import javafx.animation.AnimationTimer; 
import javafx.application.Application; 
import javafx.scene.Group; 
import javafx.scene.Scene; 
import javafx.scene.paint.Color; 
import javafx.scene.shape.Circle; 
import javafx.stage.Stage; 

import java.util.concurrent.TimeUnit; 

public class Main extends Application { 

    final int WIDTH = 600; 
    final int HEIGHT = 400; 

    double ballRadius = 40; 
    double ballX = 100; 
    double ballY = 200; 
    double xSpeed = 4; 

    long framesInSecond = 0; 
    long nextSecond = 0; 
    final long SECOND = TimeUnit.SECONDS.toNanos(1); 

    @Override 
    public void start(Stage stage) throws Exception { 
// Parent root = FXMLLoader.load(getClass().getResource("sample.fxml")); 
// primaryStage.setTitle("Hello World"); 
// primaryStage.setScene(new Scene(root, 300, 275)); 
// primaryStage.show(); 


        stage.setTitle("Basic JavaFX demo"); 

        Group root = new Group(); 
        Scene scene = new Scene(root, WIDTH, HEIGHT); 

        Circle circle = new Circle(); 
        circle.setCenterX(ballX); 
        circle.setCenterY(ballY); 
        circle.setRadius(ballRadius); 
        circle.setFill(Color.BLUE); 
        root.getChildren().add(circle); 

        stage.setScene(scene); 
        stage.show(); 

// final KeyFrame frame = new KeyFrame(Duration.millis(1000/60), new EventHandler<ActionEvent>() { 
// public void handle(javafx.event.ActionEvent e) { 
// // UPDATE 
// ballX += xSpeed; 
// 
// if (ballX + ballRadius >= scene.getWidth()) { 
// ballX = scene.getWidth() - ballRadius; 
// xSpeed *= -1; 
// } else if (ballX - ballRadius < 0) { 
// ballX = 0 + ballRadius; 
// xSpeed *= -1; 
// } 
// 
// // RENDER 
// circle.setCenterX(ballX); 
// } 
// }); 
// 
// Timeline timeline = new Timeline(); 
// timeline.setCycleCount(Animation.INDEFINITE); 
// timeline.getKeyFrames().addAll(frame); 
// timeline.play(); 

        AnimationTimer animator = new AnimationTimer() { 
            @Override 
            public void handle(long nanos) { 
                framesInSecond++; 
                if (nanos >= nextSecond) { 
                    nextSecond = nanos + SECOND; 
                    System.out.println(framesInSecond); 
                    framesInSecond = 0; 
                } 
                ballX += xSpeed; 

                if (ballX + ballRadius >= scene.getWidth()) { 
                    ballX = scene.getWidth() - ballRadius; 
                    xSpeed *= -1; 
                } else if (ballX - ballRadius < 0) { 
                    ballX = 0 + ballRadius; 
                    xSpeed *= -1; 
                } 

                circle.setCenterX(ballX); 
            } 
        }; 

        animator.start(); 
    } 


    public static void main(String[] args) { 
        launch(args); 
    } 
}