How were the portals in Portal created? | Bitwise 

The video is extremely well made, you explained something really complicated in an easy and exhaustive way

Actually great video, good explanation and interesting topic I will wait for more

Please make new content. I've discovered your channel half an hour ago and I can't stop watching your videos. There are explained so good.

Moet je echt doen!

I think it was thanks to the yourtube algorithim

Or does it? Mindfield Intro starts

Hey VSauce, Michael here

Or is it? *vsauce music intensifies*

@@De50prala Where are your fingers.*Pervert

Wait what he hearted you 4 days ago

I thought that might become a meme some day.

layman's terms

Fun fact: The Unreal Engine 1 already had portals called WarpZones. Admittedly, they had to be made at map creation/editing and they wouldn't handle hitscan, but otherwise, yeah. This shit way back in 1999. Just another reason in a long ass list of reasons why Unreal Tournament is GOAT for the PC.

can't explain that

I love how it's the same sound that "ADA" (the computer of the ship) in Outer World has. Good things don't disappear.

yeah, I wish all coding tutorials were like this because when I copy someone else's code maybe I'll understand it but there's no way I would be able to apply it to a different situation

@@mikul9204 Dependes a lot on what you want to archive. If you are teaching a general concept (as you do here), yes. No code is better. But sometimes you want to teach how to do a certain thing in a certain language. Then it's better to explain the concepts and then walk through how to put that into code

Ya, but It would have been nice if he linked to the source code though. That way we can take a look at the core algorithm.

I just don't like coding so this is the best type of video to explain what's happening.

I would like it to be a coding tutorial. Otherwise it's just useless

Make portal layer invisible to the camera

@@OutOfNameIdeas2 this is a dumb way

You have the portals camera look through and render the same image, but smaller, and overlay it in the middle of the first (at the scale). You also get a very slight intentional bend in the render, so eventually, it bends away and prevents indefinite looping at specific angles, which prevents the game from crashing due to infinite re-rendering of smaller portals. The angle you add to each render is directly comparable to how much rendering your system/engine can handle. For bad computer or engine, add more angle per render and have less portal renders. For better computer or engine, add less angle each time and therefore have a bigger "depth" by having more rendered portals. Try this sometime. Get two mirrors, preferably one on the wall and another small handheld mirror with an opaque backing. Try to see an infinite loop in the mirrors by facing them at each other. You will notice that no matter how hard you try, you can never see an infinite loop because the pattern in the mirror eventually bends off and prevents further patterns from being made. (Technically, if you had a 1-way see-through mirror and you looked directly through the back of the 1-way mirror at the wall mirror, then you could see an infinite loop, but we are coding the game to avoid this.) This principle of never seeing an infinite loop and only ever seeing so many at once is exactly how the game never crashes (in theory). Note I know nothing about the coding, but I do understand the logic behind it, so please correct me if I am wrong.

@@Turtledud3 Your idea is interesting, and it would work. However, I believe the effects of perspective would become broken (that is, the further an object is, the less there is a visual scale difference between its frontmost parts and its rearmost parts). I don't really know :)

Oh yeah, stuff like this: ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-0TZd95BCKMY.html Would be nice to have a nice demo with explanation for that

Nick Robinson Sup Nick

This is the last place I thought I'd find you

So i flew to japan to find a portal.

I am now permanently attached to the reply chain

Hmm i dont know how to see geometry frames and shit with the command prompt in source so im gonna see if someone else has photo or video evidence

@@kaydencebernard7775 Pretty sure one of the CO-OP map developer commentaries has a commentary node that shows you how the geometry changes.

Q: Who created Aperture science. A: Cave Johnson.

Q:who created Cave Johnson

@Poralisium1337 humanity

@@SalemYbor I was gonna do that

@@SteelRider who created humanity

I still don't understand the graphic part of making games (masks, shaders, redering, etc), hopefully, one day I will be able to come back to this comment and understand your solution.

@@shumanbeans well, if you have any specific questions, i might be able to answer them though if you're just starting, googling a tutorial might be beter

@Joe Duke what do you mean?

Thanks, I spent the entire video wondering why you wouldn't just use this approach.

