diff --git a/internal/loop/run.go b/internal/loop/run.go
index f92b1f8c7..cee358529 100644
--- a/internal/loop/run.go
+++ b/internal/loop/run.go
@@ -109,15 +109,12 @@ func Run(g GraphicsContext, width, height int, scale float64, title string, fps
 	currentRunContext.startRunning()
 	defer currentRunContext.endRunning()
 
-	if err := ui.CurrentUI().Start(width, height, scale, title); err != nil {
-		return err
-	}
-
 	n := now()
 	currentRunContext.lastUpdated = n
 	currentRunContext.lastFPSUpdated = n
 
-	if err := ui.CurrentUI().AnimationFrameLoop(&loopGraphicsContext{currentRunContext, g}); err != nil {
+	lg := &loopGraphicsContext{currentRunContext, g}
+	if err := ui.CurrentUI().Run(width, height, scale, title, lg); err != nil {
 		if _, ok := err.(*ui.RegularTermination); ok {
 			return nil
 		}
diff --git a/internal/ui/ui.go b/internal/ui/ui.go
index cbbc64989..665cfaea9 100644
--- a/internal/ui/ui.go
+++ b/internal/ui/ui.go
@@ -20,8 +20,7 @@ type GraphicsContext interface {
 }
 
 type UserInterface interface {
-	Start(width, height int, scale float64, title string) error
-	AnimationFrameLoop(g GraphicsContext) error
+	Run(width, height int, scale float64, title string, g GraphicsContext) error
 	ScreenScale() float64
 	SetScreenSize(width, height int) (bool, error)
 	SetScreenScale(scale float64) (bool, error)
diff --git a/internal/ui/ui_glfw.go b/internal/ui/ui_glfw.go
index 96033fdb6..0db1f8390 100644
--- a/internal/ui/ui_glfw.go
+++ b/internal/ui/ui_glfw.go
@@ -147,7 +147,7 @@ func (u *userInterface) ScreenScale() float64 {
 	return s
 }
 
-func (u *userInterface) Start(width, height int, scale float64, title string) error {
+func (u *userInterface) Run(width, height int, scale float64, title string, g GraphicsContext) error {
 	// GLContext must be created before setting the screen size, which requires
 	// swapping buffers.
 	var err error
@@ -176,7 +176,7 @@ func (u *userInterface) Start(width, height int, scale float64, title string) er
 	}); err != nil {
 		return err
 	}
-	return nil
+	return u.loop(g)
 }
 
 func (u *userInterface) glfwSize() (int, int) {
@@ -241,7 +241,7 @@ func (u *userInterface) update(g GraphicsContext) error {
 	return nil
 }
 
-func (u *userInterface) AnimationFrameLoop(g GraphicsContext) error {
+func (u *userInterface) loop(g GraphicsContext) error {
 	defer func() {
 		_ = u.runOnMainThread(func() error {
 			glfw.Terminate()
diff --git a/internal/ui/ui_js.go b/internal/ui/ui_js.go
index bb2fa42f9..d7256d4db 100644
--- a/internal/ui/ui_js.go
+++ b/internal/ui/ui_js.go
@@ -87,7 +87,7 @@ func (u *userInterface) update(g GraphicsContext) error {
 	return nil
 }
 
-func (u *userInterface) AnimationFrameLoop(g GraphicsContext) error {
+func (u *userInterface) loop(g GraphicsContext) error {
 	ch := make(chan error)
 	var f func()
 	f = func() {
@@ -262,7 +262,7 @@ func Main(ch <-chan error) error {
 	return <-ch
 }
 
-func (u *userInterface) Start(width, height int, scale float64, title string) error {
+func (u *userInterface) Run(width, height int, scale float64, title string, g GraphicsContext) error {
 	doc := js.Global.Get("document")
 	doc.Set("title", title)
 	u.setScreenSize(width, height, scale)
@@ -272,7 +272,7 @@ func (u *userInterface) Start(width, height int, scale float64, title string) er
 	if err != nil {
 		return err
 	}
-	return nil
+	return u.loop(g)
 }
 
 func (u *userInterface) size() (width, height int) {
diff --git a/internal/ui/ui_mobile.go b/internal/ui/ui_mobile.go
index 6e8fe3928..e289a5e5a 100644
--- a/internal/ui/ui_mobile.go
+++ b/internal/ui/ui_mobile.go
@@ -64,7 +64,7 @@ func CurrentUI() UserInterface {
 	return currentUI
 }
 
-func (u *userInterface) Start(width, height int, scale float64, title string) error {
+func (u *userInterface) Run(width, height int, scale float64, title string, g GraphicsContext) error {
 	u.width = width
 	u.height = height
 	u.scale = scale
@@ -74,10 +74,6 @@ func (u *userInterface) Start(width, height int, scale float64, title string) er
 	if err != nil {
 		return err
 	}
-	return nil
-}
-
-func (u *userInterface) AnimationFrameLoop(g GraphicsContext) error {
 	for {
 		if err := u.update(g); err != nil {
 			return err