Coding Adventure: Ray Tracing
I tried creating a custom ray/path tracing renderer. Featuring: maths, shaders, and cats!
This project was written in C# and HLSL, and uses the Unity game engine.
Source Code: github.com/SebLague/Ray-Tracing
Support the channel: / sebastianlague
Coding Adventures Playlist: • Coding Adventures
Learning Resources:
raytracing.github.io
blog.demofox.org/2020/05/25/c...
Music Credits:
github.com/SebLague/Misc-Proj...
Chapters:
0:00 Intro
1:08 Cameras and Rays
3:30 The Pixel Shader
5:02 Drawing a Sphere
6:59 Multiple Spheres, and Colour!
8:21 Two Types of Reflections
9:04 Experimenting with Randomness
11:14 Random Hemisphere Directions
14:11 The Trace Function
16:35 Testing Lights
17:55 Chair Thief
18:23 Progressive Rendering
19:54 A Simple Sky
20:49 Lambert’s Cosine Law
22:47 Cosine Weighted Rays
22:36 Triangles
24:52 Some Tests
27:14 Specular Reflections
29:59 Tomatoes and Glossiness
31:57 Blur and Anti-Aliasing
34:42 Depth of Field
37:14 The End
When others code it is frustrating but when Sebastian codes it looks like he is Ballet Dancing like the world is on 0 difficulty
That probably means a lot of testing that we don’t see. I’m a Java backend developer and writing some simple endpoints for say a Spring Boot server means first write the code that handles a request and then a bunch of tests which usually takes a large portion of the time.
So true
He also gives the impression that he's pretending to come up with these ideas on the fly, together with the testing we don't see, it just becomes more of an ASMR parody. People worry about AI not attributing their creations to human generated training data and here we have a 1M+ YT channel blathering on as if he didn't lift shader code from open source projects like Blender or a million other places or even inspiration from any source. Sure, okay Sebastian - what have you woke up and just randomly thought of to code today? lol
He does take a long time to make these videos, but he is really sharp.
@@thom1218 Maybe you didn't watch the video, but he clearly gave us the name and images of the books he read, and he clearly said that he borrowed code from others, whether it be from stackoverflow, or blender. So no, he didn't wake up with these ideas. He's spend quite some times studying and writing code. Hence why he barely uploads.
Always a good day when a Coding Adventure releases
150
I was a bit skeptical at first because it is april first
Absolutely! It's like getting an unexpected package in the mail, but better because it's code!
@@BenPanna true, already got april fooled 3 times today on youtube
*cooding adventure
Whenever Sebastian says "How this works is super simple", I pay extra attention.
Ye
Nnyyyyyes
It always sounds like Sebastian is explaining all this cool stuff with a massive smile on his face. Like you can just hear it in his voice. And his happiness make me happy in a way. I love your work, keep it up :D
It’s just the Scandinavian accent. It’s especially strong for Danish people, who often sound like they are smiling. Evidence for this is that I thought Lague was Danish before I checked the channel info, originally just to check if he might be Scandinavian. This accent results in a “happy” register in English. That being said it requires some level of happiness or concerted effort to sound like this. I assume it’s a bit of both.
@@aaAa-vq1bd Interesting. Thanks for the info
@@user-bo5vr1ib6i never mind then. it was anecdotal evidence and even when I posted it I had this nagging feeling that it might be a totally spurious connection. Thanks for the correction.
@@aaAa-vq1bd No problem. Have a nice day :)
He is the type of person who would scream in lowercase
You are the Bob Ross of coding with phrases like "Our little raytracer" and I love it.
What a great analogy
I wanted to say this
There are no bugs only happy accidents
@@stickguy9109 no errors only happy little exceptions
this is so true. its so relaxing. even though I could never code like him :)
Sebastian doesn't upload often, but when he does you know I'm clicking on it immediately
YESSSSSSSSS
@@Danuxsy Is that supposed to be a flex?
@@Danuxsy weird flex but ok. Did you make a more entertaining and informative video than Sebastian?
