How Games Fake Water 

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16:32 once I was trying to make the surface ripples of water running in a direction like a stream, and one of my attempts had small ripples that were just moving along the surface without any disturbance and I thought it was unrealistic and added some noise to it, then I saw water running down the street in the rain and it had super static unchanging ripples running along the surface, I felt really stupid

I've worked as a fisherman for a decade. A lot of that time was spent watching the sea and thinking 'there must be a logarithmic mixture to reproduce this effect'. Here comes Acerola to crown himself again.

this isnt just how to make water, this is a crash course in graphics programming

The man himself has come to bring us another well explained video about complex topics I will forget as soon as I try to do it myself

BABE WAKE UP-

I swear to god staring at a thing in reality, questioning whether or not I would consider it realistic if it was presented in a video game is too relatable you explained a few concepts in this video that I took like, 2 years to figure out on my own, damn you! (but thanks for sharing it for others) now I can finally point people to a specific good video when they ask for shader knowledge

On shadertoy there's a shader called "Seascape". Even with the source code right in front of me, I've never been able to understand it. This was a phenomenal explanation and I feel like I actually understand it now.

GPU Gems that are explained simply could be a whole series. You should do more of these.

Nobody does it like you. Explained well, entertaining, thorough, explained performance pitfalls and how to solve them, etc. Your work is a goldmine. Thank you!

basically becoming game dev also means becoming mathematician for that juicy wet water

I spent all day making structs do what I want them to do in my midi sequencer. This is what I needed to unwind. Hell yeah, that was some comfy overlap between audio and graphics. So many topics that are extremely familiar to someone who has spent more time with synthesizers than with code. Ultimately it all comes back to the Fourier transform when doing things involving sums of sines. Also one thing used in audio design to reduce noticeable beating (i.e. the audio analogy of tiling) is to vary each oscillator independently as a function of time. Plenty of ways to solve that issue but that's the one that immediately comes to mind for me.

I am constantly amazed at your ability to make complex topics easy to understand and fun to watch. As an aspiring game dev and current 3D artist, thank you.

I'm looking forward to the next video. The waves in Sea of Thieves look so impressive, they even have physics!

thank GOD someone finally spoke up against screenspaced reflections

Watching this at 0.25x speed to offset the goober who watched at 2x speed. Gotta internalize every detail.

Awesome video, I learned a lot! Still two minor corrections/annotations: 1) frequency is not 2/wavelength, but 1/wavelength. Probably that mistake somehow slipped in with the graph at 1:46. You can see there that you are not showing sin(x) but sin(PI*x). The natural wavelength of a sinewave is 2*PI, also known as a radian. Basically this is an angle-measurement that is based upon the arclength (= traversing the surface) of a circle with the radius of one. 2) the Blinn-Phong model is NOT in any way the basis for PBR. Blinn-Phong is an approximation on the basis on artistic criteria, calculated purely for verisimilitude, not realism. PBR models on the other hand approach the calculations on the basis of physical values. For example a light in Blinn-Phong can be brighter going out than it goes in since it is added once in the diffuse and a second time in the specular breaking energy conservation. A PBR model on the other hand only distributes the total amount of light into reflection and absorbtion, so it can never be brighter than it goes in. Oh and I didn't expect you to be this young, with the quality of your videos and complexity of the topics discussed I expected you to be an industry veteran for at least a few years!

water is one of my favorite topics when it comes to computer graphics because there's so many ways to go about implementing it. my personal favorite video game water is Mario Galaxy, because it feels really stylized and unique, without resorting to solid colors and repetitive textures like a lot of other examples for stylized water. The toxic waste in Portal 2 also looks really nice, despite basically being brown sludge.

Yes! I have been hoping for a good detailed video about FFT and iFFT realistic water. I would still like one on that spooky partial differential equation one too, but I know that it's got hands

Acerola, you're a lifesaver. You just saved the surfing mechanic I was thinking about scrapping because until now my waves looked like an unyielding herd of gelatinous migratory hillocks. still gotta work out a more performant way to make the big waves that crash and go tubular etc., but at least now it feels like I'm on the ocean, and not lost in some sort of undulating mound dimension.

“wow frass nal!” was far more funny than it should have been

I'm a physics student going into grad school, and I'm planning on working on real time fluid simulations! It's fascinating seeing it from a nonphysical, more approximate perspective. Of course Fourier series would make their appearance! The domain warping aspect is very fascinating! I would never have thought of that, but it works perfectly. It also seems to naturally result in the low regions being flat and low detail, and the high regions being spiky and high detail. That's so cool! It's also fascinating learning about all this optics stuff. That's the one bit of physics I never got. I suppose if I want to work on games (a hobby of mine) I'll have to learn it some day...

It's such a pleasure to watch an ugly looking plane of sine waves slowly but surely becoming a masterpiece

I really appreciate the quality of content that you produce! I can't remember having ever had such good, yet fun explanation on any topic!

