PragProg Customers

The Ray Tracer Challenge: Cannot get rid of acne When implement Shadows in Chapter 8.

Henrai

Henrai

The Ray Tracer Challenge: Cannot get rid of acne When implement Shadows in Chapter 8.

Hi, I’m working on the Chapter 8 of the book.
After I add add the point_offset, I’m still able to see acne:

Screen Shot 2022-03-28 at 1.08.33 AM
Screen Shot 2022-03-28 at 1.08.33 AM1200×807 158 KB

In the image above, I remove all balls to make things easier. I notice that for some of the hit point falls into the walls. Therefore it will have very small t (but greater than the epsilon) for the intersection.

I make all tests pass except “The Color with an intersection behind the ray”. Could some one explain that why this case can pass with the shadow? I think the light should be blocked by the outer ball.

May I get some suggestion to debug my code?

Here is my github repo: GitHub - Henrai/TheRayTracingChallenge

4 comments
#question/book-the-ray-tracer-challenge
1 1052 4

Most Liked

hoozifachi

hoozifachi

It’s cool. I completely understand. I can see the thread now. Thank you very much. My image looks almost exactly like the one in the thread. So it should be very helpful.

1
Post #5

Where Next?

View thread on forum
View The Ray Tracer Challenge's book portal
Post errata for this book
Post a suggestion for this book
Post a question about this book
Post a review about this book
question
Home PragProg Customers
#question/book-the-ray-tracer-challenge
1 1052 4
Last post

Popular Pragmatic Bookshelf topics Top

jeffmcompsci
PragProg Customers

Design and Build Great Web APIs: typo (page, 19, third bullet in URL list)
Title: Design and Build Great Web APIs - typo “https://company-atk.herokuapp.com/2258ie4t68jv” (page 19, third bullet in URL list) Typo:...
#pragprog#errata/book-design-and-build-great-web-apis
8 1941 7
New
raul
PragProg Customers

Distributed Services with Go: Chapter 3 suggestions
Page 28: It implements io.ReaderAt on the store type. Sorry if it’s a dumb question but was the io.ReaderAt supposed to be io.ReadAt? ...
#errata/book-distributed-services-with-go
0 1302 3
New
herminiotorres
PragProg Customers

Programming Phoenix LiveView: Typo
Hi! I know not the intentions behind this narrative when called, on page XI: mount() |> handle_event() |> render() but the correc...
#errata/book-programming-phoenix-liveview
3 1307 17
New
jeremyhuiskamp
PragProg Customers

Web Development with Clojure, Third Edition (vB17.0): create table syntax invalid
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
#errata/book-web-development-with-clojure-third-edition
0 1835 1
New
gilesdotcodes
PragProg Customers

Modern CSS with Tailwind: setting up Rails app
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...
#errata/book-modern-css-with-tailwind
3 1278 2
New
curtosis
PragProg Customers

Build a Weather Station with Elixir and Nerves: 'mix deps.get' does not work if user has not created a keyfile (page 16)
Running mix deps.get in the sensor_hub directory fails with the following error: ** (Mix) No SSH public keys found in ~/.ssh. An ssh aut...
#errata/book-build-a-weather-station-with-elixir-and-nerves
2 1457 3
New
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: SwitchCompat's thumbTint and trackTint being ignored (page 76)
I think I might have found a problem involving SwitchCompat, thumbTint, and trackTint. As entered, the SwitchCompat changes color to hol...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 2749 2
New
adamwoolhether
PragProg Customers

Distributed Services With Go: Unable to pass readiness/liveness checks. (page 210, 215)
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...
/book-distributed-services-with-go
5 1420 5
New
AufHe
PragProg Customers

Agile Web Development with Rails 7: page 113 - Seeing the list of products
I’m a newbie to Rails 7 and have hit an issue with the bin/Dev script mentioned on pages 112-113. Iteration A1 - Seeing the list of prod...
#question/book-agile-web-development-with-rails-7
0 2631 9
New
taguniversalmachine
PragProg Customers

Real-Time Phoenix: ProductChannelTest - undefined function describe/2 (pg 203)
Hi, I am getting an error I cannot figure out on my test. I have what I think is the exact code from the book, other than I changed “us...
#question/book-real-time-phoenix
0 1775 6
New

