uidriver/js: Force to update the screen when resizing

Updates #1204

internal/driver/ui.go

@@ -21,6 +21,7 @@ import (
 
 type UIContext interface {
 	Update() error
+	ForceUpdate() error
 	Layout(outsideWidth, outsideHeight float64)
 
 	// AdjustPosition can be called from a different goroutine from Update's or Layout's.

internal/uidriver/js/ui_js.go

@@ -184,13 +184,22 @@ func (u *UserInterface) update() error {
 		return nil
 	}
 	hooks.ResumeAudio()
+	return u.updateImpl(false)
+}
 
+func (u *UserInterface) updateImpl(force bool) error {
 	u.input.updateGamepads()
 	u.input.updateForGo2Cpp()
 	u.updateSize()
+	if force {
+		if err := u.context.ForceUpdate(); err != nil {
+			return err
+		}
+	} else {
 		if err := u.context.Update(); err != nil {
 			return err
 		}
+	}
 	return nil
 }
 
@@ -327,6 +336,9 @@ func init() {
 func setWindowEventHandlers(v js.Value) {
 	v.Call("addEventListener", "resize", js.FuncOf(func(this js.Value, args []js.Value) interface{} {
 		theUI.updateScreenSize()
+		if err := theUI.updateImpl(true); err != nil {
+			panic(err)
+		}
 		return nil
 	}))
 

uicontext.go

@@ -145,7 +145,7 @@ func (c *uiContext) Update() error {
 	if err := buffered.BeginFrame(); err != nil {
 		return err
 	}
-	if err := c.update(); err != nil {
+	if err := c.update(clock.Update(MaxTPS())); err != nil {
 		return err
 	}
 	if err := buffered.EndFrame(); err != nil {
@@ -154,10 +154,24 @@ func (c *uiContext) Update() error {
 	return nil
 }
 
-func (c *uiContext) update() error {
-	c.updateOffscreen()
+func (c *uiContext) ForceUpdate() error {
+	if err, ok := c.err.Load().(error); ok && err != nil {
+		return err
+	}
+	if err := buffered.BeginFrame(); err != nil {
+		return err
+	}
+	if err := c.update(1); err != nil {
+		return err
+	}
+	if err := buffered.EndFrame(); err != nil {
+		return err
+	}
+	return nil
+}
 
-	updateCount := clock.Update(MaxTPS())
+func (c *uiContext) update(updateCount int) error {
+	c.updateOffscreen()
 
 	// Ensure that Update is called once before Draw so that Update can be used for initialization.
 	if !c.updateCalled && updateCount == 0 {