Ever since I started watching your videos, I've been looking at real objects and thinking about the way it could be modelled digitally. Water has been the primary object of my attention, so I was ecstatic to see an Acerola water shader video! Thank you so much and I'm looking forward to more water shading stuff in the future :D

Nice video! This helped a lot in my understanding of lighting, other explanations I saw were really dry and didn't explain the math very well. You should also cover distortion textures! By abusing distortion and multiple scrolling textures, you can make most visible tiling go away. There's a great video by a channel named Jasper about how they used this for water in Mario Galaxy 2.

It's cool to see a breakdown of how stuff usually works, but it's much rarer to see any content explaining 'better' options. Excited for the next video :)

your honestly one of the game dev people that I like to watch I find it more better of someone explaining me how it's done than someone just tell me how to make it and just coping the code without no knowledge of how it's done, and you're more entertaining to watch than a 2 hour video of someone explaining it like you video are more faster but not to fast to were I don't understand and can't follow along

Love the video, great topic. Would love to see more water and PBR rendering topics

You and Sebastian Lague have made me realise I want to be a graphics programmer, and I thank you for that.

I really hope you get around to the more advanced wave methods. The result at the end of this video looks great but sea of thieves' waves are something else.

You explain those topics better than my professor, it's hard for me to understand certain equations without having an intuitive grasp about it. Your visualization really helps!

I have been waiting for this video to come out! YEEEESSSSSS Thank you!!!!

Always interesting. Love the editing, as always 😂 Keep it up!

Heyy thanks for another informative video! You rock, Acerola! :)

You got yourself a new suscriber ! Everything was clear and explained in a fun way, keep going 😁

Having watched a lot of your videos back to back, it's pretty apparent how good you've gotten with pacing and delivering just enough information to explain concepts without getting lost in the details. Awesome work as always, looking forward to the next one! You did raise a good question that I've never seen a satisfying answer for: why DO games include a bunch of post-processing effects that a lot of people always turn off? Are those people in the minority? Are the effects often just not done well? Is it mostly for consoles/lower-end hardware where lower framerates need more fancy effects to compensate?

Wow, expertly breakdown the details to the most basic component. Great video!

Holy shit, the amount of information is incredible, also i love how you actually manage to keep my adhs-ruined attention span

Just wanted to say that I adore your videos. They're wonderful.

Trigonometry and fluidity are two topics I would have never have guessed would apply in graphics together. Now, it makes sense!

Love the videos, mad props. One thing I do wish though is that we didn't get a 101 to graphics programming (what a normal is, what diffuse/specular are) in each video. Perhaps just refer people back to an earlier one? I know it's a difficult balance to strike to adjust it correctly for the target audience. Keep up the awesome videos!

Totally agree about screen space reflections, they're like ants: once you notice them you see them everywhere and it totally ruins immersion.

Its always a great day when i see you upload! great vid as always

I started my college degree of computer science in the beginning of this year, and even though my primary objective is not to become a graphics designer and also because i am still a noob when it comes to programing and everything, your videos still are always really amazing, informative and fun to watch. Ngl, you are even better to explain somethings than my teachers are lol, hope you grow even more here on RU-vid you deserve it

I really like how you explain things, thank you

21:26 I'm sorry to say this, but with this rendering time you brought up a great Polish meme

Really cool video! Only time I've done a realistic water shader is following Sebastian Lague's planet projects, using wave patterned normal maps

After the opening of this video and seeing all the monogatari figures, I can finally understand why your title screens always remind me of that show! It was inspired by it!

Man, wish I could make videos this entertaining. Is it just a special gift you have? Really cool

Trove of invaluable tricks as always! Thanks!

A video on fast Fourier transform would be awesome. Thanks for another amazing video acerola!

One of the best explanations I’ve ever seen. Thanks!

Great video! Excited for more water stuff next time.

That's so interesting! Great explanation!

first off. amazing video as always, goes without saying since your quality is literally unmatched not only in the graphics rendering space but across youtube as a whole secondly, your hair looks great

would love to see that more complicated wave motion 🕵

19:20 I cant believe Acerola forgot to mention the 4th forbidden reflection technique of just using a 2nd camera to render the reflections

I do like this implementation of water, it looks quite natural and great at the same time, the approach I generally go for is just to take two noise textures and use procedural sampling so that it doesn't tile but I might start using a similar approach to this in the future. also i got a bit confused because I completely forgot about the water community post and was looking on your GitHub post processing effects for different tonemappers and saw the lens flares so yea lmao, still a great video and very informative

This is just what I needed for my RTS, only don't need the render, just the waves. It's an aether map, some gameplay stuff, so I'll need to figure out how to get back the data to the cpu eventually. Thank you very mucho!!

Holy moly it’s another acerola video it truly is a wonderful day

20:13 LITERALLY ME AFTER I LEARNED ABOUT HOW POWERFUL FRESNEL IS

I've been learning opengl recently and i wrote my own code for a wave, but it was just one sine wave, and the vertices were...cubes. And i was computing the position in the cpu. Never thought i should do it in the gpu, that's brilliant. Thanks aceroler

Saw Punpun on your shelf and immediately hit the subscribe button. I already know you have good taste so the videos have to be just as good.

That video made my life way easier, thanks mate!

