How Games Have Worked for 30 Years to Do Less Work 

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I can tell you're a developer because you sound like you haven't slept in six years. That was an amazing explanation, so kudos on your tireless efforts.

8:48 What's interesting here is that for the Portal64 project (Portal port to the N64) the dev decided to skip having a depth buffer and instead sort things from furthest away to closest using the CPU. The reason for this is that the N64 has extremely limited memory bandwidth and also more CPU cycles than it can use. So he'd rather spend CPU power sorting things than clear/write 32 bits of depth data to every pixel every frame. it does also help that the nature of Portals maps makes it really easy to cull things, anything that's not in the same room or in a room that's visible through a portal, open door or window can be culled without even thinking about it. I don't think he mentioned this in his video, but given the game is running at 320x240 this presumably also saved him 150kb of memory. A not insignificant amount when he has 4mb total to work with.

I LOVED Prototype growing up. Super cool that I just stumbled across a dev on youtube. Your channel is great btw

This video is insane. All the stuff I was looking for for years on the internet, just made available in a simple, condensed, purpose-made effective educational video with no fluff. Thank you so much. If only every teacher was this good (and every research paper was readable).

I rarely do any game development, but love your content! It's good stuff. You and Acerola have become one of my favourites to watch and learn about how these digital worlds come about.

I guess the reason why Cities Skylines 2 does not bother with occlusion culling is that in a top-down perspective there are simply not many objects behind each other (in contrast to e.g. a 3rd person game).

I literally had the thoughts of "oh, so you can compare foreground and background objects in screen-space" and "you don't have a depth buffer yet, but you have the one from last frame" before those subjects came to be implemented in the demonstations. The examples were really well explained and very intuitive thanks to the visuals!

The speed at which it does all the calculations of what should be drawn and what shouldn't always blows my mind.

I'm currently making a 2D game and it kind of blows my mind that the tradeoff of not drawing objects is worth the time it takes to check what should be culled every single frame. Surely simply checking which objects should be culled is a massive processing task

So if a tree falls in the woods and no one is around to see it...

i hope youll read this, because this video has really inspired me. not only do you explain things in a really easy to understand way, you also carve out a value system of things. "this is easy. not that complicated. not a mystery really" these really help to get a feel for the underlying relationship of all the different approaches (and systems) that you would only get in a 1on1 conversation. thank you for showing its possible! great video

That's a pretty darn great summary for beginners, did this for 3 years myself and it's definitely one of the more challenging yet fun programming fields there are! P.s. i trawled through hundreds of pages of documentations and papers with no friendly youtube video to guide, you still can't avoid that really if you want to become actually good at this, but do watch the video to get an overview.

Your channel is an absolute gem, so many high quality videos about topics that are really hard to find online. Thanks.

There needs to be a VR game engine that only renders nearby objects twice (for the left & right eye) and far away objects once, because far away objects don't need stereoscopic vision. This would would save resources and improve performance.

This is definitely my new favorite of your videos. It's endlessly fascinating to me to hear about the crazy things that are done in rendering pipelines. I love the GDC presentations where they dig into the minutiae of their rendering customizations.

Glad I found this again because I wanted to let everyone know it's better than a bedtime story, I fell asleep watching and listening this and woke up to a dead phone with flat battery. Best sleep in ages.

You're a great teacher. There are only a handful of good youtube channels where you can actually digest the content. This video is gold.

Optimizing CPU performance is something I enjoy doing a lot, very interesting to see how optimizing GPU operations is done. Loved this! Also makes me grateful for game engines which mostly do this for you already haha, not sure I'd want to do this from scratch unless I really needed to get extra frames

Prototype was hands down my favorite game when it came out, and years after. So many days coming home from a crappy shift to take out my frustration on the zombies/soldiers/citizens/mutants of New York. Thanks for the memories.

Ohhhh dev who worked on prototype teaching me game dev, i feel so bleesed. I absolutely loved that game, and still love it, thank you for putting in so much effirt behind it. And thank you for these amazing teaching, keep it up man, much love and respect.

Hi Simon, I've been following you on RU-vid for a couple of years and I'm very inspired by computer graphics and game development, currently making a game on Phaser 3. Thank you for explaining interesting techniques and sharing your incredible experience, I learned a lot thanks to you

It's like if Bob's Burgers explained Computer Science

You do a great job of explaining abstract concepts in a clear and concrete way, thank you.

Subscribed. One of the best and more clear content about graphics programming that I ever seen in youtube

Explaining major breakthroughs in game industry for a given problem is so interesting! Thanks a lot Simon and keep up the good work!

