Mtg 2/25: Wed-06-Sep-2023

Outline for Today

Wiki

Link to the UR Courses wiki page for this meeting

Media

Transcript

Audio Transcript

• I just didn't want the floor
• Did you find it
• interesting so not this one this is
• okay
• I never had it open the first day or the first hi
• you don't have to knock to come in
• Okay doctor
• is there any way that I can go back and get my attendance oh
• I'm not going to penalize you for the first one for the first one Yeah Is everyone in attendance market or is attending
• you What's up
• afternoon
• okay so
• this is a live website
• this is my website
• and once you log in if you're logged into your courses
• you'll see
• this come up
• so, now that
• we're on to our courses
• so that's, that makes sense.
• I'm still
• so I had the running. I'm building this website using Jekyll. So anyone use Jekyll before. It's a static website generator. And I I picked it because I started out doing my GitHub Pages website. If I had to do over again, I probably would have used a Python exact Python tool.
• Using the Django framework would have been much faster because it does give you everything out of the box like the boilerplate itself gives you an admin token.
• Yeah, the Django is nice. But I'm not. I'm not talking about putting the Good morning sir. Good morning. Have you gotten lost? Yes I've entered the classroom so we're still seeing what half of a half of the students have been lost today I guess so just a thought you don't have to come in and say good morning to me when you're coming in late so I don't want to be too heavy handed about it but let's just try and take your place and you're welcome to come in as an undergraduate in my computer graphics class and happened to be well this is not just the computer graphics class for this was my professor for that class and some others he would lock the door once the class time started so then we were out of luck and some people would knock on the door and incur His wrath even more so I'm not gonna lock the door or anything but just come and join us and if you have questions we'll deal with them as they come up no problem there but just so we're not a big group even while we're a smaller group today still.
• Anyway, I just felt I should mention that so not I will want this to be a welcoming supportive environment but respectful as well so that makes sense okay.
• So if you if you go to your courses
• Okay, so if you log into your courses and you'll see this screen and if you go to CS 733 on Dr. haptens website
• get to this page
• because of our meeting for today
• so, our meeting again on Wednesday, so, Monday is our first Monday coming up. That'll be our first full week
• so let me
• go through a few things here. So these are your courses links. So attendance so it's a short you don't have to go through
• this page.
• So here's a shorter thing, or shorter URL to get you.
• So this is today so we're in this first week. Lock of our meeting too
• so that'll get you to the
• meeting page for today so you can tell me if this is helpful or not so
• this is
• in the participation forum you can make some comments about this and if there are problems with it
• anyway, so to get back click on meeting to then we can get through the attendance
• you haven't done attendance yet and you'd like to do the QR code take a minute to do that right now
• Please.
• For most of you arrived asked me how my weekend was. So it was good. Saskatchewan Roughriders one. So that's always a good thing as far as I'm concerned. So my son celebrated his 21st birthday this weekend. And I remember because the day we went to the hospital
• to for my wife to give birth with riders are playing in the Labor Day classic and I I remember because there's a quarterback who's never been heard from again, his name is rocky Butler, but he can't he came out of nowhere to win the game. So I said that I I'm maybe one of the few people in the world who remember him. But that was this very special day not because they won
• but just
• the two things the birth of my son and and the winner of the Labor Day game are connected. Anyway, so aside from that this is part of what I did. I thought I'm going to upgrade Ruby on my computer. And I spent several hours. So finally, with no success and I finally came up with this, I decided to ask a question on Stack Overflow
• so that was
• that was a
• few times I thought it was close to solution. I thought okay, this time it's going to work but
• no such luck.
• So me and I realized I have such an old computer that can't be upgraded to Ventura, which is the new version of the operating system. So I think I'm due for an upgrade computer this year. We have an evergreen program. So I look forward to doing that. But anyway, so that was So one thing
• so this is another
