refactor: prefer typed params for API funcs

- Introduce `SpriteName`, `SpriteCostumeName`, `SpriteAnimationName`,
  `SoundName`, `BackdropName`, `WidgetName`.
- Prefer func overloading over using `interface{}` or variadic params as
  optional params.

Signed-off-by: Aofei Sheng <[email protected]>

camera.go

@@ -59,9 +59,9 @@ func (c *Camera) worldToScreen(point *math32.Vector2) *math32.Vector2 {
 }
 */
 
-func (c *Camera) On(obj interface{}) {
+func (c *Camera) on(obj interface{}) {
 	switch v := obj.(type) {
-	case string:
+	case SpriteName:
 		sp := c.g.findSprite(v)
 		if sp == nil {
 			log.Println("Camera.On: sprite not found -", v)
@@ -83,6 +83,22 @@ func (c *Camera) On(obj interface{}) {
 	c.on_ = obj
 }
 
+func (c *Camera) On__0(sprite Sprite) {
+	c.on(sprite)
+}
+
+func (c *Camera) On__1(sprite *SpriteImpl) {
+	c.on(sprite)
+}
+
+func (c *Camera) On__2(sprite SpriteName) {
+	c.on(sprite)
+}
+
+func (c *Camera) On__3(obj specialObj) {
+	c.on(obj)
+}
+
 func (c *Camera) updateOnObj() {
 	switch v := c.on_.(type) {
 	case *SpriteImpl:

event.go

@@ -213,17 +213,17 @@ func (p *eventSinkMgr) doWhenIReceive(msg string, data interface{}, wait bool) {
 	})
 }
 
-func (p *eventSinkMgr) doWhenBackdropChanged(name string, wait bool) {
+func (p *eventSinkMgr) doWhenBackdropChanged(name BackdropName, wait bool) {
 	p.allWhenBackdropChanged.call(wait, name, func(ev *eventSink) {
-		ev.sink.(func(string))(name)
+		ev.sink.(func(BackdropName))(name)
 	})
 }
 
 // -------------------------------------------------------------------------------------
 type IEventSinks interface {
 	OnAnyKey(onKey func(key Key))
-	OnBackdrop__0(onBackdrop func(name string))
-	OnBackdrop__1(name string, onBackdrop func())
+	OnBackdrop__0(onBackdrop func(name BackdropName))
+	OnBackdrop__1(name BackdropName, onBackdrop func())
 	OnClick(onClick func())
 	OnKey__0(key Key, onKey func())
 	OnKey__1(keys []Key, onKey func(Key))
@@ -361,26 +361,26 @@ func (p *eventSinks) OnMsg__1(msg string, onMsg func()) {
 	}
 }
 
-func (p *eventSinks) OnBackdrop__0(onBackdrop func(name string)) {
+func (p *eventSinks) OnBackdrop__0(onBackdrop func(name BackdropName)) {
 	p.allWhenBackdropChanged = &eventSink{
 		prev:  p.allWhenBackdropChanged,
 		pthis: p.pthis,
 		sink:  onBackdrop,
 	}
 }
 
-func (p *eventSinks) OnBackdrop__1(name string, onBackdrop func()) {
+func (p *eventSinks) OnBackdrop__1(name BackdropName, onBackdrop func()) {
 	p.allWhenBackdropChanged = &eventSink{
 		prev:  p.allWhenBackdropChanged,
 		pthis: p.pthis,
-		sink: func(name string) {
+		sink: func(name BackdropName) {
 			if debugEvent {
 				log.Println("==> onBackdrop", name, nameOf(p.pthis))
 			}
 			onBackdrop()
 		},
 		cond: func(data interface{}) bool {
-			return data.(string) == name
+			return data.(BackdropName) == name
 		},
 	}
 }

game.go

@@ -473,7 +473,7 @@ func (p *Game) loadIndex(g reflect.Value, proj *projConfig) (err error) {
 
 	ebiten.SetWindowResizingMode(ebiten.WindowResizingModeOnlyFullscreenEnabled)
 	if proj.Camera != nil && proj.Camera.On != "" {
-		p.Camera.On(proj.Camera.On)
+		p.Camera.On__2(proj.Camera.On)
 	}
 	if loader, ok := g.Addr().Interface().(interface{ OnLoaded() }); ok {
 		loader.OnLoaded()
@@ -860,7 +860,7 @@ func (p *Game) touchingSpriteBy(dst *SpriteImpl, name string) *SpriteImpl {
 
 func (p *Game) objectPos(obj interface{}) (float64, float64) {
 	switch v := obj.(type) {
-	case string:
+	case SpriteName:
 		if sp := p.findSprite(v); sp != nil {
 			return sp.getXY()
 		}
@@ -1033,7 +1033,7 @@ func (p *Game) doFindSprite(src Shape) int {
 	return -1
 }
 