This was really awesome! I used to develop for the nintendo DS, so learning to develop with very strict constraints was really part of the job. This format with in-engine examples really set the video apart, excellent job man!

I'm a dev myself and I gotta say, 90% of this was new info and the last 10% of the new info kinda flew over my head a little. This is amazing, thanks a lot. It's not often that we get to see the nitty gritty inside stuff that you don't directly work with.

As a mechanical engineer i like how you kept this simple yet technical in terms of explanation. This is a skill in itself. You got yourself a new subscriber! Keep it up my man

Immediately subscribed. That's a really good content and you have a nice voice even for a long videos.

Somehow you manage to "destress" me while teaching what could seem like a complex topic but you manage to break it down so it seems so simple. I like your javascript projects and I have converted some of them to typescript.

Thank you so much for sharing your knowledge with us, love it when you bring out new videos!

Loved the video, I did quite a bit of reprojection shenanigans about ten years ago with the DK1 and DK2 to improve perceived frame times for stuff outside of our foveal vision!

Awesome ! thanks a lot ! The explanationn coupled with the rendering are amazing !

Easy to follow, in depth explanation of some pretty complex concepts, waht more can you wish for... Thank you

I actually loved prototype! I bought that game right when it released. I really wish they would have done more with the story, and made a good sequel. You guys really did do good work on that game. The free roam playability in the aspect like GTA, has been unmatched in that particular flavor of genre. Now I'm going to have to dust it off and see if I can get it to boot on something

Man, you're the best. Rendering is an entire discipline unto itself and it's always on the horizon of my attention/knowledge. I finally found the time to study flow fields and I'm moving onto nav meshes soon. One of your first videos was on A*, I'd be interested to hear what you have to say about group pathfinding.

A quick subscribe from me! I look forward to you going into transparency shenanigans. It surprises me that to this day it is not unlikely for a player to run across transparency issues. I remember even in the recent beautiful Armored Core 6 I found a situation where smoke consistently interacted badly with something. And in playing around with my own projects, I've gone overboard with "transparency is beautiful" too many times, and keep having to be mindful of performance impact.

I can imagine using the terrain or buildings in a city as occlusion objects has big benefits real quick.

Prototype is one of my favorites games, both of them, I hope the source code gets leaked so we can get better mods, since it doesnt feel like we're getting a new one

One of the videos on this site that I enjoyed the most. Please make more!

Fantastic education, especially for a lone developer trying to learn more, who is unsatisfied with simplistic answers. These twenty minutes were more valuable to me than many hours of the Unity "tutorials" I have watched. Thanks for being so helpful.

god...just the sheer amount of knowledge and sublime ability to explain usually not quite so straight-forward concepts (when read black-on-white from a uni slide or a blog post written in a VERY dry fashion) *THAT FREAKIN WELL* just amazes me to the point that you Sir have officially becom my role-model (no simping intended). And I mean...duh, no wonder you were (or are, dunno) a Google sofware engineer, cuz that is the level I aspire to become anyhow one day. Thank you A LOT and I hope this world blesses you and your fam for everything! Super thankful that you make such amazing vids! Cheers!

am surprised to hear you worked on Prototype... am a car guy, so the none car games i played could be counted on one hand, Prototype was one of them that i loved so much, it was like a modded gta to the younger me, just a weird amazing experience really

Truly informative. This is a great perspective, i usually hear arm chair devs talk about game development. I learned a lot here. Subbed

Very nice presentation. I learnt a lot and got some inspiration. Thank you!

This kind of quality of content is amazing as a graphics programmer to have access to. I'm amazed by your channel

Hey Simon, amazing video, I really love how you go in depth into the nitty gritty of optimization and the history of it. One such argument I'd love to hear about is collision engines, with broad, middle and narrow phases, aabb collisions, spacial partitioning, the challenges of long range ray and shape casting and so on, I feel like there are so many different interesting things to talk about in collision engines

Thanks for your work on Prototype! Has a special place in my heart

Thank you for a great explanation! If you are suddenly out of ideas how to proceed, I am personally very interested in how this process works with shadows, lights, reflections etc from the offscreen objects. By playing Hogwarts Legacy, which is an UE4-based game, I've noticed that some elements, like reflections in lakes, are often suddenly popping up when I slightly move the camera, which causes an unpleasant experience.

Really excellent video! I don't know much about graphics/rendering so I found this fascinating!

