64kramsystem

64kramsystem

The Ray Tracer Challenger: unnecessary normalization (page 73)

In the last hint (#4) of Chapter 5, the pseudocode applies a normalization to the origin ray:

  • r ← ray(ray_origin, normalize(position - ray_origin))

normalizing in this case unnecessary, since with or without, the intersections detected are going to be the same.

My supposition is that this it was an accidental addition, or that it’s a common practice, so it’s been added even if it’s not necessary.

I think it should be either removed, or, if the case is the second, some explanation should be given, in particular, because at this stage of the book, it’s not entirely clear when normalization should be performed (there is only a generic explanation at page 30), so I find it (at least, personally) confusing.

First Post!

jamis

jamis

Author of Mazes for Programmers and 1 other title

You’re right that I should explained that better. As it is: yes, you’ll detect an intersection whether the ray is normalized or not, but the distance to that intersection will differ depending on whether or not the ray is normalized. For this example, the distance doesn’t matter, just the fact of an intersection is sufficient.

So, yeah, maybe I could have left that off here. But the thinking was that for the next chapter, it would carry over. (See step #3 of “Putting It Together” in Chapter 6.)

Popular Pragmatic Bookshelf topics Top

jeffmcompsci
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list) Typo:...
New
jesse050717
Title: Web Development with Clojure, Third Edition, pg 116 Hi - I just started chapter 5 and I am stuck on page 116 while trying to star...
New
jamis
The following is cross-posted from the original Ray Tracer Challenge forum, from a post by garfieldnate. I’m cross-posting it so that the...
New
sdmoralesma
Title: Web Development with Clojure, Third Edition - migrations/create not working: p159 When I execute the command: user=> (create-...
New
herminiotorres
Hi @Margaret , On page VII the book tells us the example and snippets will be all using Elixir version 1.11 But on page 3 almost the en...
New
gilesdotcodes
In case this helps anyone, I’ve had issues setting up the rails source code. Here were the solutions: In Gemfile, change gem 'rails' t...
New
leonW
I ran this command after installing the sample application: $ cards add do something --owner Brian And got a file not found error: Fil...
New
adamwoolhether
I’m not quite sure what’s going on here, but I’m unable to have to containers successfully complete the Readiness/Liveness checks. I’m im...
New
creminology
Skimming ahead, much of the following is explained in Chapter 3, but new readers (like me!) will hit a roadblock in Chapter 2 with their ...
New
bjnord
Hello @herbert ! Trying to get the very first “Hello, Bracket Terminal!" example to run (p. 53). I develop on an Amazon EC2 instance runn...
New

Other popular topics Top

AstonJ
Just done a fresh install of macOS Big Sur and on installing Erlang I am getting: asdf install erlang 23.1.2 Configure failed. checking ...
New
AstonJ
Inspired by this post from @Carter, which languages, frameworks or other tech or tools do you think is killing it right now? :upside_down...
New
AstonJ
I ended up cancelling my Moonlander order as I think it’s just going to be a bit too bulky for me. I think the Planck and the Preonic (o...
New
AstonJ
I have seen the keycaps I want - they are due for a group-buy this week but won’t be delivered until October next year!!! :rofl: The Ser...
New
AstonJ
Do the test and post your score :nerd_face: :keyboard: If possible, please add info such as the keyboard you’re using, the layout (Qw...
New
AstonJ
Continuing the discussion from Thinking about learning Crystal, let’s discuss - I was wondering which languages don’t GC - maybe we can c...
New
Maartz
Hi folks, I don’t know if I saw this here but, here’s a new programming language, called Roc Reminds me a bit of Elm and thus Haskell. ...
New
PragmaticBookshelf
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
New
First poster: joeb
The File System Access API with Origin Private File System. WebKit supports new API that makes it possible for web apps to create, open,...
New
Help
I am trying to crate a game for the Nintendo switch, I wanted to use Java as I am comfortable with that programming language. Can you use...
New