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

duke_meister
PragProg Customers

The Ray Tracer Challenge - where are the errata?
As per the title, thanks.
/book-the-ray-tracer-challenge
6 1681 4
New
telemachus
PragProg Customers

Warnings in Python Testing With Pytest Chapter 2
Python Testing With Pytest - Chapter 2, warnings for “unregistered custom marks” While running the smoke tests in Chapter 2, I get these...
#pragprog#errata/book-python-testing-with-pytest
5 2081 1
New
GilWright
PragProg Customers

Apple Game Frameworks and Technologies: Screen image may be wrong (p 13)
Working through the steps (checking that the Info,plist matches exactly), run the demo game and what appears is grey but does not fill th...
#errata/book-apple-game-frameworks-and-technologies
11 1081 5
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
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
jskubick
PragProg Customers

Kotlin and Android Development featuring Jetpack: android:tint vs app:tint (chapter 7, p186)
I found an issue in Chapter 7 regarding android:backgroundTint vs app:backgroundTint. How to replicate: load chapter-7 from zipfile i...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 3566 3
New
Keton
PragProg Customers

Hands-on Rust: How do I debug a call chain in Rust?
When running the program in chapter 8, “Implementing Combat”, the printout Health before attack was never printed so I assumed something ...
#question/book-hands-on-rust
2 1034 2
New
dtonhofer
PragProg Customers

The Definitive ANTLR 4 Reference - "Java.g4" grammer (used on page 40) no longer passes ANTLR
@parrt In the context of Chapter 4.3, the grammar Java.g4, meant to parse Java 6 compilation units, no longer passes ANTLR (currently 4....
#errata/book-the-definitive-antlr-4-reference
0 1020 3
New
bjnord
PragProg Customers

Hands-on Rust: Chapter 3: Can't get first hello to run
Hello @herbert ! Trying to get the very first “Hello, Bracket Terminal!" example to run (p. 53). I develop on an Amazon EC2 instance runn...
#question/book-hands-on-rust
0 1147 2
New
dachristenson
PragProg Customers

Kotlin and Android Development featuring Jetpack: Transformations class doesn't seem to exist anymore (pp. 140-141
@mfazio23 Android Studio will not accept anything I do when trying to use the Transformations class, as described on pp. 140-141. Googl...
#errata/book-kotlin-and-android-development-featuring-jetpack
0 2155 5
New

Other popular topics Top

Devtalk
General Dev>Dev Chat

What dev-related stuff have you been up to?
Reading something? Working on something? Planning something? Changing jobs even!? If you’re up for sharing, please let us know what you’...
#community
1063 24245 395
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
AstonJ
General Dev>Hardware

Keyboard thock (sound)
I’ve been hearing quite a lot of comments relating to the sound of a keyboard, with one of the most desirable of these called ‘thock’, he...
/keyboards#mechanical-keyboards
14 11197 8
New
PragmaticBookshelf
Backend>Learning Resources

Concurrent Data Processing in Elixir
Learn different ways of writing concurrent code in Elixir and increase your application's performance, without sacrificing scalability or...
pragprog.com
#pragprog/elixir#published-book/book-concurrent-data-processing-in-elixir
78 6059 24
New
PragmaticBookshelf
Backend>Learning Resources

Programming Phoenix LiveView
Build highly interactive applications without ever leaving Elixir, the way the experts do. Let LiveView take care of performance, scalabi...
pragprog.com
#pragprog/elixir/phoenix#published-book/book-programming-phoenix-liveview
84 14528 26
New
PragmaticBookshelf
Community>In The Spotlight

Spotlight: Mike Riley (Author) Interview and AMA!
Author Spotlight Mike Riley @mriley This month, we turn the spotlight on Mike Riley, author of Portable Python Projects. Mike’s book ...
#author-spotlight/python#iot/book-portable-python-projects#internet-of-things
62 7035 19
New
AstonJ
AI>In The News

DeepSeek (671B) running on a cluster of 8 Mac Mini Pros with 64GB RAM each
This is cool! DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON We just witnessed something incredible: the largest open-s...
#ai#macs/deepseek
0 6695 1
New
PragmaticBookshelf
Backend>Learning Resources

Kotlin Coroutine Confidence
Escape callback hell and ship fast, clean code that reads as smoothly as it runs. Squash bugs and stamp out memory leaks with an intuitiv...
pragprog.com
#pragprog/java/kotlin#published-book/book-kotlin-coroutine-confidence
14 3688 10
New
mindriot
General Dev>Reviews

Keyboard Review: UHK60V2 vs Defy vs Voyager vs Glove80 vs Svalboard
Ok, well here are some thoughts and opinions on some of the ergonomic keyboards I have, I guess like mini review of each that I use enoug...
/keyboards#uhk60v2#defy#voyager#glove80#svalboard
5 5681 7
New
pragdave
AI>Learning Resources

A Common-Sense Guide to AI Engineering
Build robust LLM-powered apps, chatbots, and agents while mastering AI engineering principles that will help you outlast the tools and th...
pragprog.com
#pragprog
17 1852 8
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