skellt

skellt

Apple Game Frameworks and Technologies: fadeIn to alpha 1.0 when alpha was already 1.0 (p 143)

On page 143 is this code:

// Add the 'chomp' text at the player's position
let chomp = SKLabelNode(fontNamed: "Nosifer")
chomp.name = "chomp"
chomp.fontSize = 22.0
chomp.text = "gloop"
chomp.horizontalAlignmentMode = .center
chomp.verticalAlignmentMode = .bottom
chomp.position = CGPoint(x: player.position.x, y: player.frame.maxY + 25)
chomp.zRotation = CGFloat.random(in: -0.15...0.15)
addChild(chomp)

// Add actions to fade in, rise up, and fade out
let fadeIn = SKAction.fadeAlpha(to: 1.0, duration: 0.05)
let fadeOut = SKAction.fadeAlpha(to: 0.0, duration: 0.45)
let moveUp = SKAction.moveBy(x: 0.0, y: 45, duration: 0.45)
let groupAction = SKAction.group([fadeOut, moveUp])
let removeFromParent = SKAction.removeFromParent()
let chompAction = SKAction.sequence([fadeIn, groupAction, removeFromParent]) 
chomp.run(chompAction)

The fadeIn action fades alpha to 1.0 over 0.05 seconds. It is the first action in the sequence. But the label node hasn’t had its alpha tweaked and the default is already 1.0. So the fadeIn action, as it is currently written, is just adding a small delay but no fade.

Question:

Was it intended for this to actually fade? If so then we should add chomp.alpha = 0 to the upper code block. If not then perhaps the fadeAlpha action should just be a wait action?

Admittedly nobody will ever notice the difference either way due to the very short duration of 0.05 seconds. But I feel like the code doesn’t match the intent right now. I’m just not sure what the intent was.

Marked As Solved

Paradox927

Paradox927

Author and Editor at PragProg

Hi, David.

Thanks for the message.

To answer your question, the code you see in the book does indeed match the intent behind it.

For this label, I wanted a very subtle fade in effect to help prevent a jarring visual response from the player. The 0.05 seconds works to achieve this.

Of course, if you’d rather skip the fadeIn action, increase its duration, or use a wait action instead, that works too.

It’s always fun to see what others come up with on their own. There was a reader on Twitter who shared his progress with the game, and he added some extra code that randomly changes the text. I thought it was well done and added some extra charm to our blobby little green friend. :grin:

Thanks again for your comments. I appreciate all of the feedback you’re giving about this book.

EDIT: My apologies, I looked a little closer at the code, and you’re right—I am missing the initial setting of chomp.alpha = 0.0. You’ll see this correction in the next update.

Where Next?

Popular Pragmatic Bookshelf topics Top

abtin
page 20: … protoc command… I had to additionally run the following go get commands in order to be able to compile protobuf code using go...
New
mikecargal
Title: Hands-on Rust: question about get_component (page 295) (feel free to respond. “You dug you’re own hole… good luck”) I have somet...
New
jeremyhuiskamp
Title: Web Development with Clojure, Third Edition, vB17.0 (p9) The create table guestbook syntax suggested doesn’t seem to be accepted ...
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
leba0495
Hello! Thanks for the great book. I was attempting the Trie (chap 17) exercises and for number 4 the solution provided for the autocorre...
New
jskubick
I’m running Android Studio “Arctic Fox” 2020.3.1 Patch 2, and I’m embarrassed to admit that I only made it to page 8 before running into ...
New
jskubick
I’m under the impression that when the reader gets to page 136 (“View Data with the Database Inspector”), the code SHOULD be able to buil...
New
akraut
The markup used to display the uploaded image results in a Phoenix.LiveView.HTMLTokenizer.ParseError error. lib/pento_web/live/product_l...
New
s2k
Hi all, currently I wonder how the Tailwind colours work (or don’t work). For example, in app/views/layouts/application.html.erb I have...
New
redconfetti
Docker-Machine became part of the Docker Toolbox, which was deprecated in 2020, long after Docker Desktop supported Docker Engine nativel...
New

Other popular topics Top

AstonJ
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...
New
malloryerik
Any thoughts on Svelte? Svelte is a radical new approach to building user interfaces. Whereas traditional frameworks like React and Vue...
New
DevotionGeo
I know that these benchmarks might not be the exact picture of real-world scenario, but still I expect a Rust web framework performing a ...
New
siddhant3030
I’m thinking of buying a monitor that I can rotate to use as a vertical monitor? Also, I want to know if someone is using it for program...
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
AstonJ
If you want a quick and easy way to block any website on your Mac using Little Snitch simply… File > New Rule: And select Deny, O...
New
First poster: bot
zig/http.zig at 7cf2cbb33ef34c1d211135f56d30fe23b6cacd42 · ziglang/zig. General-purpose programming language and toolchain for maintaini...
New
AnfaengerAlex
Hello, I’m a beginner in Android development and I’m facing an issue with my project setup. In my build.gradle.kts file, I have the foll...
New
AstonJ
This is cool! DEEPSEEK-V3 ON M4 MAC: BLAZING FAST INFERENCE ON APPLE SILICON We just witnessed something incredible: the largest open-s...
New

Sub Categories: