internal/ui: refactoring: reduce usages of renderThread

Updates #2714

internal/graphicscommand/commandqueue.go

@@ -45,12 +45,16 @@ const (
 
 var vsyncEnabled int32 = 1
 
-func SetVsyncEnabled(enabled bool) {
+func SetVsyncEnabled(enabled bool, graphicsDriver graphicsdriver.Graphics) {
 	if enabled {
 		atomic.StoreInt32(&vsyncEnabled, 1)
 	} else {
 		atomic.StoreInt32(&vsyncEnabled, 0)
 	}
+
+	runOnRenderThread(func() {
+		graphicsDriver.SetVsyncEnabled(enabled)
+	}, true)
 }
 
 // FlushCommands flushes the command queue and present the screen if needed.

internal/ui/ui.go

@@ -81,6 +81,8 @@ type UserInterface struct {
 	whiteImage *Image
 
 	mainThread thread.Thread
+
+	// TODO: Remove this (#2714).
 	renderThread thread.Thread
 
 	userInterfaceImpl

internal/ui/ui_glfw.go

@@ -1287,10 +1287,7 @@ func (u *UserInterface) setFPSMode(fpsMode FPSModeType) error {
 	}
 
 	vsyncEnabled := u.fpsMode == FPSModeVsyncOn
-	graphicscommand.SetVsyncEnabled(vsyncEnabled)
-	u.renderThread.CallAsync(func() {
-		u.graphicsDriver.SetVsyncEnabled(vsyncEnabled)
-	})
+	graphicscommand.SetVsyncEnabled(vsyncEnabled, u.graphicsDriver)
 
 	return nil
 }
@@ -1341,6 +1338,7 @@ func (u *UserInterface) update() (float64, float64, error) {
 
 	// Initialize vsync after SetMonitor is called. See the comment in updateVsync.
 	// Calling this inside setWindowSize didn't work (#1363).
+	// Also, setFPSMode has to be called after graphicscommand.SetRenderThread is called (#2714).
 	if !u.fpsModeInited {
 		if err := u.setFPSMode(u.fpsMode); err != nil {
 			return 0, 0, err