A lot of Metal examples, including ones from Apple, use MTLPixelFormat.bgra8Unorm as the pixelFormat in the pipeline state. I was wondering if you had any insight as to whether or not this might be preferred over, say, MTLPixelFormat.rgba8Unorm, which has a more familiar RGBA ordering or even something like MTLPixelFormat.rgba8Unorm_srgb.
I remember some old graphics cards/OpenGL drivers preferred BGRA, which made it a faster choice in some cases. I had thought that was lost in the past though.
Perhaps there is a later section of the book that discusses when and why to choose one of the other many formats. I haven’t looked ahead yet.