# 📚 Official Books **URL:** https://forums.kodeco.com/c/books/6.md?page=63 [Latest](https://forums.kodeco.com/latest.md) · [Categories](https://forums.kodeco.com/categories.md) · [Tags](https://forums.kodeco.com/tags.md) **Page:** 64 --- ## [Xcode Letter Definitions](https://forums.kodeco.com/t/xcode-letter-definitions/119912)
**Author:** [@geezer](https://forums.kodeco.com/u/geezer)\ **Replies:** 1\ **Last updated:** [September 14, 2020, 3:44pm UTC](https://forums.kodeco.com/t/xcode-letter-definitions/119912 "2020-09-14T15:44:55Z")
What are the letters to the far left of the attached image in Xcode called and where do I find their meanings? I can take a guess what some mean from what we have learned so far but would like to be certain. --- ## [SceneKit diffuse color in fragment shader](https://forums.kodeco.com/t/scenekit-diffuse-color-in-fragment-shader/119867)
**Author:** [@ahoudart](https://forums.kodeco.com/u/ahoudart)\ **Replies:** 2\ **Last updated:** [September 14, 2020, 7:44am UTC](https://forums.kodeco.com/t/scenekit-diffuse-color-in-fragment-shader/119867 "2020-09-14T07:44:04Z")
Hi guys, I’m trying to apply a fragment shader on a SceneKit node to achieve non-photorealistic render. I would like to use the diffuse and ambiant colors of each vertex group as the base color in the fragment shader. I… --- ## [Chapter 19: Unexpectedly found nil](https://forums.kodeco.com/t/chapter-19-unexpectedly-found-nil/119260)
**Author:** [@steveb\_la](https://forums.kodeco.com/u/steveb_la)\ **Replies:** 3\ **Last updated:** [September 12, 2020, 4:57pm UTC](https://forums.kodeco.com/t/chapter-19-unexpectedly-found-nil/119260 "2020-09-12T16:57:08Z")
I’m getting an error in iOS Apprentice 8.3.0 Chapter 19. Here is the code in AllListsViewController.swift: let cell: UITableViewCell! if let c = tableView.dequeueReusableCell( withIdentifier: cellIdent… --- ## [Chapter 7 - Using web view](https://forums.kodeco.com/t/chapter-7-using-web-view/119491)
**Author:** [@pricetd1024](https://forums.kodeco.com/u/pricetd1024)\ **Replies:** 1\ **Last updated:** [September 12, 2020, 9:05am UTC](https://forums.kodeco.com/t/chapter-7-using-web-view/119491 "2020-09-12T09:05:02Z")
While working through Bull’s Eye, everything was working fine until I switched the info screen to a web view. Actually, it still works as advertised, except that I’m getting the messages below in my log. Suggestions? WF… --- ## [Feedback / Errata](https://forums.kodeco.com/t/feedback-errata/42125)
**Author:** [@seano](https://forums.kodeco.com/u/seano)\ **Replies:** 13\ **Last updated:** [September 11, 2020, 6:42am UTC](https://forums.kodeco.com/t/feedback-errata/42125 "2020-09-11T06:42:31Z")
In v0.9.1, p.99, the “post-swap” diagram has minor mistake: remove dotted line & add solid line between node 27 and 37. I guess the text on p.98 also is not clear (or is inferred) that once node 27 is swapped into place… --- ## [Map operator Implementation Chapter 22](https://forums.kodeco.com/t/map-operator-implementation-chapter-22/117510)
**Author:** [@arrmixer](https://forums.kodeco.com/u/arrmixer)\ **Replies:** 5\ **Last updated:** [September 10, 2020, 6:44pm UTC](https://forums.kodeco.com/t/map-operator-implementation-chapter-22/117510 "2020-09-10T18:44:16Z")
Greetings I was just wondering if the map operator placement matters in this case. Should it be after the subscribOn operator? Also, since we are using Live Data’s post value, there is no need to observeOn on the main th… --- ## [Render CMSampleBuffer with metal](https://forums.kodeco.com/t/render-cmsamplebuffer-with-metal/119664)
**Author:** [@richmond\_jam](https://forums.kodeco.com/u/richmond_jam)\ **Replies:** 1\ **Last updated:** [September 10, 2020, 3:00am UTC](https://forums.kodeco.com/t/render-cmsamplebuffer-with-metal/119664 "2020-09-10T03:00:11Z")
Hello Caroline, if I need to render CMSampleBuffer, how can I use metal to do it is better? --- ## [CameraMovement script errors](https://forums.kodeco.com/t/cameramovement-script-errors/119337)