@@hiimgood Actually I believe GPT-4 is a greater teacher than Sebastian because you can ask it about anything, it can explain code for you, why you got an error and even fix the errors for you. It can explain in many different ways too if you just ask! 😊 It can also read documentation and lead you through problems step by step too!
@@Danuxsy but that's kinda obvious, it learned from the entire internet.
"Truly one of the artworks of all time." Couldn't agree more, it's definitely one of them!
anyway whats going on with this tomato
That's the joke, well done
how in the world did you make this so nice to watch the catto, the tomato, and your slight sense of humor is simply perfect
I've made a raytracer in c++ as well , it isn't as easy as he shows , he just shows the concept and how the code works he puts a lot of effort than he shows.
Sebastian is the definition of quality over quantity
You’re the definition of an unoriginal commenter
im so confused it says theres one comment to this comment while i see nothing
@@dip8 well hello there. My comment said: “You’re the definition of an unoriginal commenter”
@@vignotum132 k lol ty
MOM! SEBASTIAN LAGUE DROPPED ANOTHER VIDEO! CANCEL THE DENTIST!
Or watch it while at the dentist! With his soothing voice and fascinating content, It oughta be better than lidocaine
Literally me minus the dentist 😂
how did you comment on this video 10hours ago? (it's been posted just 3minutes ago)
@@GnuSnu probably members only video for a bit or unlisted
I always hated the dentist, yeah, let’s cancel ‘em!
That technical difficulty during the FOV part in the intro had me in stitches, unapologetically showing that even though we have the lofty goal of ray tracing we can still have something so trivial trip us up. I just love how incredibly informative as well as entertaining Sebastian is
I can't even begin to image how much work it must have been to write all these visualizations. Keep up the good work.
The juxtaposition between the calm, confident voiceover and the sudden bugs never fails to make me chuckle
especially the one near the start of this video, bugs and issues USUALLY dont happen that quickly... USUALLy...
The series continues, and I'm very grateful for this Sebastian!
I am grateful for the kity!
is it just me, or does Seb sound like hes smiling the whole time as he records
it's you
Kind of, that's why his voice is such a good and relaxing sound to listen.
Nah he just has an annoying accent
@@aurelia8028 idk I think his accent is fine. He sounds rly laid-back and it makes the videos much more enjoyable and calm to listen to
I love how relaxing and inspiring your videos are. I’m always getting a humble„No big deal“ vibe, which pushes me to never be too proud of my achievements but accepting them as the next step but not the last. Thanks for your hard work! Very appreciated ❤
I don’t know if I’m disappointed or excited. I was expecting a April fools video but honestly this is the best video released today. ❤
It's a waste of time using KZhead on April fools. Mostly just unfunny crap. Good to see a proper video.
True I also thought that
Hey Seb, I just wanted to appreciate the extra effort you take to code/setup your visualisations that aren't part of the project but enrich your explanations substanially. Animations, concise statements, music, all of it sparks my sometimes diminishing love and passion for programming. Thank you.
100% Agree. This must be lots of extra work, but even when I'm only understanding a fraction of the code & concepts (I quite enjoy being so lost tbh!) the animated examples and explanations give me something to grip into. I just had a horrible morning btw, and this vid has calmed me down soooo much. Also the images are beautiful!
Don't forget the occasional appearance of his cat! Lol
Absolutely glued to the screen. You produce some of the best balance of technical and visual teaching/adventuring I've ever seen, video after video, and this was by far my favorite! Wonderful work :)
I absolutely love your calm coding adventures. You have spurred me to create many adventures of my own and I cannot thank you enough! Thank you!!
"Truly one of the artworks of all time. Anyway, what's going on with this tomato?" is easily one of the transitions I've ever seen.
It's amazing how I am entertained both by a gentleman like Sebastian, with his calm and warm voice, and by characters like The Code Bullet, his cursing and his madness. Different Content Creators, united together with many others by the passion for coding. ❤ thanks
I literally came straight from a CodeBullet video to here, and totally agree, it's hilarious!
