How Lighting (Basically) Works in Games
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- เผยแพร่เมื่อ 30 ก.ย. 2024
- Edit: There is a mistake towards the beginning. A green object REFLECTS green and absorbs everything else. I had this fixed on day one with an annotation, but those are kind of unreliable :)
I am not an artist or lighting expert, so I didn't want to confidently say "How Lighting Works". But this video was requested by a few people, so I compiled a few basic things I've noticed as a programmer and a player of games. Please leave a comment if there are ideas you'd like to clarify or expand on! Or leave a request for a topic or tutorial you're interested in.
This was a cool blog post from nearly 10 years ago that gave me some ideas for this episode: www.moddb.com/t...
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Little mistake. RED coloured things REFLECT RED light and ABSORBS OTHER. If light is absorbed, we can't see it.
but but he is right kiddo
Król Cieni /// Exactly what I tough as well
@@UmmadikTas um WTF is wrong with you it's constructive criticism
@@UmmadikTas plus, it's general knowledge to know reflected light is what we see and absorbed light is light we do not see.
Yeah i was confused for a bit after two years of studying physics i thought it all went to nothing
The Order: 1886 is an extremely impressive tech demo.
*clap clap clap*
Certainly is. Great, great antialiasing on very thin objects that would "flicker" in other games, shame about the actual game
The interesting thing is that light sources themselves aren't usually _active_: The actual (surface-) _shaders of objects themselves_ will look for nearby or global light sources and compute the surface color from that - traditionally, no ray casting from the light source itself is actually done here. The light sources themselves are merely abstract properties sitting around to be read.
There are other things like image and lighting effects where raycasting may be done, but that's not usually the case
1:17 just because no ones pointed this out yet from what i see: you said it backwards. If a ball is red that means it *reflects* red light and absorbs all other wavelengths. the red light leaves the source, reflects off the ball and back to your eyes. black means everything was absorbed thats why black things get hotter in the sun because the energy is absorbed and heats up the material
you got the optics the wrong way around - if red objects only absorbed red, there would be no red light coming from it, so it wouldn't look red - an object absorbs every colour but the one you see, which it reflects (so that your eyes can receive them and see that colour).
More correctly, different stuff absorbs different wavelengths differently. It is not working in a way that a red object is absorbing 100% of other wavelengths, only black hole could do that. It just absorbs them more then the red wavelength in comparison.
I know you probably know that. Just for the others 😊
Small correction - at 1:15 it should be "reflects red light and absorbs all the other colors". The reason it looks red is because red is the only color that bounces off and gets to our eyes - the other colors are absorbed, so they don't get reflected back. So shining blue light onto a red object makes it appear black because blue is not reflected.
+9andrej6 Oops, sorry! I knew I mixed a few things up. Thanks, will correct it!
if one is inside a transparent red ball, then he sees everything inside illuminated by and only red color. if the balls surface reflects red and absorbs the rest, then he should be illuminated just by the 'rest'. this reasoning of mine may be flawed, though.
*"if one is inside a transparent red ball"*
That would be transmitted light, as seen through a red gel lighting filter. A solid red ball (or pigment) just absorbs all wavelengths except the red part of the spectrum. A filter will pass only a narrow band of wavelengths, absorbing the rest (apart from a little reflection and scattering within the medium). Different physics. It's complicated.
9andrej6 thanks for clarification. I was going to say the same then I found your comment.. :)
That is correct. That is why plants are green. Chloroplasts absorb red and blue light, but reflect green because they can't use it. The reflected light is then sent back out into space and makes the plant appear green. Absorbed light is not reflected, and therefore the object will not appear that color.
I wished you talked more about the math like you do in other videos.
The best part of the video was the last part.
"hopefully no one jumps back to look at this". HA! You underestimate my space bar skills
same
Use , and . to advance frame by frame. Could save some time next time you run into a quick shot.
jc78244 AHHH thank you so much! this will come in handy...but..I was so proud of my spacebar skills :(
Very, illuminating :)
3:06 Sorry,i did back to take a look :)
A red object absorbs ALL light of all colors EXCEPT RED. Only red light is reflected, as a result the object seems to be red. Black objects absorb (nearly) all visible light, white objects reflect nearly all light.
Generally light is electromagnetic radiation and our eyes are constructed to be able to register it. Purple light has the highest frequency, red the lowest (Visible Light!). Before Purple, visible light comes UV (ultraviolet) light, after red comes IR (infrared).
Manuauto You never saw black or white thing. If something is black, it absorb all light, and doesn't emit it. Even Black Holes emit light. White things reflect all light and/or emit all light colours.
Król Cieni I don't understand your point. What are trying to say? Or did you even read my comment carefully?