-func (p *Game) findSprite(name string) *SpriteImpl {
+func (p *Game) findSprite(name SpriteName) *SpriteImpl {
 	for _, item := range p.items {
 		if sp, ok := item.(*SpriteImpl); ok {
 			if !sp.isCloned_ && sp.name == name {
@@ -1045,7 +1045,6 @@ func (p *Game) findSprite(name string) *SpriteImpl {
 }
 
 // -----------------------------------------------------------------------------
-
 func (p *Game) drawBackground(dc drawContext) {
 	c := p.costumes[p.costumeIndex_]
 	img, _, _ := c.needImage(p.fs)
@@ -1156,7 +1155,9 @@ func (p *Game) onHit(hc hitContext) (hr hitResult, ok bool) {
 
 // -----------------------------------------------------------------------------
 
-func (p *Game) BackdropName() string {
+type BackdropName = string
+
+func (p *Game) BackdropName() BackdropName {
 	return p.getCostumeName()
 }
 
@@ -1166,24 +1167,64 @@ func (p *Game) BackdropIndex() int {
 
 // StartBackdrop func:
 //
-//	StartBackdrop(backdropName) or
-//	StartBackdrop(backdropIndex) or
+//	StartBackdrop(backdrop) or
+//	StartBackdrop(index) or
 //	StartBackdrop(spx.Next)
 //	StartBackdrop(spx.Prev)
-func (p *Game) StartBackdrop(backdrop interface{}, wait ...bool) {
+func (p *Game) startBackdrop(backdrop interface{}, wait bool) {
 	if p.goSetCostume(backdrop) {
 		p.windowWidth_ = 0
 		p.doWindowSize()
-		p.doWhenBackdropChanged(p.getCostumeName(), wait != nil && wait[0])
+		p.doWhenBackdropChanged(p.getCostumeName(), wait)
 	}
 }
 
-func (p *Game) NextBackdrop(wait ...bool) {
-	p.StartBackdrop(Next, wait...)
+func (p *Game) StartBackdrop__0(backdrop BackdropName) {
+	p.startBackdrop(backdrop, false)
+}
+
+func (p *Game) StartBackdrop__1(backdrop BackdropName, wait bool) {
+	p.startBackdrop(backdrop, wait)
+}
+
+func (p *Game) StartBackdrop__2(index int) {
+	p.startBackdrop(index, false)
+}
+
+func (p *Game) StartBackdrop__3(index int, wait bool) {
+	p.startBackdrop(index, wait)
+}
+
+func (p *Game) StartBackdrop__4(index float64) {
+	p.startBackdrop(index, false)
+}
+
+func (p *Game) StartBackdrop__5(index float64, wait bool) {
+	p.startBackdrop(index, wait)
 }
 
-func (p *Game) PrevBackdrop(wait ...bool) {
-	p.StartBackdrop(Prev, wait...)
+func (p *Game) StartBackdrop__6(action switchAction) {
+	p.startBackdrop(action, false)
+}
+
+func (p *Game) StartBackdrop__7(action switchAction, wait bool) {
+	p.startBackdrop(action, wait)
+}
+
+func (p *Game) NextBackdrop__0() {
+	p.StartBackdrop__6(Next)
+}
+
+func (p *Game) NextBackdrop__1(wait bool) {
+	p.StartBackdrop__7(Next, wait)
+}
+
+func (p *Game) PrevBackdrop__0() {
+	p.StartBackdrop__6(Prev)
+}
+
+func (p *Game) PrevBackdrop__1(wait bool) {
+	p.StartBackdrop__7(Prev, wait)
 }
 
 // -----------------------------------------------------------------------------
@@ -1282,6 +1323,8 @@ func (p *Game) ClearSoundEffects() {
 
 type Sound *soundConfig
 
+type SoundName = string
+
 func (p *Game) canBindSound(name string) bool {
 	// auto bind the sound, if assets/sounds/{name}/index.json exists.
 	prefix := "sounds/" + name
@@ -1293,7 +1336,7 @@ func (p *Game) canBindSound(name string) bool {
 	return true
 }
 
-func (p *Game) loadSound(name string) (media Sound, err error) {
+func (p *Game) loadSound(name SoundName) (media Sound, err error) {
 	if media, ok := p.sounds.audios[name]; ok {
 		return media, nil
 	}
@@ -1317,9 +1360,6 @@ func (p *Game) loadSound(name string) (media Sound, err error) {
 //	Play(video) -- maybe
 //	Play(media, wait) -- sync
 //	Play(media, opts)
-//	Play(mediaName)
-//	Play(mediaName, wait) -- sync
-//	Play(mediaName, opts)
 func (p *Game) Play__0(media Sound) {
 	p.Play__2(media, &PlayOptions{})
 }
@@ -1338,21 +1378,22 @@ func (p *Game) Play__2(media Sound, action *PlayOptions) {
 		panic(err)
 	}
 }
-func (p *Game) Play__3(mediaName string) {
-	p.Play__5(mediaName, &PlayOptions{})
+
+func (p *Game) Play__3(media SoundName) {
+	p.Play__5(media, &PlayOptions{})
 }
 