**Author:** [@thetntyeeter](https://forums.kodeco.com/u/thetntyeeter)\ **Replies:** 1\ **Last updated:** [September 6, 2020, 6:35am UTC](https://forums.kodeco.com/t/cameramovement-script-errors/119337 "2020-09-06T06:35:11Z")
So I did exactly as said for the CameraMovement script, but it still shows these errors I’m new to Unity and C#, so if anyone could explain, pls and thx This is what my code looks like: using System.Collections; usi… --- ## [Chapter 11 Tessellation](https://forums.kodeco.com/t/chapter-11-tessellation/119312)
**Author:** [@richmond\_jam](https://forums.kodeco.com/u/richmond_jam)\ **Replies:** 1\ **Last updated:** [September 5, 2020, 10:29pm UTC](https://forums.kodeco.com/t/chapter-11-tessellation/119312 "2020-09-05T22:29:44Z")
Hello Caroline, in the source code Renderer.swift, I can not understand what is size meaning in lazy var tessellationFactorsBuffer. Why divided by 2? --- ## [Using protocols for detail view controllers](https://forums.kodeco.com/t/using-protocols-for-detail-view-controllers/119288)
**Author:** [@ericlm](https://forums.kodeco.com/u/ericlm)\ **Replies:** 3\ **Last updated:** [September 5, 2020, 5:03pm UTC](https://forums.kodeco.com/t/using-protocols-for-detail-view-controllers/119288 "2020-09-05T17:03:09Z")
Hi, I’m working on the Checklist app, and I’m trying to reduce code duplication in the ListDetailViewController and the ItemDetailViewController. To do so, I first created a DetailViewController protocol with an extensio… --- ## [Interoperability between MSL and C++ Libraries](https://forums.kodeco.com/t/interoperability-between-msl-and-c-libraries/119214)
**Author:** [@quaternionboy](https://forums.kodeco.com/u/quaternionboy)\ **Replies:** 1\ **Last updated:** [September 5, 2020, 1:45am UTC](https://forums.kodeco.com/t/interoperability-between-msl-and-c-libraries/119214 "2020-09-05T01:45:31Z")
Interoperability between Metal Shading Language (MSL) and C++ Libraries I’m developing an iOS app and solved the interoperability Swift-C++ in the CPU side wrapping the C++ classes in Objective-C. But on the GPU side, I… --- ## [Metal By Tutorials new version](https://forums.kodeco.com/t/metal-by-tutorials-new-version/119258)
**Author:** [@richmond\_jam](https://forums.kodeco.com/u/richmond_jam)\ **Replies:** 1\ **Last updated:** [September 5, 2020, 1:33am UTC](https://forums.kodeco.com/t/metal-by-tutorials-new-version/119258 "2020-09-05T01:33:27Z")
Hello Caroline, I find the second edition new book goes on sale. If I have the first edition, may I need to buy this new book? And they are different too much? --- ## [Ch 15: alert(item:) takes a Binding, not a Publisher](https://forums.kodeco.com/t/ch-15-alert-item-takes-a-binding-not-a-publisher/110486)
**Author:** [@rnikander](https://forums.kodeco.com/u/rnikander)\ **Replies:** 2\ **Last updated:** [September 4, 2020, 8:16am UTC](https://forums.kodeco.com/t/ch-15-alert-item-takes-a-binding-not-a-publisher/110486 "2020-09-04T08:16:10Z")
In chapter 15 the book says: The alert(item:) modifier controls an alert presentation on-screen. It takes a publisher with an optional output called the item. Whenever that publisher emits a non-nil value, it presents … --- ## [Wield \* in command git add tutorials/\*](https://forums.kodeco.com/t/wield-in-command-git-add-tutorials/119096)
**Author:** [@justinlearnios](https://forums.kodeco.com/u/justinlearnios)\ **Replies:** 1\ **Last updated:** [September 4, 2020, 6:07am UTC](https://forums.kodeco.com/t/wield-in-command-git-add-tutorials/119096 "2020-09-04T06:07:50Z")
in Chapter 3 Committing your changes, under the section How Git views your working tree, I tried command git add tutorials/\* but it didn’t work and got an error message: zsh: no matches found: tutorials/\* but I tried g… --- ## [DataTaskPublisher to Future or AnyPublisher for API Client method](https://forums.kodeco.com/t/datataskpublisher-to-future-or-anypublisher-for-api-client-method/115829)
**Author:** [@weenzeel](https://forums.kodeco.com/u/weenzeel)\ **Replies:** 2\ **Last updated:** [September 4, 2020, 6:06am UTC](https://forums.kodeco.com/t/datataskpublisher-to-future-or-anypublisher-for-api-client-method/115829 "2020-09-04T06:06:19Z")
I’ve just finished reading Combine: Asynchronous Programming with Swift. I really enjoyed it. Great disposition, pedagogic and clear, high-quality sample code. Well done! I Really learned a lot! I’m implementing (for th… --- ## [Chapter 2: Routing with parameter](https://forums.kodeco.com/t/chapter-2-routing-with-parameter/42292)
