Allow ebiten.Run execution to be profiled

internal/ui/window.go

@@ -3,6 +3,9 @@ package ui
 import (
 	"flag"
 	"fmt"
+	"log"
+	"os"
+	"runtime/pprof"
 
 	"github.com/hajimehoshi/ebiten"
 	"github.com/hajimehoshi/ebiten/ebitenutil"
@@ -12,6 +15,8 @@ import (
 var (
 	winX = flag.Int("win-x", 1280, "width of the view-map window")
 	winY = flag.Int("win-y", 1024, "height of the view-map window")
+
+	cpuprofile = flag.String("cpuprofile", "", "write cpu profile to `file`")
 )
 
 type Window struct {
@@ -91,5 +96,17 @@ func (w *Window) Run(updateFn func() error, drawFn func(*ebiten.Image) error) er
 	w.updateFn = updateFn
 	w.drawFn = drawFn
 
+	if *cpuprofile != "" {
+        f, err := os.Create(*cpuprofile)
+        if err != nil {
+            log.Fatal("could not create CPU profile: ", err)
+        }
+        defer f.Close() // error handling omitted for example
+        if err := pprof.StartCPUProfile(f); err != nil {
+            log.Fatal("could not start CPU profile: ", err)
+        }
+        defer pprof.StopCPUProfile()
+    }
+
 	return ebiten.Run(w.run, *winX, *winY, 1, w.Title)
 }