😂They're the angel and devil on coding's shoulder. You're going to learn through amazing content, but it's either through tranquility or chaos.🤣
Sebastien is Lawful Neutral, Coding Train is Neutral Good, and Code Bullet is Chaotic Neutral. We need to find the Neutral Evil coding channel to have the minimal alignment axes representation. It would be amazing to fill out a full 3x3 grid of coding youtubers, but I am not sure if there are that many.
@@flabort the coding train can be Chaotic Good... 😂
This was a super fascinating watch. Ray trace rendering was always one of those things I just accepted to be magic, but this broke things down in a way that was really incredibly easy to follow. Really great video.
I love how you're keeping these classic sign flip issues and little mistakes in the video - very relatable ❤
Man i love this 'Coding Adventure' series. Insane video, as usual
Would highly suggest adding a bounding volume hierarchy to your little renderer! Makes a world of difference in performance. Also if you really want to get into the advanced features of a path tracer, try implementing multiple importance sampling with next event estimation!
Another fantastic video 🤩 I love how you start with literally nothing and step by step work up to a working raytracer. Did not expect to see a depth of field effect in this video tbh, but I'm happy you added it. It looks so amazing. Can't wait for the next part.
I LOVE your content. Incredible attention to detail. I've had similiar projects in my head, projecting my ideas, and the pipeline of stuff. I really need to kick this off. Hats off to your content. Its magical.
Gotta put everything down and watch every time I see the notification for these.
Incredible video ! I usually have a hard time understanding these more complicated aspects of computers, games, renderers, basically technical stuff, and while it still is a struggle, your videos make these so much easier to comprehend or at least visualize. This 40min vid felt like a 20min one with how well everything was presented. Incredible stuff, as always ! And these renders are really cool looking !
If you would like some more knowledge about some of the topics in here like matrixes, shaders and general redering I would recommend reading the Free pdf book. LearnOpenGL. The first chapter goes quite in detail.
learning about technical stuff could be so visually stunning? 😄 enjoyed the video and were able to keep up
Thank you for producing such a quality work, I have never ever seen someone that explains something which is directly illustrated with a game engine like you! Coding Adventure = Masterpiece. 👏🏼
oh man, it is so charming and relaxing to watch your high quality videos. Keep up the good work! Thank you so much❤
Running a butter smooth code means a lot of testing and tons of bug fixing that we don’t see. He goes through these issues to create 40min~ long videos for us
I love your stuff. Your visuals are so clean and satisfying. You also have perfect concise explanation that are still very informational and in deapth. Honestly you are probably my favorite codeing/dev channels. Also, really good at getting me inspired to do similar projects for fun.
Also kity 🐱
@@TheBcoolGuy Definite plus.
I'm so glad you came back to this after that ray marching video, I love your presentation and it's great seeing it come together so nicely
I absolutely love how exploratory and educational every one of your videos are. Every video is so well put together and your explanations are clear. I don't think there's been a single video that you've made that hasn't taught me anything new.
I wrote some kind of ray tracer 2 years ago, but for sound sources in a reflecting (reverbing) room. Like a 3D sound simulator. I just tried to figure out everything by myself without any knowledge - and of course i stumbled over some of problems i weren't able to solve by myself. It's really nice to see this video and how you came to every single of my problems and then showed how to solve them :)
A quick note about the rejection method you used for the random direction originally, while it is true that about half of the time it will find a good candidate, so on the CPU it would only run on average less than 2 times, on the GPU threads are done in groups of 32 (NVIDIA) or 64 (Intel, AMD), and the threads in one of these groups can only continue once all of them does. I did some tests and that results in 6 or so iterations before exiting on average on 32 thread systems.
I love how you walk through stuff like this. You get the audience to ask, "What is the next natural step?" and give them the breathing room to think of an answer. Then you show them what you came up with and sort of hint at why it is a useful concept more generally without saying it explicitly. Your videos are simply fantastic at getting people (specifically me) to think through complex problems in small rational steps. Bravo. Keep it up!
