Report average frame time.

fast/main.go

@@ -39,6 +39,8 @@ func loop(w *app.Window) error {
 	q := w.Queue()
 	face := faces.For(regular, ui.Sp(16))
 	lst := layout.List{Axis: layout.Vertical}
+	times := make([]int64, 100)
+	timesIndex := 0
 	for {
 		e := <-w.Events()
 		switch e := e.(type) {
@@ -54,7 +56,19 @@ func loop(w *app.Window) error {
 			}
 			lst.Layout()
 			w.Update(ops)
-			log.Printf("Frame time: %s\n", time.Since(stime))
+			dur := time.Since(stime)
+			//fmt.Printf("Frame time: %s\n", dur)
+			times[timesIndex] = dur.Nanoseconds()
+			timesIndex++
+			if timesIndex == 100 {
+				timesIndex = 0
+				var avg int64
+				for i := 0; i < 100; i++ {
+					avg += times[i]
+				}
+				avg = avg / 100000
+				fmt.Printf("Average frame time: %d microseconds\n", avg)
+			}
 		}
 	}
 }

slow/main.go

@@ -37,6 +37,8 @@ func loop(w *app.Window) error {
 	family := &shape.Family{Regular: regular}
 	gtx := &layout.Context{Queue: w.Queue()}
 	lst := &layout.List{Axis: layout.Vertical}
+	times := make([]int64, 100)
+	timesIndex := 0
 	for {
 		e := <-w.Events()
 		switch e := e.(type) {
@@ -51,7 +53,19 @@ func loop(w *app.Window) error {
 				})
 			}
 			w.Update(gtx.Ops)
-			log.Printf("Frame time: %s\n", time.Since(stime))
+			dur := time.Since(stime)
+			//fmt.Printf("Frame time: %s\n", dur)
+			times[timesIndex] = dur.Nanoseconds()
+			timesIndex++
+			if timesIndex == 100 {
+				timesIndex = 0
+				var avg int64
+				for i := 0; i < 100; i++ {
+					avg += times[i]
+				}
+				avg = avg / 100000
+				fmt.Printf("Average frame time: %d microseconds\n", avg)
+			}
 		}
 	}
 }