ui: Add fps, tps display

internal/ui/window.go

@@ -2,8 +2,10 @@ package ui
 
 import (
 	"flag"
+	"fmt"
 
 	"github.com/hajimehoshi/ebiten"
+	"github.com/hajimehoshi/ebiten/ebitenutil"
 	"github.com/hajimehoshi/ebiten/inpututil"
 )
 
@@ -20,6 +22,8 @@ type Window struct {
 	// User-provided update actions
 	updateFn func() error
 	drawFn   func(*ebiten.Image) error
+
+	debug bool
 }
 
 // 0,0 is the *top left* of the window
@@ -31,6 +35,7 @@ func NewWindow(title string) (*Window, error) {
 	return &Window{
 		Title:         title,
 		KeyUpHandlers: make(map[ebiten.Key]func()),
+		debug:         true,
 	}, nil
 }
 
@@ -68,6 +73,12 @@ func (w *Window) run(screen *ebiten.Image) error {
 		if err := w.drawFn(screen); err != nil {
 			return err
 		}
+
+		if w.debug {
+			// Draw FPS, etc, to the screen
+			msg := fmt.Sprintf("tps=%0.2f fps=%0.2f", ebiten.CurrentTPS(), ebiten.CurrentFPS())
+			ebitenutil.DebugPrint(screen, msg)
+		}
 	}
 
 	return nil