Manuauto Black objects doesn't reflect any light, and doesn't emit it. Light, that humans can't see also count as... Well, light. Ultraviolet is colour. Infrated is also colour. Even microwaves, radiowaves, X-ray and Gamma ray!
So? Partly that's exactly what I wrote.
BUT: " Infrated is also colour. Even microwaves, radiowaves, X-ray and Gamma ray!" To that I have to say that we can't see it with our eyes. These radio-magnetic frequencies are either too high or too low to be picked up by our receptors in our eyes. They are not color.
Manuauto They actally are. Some creatures can see them.
Okay but about your explanation of how colour work : it's the *exact opposite* of what you said.
A red ball is seen red because it *reflects* red and absorbs the rest.
Obviously; she's added annotations correcting that already :)
(Seriously, there was ONE point to get across^^)
Don't forget the plethora of people already making the same comment to which she already replied too XD
you've got it mixed up red ball reflects red light and absorbs app other colors
I agree with you. The picture is correct, but her explanation of why it looks the way it is is mixed up.
Another great video, thanks for sharing! I really like that your videos are so clear, concise and easy to understand - it really helps when learning this stuff! As a suggestion for something I'd like you to cover (as you said in the outro) - what about procedural generation and perlin noise? :)
Gameplay > graphics. Many 30 yo 2D games are better than The Order: 1886
Nice video. Love the info and your way of telling them. But you're going a little fast with the example pictures. I can barely read the text underneath them and look at them before they are gone.
Absoebs everything except red. Black absorbs everything.*
Tiny note on the lighting equations: The extra cos theta is unnecessary since N dot L ~= cos theta, and what this means is simply that the more parallel the lighting vector is to normal vector, the brighter the shading should be. Along with a solution for specular reflection (simulated using an exponent in Phong shading), this pretty much describes all of video game lighting up until about 10 years ago, definitely all *real-time* lighting (games as early as Quake 2 had pre-calculated radiosity, the reflection of a light ray from one surface to another).
Speaking of, you know what would be a neat video series? The history of video game lighting, from the flat shading of Alone in the Dark and Starfox to the hand-shaded surfaces of the 2.5D shooters, to lightmaps, to per-pixel lighting and normal maps (Chronicles of Riddick, of all games, is the first I remember with this feature), to the ubiquity of the Unreal Engine's deferred rendering, to the modern era of of global illumination and materials based lighting. How something works is interesting, but how something's changed over time is probably more interesting, since the former is usually pure math.
+Andy H Yes the original equation has N dot L, the dots in the video are multiplication operators (* instead of x), so it's actually |N||L|cos(theta) in the video. I'm still figuring out the balance of how much I should simplify math :) That sounds like a great idea! Comparing development techniques over time, I like it.
I'm the another one who was puzzled by this.... Now it's clear. "N" and "L" occured to be absolute values, not vectors as thay were called in video. Maybe it was better to put them in straight braces like you did in comments.
Anyway, the channel is great! It is much easier to get basic (even main) ideas of CG represented in this manner, rather than from lectures where they're covered with lot of varuables and formulas. Thanks for the videos :)
Ha! Youre puzzled? I know nothing about making 3d graphics and just read through this conversation, sounds like you guys are talking half alien lol!
So you talked about vertex lighting in the technical aspect
But what about another video for pixel lighting and shadows? :)
You bet I jumped back to look at that! :D
Good stuff. Really interesting.
Hi!
That video was once again great! I really like your "How X Works in Games"-videos.
However I find it a bit odd that you talk for the first nearly 6 minutes about the game design aspect of lighting, then you state that you aren't an expert in that topic but you know the math and theory behind lighting much better. After that you just take around 2.5 minutes to talk about the math and theory of lighting models.
Personally I am more interested in the "technical theory"-part. Of course the game design part is important as well but there are already quite a few channels covering that while I don't know a single one that covers the technical part as well as you do. I'm not telling you to remove the game design aspect I'd just recommend to maybe balance the two.
Ok, enough critique. Let's talk about lighting: using OpenGL I have already messed around with lighting on a lower level quite a bit. The lighting models you have mentioned describe pretty well how lighting is done in most games. However when you apply just those lighting effects to a bigger scene with multiple objects you lack an important thing: depth perception. The solution to this are shadows. Unfortunately all common solutions to create shadows in a rendered scene are ugly hacks. The two most common one are shadow maps which get pixely and blurry and volumetric shadows which are computationally expensive. If we would render scenes using ray tracing there would be nicer and cleaner solutions, but that's rarely done for different reasons.
Overall I have to say: your videos are inspiring and entertaining to watch.
Keep it up!