• your courses link so that tells you what's going on today
• so I don't mean to make this all about going through links in the class but I just thought I'd point out where the links are so people can
• see
• what's coming up
• so
• and here's a reminder about response that opens after class and closes at 11pm tonight
• so this gives you
• not just today but things in the future upcoming so we have that choice for midterm date. So you're gonna fill that out if you haven't already
• okay
• senator and brother in 10 cards I just want to make sure I'm just gonna circle your names if you'd like to be called.
• Yeah, I found you here I'm just gonna say that's a particularly difficult combination of yellow highlighter on white background it's like reading an invisible link
• okay everyone's
• Okay
• 10 cards and they would like to be called so I'll try and make use of this information and see if you can still bring them for next week and I'll try and get familiar with that so writing responses so I just want to go back to our meeting
• so after the
• meeting happens I'll post pictures of the blackboard green board, chalk board whatever you want to call it
• and then I have the transcript from otter
• so maybe
• third is if you're doing wikis if you're going to augment the wiki with some of the material from the transcript, you can maybe use the transcript as a guide to what we discussed.
• So I have a link to the
• wiki page from last day.
• So thank you for
• putting that up
• so these are the summary of responses
• so I've marked a few that I that I didn't get back I'll finish marking the ones from Friday
• so this one
• I'll give you a mark one out of two for this but still remember the instruction so
• so a couple of things.
• So pick one of
• one of the three headings
• the most important thing that I encountered the most difficult thing for me to understand think about which I'd like to know more and in the instructions it says don't write a description of what we did just give your impression best.
• Friends, think of these as questions you're answering. So you pick a question What is the most important thing that I encountered or what is the most difficult thing for me to understand? Or what is the thing about which I'd most like to know more? And write an answer based on that. 512 characters
• so excited to know more maybe that would fit under here so I don't want to make this too difficult. I'm not trying to nitpick here but I just would like you to take it on in a thoughtful way
• Okay, so
• a couple of responses to the responses
• so there's a comment about
• specifying color as let's take a picture
• so hex digits go from zero to f so we're letters take over from 10 is a, b is 1112 is C 13 is D, 14 is E and 15 is F so that all familiar.
• So
• I thought this is an opportunity for me to show you a magic trick they were like magic tricks. Okay, so I like a volunteer and I'd like you to pick a number between zero and 15 Don't tell me keep it to yourself. I'm going to ask you four questions and based on your answers I'm going to psychically sense your answer and give you give you the number you've guessed you've selected
• Okay, who's the volunteer? Okay. Shoe. Yep, that's how I know but you're fine there.
• I just wanted to know that. I can think of today's announcement a profit. Okay, do your thinking you have a number. Okay, so
• number on this card
• is remember on this card? Yes.
• So that's what the card looks like.
• This is the first card I showed
• on this card I guess
• finds your number in this card
• sensing psychic energy
• number seven yes
• anyone familiar with this magic trick
• okay to have another volunteer All right
• yes
• okay is your number on this card
• is your number on this card
• number in this card
• is your number on this card
• blocking
• numbers for that is correct
• okay so Are you sure you're Dr Hepting and not talk to Houdini
• Yeah well I'm not very good at escaping
• anyway let's so let's any ideas about how this is working who believes that I'm using my ESP my my magician's abilities to guess your numbers that's good that nobody thinks magical abilities.
• Okay, so we're gonna pick a number between zero and 15. So what do we notice about the numbers that I asked you to pick from? As we go into 115 Yeah, okay
• this is another way to save zero and 15 right
• so it's like
• a VG two quickly here
• Okay, so, here we talked about four
• bits
• and does the number four come up anywhere in that trick?
• Just once
• in your in your guests it did. But is there more generally in this? How many cards do I have?
• So let's write out our hex digits here.
• Zero is if you
• write his four bits it's four zeros
• and ones 15 At
• the other end
• let's see right so it's all once
• they were no
• joke about how there's 10 kinds of people in the world