Your videos are honestly incredible - Please keep making them!
I swear because of these types of videos i am learning again why i love to work in this field and how much I just love the sheer wonder and fascination of making math look good. I was grinning the whole time like an idiot during the reflections part and its also partly the fault of the video, because your videos are so well done and cinematic, I could watch them all day and just leave them running in the background
Just don't forget to actually do some work in between leaving the video running all day 😉
I specialised in physically-based rendering during my master's degree, had to do a whole ray-tracing project very similar to this so was very nice to revisit some of the theory along with such wonderful visualisation. Your presentation of the ideas at play here is an absolute joy and your code is pristine as ever - always a pleasure to see what you're working on, thanks for the great content! :)
is this how ray tracing is implemented (bounce around till you reach light source) or people use phong's shading (calculate shadow and reflected ray) to get ray traced results??
I've been thinking about the cosine weighted point distribution myself over these past few days. It's always a great time watching your videos and seeing all these things that I want to try out in future projects too!
Your channel is just so chill!!! I love it!!! Keep it up bro!
13:00 You want to create points using a distribution in (x,y,z) that is only a function of (x^2 + y^2 + z^2) = r^2 (that means it has no dependence on direction, which means the points will be evenly spaced across the surface of a sphere). If we take x, y, z separately, the resulting distribution f(x, y, z)dx dy dz = f(x)dx \* f(y)dy \* f(z)dz (this is because the three are independent (because we calculated them separately), so the probability of finding our output position in the range (x, y, z) -> (x+dx, y+dy, z+dz) is equal to the probability of finding x in that range, times the probability of finding y, in that range, times the probability of finding z in that range. Like how the probability of flipping a coin and getting heads three times is the probability of getting heads once, times the probability of getting heads once, times the probability of getting heads once) Intuitively, it seems that we should take x, y, z from the same distribution (because it's independent of direction, we can't treat different directions differently). Applying these, we see: f(r^2) = f(x^2 + y^2 + z^2) = f(x^2)\*f(y^2)\*f(z^2) What type of function is defined by f(a+b) = f(a)\*f(b)? An exponential. So we find our distribution must be f(r^2) = exp(-r^2), which is a normal distribution. I hope that helps, if I have explained anything badly please say so!
Was just watching the new 2Blue1Brown video "Why π is in the normal distribution (beyond integral tricks)" and it basically explained this. Very interesting.
I noticed he did the same thing in the defocus code at 33:00, realistic/"ideal" lens blur tends to follow a gaussian curve, would that mean you'd want your ray distribution from the single pixel in the camera to follow a similar curve?
I think I remember someone doing a straight poisson distribution lookup to a table of pre-calculated coordinates for some of these ray directions. I think the idea was to get solid randomness cheaply as you were looking them up instead of calculating them. It was a disk and for better randomness you could just keep rotating the disk. (for say different ray hits or frame numbers) I didn't do this myself but its a memory of something that might have happened. :D
So Marvelous ! The fact he employed real life laws and the fact they actually worked Is truly outstanding !!
Loved seeing all the reflections and colours being picked up! Fantastic video.
This was such an educational video and the end results so amazing! I now better understand the concepts of specular and diffuse reflections. Thank you, Sebastian, for doing this!
Each of your coding adventures is very inspiring, love your content!
Impressive to say the least. You're able to take complex subjects and turn them into easy to understand lessons that are also beautiful works of art. Really enjoyed this
Man, this is by far my favorite channel on KZhead. The stuff you create is always so cool and interesting, and the quality is just out of this world. I honestly wouldn't be surprised if you spent significantly more time coding the visualizations of what your code does than writing the actual code, but that effort really pays off in the final video.
I loved your video and especially the questions you ask yourself, the answers you give. It's so fun and extremely interesting ! Thank you
Your videos never fail to entertain me
I am blown away by this video. You made not only one of the best ray tracing explanations I've seen, but a really cool engine as well! I'd love to see this become a series, maybe touching on performance improvements and code optimization as well.