Bro these videos are amazing where have you been in my yt feed all this time

You are amazing!! Thanks...I m looking into game dev. but as I learn on you RU-vid I only find channels tells you how to make games but not about the math of the games.

As a UI programmer your videos have helped me understand more about graphics than any other. Well done chap

The replay stats on various parts of this video are gonna go crazy and I love it

Love your videos. Hope you get to 100k soon.

Great explanation for anyone new to 3D and starting to play with shaders and procedural textures. Next, could you show how to make froth on the wave peaks?

It is always nice when a new Acreola Video rolls out

So I’ve been watching you for a while and I’ve always loved watching these videos despite me barely understanding anything. This was the first time I watched an acerola vid and felt like I actually understood most of it, so much so that it motivated me to download unity and learn shader coding to replicate this water effect. I actually managed to get a nice looking sum of sines with lambertian diffuse and blinn-phong specular! I’ve never touched graphics programming or even a game engine before and somehow this video single handedly dragged me past the barrier. But I’ve kinda been learning exclusively shader programming and avoiding learning Unity itself, apart from like, “Shader Lab” *shudders* Now it seems I actually have to learn Unity to make a script that automatically generate waves with decreasing amplitudes and wavelengths instead of entering those parameters manually

Every other Ace video I go like that "Oh" gif, starring Chi McBride No better way to convey how this feller here makes me understand stuff that hadn't really sunk in

I finally found a use for all the knowledge obtained from calculus classes: being able to understand Acerola's videos

First and foremost: Beautiful results, excellent in-depth info, very entertaining and funny. Acerola continues to be one of the best graphics programming edutainment channels I know on YT. Looking forward to the follow-up video, but no pressure. We should be thankful to get these, so I am now considering signing up for Patreon, if there isn't a better (more direct) way to support these accessible, relevant and honestly simply good videos. On topic: A few years ago I created an ocean system for a game that was featuring a lot of water, both visually and mechanically. As pointed out, that Gerstner waves aren't that easy to control and that is a very good point and the reason I chose to not use them. If you need a lot of game design control over water, I found that simple and small look-up textures did the trick. Artists set up simple animation curves in the editor along with additional parameters (calm vs. stormy water looks very different, so you want different contributions from different frequency bands), which were then baked on start-up and evaluated in simulation steps on the CPU and GPU respectively. So, artists could shape waves to look like Gerstner or any other type of non-overlapping wave. They could also have multiple peaks at different heights etc. Amplitudes were controllable locally, as it was just another runtime simulation parameter, so it was easier to control the chaotic patterns when the situation demanded it. You don't want players to be frustrated, because they got unlucky with an extreme trough and couldn't reach a safe spot in time. The solution was very fast on last generation hardware and its synchronous but independent implementation meant that no data beyond basic control parameters needed to be transferred between processors. The GPU computed a height map (there was more than just waves that shaped the water) for rendering and the CPU simply computed samples on demand when queried by gameplay systems, so no height map was required (we also had orders of magnitude fewer queries than the sample count required to compute such a map).

Such a well made video! Keep up with the great content.

IM SO HAPPY you have so many monogatari figures. bro thats my favorite anime of all time. bro just HAD to show them all off

Phenomenal video, Acerola!

Seeing your video makes me question my Game Development Skills and knowledge. Nice Video can you make can you a series from basic of Game Development Mathematics to advance. Love your videos.

I really hope you'll teach us a little bit about the system sea of thieves uses. since i'm very curious to find out how they achieved such good looking water. And you have a great way of explaining these concepts and formulas, as well as visualizing every step to make it easy to follow for people who lack Graphics programming skills.

Something to mention with Sea of Thieves, you actually can see the repetition in the water from high viewing angles i.e. climbing a mountain. It is just very expertly hidden behind all of their other fancy work.

Very well explained and I learned a lot. I think its okay to not show something on screen for every noun and verb. Sometimes it felt excessive.

14:00 - You also need to sample the collision points at least 3 times to get an accurate surface function for the CPU. It was honestly really simple once I got hang of it.

As amazing and interesting this and other videos from your channel are, i cannot help to feel a little overwhelmed by how many topics are related and used all ar once! Can you provide some advices or resources to learn and truly comprehend this without dying trying?😊

"turn that poop, into wine" - L. Ron Hoyabembe

Great video! I wasn't so focused on math formulas since my university days 6-7 years ago.

i love your editing so much you dont understand

I’d love to see you take on the FOV shader of Hyperdemon (assuming it’s a shader at all). They took a really unique approach to it that deserves more attention.

Wow fresnel ... You got me there acerola ... What an enjoyable video ... Thanks a bunch

9:59 shoutout the Professor

Amazing work!

Nice haircut, just as fresh as your water. Those specular highlights.

New favourite acerola video. One day I will be epic like you!

I love this channel so much

Looks awesome!

This dude is actually the goat! What a generous man to be spend his free time doing this for us

Was watching the catalogue of vids wishin I could peep a new vid today Lesszzgoooooo

I'd love to see you attempt the FFT water simulation!

Great job! Your channel is a hidden gem. I wish you to hide it even better!