loop: Remove dependency from audio to loop

audio/audio.go

@@ -39,7 +39,6 @@ import (
 	"github.com/hajimehoshi/oto"
 
 	"github.com/hajimehoshi/ebiten/internal/clock"
-	"github.com/hajimehoshi/ebiten/internal/loop"
 )
 
 type players struct {
@@ -233,7 +232,7 @@ func (c *Context) ping() {
 }
 
 func (c *Context) loop() {
-	loop.RegisterPing(c.ping)
+	clock.RegisterPing(c.ping)
 
 	// Initialize oto.Player lazily to enable calling NewContext in an 'init' function.
 	// Accessing oto.Player functions requires the environment to be already initialized,
@@ -263,7 +262,7 @@ func (c *Context) loop() {
 		c.m.Unlock()
 		c.frames++
 		clock.ProceedPrimaryTimer()
-		bytesPerFrame := c.sampleRate * bytesPerSample * channelNum / loop.FPS
+		bytesPerFrame := c.sampleRate * bytesPerSample * channelNum / clock.FPS
 		l := (c.frames * int64(bytesPerFrame)) - c.writtenBytes
 		l &= mask
 		c.writtenBytes += l

internal/clock/clock.go

@@ -20,14 +20,23 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/sync"
 )
 
+const FPS = 60
+
 var (
 	m               sync.Mutex
 	primaryTime     int64
 	lastPrimaryTime int64
 	frames          int64
 	logicalTime     int64
+	ping            func()
 )
 
+func RegisterPing(pingFunc func()) {
+	m.Lock()
+	ping = pingFunc
+	m.Unlock()
+}
+
 // ProceedPrimaryTimer increments the primary time by a frame.
 func ProceedPrimaryTimer() {
 	m.Lock()
@@ -35,13 +44,16 @@ func ProceedPrimaryTimer() {
 	m.Unlock()
 }
 
-// Frames returns an integer value indicating how many logical frames the game should update.
-//
-// Frames also updates the inner timer states.
-func Frames(now int64, fps int) int {
+// Update updates the inner clock state and returns an integer value
+// indicating how many logical frames the game should update.
+func Update(now int64) int {
 	m.Lock()
 	defer m.Unlock()
 
+	if ping != nil {
+		ping()
+	}
+
 	// Initialize logicalTime if needed.
 	if logicalTime == 0 {
 		logicalTime = now
@@ -74,20 +86,20 @@ func Frames(now int64, fps int) int {
 		// As the primary time can be updated discountinuously,
 		// the system clock is still needed.
 
-		if t > 5*int64(time.Second)/int64(fps) {
+		if t > 5*int64(time.Second)/FPS {
 			// The previous time is too old.
 			// Let's force to sync the logical time with the OS clock.
 			sync = true
 		} else {
-			count = int(t * int64(fps) / int64(time.Second))
+			count = int(t * FPS / int64(time.Second))
 		}
 	}
 
 	// Stabilize FPS.
-	if count == 0 && (int64(time.Second)/int64(fps)/2) < t {
+	if count == 0 && (int64(time.Second)/FPS/2) < t {
 		count = 1
 	}
-	if count == 2 && (int64(time.Second)/int64(fps)*3/2) > t {
+	if count == 2 && (int64(time.Second)/FPS*3/2) > t {
 		count = 1
 	}
 	if count > 3 {
@@ -98,7 +110,7 @@ func Frames(now int64, fps int) int {
 	if sync {
 		logicalTime = now
 	} else {
-		logicalTime += int64(count) * int64(time.Second) / int64(fps)
+		logicalTime += int64(count) * int64(time.Second) / FPS
 	}
 	return count
 }

internal/loop/run.go

@@ -22,7 +22,7 @@ import (
 	"github.com/hajimehoshi/ebiten/internal/sync"
 )
 
-const FPS = 60
+const FPS = clock.FPS
 
 func CurrentFPS() float64 {
 	if theRunContext == nil {
@@ -76,17 +76,6 @@ func End() {
 	theRunContext = nil
 }
 
-func RegisterPing(ping func()) {
-	<-contextInitCh
-	theRunContext.registerPing(ping)
-}
-
-func (c *runContext) registerPing(ping func()) {
-	c.m.Lock()
-	c.ping = ping
-	c.m.Unlock()
-}
-
 type Updater interface {
 	Update(updateCount int) error
 }
@@ -99,13 +88,7 @@ func Update(u Updater) error {
 func (c *runContext) update(u Updater) error {
 	n := now()
 
-	c.m.Lock()
-	if c.ping != nil {
-		c.ping()
-	}
-	c.m.Unlock()
-
-	count := clock.Frames(n, FPS)
+	count := clock.Update(n)
 	if err := u.Update(count); err != nil {
 		return err
 	}