Just a small tip for visualization, I have trouble seeing a difference between Red and Green, which was worse with the Green and Yellow examples - and for those with Colorblindness, contrast is always the eye's first priority over color. Better to use colors that are complimentary, or better yet, just white and black for visualization. (And yes, it's hard for us in Graphics Programming) :p Really love your video! super simple and a great start to understanding graphics and optimization. Subscribed :3

Loved this, as an enterprise software engineer with no game development experience, I found this highly interesting and really easy to understand. You did an amazing job, thanks and you have another subscriber. 😁

great summary, thank you for doing work to condense all these techniques into easy to grasp visuals.

Man, I've done Game dev for over a decade and this still sounds amazing :) Love your channel!

As someone who never made it that far past the Painter's Algorithm section in any graphics book, this was great 🙂

What learned me a lot of optimization was actually the source engine when it came to mapping in Hammer. Now using your video to learn more about other types of optimizations that might be possible for Source or at least in Hammer. Thanks for sharing this type of content and information to anyone that wants it! I am also going to code my own game that is heavily inspired by a game that is poorly optimized. So watching these will hopefully ensure I will not make the same mistakes those developers did.

I am enlightened wow! I am really into game dev and graphics and the topics you ve pointed in the video are amazing i ve learned so many things

Great video as always! Thanks for the incredible overview. I've been wondering about occlusion culling for a long time as I was thinking of implementing it in my toy engine and now I finally feel confident about how to do it properly. Sadly it seems like a lot of work implement the two pass system so I probably will never do it, lol.

I am not graphic engineer, but the content you make is extremely interesting to watch. Thank you for your work sir

Nice video. I had once read a paper on culling strategies. Its just amazing how smart people are in the gaming industry. Some of the most amazing algorithms came from the gaming industry.

I never worked with game development, but I love this channel. I love to hear about clever solutions to optimization problems. This video was particularly interesting.

That last "state-of-the-art" demonstration is so cool! I honestly never even realised it was common to do visibility culling outside of precomputed visibility structures. But not only is it done, there's some very interesting algorithms to lean on. I especially love algorithms that don't rely on temporal reprojection, so that last one (use objects visible in the last frame as occluders) is quite fascinating to me.

Thanks man for this informative video. You are doing great job

Cool stuff. I've sometimes wondered how games do this and avoid unnecessary work. Thanks for sharing

amazing video. Your expertise are super evident

This is information rich / dense yet so simple. thanks!

You worked on Prototype? That's one of my favorite games! The video is very informative, and relatively easy to understand even to someone who knows nothing about game development, though there's a minor issue with captions. At a few points the captions are mismatched, like at 12:10, at it takes a few seconds for them to catch up.

really appreciated this, and good visualizations to go with the explanation. thank you!

I appreciate that you go straight to the topic

Excellent video, so interesting and clearly explained. Nice work. And you made me reinstall Prototype (at least trying to ... ).

This is awesome. I have always been left scratching my head after reading papers and watching whatever few videos even exist about the more advanced culling methods here. Is there any chance you have a github with source or will you make a course covering each topic in detail with in depth code examples? I think people would buy it. Thanks for the video!

You worked on prototype??? Bro that is like my favourite game! Keep it up

Off topic but those trees in your demo is beautiful! I really like the style of them!

For me, the most interesting thing is, how the "MOV AX,CS" and similar lines became an open world game with theoretically unlimited gaming time. 40-50 years ago one or two people worked on a project (code, music, gfx was the same person sometimes) and then, 20-25 years ago the games became so complex that some pc games had longer credits list than a Hollywood movie.

I just discovered a new excellent channel, then looked at your channel, and I found out I had already watched a few of your videos.

Woah! 😮 Crazy you worked on Prototype. I loved that game, and I have always remembered it from time to time. Maybe you could make a video about your work on the game.

Never learned about HBZ, i just knew i had a depth buffer i could access. Great video! Well done at explaining how it works! Don't know how i will use this information atm, but I'm sure it will help me one day down the line. Also now I have lot's of questions in my head how this might be shared with both eyes for VR.

i love your content so much simon, all of it its amazing

I have always been fascinated as to how games were rendered on screen. Great video.

Wow. Who knew that Bob Belcher was an expert in graphics programming?

That is really cool you worked on Prototype. I really enjoyed that game.