+tdc Hey, thanks for the feedback! I was trying to introduce the topic to someone who might not know much math or programming. I can do a purely technical video in the future to cover more of those topics. Still trying to balance what the average person finds interesting, and what a programmer finds interesting!
You should do that! :D
TheHappieCat I would love a "how shadows work in games"
I know you're working on your game right now, so I guess if you do decide to make it, it might take a while.
Blinn > Phong. Deal with it ;P
hmm i guess when i play a terrible game its just a really bad game for me, but when you play a terrible game this must be much harder, when you can actually see and understand on how many level people fucked up.
Basically when Dev's say "Remastered" they mean better lighting? Ok with the occasional patches here and there...
While you talked about RGB it came to my mind that you maybe could do a video about RGB vs sRGB, what's Gamma and Linear Space and spiced with the non-related pre-multiplied-alpha topic because those are issues which to me often seem "blurry" to understand if you know what I mean :D
it should be the other way arroun i think. the red ball absorbs all light but red. it reflects red light, making it appear red.
I jumped back to look at the single frame of you. :P No amount of slicing gets by my eye...I think.
When you used Bloom Waker: HD as game that reflected too much light, that was good joke, but you should have immediately followed it up with Doom 3 when you said games could have too little light.
Oh wait, but then you complimented it. I don't think anyone denies that Wind Waker: HD looks like a better game than the GameCube version, (though that's questionable when it runs on Dolphin at ultra setting), but clearly, they oversaturated the game with reflection.
In regards to the Order, whether the elements aside from the visuals were so utterly inadequate that it made the visuals almost immaterial in judging the game, I won't say, but if you look at the game's, you can clearly see numerous tricks the developers used to achieve high fidelity that it became distracting. Uncharted 4 approaches the visual fidelity of The Order and it's actually a game.
Actually Quantum Physics got light wrong, photons, a quantum packet of light, just so you know I know the definition lol, dont actually exist but light is more of a ripple on the ether like sonmeone standing in a pond and waving their arms forming waves. So I agree light is an electro-magnetic wave but it is more on the lines of pressure and flow. This makes the speed of light non-existent since light doesnt have speed. It would fill this comment on explaining it but you get the picture and if you subscribe to the Quantum Theory, we will agree to disagree.
You are super intelligent, more so then me, I know obscure facts, but I believe everything that Tesla said and did, so that way you know what I believe when it comes to physics. Gravity and Relativity are BS and there is alot we are yet to discover but we will, we came this far. I love an intelligent women. I am not being sarcastic either I mean what I say. I might not be right all the time but I mean it and until I get new evidence, I know what I know and I hope to learn volumes from you.
5:18 I dont agree with this, i feel like good game design should make you want to explore instead of blasting past everything, the aim shouldnt be to get to the next part and to the next part, the fun should be in solving the mystery otherwise whats the point? and lets say you ARE invested and want to solve the mystery, spotlights make it too easy you dont feel like you figured out this amazing mystery yourself you feel like the game is holding your hand saying: "look here stupid!"
then you start blindly walking from one highlighted thing to the next and then it just becomes a task and a chore, you stop thinking and just do, im sure most people know what im talking about.
Im the sort of person that when i visit a new town/city i want to see the locals and what its really like to live there not see the tacky tourist attractions.
dude now i feel like an idiot for totally ignoring those sign an bible verses in bioshock infinite. i just rushed through the tower like an idiot. i just wanted to get the part i start killing stuff as soon as possible. and really thats all i do nowadays. long ago i used take my time and go everywhere/break the game. but back then there was like one game per year that worked on my pc. and there wasn't that many games either.
Should check out the Brigade 3 engine, it uses photons to calculate accurate and realistic lighting.
You will see games that use fake lighting as inferior to it and will no longer be impressed by the next-gen game tech demo because the lighting will never look as real as what it does in Brigade 3.
You sound exactly like a female version of gbay99
so how do shadows work? do i understand it right, that they are actually transparaent shaded polygones of the silouette of an object in the way of an direct light source?
absorption and reflexion are inverted in your explanation. A red ball REFLECT red,
Great video. Really interesting
Did you confuse absorb and reflect at 1:15? If an object is red, it absorbs green and blue and we see the reflected red light, right?
I don't know why, but to me N64 had a bad lighting compared to PS1
if u can't stop it at the moment just make ur video slower then pause it ez so u dont have to do the timing and stuff and great video
A red ball doesn't absorb red light. A red ball reflects red light and absorbs all other light
So you need only one minute to get color and light theory completely WRONG. Good job!
