Fix macOS tests

Main thread locking hangs OpenGL emulators.

.github/workflows/build.yml

@@ -18,7 +18,7 @@ jobs:
   build:
     strategy:
       matrix:
-        os: [ ubuntu-latest, macos-13, windows-latest ]
+        os: [ ubuntu-latest, macos-12, windows-latest ]
     runs-on: ${{ matrix.os }}
     steps:
       - uses: actions/checkout@v4
@@ -42,7 +42,7 @@ jobs:
           xvfb-run --auto-servernum make test verify-cores
 
       - name: macOS
-        if: matrix.os == 'macos-13'
+        if: matrix.os == 'macos-12'
         run: |
           brew install pkg-config libvpx x264 opus sdl2 jpeg-turbo
           make build test verify-cores

pkg/worker/caged/libretro/nanoarch/nanoarch.go

@@ -169,6 +169,8 @@ func (n *Nanoarch) CoreLoad(meta Metadata) {
 	n.Video.gl.autoCtx = meta.AutoGlContext
 	n.Video.gl.enabled = meta.IsGlAllowed
 
+	thread.SwitchGraphics(n.Video.gl.enabled)
+
 	// hacks
 	Nan0.hackSkipHwContextDestroy = meta.HasHack("skip_hw_context_destroy")
 
@@ -868,6 +870,7 @@ func deinitVideo() {
 	Nan0.Video.gl.enabled = false
 	Nan0.Video.gl.autoCtx = false
 	Nan0.hackSkipHwContextDestroy = false
+	thread.SwitchGraphics(false)
 }
 
 type limit struct {

pkg/worker/thread/mainthread_darwin.go

@@ -13,6 +13,8 @@ type fun struct {
 var dPool = sync.Pool{New: func() any { return make(chan struct{}) }}
 var fq = make(chan fun, runtime.GOMAXPROCS(0))
 
+var isGraphics = false
+
 func init() {
 	runtime.LockOSThread()
 }
@@ -38,8 +40,17 @@ func Run(run func()) {
 
 // Call queues function f on the main thread and blocks until the function f finishes.
 func Call(f func()) {
+	if !isGraphics {
+		f()
+		return
+	}
+
 	done := dPool.Get().(chan struct{})
 	defer dPool.Put(done)
 	fq <- fun{fn: f, done: done}
 	<-done
 }
+
+func Switch(s bool) {
+	isGraphics = s
+}

pkg/worker/thread/thread.go

@@ -2,5 +2,6 @@
 
 package thread
 
-func Wrap(f func()) { f() }
-func Main(f func()) { f() }
+func Wrap(f func())         { f() }
+func Main(f func())         { f() }
+func SwitchGraphics(s bool) {}

pkg/worker/thread/thread_darwin.go

@@ -8,3 +8,5 @@ func Wrap(f func()) { Run(f) }
 
 // Main calls a function on the main thread.
 func Main(f func()) { Call(f) }
+
+func SwitchGraphics(s bool) { Switch(s) }