@Joe Duke ah, alright, no i've never used a 3rd party game engine so i 've no idea what they're like

I guess it's basic to actual game devs. It seemed very simple and straightforward the way he broke it down. But I realize now that that's definitely because I have background in this, Unity in particular. So the basics of portals.. if you know a bit about game development.

i think this would count as the basics, though functional it lacks some important mechanics that i recall were implemented in the games, namely the conservation of diagonal velocity to the portal utilized in portal 2 along with the infinite mirrors effect you can get by placing two portals across from each other

Yeah this is just the basics

@@CabbageGod I can confirm that. I created a portal effect myself a while ago and when you have done that you will know that this was just the basics. Implementing it had a bit more to it than these basics. For example, you will also have to use oblique frustum for each camera to make it look right. This means that you set a plane in 3D space where one side of this plane will not be rendered by the camera. This is necessary to clip everything behind the wall the portal is sitting on. For example, imagine a thin wall with a portal on it. Behind the wall, there is a box. Without oblique frustum, the box will get rendered when the camera is behind it and this will look odd when looking through the portal. With it on, the box will not be rendered. There are a lot of other details, like raycasting (shooting an invisible line to detect an object; used for example for picking up boxes in Portal) through portals, keeping the box in front of you while it is on the other side of the portal, physically at a completely different position, etc.

@@CabbageGod The camera part would kill me. The physics part is not straight forward, but that should be fine. I might figure it out in few days if I didn't give up

can you make tutorial or upload project files please?

Can I get some of your brain?

Can you elaborate a bit more on this strategy?

If there is enough interest, I will record a tutorial when I find some time

Samuel Van Allen That would be great.

yes there are

@Sébastien Levesque there is this portal shooter

I know that's not the point but there are some really good Portal2 mods.

try mari0

Well, there is the predecessor of which portal is a RIP-off (game mechanic, not story). "Narbacular Drop". According to wikipedia, valve hired some of the devs of this game

Maybe he'll come back and see his channel booming?

youtube has been doing this nonsense a lot lately..

​@@cembaturkemikkiran4109 Check out the channel mix and jam, it does the same kind of thing showcased in this video but the channel is active

Check out the channel mix and jam, it does the same kind of thing showcased in this video but the channel is active

@@hubjump Check out the channel mix and jam, it does the same kind of thing showcased in this video but the channel is active

NOBODY'S GOING TO SPACE MATE

No FBI, No.

aight brb

If you ever programmed a 3D camera position matrix, it's actually pretty straightforward. The portal basically transports light rays, so we can either move the whole scene to be where the portal shows or move the camera. This is the same how mirror/water reflections work, just flip the camera to the other side, render it to a texture and map it to the reflective surface.

And viewer be like, "let's watch this content which we dont want to just for the sake of getting like by comenting comment which there is already like a infinite of them"

...call me maybe?

XD

How did you solve the camera clipping through the wall? gyazo.com/435e1ce3f34e10c2bafecf7cd9ee13e7

If the camera is clipping through the wall before the player teleports to the other portal, you would either need to teleport the player a bit sooner, or change the clipping plane of the camera to be much closer to the player. Since you'll basically have your face pressed up against the wall, your camera has to have a really close near-clipping plane :)

lol hey look its Smashen!! are you planning to upload portal or splitgate arena warfare to your channel now?? >.>

@@daetheknight. You know me from somewhere? Currently I am a DBD youtuber. I once had Portal lets plays on my channel a long time ago 😆 Not sure how people react if I suddenly upload other games

@@smashenYT lol I watch your dbd videos all the time. Even join your stream when I can catch it. You can do a test video and see how people respond to it. Plenty of other toobers try it. And if it works then you have more things you can do. If it doesn't then you can go back to dbd

@@daetheknight. yea your name seemed familiar. RU-vid recommends this to everyone I guess 😆 You want that in English on my main channel?

@@smashenYT si, creo que el lenguaje seria perfecto

*S P E E D Y T H I N G G O I N S P E E D Y T H I N G G O O U T*

@@thepixelkings3491 lmao i was a bout to reply this

SandeMC exactly same xd

Asking the same thing. Is the image stretched or is it positioned to make it seem like we're looking through a hole? What does the whole portal look like if it was the whole wall? How is it supposed to look like if we were to look at it in a different angle (assuming the viewpoint is still connected to the player's camera than the second one)? I got all the things listed here expect for the distance part. I honestly can't wrap around my head around it.

its stretched out. Its like changing FOV in a game.