You should come work for Nvidia, let me know if you want a referral
Lighting in Fallout 4 is horrible I love the game but gosh I hate the lighting so much
I don't know why I thought this is about how to make a thunder storm in games lol
Some of us like to see every single frame and comment, 3:06
3:06. so Why put it in the video in the first place?
now i understand everything about games
Bethesda Game Studios should watch this video
No dislikes damn that's cool ahah
Hey, your videos are very informative and easy to understand. Could you do a video on what deferred rendering is? And what forward rendering is ?
3:06 haha sorry but I jumped back.
Isn't it the other way round? The red ball absorbs all the other colors and reflects red light, that's why we see red. And black object absorb most light, therefore no light reaches our eyes so it looks dark.
+Legit Name Yeah, just fixed that. I think I mixed them up in my notes and then read it without thinking.
Was I the only one who went back to 3:06? 😜
So when light hits an object and reflects from it and then comes to your retina, you see the object.
So what you see is what is reflected.
If ball looks red, it reflects red.
If you strike a ball which was red under white light, with a light which has only green and yellow, Ball will absorb these two colors and will look black.
When your describing, which is beautiful, Phong and Lamertian Lighting are the Uppercase Letters mean those are constants and its always cos (theta)?
Any chance you could do something about Simulators? Cause Simulators often get the fun aspect of "Oh development is taking too long" when a lot of research is required.
Great topic. Bad teaching.
No dislikes, keep it up
Why did you put a single frame of yourself into the video? :D
I don't write donw the exact second of the frame here. Perhaps you don't want anyone to see the picture. :)
This is at least one explanation for why you hid it.
In my opinion, as far as math and physics goes, I think you should give us what you got, and connect it with programming using lots of jargon and very brief explanations without distracting from the main topic. This is because it seems like you've covered most of basics in game design, and the tough concepts are up to the viewer to research, and terms and subconcepts that are not understood by the viewer are just a Google search away. I like how you include the mathematical methods and programming terms already because they're all huge concepts on their own. I'm just saying this cause I decided to take up tensor calculus with just a basic exposure to linear algebra and I've found myself somehow handling the information density by supplementing the material with further imbedded research during the video. Also the guy is an outstanding educator and so are you so I think you should make an "advanced" segment cause I know you want to share your physics knowledge but avoid it ;)
You did a complete 180 on the concept of reflection and absorption of wavelengths. Still nice video as usual. Just edit it out. 😊😊
Lol why so many cats?? :P
3:06 caught you! :P
On a serious note, lighting while rendering scenes in 3d using blender taught me its importance (in the difference it makes and how photorealism works). Plus as you already mentioned it sets the tone of the picture/scene.
I jumped back to look at that!
3:06 caught you! :P
On a serious note, lighting while rendering scenes in 3d using blender taught me its importance (in the difference it makes and how photorealism works). Plus as you already mentioned it sets the tone of the picture/scene.
Thanks for all you do. I just started game design a few months ago and made a mistake of jumping right in without any understanding of the basics. Watching your vids really helped me to comprehend and think about how I need to go about creating artistic and interesting assets. Please keep up the great work!
A month ago I realise that the Lighting is pretty fundamental for a good design of a video game, I really liked your video :D
this video has 0 dislikes
wow, that's a lot of maths just to light spazzing tf2 models in Garry's Mod
I’m learning so much! I thought these kinds of lighting were just names!
wow, everyone is trying to fix the boo boo...lol. Great vid, love the kitties being drawn everywhere hehe
Too bad, I looked back to see your old selfie. XD
Also, what's the game at 4:14?
The second Maximo popped up i knew you had read Level UP: guide to game design.
Can you please make a video on physical based shading/lighting and deferred rendering ?
hahah Alien Isolation
omg I feel so dumb.
what happened to her channel i would love to see more content from her in the future?
DoDDD RTX 2080 ti and everything is resolved : > }
Great video
Awesome video!
Nice tutorial.
interesting video, love the The Order 1886 shoutout at the end. I still feel somewhat bad for the studio for the sheer amount of undue hatred they got tossed their way.
By the way, I have a question for you. Not sure if you're the best person to ask, but you're the best person to answer this question who I personally know of, so here goes. I'm 25 years old and looking to get into computer science next year. I have 9 months to get my fundamentals up to scratch when it comes to the maths required. Do you reckon that's doable at all, for the average person?
+HecklerSC2 It's very dependent on you, your goals, and the requirements. I want to say yes, since lots of things are possible with hard work. Try looking at online courses and see how fast you are able to complete them to get an estimate!
you dont even know how reflecting light work xD
Thanks
WOW 0 dislikes!
Really great video!
happy halloween today c:
4:17 wat is dis game :o?
Great vid!
3:055 min
so basically you can do physics art game dev maths
i feel stupid :D
thx for the vid