• those who understand binary and those who don't
• right so that's number two in binary.
• Mr again, it's 1112
• think those match up all right so what's the other connection between that table? You can Oh, you don't need to correct me. You get the idea, right.
• What's the connection between ones and zeros? And what I was asking you to do?
• I asked you for a yes or no answer right
• yes
• so in what I was asking you is tell me your number think of your number in decimal and then I'm asking you for questions which you're encoding you're telling me the number in binary
• so when
• so the numbers here on the one card the first card are all the ones that have the Lord or bitset and so that happens to be eight of them and they fit nicely on a card like this and then the two card has ones that are next position value of two four card has that and the eighth card has just one starting at eight to 15 So if we say no to all the cards all right guess is zero. So now our algorithm
• to do this is
• start with you start with set your guests to zero keep track of the yeses and add them to your guests. So if you guess number seven or if if the participant said no number seven, don't say yes to the one two and four cards, no to the eight card so one plus two plus four is seven and I'm not gonna get in trouble with any magicians union for time that story. So that makes sense. So this is a way we can think of
• we can encode values with bits so we can encode 16 values with four bits, we can encode 256 values with eight bits and as we talked about last day, so two hex digits 256 values that's a common way to represent values for the different color channels. We'll talk about color in computer graphics so
• okay then
• don't know if I should try and do this again see.
• So here's a car asking me about my computer graphics work so I
• this is on my website, a collection of images
• and some other things I've done related to fractals.
• I was going to add a link to a newer thing that I did last year. Video
• For our next meeting
• so I'm
• a president I'm interested in, right, you can look at the collection of my publications if you'd like
• me to do some
• updating on that material on the website but useful open data, so linked open data and other kinds of other forms of open data.
• We can make them more accessible and usable for people, for citizens to contribute and to use them. Anyway, so here's the countable course structure.
• So I will post the official syllabus today. My technical difficulties got in the way of fulfilling that. I said I was gonna have it done today, before class, but I'll get to you today.
• So here's the textbook link.
• So that's the pure publishers website, the Canadian website for accessing. So if you there might be earlier versions available. So it's, it's a reference for you. It's not required. And here's the website to support
• a textbook. So we'll be looking
• at examples from there. So a question. Oh, great distribution. So we talked about this last day. So 10% for the midterm 40% For the final 40% for five assignments and 10% for participation. There's a common WebGL versus OpenGL.
• So we have GL is
• a Javis is a web implementation of OpenGL embedded 2.0 for embedded systems. So there are a few differences
• so I guess the next thing, and I'm not sure what is coming along is sort of WebGL that might be web GPU. Because the code we'll be writing this time talks about is making use of the GPU
• Anyway, okay, so I'll be doing was getting three Gs installed and
• anyone try that out?
• Right, yeah. Okay. All right. So we'll talk about that again on Monday.
• Go through so.
• We'll go through that example and some WebGL code
• combination sound
• fun and quantization
• sorry
• so this is the audience participation part and ask a question you can feel free to answer or ask another question
• okay let me talk some more than
• for all I need to be writing bigger way back in the back back I'll try and submit I need a
• truck in the truck
• so what are creating an image
• on the screen so
• so if it's on the screen we have a final resolution so maybe it's 4k so
• it's
• I'm not sure what the resolution of my screen is here anyway
• so when we're talking about what makes up
• an image
• is there a word that comes to mind that you're familiar with?
• Okay so what is a pixel
• so
• it's a physical convener which contains all three goals or GDP
• the starting point for our discussion
• we're not actually
• it's not a single
• let's see if we can zoom in here
• now this isn't
• anyway so they did let me try this me get back to our basic resolution
• not sure what I'm missing here
• there we go
• sooner zooming in
• it's difficult to see here but the idea is it's it's not a single location on screen that has contains the red green and blue red green and blue are separate but they're in close proximity so the impression is that we get the color
