ui: Rename SetTPS -> SetMaxTPS, Introduce UncappedTPS

examples/windowsize/main.go

@@ -152,7 +152,7 @@ func update(screen *ebiten.Image) error {
 	ebiten.SetRunnableInBackground(runnableInBackground)
 	ebiten.SetCursorVisible(cursorVisible)
 	ebiten.SetVsyncEnabled(vsyncEnabled)
-	ebiten.SetTPS(tps)
+	ebiten.SetMaxTPS(tps)
 
 	if inpututil.IsKeyJustPressed(ebiten.KeyI) {
 		ebiten.SetWindowIcon([]image.Image{createRandomIconImage()})
@@ -175,6 +175,10 @@ func update(screen *ebiten.Image) error {
 	screen.DrawImage(gophersImage, op)
 
 	x, y := ebiten.CursorPosition()
+	tpsStr := "Uncapped"
+	if tps := ebiten.TPS(); tps != ebiten.UncappedTPS {
+		tpsStr = fmt.Sprintf("%d", tps)
+	}
 	msg := fmt.Sprintf(`Press arrow keys to change the window size
 Press S key to change the window scale
 Press F key to switch the fullscreen state
@@ -186,7 +190,7 @@ Press T key to switch TPS (ticks per second)
 Press Q key to quit
 Cursor: (%d, %d)
 FPS: %0.2f
-TPS: %d`, x, y, ebiten.CurrentFPS(), ebiten.TPS())
+TPS: %s`, x, y, ebiten.CurrentFPS(), tpsStr)
 	ebitenutil.DebugPrint(screen, msg)
 	return nil
 }

graphicscontext.go

@@ -83,11 +83,9 @@ func (c *graphicsContext) initializeIfNeeded() error {
 
 func (c *graphicsContext) Update(afterFrameUpdate func()) error {
 	tps := int(TPS())
-	count := clock.Update(tps)
-
-	updateCount := 1
-	if tps >= 0 {
-		updateCount = count
+	updateCount := clock.Update(tps)
+	if tps == UncappedTPS {
+		updateCount = 1
 	}
 
 	if err := c.initializeIfNeeded(); err != nil {

run.go

@@ -564,13 +564,20 @@ func TPS() int {
 	return int(atomic.LoadInt32(&currentTPS))
 }
 
-// SetTPS sets the TPS (ticks per second), that represents how many updating function is called
-// per second.
+// UncappedTPS is a special TPS value that means the game doesn't have limitation on TPS.
+const UncappedTPS = -1
+
+// SetMaxTPS sets the maximum TPS (ticks per second),
+// that represents how many updating function is called per second.
 // The initial value is 60.
 //
-// If the given tps is negative, TPS is unfixed and the game is updated per frame.
+// If tps is UncappedTPS, TPS is uncapped and the game is updated per frame.
+// If tps is negative but not UncappedTPS, SetMaxTPS panics.
 //
-// SetTPS is concurrent-safe.
-func SetTPS(tps int) {
+// SetMaxTPS is concurrent-safe.
+func SetMaxTPS(tps int) {
+	if tps < 0 && tps != UncappedTPS {
+		panic("ebiten: tps must be >= 0 or UncappedTPS")
+	}
 	atomic.StoreInt32(&currentTPS, int32(tps))
 }