**Author:** [@in8bits](https://forums.kodeco.com/u/in8bits)\ **Replies:** 8\ **Last updated:** [September 2, 2020, 8:24am UTC](https://forums.kodeco.com/t/chapter-2-routing-with-parameter/42292 "2020-09-02T08:24:48Z")
Just started on the book and already hit a hurdle when adding a route with a parameter. I installed Vapor via Homebrew exactly as described in the book, all went well. However the example in the books is: router.get("he… --- ## [Chapter 14: Animations mistake](https://forums.kodeco.com/t/chapter-14-animations-mistake/93894)
**Author:** [@d9rad](https://forums.kodeco.com/u/d9rad)\ **Replies:** 1\ **Last updated:** [January 11, 2020, 3:49pm UTC](https://forums.kodeco.com/t/chapter-14-animations-mistake/93894 "2020-01-11T15:49:35Z")
I’m going through the part in chapter 14 where we try to animate the flight details by manipulating the offset (page 482 on the epub): if showDetails { FlightDetails(flight: flight) .offset(x: showDeta… --- ## [Basic Question about Swift](https://forums.kodeco.com/t/basic-question-about-swift/118905)
**Author:** [@richmond\_jam](https://forums.kodeco.com/u/richmond_jam)\ **Replies:** 1\ **Last updated:** [September 1, 2020, 1:18pm UTC](https://forums.kodeco.com/t/basic-question-about-swift/118905 "2020-09-01T13:18:42Z")
Hello Caroline, long time no see. I have a basic question. Would you please tell me why using try textureLoader.newTexture(…) to compile successfully in chapter 6 source code. I thought maybe use try! or try? without do… --- ## [Source Code Location](https://forums.kodeco.com/t/source-code-location/118178)
**Author:** [@geezer](https://forums.kodeco.com/u/geezer)\ **Replies:** 6\ **Last updated:** [August 27, 2020, 6:33pm UTC](https://forums.kodeco.com/t/source-code-location/118178 "2020-08-27T18:33:35Z")
Where can I find the source code for the ePub iOS apprentice? I have v8.3.0. Thanks. --- ## [About Push notifications with vapor](https://forums.kodeco.com/t/about-push-notifications-with-vapor/79073)
**Author:** [@choioi](https://forums.kodeco.com/u/choioi)\ **Replies:** 11\ **Last updated:** [August 27, 2020, 2:52pm UTC](https://forums.kodeco.com/t/about-push-notifications-with-vapor/79073 "2020-08-27T14:52:41Z")
Sorry but there doesn’t seem to be this topic in the forum. Does anyone share or suggest which to use? i found something: Any other idea? --- ## [Chapter 21: Jawwad GitHub account page not found](https://forums.kodeco.com/t/chapter-21-jawwad-github-account-page-not-found/118379)
**Author:** [@sparklydust](https://forums.kodeco.com/u/sparklydust)\ **Replies:** 2\ **Last updated:** [August 26, 2020, 6:07pm UTC](https://forums.kodeco.com/t/chapter-21-jawwad-github-account-page-not-found/118379 "2020-08-26T18:07:29Z")
Hello, When trying to fetch Jawwad Fork, allow-custom-range branch, Git shows me this error: git fetch GitHub - jawwad/git-book-fizzbuzz: Sample project for the Forking Workflow chapter of Mastering Git allow-custom-ra… --- ## [Ch 14: Debugging a Fatal error: Unexpectedly found nil while unwrapping an Optional value](https://forums.kodeco.com/t/ch-14-debugging-a-fatal-error-unexpectedly-found-nil-while-unwrapping-an-optional-value/118355)
**Author:** [@annenies](https://forums.kodeco.com/u/annenies)\ **Replies:** 2\ **Last updated:** [August 26, 2020, 4:01pm UTC](https://forums.kodeco.com/t/ch-14-debugging-a-fatal-error-unexpectedly-found-nil-while-unwrapping-an-optional-value/118355 "2020-08-26T16:01:23Z")
After finishing the steps up to page 350, when I run my code I get “Fatal error: Unexpectedly found nil while unwrapping an Optional value.” It’s highlighting " let label = cell.viewWithTag(1001) as! UILabel" in the newl… --- ## [buildPipelineState() limits?](https://forums.kodeco.com/t/buildpipelinestate-limits/118365)
**Author:** [@barnetta](https://forums.kodeco.com/u/barnetta)\ **Replies:** 1\ **Last updated:** [August 26, 2020, 7:59am UTC](https://forums.kodeco.com/t/buildpipelinestate-limits/118365 "2020-08-26T07:59:04Z")
So I’ve been working from the materials in the book and trying to develop my own project with GPU-driven rendering like Chapter 15, but running from generated meshes rather than imported models. And everything seemed wel… --- ## [Why my model look different](https://forums.kodeco.com/t/why-my-model-look-different/118160)