• ID each pixel has
• so you can see each
• pixel has a value associated with it
• how do you associate a value with excellent?
• Something else is as quick as a pixel a square or a rectangle
• does it have some
• built in geometry that we're when you zoom into it like this does make squishes maybe So it's not inherently a square so if you want things to look nice on the screen
• we'll make them square
• do much better with a whiteboard and a marker console I'll have to recalibrate my writing a little bit I think so when you have issues reading when I'm scribbling on the board please let me know
• so
• 1416 by
• nine so that's
• it more traditional earlier displays were
• forced by free
• read a square one to one
• does anyone seen bad websites where pictures of people are stretched and contorted and imagined so happens too often so not keeping an eye preserving the aspect ratio of the image
• so it's better to think of pixels as samples of this continuous phenomenon that we're trying to represent attorney discretize
• see some
• smiles are you laughing with me or
• anyway
• so the pixel is a sample
• so since we have
• a zoomed in image here that's
• so you can see it's not
• displaying text or not just
• producing the outline
• so, there are some pieces that are darker than we were also
• let's start here.
• So that's,
• that's the center so the way to interpret this
• So you can please forgive my knots square drying here
• with so this so we're taking a sample of a dot here so it translates into
• so
• this one in the middle gets full value because it's
• it's fully covered by the by the auditor sampling
• and then the other ones get less than
• two the reason why it's spread out like this
• okay one minute left. So, anti aliasing
• never understood what it means.
• Okay, so
• Zaven heard the Nyquist Shannon, or Shannon Nyquist.
• So the idea is if you want to reconstruct a continuous signal, you need to sample it twice the highest frequency
• so
• when we're doing pixels we want to make sure that
• in this case so what happens if we have an object like that
• like that
• so at first sight if we take a sample from the
• middle of
• the region so if we say
• we're going to treat pixels as squares, and we're going to sample in a grid like this. So, here we can get a set we're gonna hit for this one.
• But we'll miss this one. So this is
• so aliasing because we're not sampling at a high enough rate if you want to want to represent this. We have to make the samples close enough together to catch that. Thank you A mesh screen that we're trying to if you want to catch for panning for gold
• or something valuable
• we have segments and sad I want to make use a screen that's bigger than a piece of and we're looking for it to be on the safe side you want to make it twice as fine as the thing we're looking for
• so you may have heard about this
• in terms of audio
• CD is sampled at 44.1 kilohertz and that's because
• most people can hear up to 22 kilohertz so sampling at twice the rate that makes sense okay, so thank you for your attention today we'll try and
• pick things up just trying
• so please
• look at three Jas get that started and then we'll look at some look at the interactive website
• Thank you for today
• have a good weekend thanks.
• Says but there might be somebody who computer science officer if you're interested in
• getting the stem
• myself
• okay, you're clear you're free to
• okay, you're clear you're free to

Responses

What important concept or perspective did you encounter today?

• I learned pixels, they are defined as physical containers with RGB components. i also learned about the anti aliasing very easily.
• I learned about the Pixels and Sampling and anti-aliasing more clearly, pixels are samples of a continuous phenomenon
• How aliasing is is the effect that creates jagged lines in images and how it can be mitigated using the sampling at a frequency higher than the Nyquist Sampling Frequency
• During today's meeting, I discovered that the binary guessing game was quite intriguing. I made an attempt to reproduce and resolve the problem mentioned in the following Stack Overflow post: https://stackoverflow.com/questions/77047179/build-failed-macos-12-6-8-using-ruby-build-20230904-rbenv-install-3-1-2. Regrettably, I was unable to find a solution.

Was there anything today about which you would like to know more?

• First of all, the magic which professor displayed in the class was very interesting. Now I'll be befooling my sister with this trick. Secondly, I heard the term WebGL from professor. I am keen to deep dive about this in the times to come.
• In today's graphics class, we explored pixels – the tiny containers of RGB color and how they shape our on-screen images.