particle explosion

Practiced http://codepen.io/thebabydino/pen/vgXrZm
https://netopyr.com/2012/06/14/using-the-javafx-animationtimer/

import java.time.Duration;
import java.util.Random;

import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.scene.Scene;
import javafx.scene.input.KeyCode;
import javafx.scene.input.KeyCodeCombination;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;

public class Main extends Application {

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

 @Override
 public void start(Stage stage) throws Exception {
  final int size = 400;
  final Rectangle[] rectangles = new Rectangle[size];
  final long[] delays = new long[size];
  final double[] angles = new double[size];
  final long duration = Duration.ofSeconds(3).toNanos();
  final Random random = new Random();

  for (int i = 0; i < size; i++) {
   rectangles[i] = new Rectangle(5, 5, Color.hsb(random.nextInt(360), 1, 1));
   delays[i] = (long) (Math.random()*duration);
   angles[i] = 2 * Math.PI * random.nextDouble();
  }
  stage.setScene(new Scene(new Pane(rectangles), 500, 500, Color.BLACK));
  stage.getScene().getAccelerators().put(new KeyCodeCombination(KeyCode.ESCAPE), () -> System.exit(0)); 
  stage.show();

  new AnimationTimer() {
   @Override
   public void handle(long now) {
    final double width = 0.5 * stage.getWidth();
    final double height = 0.5 * stage.getHeight();
    final double radius = Math.sqrt(2) * Math.max(width, height);

    for (int i = 0; i < size; i++) {
     Rectangle r = rectangles[i];
     double angle = angles[i];
     long t = (now - delays[i]) % duration;
     double d = t*radius/duration;
     
     r.setOpacity((duration - t)/(double)duration);
     r.setTranslateX(Math.cos(angle)*d + width);
     r.setTranslateY(Math.sin(angle)*d + height);
    }
   }
  }.start();
 }



}

styled using hilite.me

download code