Revert "ui: Bug fix: SetVsyncEnabled before Run didn't work on macOS"

This reverts commit 042b30a516.

internal/graphicsdriver/metal/driver.go

@@ -233,11 +233,10 @@ type Driver struct {
 	src *Image
 	dst *Image
 
-	vsync        bool
 	maxImageSize int
 }
 
-var theDriver = Driver{vsync: true}
+var theDriver Driver
 
 func Get() *Driver {
 	return &theDriver
@@ -396,7 +395,7 @@ func (d *Driver) Reset() error {
 		// MTLPixelFormatBGRA10_XR_sRGB.
 		d.ml.SetPixelFormat(mtl.PixelFormatBGRA8UNorm)
 		d.ml.SetMaximumDrawableCount(3)
-		d.ml.SetDisplaySyncEnabled(d.vsync)
+		d.ml.SetDisplaySyncEnabled(true)
 
 		replaces := map[string]string{
 			"{{.FilterNearest}}":      fmt.Sprintf("%d", graphics.FilterNearest),
@@ -571,11 +570,7 @@ func (d *Driver) ResetSource() {
 }
 
 func (d *Driver) SetVsyncEnabled(enabled bool) {
-	mainthread.Run(func() error {
-		d.ml.SetDisplaySyncEnabled(enabled)
-		d.vsync = enabled
-		return nil
-	})
+	d.ml.SetDisplaySyncEnabled(enabled)
 }
 
 func (d *Driver) VDirection() graphicsdriver.VDirection {

internal/mainthread/mainthread.go

@@ -14,39 +14,16 @@
 
 package mainthread
 
-import (
-	"runtime"
-	"sync"
-)
-
-var (
-	funcs   chan func()
-	running bool
-
-	m sync.Mutex
-)
-
-func init() {
-	runtime.LockOSThread()
-}
+var funcs = make(chan func())
 
 // Loop starts the main-thread loop.
 //
 // Loop must be called on the main thread.
 func Loop(ch <-chan error) error {
-	m.Lock()
-	funcs = make(chan func())
-	m.Unlock()
 	for {
 		select {
 		case f := <-funcs:
-			m.Lock()
-			running = true
-			m.Unlock()
 			f()
-			m.Lock()
-			running = false
-			m.Unlock()
 		case err := <-ch:
 			// ch returns a value not only when an error occur but also it is closed.
 			return err
@@ -55,19 +32,7 @@ func Loop(ch <-chan error) error {
 }
 
 // Run calls f on the main thread.
-//
-// Run can be called even before Loop is called.
-//
-// Run can be called recursively: Run can be called from the function that are called via Run.
 func Run(f func() error) error {
-	// Even if funcs is nil, Run is called from the main thread (e.g. init)
-	m.Lock()
-	now := funcs == nil || running
-	m.Unlock()
-	if now {
-		return f()
-	}
-
 	ch := make(chan struct{})
 	var err error
 	funcs <- func() {

internal/ui/ui_glfw.go

@@ -76,6 +76,7 @@ var (
 )
 
 func init() {
+	runtime.LockOSThread()
 	hideConsoleWindowOnWindows()
 	if err := initialize(); err != nil {
 		panic(err)