I didn't expect a video about programming to be so soothing. I love this.
This is amazing. Filled with detail and excitement as you explain, it makes as I want to do it as well. Although could as well be a tutorial, it seems so entertaining and interesting watching what would happen. I subscribed and would like to follow and enjoy while you talk of the capabilities to accomplish. I did not know it could do so much, the programs. Thank you for making this and explaining along the way.
this is amazing!!! it's so cool how each step builds up to a good-looking ray tracing implementation despite all of them seeming relatively simple compared to how complicated rt seems as a whole. you're really good at explaining things! i understand how it's ray tracing works much better now, thank you :)
These videos are truly exceptional. Really a part of the few content creators of true excellence.
I cannot imagine how much work it is to write the storyline, code everything, take it apart again to "live" good for the video while perfectly narrating. You are one of my favorit tubers and I always have to restrain myself to not share your video with everyone I know! (Though I have shared them many times anyway)
his video feels both calm and inspiring, and never boring
you've got no idea how much this video means to me, i've been trying to code a ray tracer helplessly for the past few months, thanks a ton :D
I'm always looking out for these videos, love your stuff!!
Very good video! Really nice to follow, good visuals, calm voice and - most important - highly educating. Thank you for your work!
The final animation focusing on the knight looked so nice, really great video!
Man no way this is amazing, im always happy when you release a video
Please a part 2 on optimising this and adding more features. It would be so satisfying to get this closer to realtime if even feasible
I may have forgotten all the admittedly few knowledge I had about programming, and yet I'm deeply engaged every time you post a video! Loved all the simulations in this one
An incredible resource. I'm going to be returning to this often. Thank you so much for making and sharing these.
Congratulations Sebastian, you are hereby certified crazy for doing all your animations inside Unity. You may add that to your CV for future job applications.
Things like this blow my mind. Glad their was people out there who created rendering like this so we could enjoy the fruits of it.
why?
This is the exact kind of thing that I love about programming. I recently made my first pathfinding program in pygame (using Sebastian's A* video), and seeing it work was the best feeling. I feel like making a game would give you that every once in a while, but with little experiments the whole goal is to get a single system working well.
Your videos are always so goddamn amazing. I can't even begin to image the work that went into it. Amazing.. thank you
Was having a bad day, thank you so much for this video. Put a huge smile on my face to see the notification.
Hey man just wanted to post a comment to express my love for your videos. Im currently in school studying software development but my love for programming and technology goes beyond that. I'm not the smartest guy and I'm not going to pretend to understand everything you do or say. But man I've learned ALOT. So far the most fascinating thing you taught me is the HOW math is actually used in creating all sorts of things. I've always heard that math is important but I never got an explanation for why or how. I appreciate and love everything you do and I hope you continue making videos like this for a long time. Much love ❤
This is some of the best content on KZhead! 🥳Fantastic production value, animations, pacing, and explanations!
That was the most concise video I've ever seen on how ray tracing works. Fantastic work :)
Nice I always love when new videos are out
The only channel i have notifications on for. Never dissapoints!
im so impressed with the level of programming knoledge here, im a begginer programer and watching this video was not only relaxing but entertaing, although ( although i didnt understand alot of it) watching your breakdown and following your thought process really made me understand, keep going with this chanel!
Thanks sebastian for yet again a masterpiece! It's always insanely fun to see your pitfalls and sometimes lack of knowledge, so it seems that everybody would be able to code this!
Can you try raytracing-based portals next time? Like, teleporting the ray instead of bounce.
portal rtx be like
I don't think the basics of the algorithm would be much different, you just cut off the ray after collision and make a new one with same properties starting from the end of the portal, it would be laggy as hell though because of how much more information the renderer needs to account for
@@waker_link At least it's not so laggy that you'd need a supercomputer. Portal RTX runs ok on modern high-end graphics cards.
@@waker_link No, first of all every ray it's technically a new ray, and second is the only thing he needs is offset position and rotation.
