Add piloop.Stop() function

This function can be used to stop the game loop.

Author: elgopher

_examples/stop/main.go

@@ -0,0 +1,16 @@
+package main
+
+import (
+	"github.com/elgopher/pi/piebiten"
+	"github.com/elgopher/pi/pikey"
+	"github.com/elgopher/pi/piloop"
+)
+
+func main() {
+	// stops the game loop when user pressed Escape key
+	pikey.RegisterShortcut(piloop.Stop, pikey.Esc)
+
+	piebiten.Run() // this function ends without panic once game loop is stopped
+
+	// Code in here is executed after loop is stopped
+}

piebiten/internal/ebitengame.go

@@ -4,12 +4,13 @@
 package internal
 
 import (
+	"math"
+	"time"
+
 	"github.com/elgopher/pi/piaudio"
 	"github.com/elgopher/pi/piebiten/internal/audio"
 	"github.com/elgopher/pi/piebiten/internal/input"
 	ebitenaudio "github.com/hajimehoshi/ebiten/v2/audio"
-	"math"
-	"time"
 
 	"github.com/hajimehoshi/ebiten/v2"
 
@@ -40,6 +41,7 @@ func RunEbitenGame() *EbitenGame {
 	}
 
 	pidebug.Target().SubscribeAll(game.onPidebugEvent)
+	piloop.Target().Subscribe(piloop.EventStop, game.onPiloopStopEvent)
 
 	return game
 }
@@ -87,9 +89,14 @@ type EbitenGame struct {
 	inputBackend *input.Backend
 
 	ebitenFrame int // frame incremented on each Ebiten tick
+
+	stopped bool
 }
 
 func (g *EbitenGame) Update() error {
+	if g.stopped {
+		return ebiten.Termination
+	}
 	if ebiten.IsWindowBeingClosed() {
 		piloop.Target().Publish(piloop.EventWindowClose)
 		return ebiten.Termination
@@ -217,3 +224,7 @@ func (g *EbitenGame) onPidebugEvent(event pidebug.Event, _ pievent.Handler) {
 		g.paused = false
 	}
 }
+
+func (g *EbitenGame) onPiloopStopEvent(piloop.Event, pievent.Handler) {
+	g.stopped = true
+}

piloop/event.go

@@ -13,4 +13,5 @@ const (
 	EventDraw        Event = "draw"         // after pi.Draw
 	EventLateDraw    Event = "late_draw"    // after EventDraw
 	EventWindowClose Event = "window_close" // when a user closes the window (desktop only)
+	EventStop        Event = "stop"         // when game loop is stopped by calling piloop.Stop()
 )

piloop/piloop.go

@@ -17,6 +17,10 @@ func DebugTarget() pievent.Target[Event] {
 	return debugTarget
 }
 
+func Stop() {
+	Target().Publish(EventStop)
+}
+
 var (
 	target      = pievent.NewTarget[Event]()
 	debugTarget = pievent.NewTarget[Event]()