Great video, I wish it was made a few years ago :-) In my occlusion culling journey, I originally took the HiZ approach on the GPU which worked out great at first. It became a problem though when I wanted to do more with the visible entities. I tried in several ways to send data back to the CPU but there's just too much latency and not enough types of indirect commands to keep it on the GPU, so I went the CPU route instead. Intel has a great paper for their method of CPU-side HiZ implementation, "Masked Software Occlusion Culling". They also provide an open source implementation which has performed well for my application.

Great video. I'm a 3dArtist, not a programmer of any sort and there might have been a simple explanation for it that I've missed but how does culling account for things like long shadows or global illumination, that leaks from off-screen into the visible scene? ...Maybe worth a part2? :)

Interesting and educational. Thanks Simon!

Prototype was one of my favorite games back in the day. Very cool to hear about it here.

I was waiting so long for you to bring up temporal cohesion.

I don't know why I watched this whole thing and took notes. I don't work at all in this field, but it's so interesting. THanks!

Gran Turismo has used this technique for at least 2 decades. WipEout 2048 also used this technique on PS Vita, but if you do some funky things with the photomode camera, you can see loads of massive black boxes through large chunks of level geometry labeled in bold red font "Blocker."

Mr.doob is one of your patrons! Actually I’m not surprised. GG

As always, your videos are incredibly good for people wanting to get into game development. Thank you! ❤

Thanks for sharing this! Very interesting topic!

You sound EXACTLY like MadSeasonShow. Thankyou for your wisdom from a new graphics programmer currently learning how to make game engines. Have managed to acquire some great books such as GPU Gems and cant wait until I get to the point I can handle DX12 and VULKAN. I am not surprised someone as talented as yourself was involved in Prototype, it shows. 😊

I dont know much about this stuff, but this was really understandable, great explanation

I was thinking long about how to deal with not just culling, but ray tracing, collisions and gravity simulation too, for a space game. and yeah, cache optimization is important, but so are tree structures, esp for stuff where everything interacts with everything. I want to do a hybrid approach, where the tree nodes serve as containers (indexes) for arrays of properties. I'm super excited for it!!!! but for now i gotta work on simpler games so i can make a name for my self, and make it as a game developer \o/

This was very informative. I'm not really involved in any game dev. Thank you!

WAIT YOU WORKED ON PROTOTYPE THAT SO COOL I STILL LOVE THAT GAME

What an elegant way to solve the depth buffer dependency issue. Render the simpler version of the view to extract depth data and then render the high resolution view.

Hey simon, one thing I'd like to see if you could put it up for your patrons to vote for: Rendering in high motion/scene change situations. Eg: Racing sims. While yes, in flight sims planes move faster, a majority of the time you're higher up in the sky, so objects tend to "draw" at around the same area of the scene, but racing sims are interesting (especially in cockpit, and especially in VR) because of the fact that unlike most games where the scene doesn't change TOO much (either the area is reasonably within the same occlusion area or the objects are usually from fairly "similar" angles, VR + racing sims equals fast pace forward movement with often a lot of head jiggle/turning/tilting. Add in suspension modelings, hairpin corners, etc, I've been thinking about all the optimization methods I just can't think of any good ones for racing sims that wouldn't ruin the experience. Particularly when you have something like 4 mirrors in a car (say 3 real and 1 "virtual" in the form of a "rear view camera" It's honestly kind of crazy to think about when considering the processes that most games use, because you want really high up close detail (buttons, texture art for dashes, 3D pins for dashes (especially in VR where flat physical dashes look horrible), and then transparency rendering like windows, fences, buildings, etc. The reason is I play a lot of iRacing and we end up with a lot of folks expecting 120fps in really heavy loads on it, which... well, I'd love to be able to explain that to someone. It just sounds like racing sims as a whole are the WORST possible rendering scenario of any game due to their complexity in many different areas. [Not to mention that iRacing does a lot of external-track art for broadcasting cameras that includes off-track objects you'd really only see for scenic games or tv broadcast spanning cameras. Obviously don't expect any response or coverage on this one, but I figured use cases around specific types of games and rendering pipelines regarding those games might be an interesting topic as it can vary from something like an FPS, RTS, or racing sim in how things are even able to be processed. (Like Horizon Zero Dawn/Death Stranding/Decima engine stuff looks GREAT but I dont see it working with something like a racing sim) Anyways, sorry for the spam, just wanted to send something while I was thinking of it

Super interesting stuff, but I gotta say as we got to the more complex stuff, it started to fly over my head a little bit. You had great visual illustrations for the simpler stuff, but not for the more complex stuff. Probably would be more difficult to make, but would certainly help! One example of where I got lost was the hierarchy tree stuff.