Other popular topics Top

AstonJ
General Dev>Hardware

Which keyboard do you have?
If it’s a mechanical keyboard, which switches do you have? Would you recommend it? Why? What will your next keyboard be? Pics always w...
#hardware/keyboards#sticky#mechanical-keyboards
144 9115 50
New
PragmaticBookshelf
Backend>Learning Resources

Seven Languages in Seven Weeks
Ruby, Io, Prolog, Scala, Erlang, Clojure, Haskell. With Seven Languages in Seven Weeks, by Bruce A. Tate, you’ll go beyond the syntax—and...
pragprog.com
#pragprog/clojure/erlang/haskell/prolog/ruby/scala#published-book/book-seven-languages-in-seven-weeks
5 5730 1
New
PragmaticBookshelf
Backend>Learning Resources

Testing Elixir
Write Elixir tests that you can be proud of. Dive into Elixir’s test philosophy and gain mastery over the terminology and concepts that u...
pragprog.com
#pragprog/elixir#published-book/book-testing-elixir
33 5004 8
New
AstonJ
General Dev>Hardware

Poll: Which keyboard layout do you use?
poll poll Be sure to check out @Dusty’s article posted here: An Introduction to Alternative Keyboard Layouts It’s one of the best write-...
colemakmods.github.io
#polls/keyboards
10 6048 11
New
PragmaticBookshelf
Android>Learning Resources

Kotlin and Android Development featuring Jetpack: Build Better, Safer Android Apps
Start building native Android apps the modern way in Kotlin with Jetpack's expansive set of tools, libraries, and best practices. Learn h...
pragprog.com
#pragprog#android#game-dev/kotlin#published-book/book-kotlin-and-android-development-featuring-jetpack
7 5084 1
New
DevotionGeo
General Dev>Dev Chat

The V Programming Language
The V Programming Language Simple language for building maintainable programs V is already mentioned couple of times in the forum, but I...
#programminguages/v
21 13874 7
New
PragmaticBookshelf
Backend>Learning Resources

Agile Web Development with Rails 7
Rails 7 completely redefines what it means to produce fantastic user experiences and provides a way to achieve all the benefits of single...
pragprog.com
#pragprog#web-development/ruby/rails#published-book/book-agile-web-development-with-rails-7
32 6600 9
New
PragmaticBookshelf
Backend>Learning Resources

Effective Haskell
Build efficient applications that exploit the unique benefits of a pure functional language, learning from an engineer who uses Haskell t...
pragprog.com
#pragprog/haskell#published-book/book-effective-haskell
15 10218 1
New
PragmaticBookshelf
Backend>Learning Resources

Engineering Elixir Applications
Develop, deploy, and debug BEAM applications using BEAMOps: a new paradigm that focuses on scalability, fault tolerance, and owning each ...
pragprog.com
#pragprog/elixir#published-book/book-engineering-elixir-applications
40 7136 21
New
AstonJ
AI>Chat

How to: Run DeepSeek on Mac, Windows, and Linux!
This is a very quick guide, you just need to: Download LM Studio: https://lmstudio.ai/ Click on search Type DeepSeek, then select the o...
#macs/deepseek#guides#lm-studio
14 9328 10
New
Back to top

Latest in The Ray Tracer Challenge

The Ray Tracer Challenge Portal ❯

PragProg Customers

Pragmatic Bookshelf PragProg Customers ❯

Latest on Devtalk

Devtalk ❯

We ❤️ helpful members!

We reward our most helpful members via our MOTM scheme - by giving away a whopping 25 books per year!

Member of the Month

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

Categories:

Sub Categories:

Popular Portals

Devtalk Sponsors

Pragmatic Bookshelf

Practical resources that improve the lives of professional developers.

Erlang Solutions

We build trusted fault-tolerant systems that scale to billions of users.

Honeybadger

Real-time error tracking, performance insights, and observability for devs.

EEF

Supporting innovation across the BEAM ecosystem.

coders51

We build reliable cloud platforms for business-critical systems.

Manning Publications

Develop your skills with books, videos, and courses.

AppSignal

Catch errors, track performance, monitor hosts and more.

WyeWorks

Enabling companies to succeed by building software people love.

Pragmatic Studio

Courses that move you from confusion to "Aha, now I get it!"

Linux New Media

Publishing Linux Magazine, ADMIN, and MakerSpace for 25+ years.

View all our sponsors ❯

We're in Beta

About us Mission Statement See our Roadmap