Metal by Example

This repository holds the sample code for the book Metal by Example by Warren Moore.

Converting to macOS App

This fork of the repo converts the code to work as macOS applications with NSViews. Since Swift and iOS development is more popular it's difficult to come by Objective-C and Metal resources so maybe this information will be helpful for someone looking for something similar.

I had considered making the conversion dual iOS/macOS support such that they coexisted in the same project and shared code but due to some changes that were made it seemed that this type of conversion and the ability to diff the changes in GitHub would be easier for reference material purposes.

Navigating the differences

Differences for converting to macOS applications have single commits for each chapter so that you can diff them in GitHub. If you've already read the material or want to better understand some of the differences between iOS and macOS development these are links to the project specific commits showing diffs of the original iOS version.

• 02-ClearScreen
• 03-DrawingIn2D
• 04-DrawingIn3D
• 05-Lighting
• 06-Texturing

Notable changes so far

Metal Specific changes

1. Vertex Uniforms in the shader was changed from constant to device, this was due to the constant address space specifications which align the offset to 256 bytes in macOS. setVertexBuffer Documentation

2. Setting the texture storage mode to MTLStorageModePrivate because it seems the macOS version is a little less lenient on the memory management throwing an error saying it must be allocated with MTLResourceStorageModePrivate. Since in at least example 04 the texture is only accessed in the GPU we'll follow the guidelines and override the default of MTLStorageModeManaged to avoid errors. Metal Best Practices Guide

NSView, MTKViews and Application related changes

1. I suspect MTKView is newer than the book literature as this was found by looking at the examples and documentation on the Apple Developer site and appears to have UIView support as well as MTKView. In this conversion MBERenderer interface makes use of MTKViewDelegate, this reduces the usage of the MBEMetalView but gives the advantage of utilizing the MTKView drawableSizeWillChange such that the macOS application window can be dynamically resized. Downside is that RenderPassDescriptor and depthTexture setup have been moved to the MBERenderer to achieve this.

2. CADisplayLink doesn't exist in macOS but CVDisplayLink can be used to sync the timing of the redraw with the display. Since you could have multiple displays and determining the monitor the application windows was on seems overkill for owning one monitor this assumes you're running these examples on the main display with CGMainDisplayID().