-func (p *Game) Play__4(mediaName string, wait bool) {
-	p.Play__5(mediaName, &PlayOptions{Wait: wait})
+func (p *Game) Play__4(media SoundName, wait bool) {
+	p.Play__5(media, &PlayOptions{Wait: wait})
 }
 
-func (p *Game) Play__5(mediaName string, action *PlayOptions) {
-	media, err := p.loadSound(mediaName)
+func (p *Game) Play__5(media SoundName, action *PlayOptions) {
+	m, err := p.loadSound(media)
 	if err != nil {
 		log.Println(err)
 		return
 	}
-	p.Play__2(media, action)
+	p.Play__2(m, action)
 }
 
 func (p *Game) StopAllSounds() {
@@ -1433,7 +1474,7 @@ type ShapeGetter interface {
 // Instead of being used directly, it is meant to be called by `Gopt_Game_Gopx_GetWidget` only.
 // We extract `GetWidget_` to keep `Gopt_Game_Gopx_GetWidget` simple, which simplifies work in ispx,
 // see details in https://github.com/goplus/builder/issues/765#issuecomment-2313915805.
-func GetWidget_(sg ShapeGetter, name string) Widget {
+func GetWidget_(sg ShapeGetter, name WidgetName) Widget {
 	items := sg.getAllShapes()
 	for _, item := range items {
 		widget, ok := item.(Widget)
@@ -1445,7 +1486,7 @@ func GetWidget_(sg ShapeGetter, name string) Widget {
 }
 
 // GetWidget returns the widget instance (in given type) with given name. It panics if not found.
-func Gopt_Game_Gopx_GetWidget[T any](sg ShapeGetter, name string) *T {
+func Gopt_Game_Gopx_GetWidget[T any](sg ShapeGetter, name WidgetName) *T {
 	widget := GetWidget_(sg, name)
 	if result, ok := widget.(interface{}).(*T); ok {
 		return result

monitor.go

@@ -37,7 +37,7 @@ import (
 // Monitor class.
 type Monitor struct {
 	game    *Game
-	name    string
+	name    WidgetName
 	size    float64
 	target  string
 	val     string
@@ -304,7 +304,7 @@ func (p *Monitor) hit(hc hitContext) (hr hitResult, ok bool) {
 
 // -------------------------------------------------------------------------------------
 // IWidget
-func (pself *Monitor) GetName() string {
+func (pself *Monitor) GetName() WidgetName {
 	return pself.name
 }
 

spbase.go

@@ -174,7 +174,7 @@ func (p *imageLoaderByCostumeSet) load(fs spxfs.Dir, pt *imagePoint) (gdi.Image,
 // -------------------------------------------------------------------------------------
 
 type costume struct {
-	name             string
+	name             SpriteCostumeName
 	img              delayloadImage
 	faceRight        float64
 	bitmapResolution int
@@ -296,7 +296,7 @@ func initCSPart(p *baseObj, img *costumeSetImage, faceRight float64, bitmapResol
 	}
 }
 
-func addCostumeWith(p *baseObj, name string, img *costumeSetImage, faceRight float64, i, bitmapResolution int) {
+func addCostumeWith(p *baseObj, name SpriteCostumeName, img *costumeSetImage, faceRight float64, i, bitmapResolution int) {
 	c := newCostumeWith(name, img, faceRight, i, bitmapResolution)
 	p.costumes = append(p.costumes, c)
 }
@@ -334,7 +334,7 @@ func (p *baseObj) initFrom(src *baseObj) {
 	p.costumeIndex_ = src.costumeIndex_
 }
 
-func (p *baseObj) findCostume(name string) int {
+func (p *baseObj) findCostume(name SpriteCostumeName) int {
 	for i, c := range p.costumes {
 		if c.name == name {
 			return i
@@ -345,7 +345,7 @@ func (p *baseObj) findCostume(name string) int {
 
 func (p *baseObj) goSetCostume(val interface{}) bool {
 	switch v := val.(type) {
-	case string:
+	case SpriteCostumeName:
 		return p.setCostumeByName(v)
 	case int:
 		return p.setCostumeByIndex(v)
@@ -373,8 +373,7 @@ func (p *baseObj) setCostumeByIndex(idx int) bool {
 	}
 	return false
 }
-
-func (p *baseObj) setCostumeByName(name string) bool {
+func (p *baseObj) setCostumeByName(name SpriteCostumeName) bool {
 	if idx := p.findCostume(name); idx >= 0 {
 		return p.setCostumeByIndex(idx)
 	}
@@ -393,7 +392,7 @@ func (p *baseObj) getCostumeIndex() int {
 	return p.costumeIndex_
 }
 
-func (p *baseObj) getCostumeName() string {
+func (p *baseObj) getCostumeName() SpriteCostumeName {
 	return p.costumes[p.costumeIndex_].name
 }