Just imagine putting a camera six steps away from portal, 3 steps ahead of the 9 steps portal, because you are looking from nine steps the resolution is for example 1600 x 800, because field of view increases with distance, so now you just crop the displayed resolution to the correct resolution to maybe 1200 x 800 and display it on the exact same mirror size as the portal enlarging the object and making it look closer, all the while calculating the correct setps

I don't if this is the right explanation but: The image on the portals comes from the image gathered by the portal camera. The camera gathers image in a ratio that is similar to display (most likely 16:9) which is longer horizontally. But if we try to project that in a portal which is longer vertically (likely 1:2), the image produced would be squeezed in the horizontal axis. In order to counter the squeezing of the image in the horizontal axis, we just stretch the image horizontally before projecting it in the portal plane. Also as he mentioned, we don't need all the information that cannot be seen through the other side so we just discard it and scale it up so the portal only projects what the player must see. Hope this helps, although I don't know if this is the exact thing that he is mentioning in the video.

That's actually very important.

I haven't really gotten much exposure yet. I try to just keep making videos and hopefully we'll gain some subs some day :) Can I ask: how did you come across my channel?

I'm not the guy, I'm another guy, and I'm not 100% sure how I got here, but I can trace it back probabilistically. I'm gonna say that probably you were listed along some other lesser known game development channels in some reddit r/gamedev post about "good game analysis channels", to which I'll venture to say that a disclaimer was probably added about how your channel "is not updated often but the videos are great practical in depth stuff" to which I would have agreed after browsing the backlog. I probably subscribed after checking out this along a few other channels on the list and I remained subscribed with the hopes of sometime getting one of the cool videos produced here, such as this one. That's enough with hypothetical remembrances. This video was indeed very cool. I appreciate your practical quest and analytical process walkthrough. I thought it was thorough, thought provoking, motivating and engaging. Keep at it!

You sure will! Keep up good work! I think I was looking for Hotline Miami analysis. That brought me here, I like what I see, so I sub.

Владимир Остапенко 698 now, vladimir :D

You showed up in related vids for me, but I'm actually the head of social media at a Toyota dealership and I 'd love to lend you my marketing and branding skills to help you get exposure. I was so shocked to see you had under 1,000 subs, but from the sound of this guys comment you've already come a long way in a year. I don't wanna get paid or anything. I really just enjoy your content and want to help it reach more people. I hope to hear back from you (:

Yup. Though unfortunately, the visual side is buggy as hell due to GMod's limitations, and the physics is wonky as hell too.

@@randomcatdude ye, i imagine it's tricky without rebuilding the source engine

thats how programming works lol

Is that a motherfucking jojo reference

but that would also cause issues with room overlap, where if the duplicate was on top of another room it would break.

That's a good idea but it would pretty much then double the gpu the game needs to run which is no fun

what puzzles me is how they manage to implement them in Darksiders

Darksiders was awesome. It had pretty much any game mechanic you could imagine in there.

yeah, that is why test chambers are separated in both games

create another cube at position: offset + pos = (current portal - position) + other portal. And something similar to rotation. then when exit destroy that clone.

@@thewowo Yeah but how do you set collision?

@@MMedic23 well, thats more complicated; make invisible walls around the portal and make that the things in the portal only collide with that walls.

@@MMedic23 or disable the clone's collider an rigidbody

That is probably just the skybox or the hall of mirrors effect, you cant just instantly place entire rooms easily like that in the source engine.

You just saw the nodraw.

@@KaNofbeans could be, just saying what it looked like lol

@@sharp14x definitely not nodraw, no nodraw effects and there was nothing behind the wall in question the same shape as the room being shown (bear in mind this was a rectangular puzzle editor room)

@@Starwort I would guess this is a result of the stencil-buffer rendering. I'm no expert, but perhaps if the wall around the portal vanished it might not stencil out a proper portal shape and would just render the entire room. If they just placed an entire copy of the room behind the portal, you'd be able to place a portal at the edge of a wall and see the copy of the room appear behind that wall.

I also made some portals in UE4 and I have the exact same issue. Did you solve it?

I haven't really thought about this and I've never done any game programming, but couldn't you make it so rendering "rays" can only hit stuff after they've passed through the portal or something?

Maybe you can simply adjust the render distance in order to render only from the portal. That way, objects between the camera and the portal won't be rendered

@@Asjagadra yeah that kind of works, but at some angles it doesnt