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Comment my CG Tutorial!

Started by Lode Jul 8, 2004 at 12:13 PM 15 replies 1.3k views

Original Post

Jul 8, 2004 at 12:13 PM

I've started working on a computer grahpics tutorial. Only a few articles are ready but more will follow! I'd like you to preview it and give comments, and here's the link: Lode's Computer Graphics Tutorials e.g. comment on things like: -Are the texts are written well or not? (note that English isn't my main language...) -Am I clear enough in my explanations? (the Fourier Transform on images should be something pretty hard if you've never heard about it, so is the article clear enough?) -Is the code good or horrible? I did the code the way you'll see there because I don't want to add complete c++ code every time but some short script-like thingies -Is such a tutorial even needed or are there enough of those already? -Are there any particular subjects you'd like to see covered? (anything software rendering, oldskool demo or image processing related, no 3D hardware) -Any positive or (constructive) negative feedback? -How to copyright things like this the proper way? Thanks a lot for your comments! EDIT: tried to make a more attractive title? [Edited by - Lode on July 19, 2004 8:01:41 AM]

Lode

Jul 8, 2004 at 2:07 PM

Aw, why's everyone ignoring it? :(

Grizwald

Jul 8, 2004 at 2:21 PM

not bad

your code isn't very readable though

it should be broken down and you should show how the FFT's are implemented in code, don't just throw a 3 page C file out there ;)

I would recommend a nehe-style sourcecode segment, where you throw out about 6-20 lines, and break it down for the reader. Don't spoonfeed us your spaghetti code
hehe

I have not seen many good FFT/Image manipulation tutorials, so you are good there

Maybe you could cover created a psuedo randome wave height (or normal) map using FFT that could be used in a pixel shader (i know you said no 3D hardware, but that would be an awesome tutorial!)

But my biggest gripe is the source-code problem

other than that, MUY BIEN CHICO

Lode

Jul 8, 2004 at 4:09 PM

Thanks for the comments!

I've now modified it a bit more to the nehe style, with the large code in the Fourier Transform tutorial broken into several pieces, and a little bit more explanations about the code in between. Here's this new file:

http://www.student.kuleuven.ac.be/~m0216922/CG/fourier.html

Is it any better?

Thanks!

Grizwald

Jul 8, 2004 at 8:54 PM

much much much better

Lode

Jul 9, 2004 at 5:51 PM

I've updated it with a new article! Namely the chapter "Light and Color": how we see light and color, color models, code for color model conversions, and some color arithmetic on images!

I'd be very pleased if I could get some more comments, also on the other articles :)

Thanks!

Melekor

Jul 9, 2004 at 7:27 PM

Wow. All of those texts are excellent! I can tell you put a lot of hard work into them. I've added your page to my favorites :)

ndr

Jul 9, 2004 at 8:31 PM

Nice work, well written from what I read and useful (I looked at color stuff mainly). Added it to bookmarks, I'll check back now and then if you update it :)

Mulligan

Jul 9, 2004 at 10:11 PM

good stuff, i like em

Grizwald

Jul 9, 2004 at 11:53 PM

The light and color section is awesome!!!

you should do some on rotation and scaling
maybe using filters to scale? (bilinear, trilinear, nearest neighbor)
anti-aliasing
Noise generation (perlin and others)
PROCEDURAL TEXTURES!!!

just some ideas for ya

Lode

Jul 10, 2004 at 3:43 AM

Procedural textures is something I hadn't though about yet, but it's a very good idea, and very useful, so I'll add it to the list :)

Thanks :)

codemonster

Jul 10, 2004 at 6:32 AM

*wow* obviously you've put lots of efforts into this!
i like your article about light and color. it's very felicitous.
your work on FT is good, too, but the code is an unrestrained beast! you could consider mentioning or highlighting the "important" code parts only and let the reader download the rest of the source code as an archive or so.

all in all: great work, m8! (i added a link to your page on my site)

[Edited by - codemonster on July 10, 2004 3:32:28 PM]

Lode

Jul 11, 2004 at 3:56 PM

There are two new articles, about recursion trees and julia/mandelbrot sets :)
Both are quite short though.
Next will come a few oldskool demo effects :)

python_regious

Jul 11, 2004 at 4:09 PM

Well, I just skimmed through your FT tutorial, and it was pretty good. However, I think it went into too much implementation details. I think a more detailed discussion of the algorithm would have been useful, with just a link to the source, if needed by the reader.

I didn't see a section discussing issues such as spectral leakage, different types of windows ( hanning, blackman, and so forth ), and how they help the issue of spectral leakage.

Still, a nice article. Well done :)

python_regious

Jul 11, 2004 at 4:11 PM

Also, I think your section on signals was brief at best. What sort of audience is this aimed at? Very beginner, someone with knowledge of signals, and basic analysis of signals, or someone who knew it, and just wants primer of sorts?

Lode

Jul 11, 2004 at 4:15 PM

Hamming windows and such weren't included in the tutorial, because it's not supposed to be a tutorial about general signal processing, but about a very small application of it: filters on images. I never saw any ugly effects on images due to this leakage myself, only on audio and electronic signals. Correct me if I'm wrong.

The target audience is anyone interested in different aspects of software computer graphics, not electronic engineers and such :)

The introduction about signals in the beginning was more meant to give better understanding of what happens to the images.

I think I may add something about how correlation can be used for pattern recognision later though.

EDIT: Ok, you're right: those Hamming, Butterworth, etc... filters do give some nicer results. Thanks for pointing that out! :)

python_regious

Jul 11, 2004 at 4:19 PM

Quote:
Original post by Lode
Hamming windows and such weren't included in the tutorial, because it's not supposed to be a tutorial about general signal processing, but about a very small application of it: filters on images.

Fair play, makes sense then.

Quote:

I never saw any ugly effects on images due to this leakage myself, only on audio and electronic signals. Correct me if I'm wrong.

Well, I've only ever noticed it on audio and electrical signals aswell, but then I've only ever really used the DFT/FFT on those...

Quote:

The target audience is anyone interested in different aspects of software computer graphics, not electronic engineers and such :)

Hehe, yeah ok. Still, there's nothing wrong with electronic engineers! [wink]

Quote:

The introduction about signals in the beginning was more meant to give better understanding of what happens to the images.

Ok, given your target audience, you probably got it about right.

EDIT in response to your edit: Heh, no problem! [smile]

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