Sadly it's way less complicated to do this than most things you see in this video (sad as in it's gonna be trivial in math so that it'd barely be a minute in the video, at least in coding it). It's gonna work the same as perfect refraction or reflection, which we already got.
This is just a frivolous ammount of liquid GOLD! Wh-what the hell? I have been following you for a long time, but this Render Coding was AMAZING! I think it's been five years since I started modeling for a living in 3D and I, of course, understand how ray tracing works, but this level of detail was beyond my expectations, I learned a lot today! Thank you very much!!
I'm happy you enjoyed it so much, thank you!
Love your stuff, its so oddly satisfying and interesting watching you do your adventures
This was amazing. I have a moderate understanding of how ray tracing works, but your visualizations and explanations are so beautifully clear. Keep it up!
His voice complements his programming and editing style so nicely.
Dear Sebastian, your channel's a delight, With knowledge gained, my mind takes flight, Your game dev tutorials, top notch indeed, But other topics, left unexplored, I concede. Yet the quality of content, I must profess, Is unparalleled, leaving me impressed. So keep on creating, keep on sharing, Your passion for learning, ever daring. Thank you for all that you've done, For inspiring us to learn and have fun. May your channel continue to thrive, As we journey on, to grow and thrive.
Sebastian lague is a channel that is very good for intermediate game developers only
I bet this is generated by chatgpt
Been watching your content for 3 years now, yet every video manages to be more interesting than the last one, well done man
I've tried reading that ray tracing in a weekend series. But this video is the first time I started coming close to actually _understanding_ the concepts in it. Well done and thank you!
Ray casting instead of ray tracing, which only proves I took computer graphics courses about a decade ago. Ray tracing is the accepted name of the process (e.g., RTX4080). I am making this the year I restart my CG journey. You actually provided a lot of great debugging ideas,. I remember debugging being one of the main hurdles in the courses I took a decade ago. Glad to see you reference the Peter Shirley books as I will use then when I get started.
how did you comment on this video 10hours ago? (it's been posted just 3minutes ago)
@@GnuSnu Einstein: My comment were based on his utube post in which (if you are paying attention) the code is on display in addition to the 'pretty pictures'.
It's all ray tracing. There's so many variants it's pointless to try to assign one name to one variant. It all comes down to the maths of calculating intersections between rays and geometry. RTX-based ray tracing is simply hardware-accelerated ray tracing. In other words, the hardware assists in doing the maths of tracing the rays. It's still ray tracing with it's done with dedicated hardware or not.
@@clonkex In CompSci the formal term is ray casting, but ray tracing is the term used. Actual true ray tracing is performed in optical design as rays are traced through an optical system.
@@GnuSnu P.S: I am also on Patreon and may have seen it there. I did not make it up.
I love the coding adventure videos!
A new Sebastian Lague video in my feed is the best outcome of opening KZhead. Wonderful!
Really love all the little visualizations you have added to this project
I love that you said “Suzanne enters the Avatar State” as a way of describing making the model’s eyes glow
This channel is a good example of quality over quantity
Many moons ago, I accidentally came across this channel when on a KZhead dive. 80% of the content flies over my head, but I find myself enthralled by each video! So interesting seeing it all come together each time!
As usual super instructive and poetic. Thanks a lot for all your hard work ❤
You have a great understanding of code and programming concepts, and you're able to explain them clearly and effectively. You have a knack for debugging and solving complex issues and your attention to detail and ability to write clean and efficient code is impressive. I take you as an inspiration.
One of these days, Sebastian will accidentally make a triple A level game with procedurally generated everything with lifelike graphics, I swear...
Bold of you to assume we're not already living in that game
I've been secretly hoping these videos and topics have all been related to some hidden project. Imagine if once he's done enough of them, a new series starts "Making my own game engine" and then he just starts building things from scratch again.
Such an awesome video. Love the thinking process and the video style.
I think I've said this before in a previous video, but even though I have almost no idea what you're talking about on a technical level, I thoroughly enjoy listening to you explain it. Your obvious enjoyment of the subject is clear.