[swift3][osx][ios][metal]Metal app on iOS with Simulator (metal not run)

Info.plist

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE plist PUBLIC "-//Apple//DTD PLIST 1.0//EN" "http://www.apple.com/DTDs/PropertyList-1.0.dtd">
<plist version="1.0">
<dict>
	<key>CFBundleDevelopmentRegion</key>
	<string>en</string>
	<key>CFBundleExecutable</key>
	<string>metalview</string>
	<key>CFBundleIdentifier</key>
	<string>bellbind.example.metalview</string>
	<key>CFBundleInfoDictionaryVersion</key>
	<string>6.0</string>
	<key>CFBundleName</key>
	<string>MetalView</string>
	<key>CFBundlePackageType</key>
	<string>APPL</string>
	<key>CFBundleShortVersionString</key>
	<string>1.0</string>
	<key>CFBundleVersion</key>
	<string>1</string>
	<key>LSRequiresIPhoneOS</key>
	<true/>
	<key>UIRequiresFullScreen</key>
	<true/>
	<key>UISupportedInterfaceOrientations</key>
	<array>
		<string>UIInterfaceOrientationPortrait</string>
		<string>UIInterfaceOrientationLandscapeLeft</string>
		<string>UIInterfaceOrientationLandscapeRight</string>
	</array>
</dict>
</plist>

Makefile

phone:="iPhone 7"
#phone:="iPhone 7 Plus"
udid:=$(shell xcrun simctl list|ruby -ne 'exit(print($$1).to_i) if /^    '$(phone)' \(([\-a-fA-F0-9]+)\)/')

#bin:=webkit
bin:=$(shell xmllint --xpath '//key[text()="CFBundleExecutable"]/following::string[1]/text()' Info.plist)
src:=$(bin).swift
appdir:=$(bin).app/
appid:=$(shell xmllint --xpath '//key[text()="CFBundleIdentifier"]/following::string[1]/text()' Info.plist)

echo:
	echo "$(phone)"
	echo "$(udid)"

default.metallib: shaders.metal
	xcrun -sdk iphoneos metal -Wall -Wextra -std=ios-metal1.2 \
		shaders.metal -o shaders.air
	xcrun -sdk iphoneos metal-ar rcs shaders.metal-ar shaders.air
	xcrun -sdk iphoneos metallib -o default.metallib shaders.metal-ar
	rm shaders.metal-ar shaders.air

simapp: default.metallib
	xcrun -sdk iphonesimulator swiftc -target x86_64-apple-ios10.2 $(src)
	mkdir -p $(appdir)
	cp Info.plist $(bin) default.metallib $(appdir)

phoneapp: default.metallib
	xcrun -sdk iphoneos swiftc -target arm64-apple-ios10.2 $(src)
	mkdir -p $(appdir)
	cp Info.plist $(bin) default.metallib $(appdir)

open:
	open -a Simulator --args -CurrentDeviceUDID $(udid)

# install and uninstall app to the booted simulator (require to open)
install:
	xcrun simctl install $(udid) $(appdir)

uninstall:
	xcrun simctl uninstall $(udid) $(appid)

showlog:
	tail -f ~/Library/Logs/CoreSimulator/$(udid)/system.log

metalview.swift

import UIKit
import MetalKit


class MetalDelegate: UIResponder, MTKViewDelegate {
    func mtkView(_ view: MTKView, drawableSizeWillChange size: CGSize) {
        NSLog("mtkView called")
    }
    func draw(in view: MTKView) {
        // data
        let verts = [
          vector_float2(-1, -1), vector_float2(-1, 1), vector_float2(1, 1),
          vector_float2(-1, -1), vector_float2(1, 1), vector_float2(1, -1),
        ]
        NSLog("**********3********")

        // device
        guard let device = view.device else {
            NSLog("Fail to get device")
            return
        }
        NSLog("**********4********")

        // shaders
        let plDesc = MTLRenderPipelineDescriptor()
        plDesc.colorAttachments[0].pixelFormat = view.colorPixelFormat
        do {
            let lib = try device.makeLibrary(filepath: "default.metallib")
            plDesc.vertexFunction = lib.makeFunction(name: "vertexShaeder")
            plDesc.fragmentFunction = lib.makeFunction(name: "fragmentShaeder")
        } catch let error {
            NSLog("Fail to load library: \(error)")
            return
        }
        NSLog("**********5********")

        // commands
        let commandBuf = device.makeCommandQueue().makeCommandBuffer()
        guard let passDesc = view.currentRenderPassDescriptor else {
            NSLog("Fail to get passDesc")
            return            
        }
        let encoder = commandBuf.makeRenderCommandEncoder(descriptor: passDesc)
        NSLog("**********7********")
        
        do {
            let plState =
              try device.makeRenderPipelineState(descriptor: plDesc)
            encoder.setRenderPipelineState(plState)
            NSLog("**********6********")
        } catch let error {
            NSLog("\(error)")
            return
        }
        
        let vertsBuf = device.makeBuffer(
          bytes: verts,
          length: verts.count * MemoryLayout.size(ofValue: vector_float2.self))
        encoder.setVertexBuffer(vertsBuf, offset: 0, at: 0) //=> [[buffer(0)]]
        encoder.drawPrimitives(type: .triangle, vertexStart: 0, vertexCount: 3)
        encoder.endEncoding()
        NSLog("**********8********")
        
        guard let drawable = view.currentDrawable else {
            NSLog("Fail to get drawable")
            return
        }
        commandBuf.present(drawable)
        commandBuf.commit()
        NSLog("**********9********")
    }
}

class AppDelegate: UIResponder, UIApplicationDelegate {
    var window: UIWindow?
    func application(
      _ application: UIApplication,
      didFinishLaunchingWithOptions launchingOptions:
        [UIApplicationLaunchOptionsKey : Any]? = nil) -> Bool {
        let frame = UIScreen.main.bounds
        let win = UIWindow(frame: frame)
        win.rootViewController = UIViewController(nibName: nil, bundle: nil)
        win.backgroundColor = UIColor.white
        win.makeKeyAndVisible()

        NSLog("**********1********")
        let device = MTLCreateSystemDefaultDevice()
        NSLog("\(device): when nil, Metal would not use (ins Simulator)")
        let metalView = MTKView(frame: frame, device: device)
        metalView.clearColor = MTLClearColorMake(1.0, 1.0, 1.0, 1.0)
        metalView.colorPixelFormat = .rgba8Unorm
        metalView.delegate = MetalDelegate()
        win.addSubview(metalView)
        NSLog("**********2********")
        
        window = win
        return true
    }
}

CommandLine.unsafeArgv.withMemoryRebound(
  to: UnsafeMutablePointer<Int8>.self, capacity: Int(CommandLine.argc)) {
    argv -> Void in
    UIApplicationMain(
      CommandLine.argc, argv, nil, NSStringFromClass(AppDelegate.self))
}

shaders.metal

//-*- mode: c++ -*-
#include <metal_stdlib>


vertex metal::float4
vertexShader(const device metal::float2* verts [[buffer(0)]],
             metal::uint vid [[vertex_id]]) {
  return metal::float4(verts[vid], 0.0, 1.0);
}

fragment metal::float4
fragmentShader(metal::float4 pos [[stage_in]]) {
  return metal::float4((1.0 + pos.x) / 2.0, (1.0 + pos.y) / 2.0,
                       (2 + pos.x + pos.y) / 4, 1.0);
}

IMPORTANT: Simulator cannot run iOS app with Metal

(This is a preparation for someday would run Metal on Simulator)