trivially have the same sign. The difference in sign is only due to the last term, after the fraction.
@tobias633
Ай бұрын
Can't wait for Sept. 3rd, greetings from Austria 😄
@TrollingAround
Ай бұрын
I'd love to see the quad tree optimisation.
@neoncyber2001
Ай бұрын
Oh if only I I had this video a few years ago when I was trying to figure out elastic collisions for my own physics library!
@jayjasespud
Ай бұрын
Always here for a ride on the Coding Train.
@pingyboy3400
27 күн бұрын
Amazing explanations
@julianjackson8756
Ай бұрын
Pre-ordered. Can’t wait!
@QW3RTYUU
Ай бұрын
dude! you gave me the nudge necessary to also preorder. I remember the first edition and reading it online was fun. now it'll be in my library forever, aside my unopen vinyls (I have vinyls but no turntables, what a weird thing to do)
@hope124-c7v
Ай бұрын
My favourite teacher 😍
@henrik3657
Ай бұрын
I would allways, check for screen bounderies , top, bottom, left , right , if sphere is coliding with these bounderies, then increment or decrement x, y acordingly. Like , if x> 800 { x=x-1 } This is the simple way of doing it.
@riccardoluise8630
Ай бұрын
Your videos are so motivating man. Thank you immensely 🥰🥰
@pierrebaillargeon9531
Ай бұрын
When redistributing the overlap, the distribution should be proportional to their velocity, not just divided equally between the two. Also, it might be possible that pushing them back would move them off-limit, behind a wall.
@TheCodingTrain
Ай бұрын
Ohhhh such a good point!!
@cret859
Ай бұрын
As alway, a truly nice video. A good recollection of all the 'nature of code' spirit and how to code it ! So nice... What next to do ? Optimize your algorithm and implementation in BASIC to make it run on your vintage Apple ][. May it be able to handle just a dozen of particules ?
@dgo4490
Ай бұрын
The circles should also squish when they collide based on the collision vectors. Then have small rigid metal balls vs big and squishy balls.
@sulaimanadewale320
Ай бұрын
might be my first book purchase
@ncot_tech
Ай бұрын
At 29:55 my Roku streaming box lost its mind trying to decode the video with all the moving stuff in the corner. Everything turned into MPEG artifacts. It was quite fascinating. Also while I don't enjoy Javascript, the book is interesting to me because I know all the cryptic maths will be explained in code that I can read and make sense of.
@davidgeorge4944
Ай бұрын
This video is really tremendous
@2wheels2
Ай бұрын
2:25 hey, if you do make your own game with something like C or C++ from scratch, u cant just make this simplification. every frame has a different dT relative the the previous frame. always check the dt of the current frame and use that for your physics.
@user-vz2ti7pd1p
Ай бұрын
I remember doing this as a project for my intro game dev class. I only wished this was made earlier 😂
@martinmckee5333
Ай бұрын
Looking into the math is never a bad thing.
@brettbreet
Ай бұрын
Yes! Yes! Yes! I'll have more of this please!
@beautifulsmall
Ай бұрын
ok, 40s in im buying that book, building your own physics engine. is multiplying by -1 quicker than v=-v . first principles is actuall alot less scary than most people think, even thermodynamics.
@lukasjetu9776
Ай бұрын
30:00 i love bitrate
@neozeo4245
10 күн бұрын
Yoo please add gravity to see if the big circles get sorted up like in a unsorted Lego box, that would be a nice animation
@redpug5042
Ай бұрын
now try continuous collision detection. for a start, you can find the time t at which two particles will collide using the quadratic formula with the terms: a = ||v1-v2|| b = 2*dot(v1-v2, p1-p2) c = ||p1-p2|| - (r1+r2)^2
@dmitry5449
Ай бұрын
Простая школьная физика и такой потрясный результат 👍
@jackhodgson
Ай бұрын
Yes, very interesting. Thanks.
@ragedprogrammer3952
Ай бұрын
are you going to teach us to do the rigid body collisions engine in your book without libraries, just from scratch?
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