**Author:** [@relaxslow](https://forums.kodeco.com/u/relaxslow)\ **Replies:** 5\ **Last updated:** [August 25, 2020, 10:38pm UTC](https://forums.kodeco.com/t/why-my-model-look-different/118160 "2020-08-25T22:38:19Z")
I proceed to chapter 6 Texture. There is a little problem not very critical . I build a model in blender ,but when I import it into my project and check it by click it in the file navigator, it shows complete white . se… --- ## [Debugging a Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value: file error](https://forums.kodeco.com/t/debugging-a-fatal-error-unexpectedly-found-nil-while-implicitly-unwrapping-an-optional-value-file-error/118007)
**Author:** [@steveb\_la](https://forums.kodeco.com/u/steveb_la)\ **Replies:** 4\ **Last updated:** [August 25, 2020, 4:41pm UTC](https://forums.kodeco.com/t/debugging-a-fatal-error-unexpectedly-found-nil-while-implicitly-unwrapping-an-optional-value-file-error/118007 "2020-08-25T16:41:46Z")
I’m getting this error in Chapter 17 of iOS Apprentice 8.3.0. On page 427, it suggests that I can run the app and add items under a checklist. I’m able to add a new checklist, but I get the above error when I click on … --- ## [Book Language not english](https://forums.kodeco.com/t/book-language-not-english/118249)
**Author:** [@ritzy](https://forums.kodeco.com/u/ritzy)\ **Replies:** 4\ **Last updated:** [August 25, 2020, 9:43am UTC](https://forums.kodeco.com/t/book-language-not-english/118249 "2020-08-25T09:43:40Z")
I think there is some technical glitch because of which the text in the book is in some other language not english. --- ## [Nothing prints in the log in the when I run the included projects](https://forums.kodeco.com/t/nothing-prints-in-the-log-in-the-when-i-run-the-included-projects/103030)
**Author:** [@joakim\_sjostedt](https://forums.kodeco.com/u/joakim_sjostedt)\ **Replies:** 8\ **Last updated:** [August 25, 2020, 4:35am UTC](https://forums.kodeco.com/t/nothing-prints-in-the-log-in-the-when-i-run-the-included-projects/103030 "2020-08-25T04:35:05Z")
On the very first starter project I run it through the terminal using ./bootstrap.sh (page 42). The playground file opens in a regular Xcode project without the nifty playground stuff. Perhaps this is intended, dunno, an… --- ## [Blender vs. parametric mesh coordinates](https://forums.kodeco.com/t/blender-vs-parametric-mesh-coordinates/117996)
**Author:** [@jdh37](https://forums.kodeco.com/u/jdh37)\ **Replies:** 7\ **Last updated:** [August 24, 2020, 12:37am UTC](https://forums.kodeco.com/t/blender-vs-parametric-mesh-coordinates/117996 "2020-08-24T00:37:12Z")
I have enjoyed the MbT book immensely. In the simple lighting example (Ch. 5), I created a couple of parametric meshes and added them to the models for display. However, they have the wrong orientation relative to the … --- ## [Creating a Model Object With a Parametric Mesh](https://forums.kodeco.com/t/creating-a-model-object-with-a-parametric-mesh/45026)
**Author:** [@johnlobe](https://forums.kodeco.com/u/johnlobe)\ **Replies:** 5\ **Last updated:** [March 14, 2020, 12:31am UTC](https://forums.kodeco.com/t/creating-a-model-object-with-a-parametric-mesh/45026 "2020-03-14T00:31:24Z")
I am getting a sense of the realism that can be created with PBR shading. To explore it properly, I want to properly follow the approach in the Maps and Materials chapter of the book - the Model object containing an arra… --- ## [Chapter 32 : CoreDara, how to share some fields?](https://forums.kodeco.com/t/chapter-32-coredara-how-to-share-some-fields/117856)
**Author:** [@amitsrivastava](https://forums.kodeco.com/u/amitsrivastava)\ **Replies:** 2\ **Last updated:** [August 22, 2020, 9:44pm UTC](https://forums.kodeco.com/t/chapter-32-coredara-how-to-share-some-fields/117856 "2020-08-22T21:44:04Z")
chapter 32 by Eli Ganim, has been useful in saving my data on local device, now working on a slightly different scenario, i have an Entity called TouristLocations which has attributes like name, location , website, type … [Previous page](https://forums.kodeco.com/c/books/6.md?page=62) [Next page](https://forums.kodeco.com/c/books/6.md?page=64)