Latest posts of: jboadas - Java-Gaming.org

Well I got the time to put toguether a simple barebones example of a JavaFX 8 Game loop
maybe not the best but it get the work done.

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package library;

import javafx.animation.AnimationTimer;
import javafx.application.Application;
import javafx.collections.ObservableList;
import javafx.geometry.Bounds;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.layout.Background;
import javafx.scene.layout.BackgroundFill;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Polygon;
import javafx.scene.text.Font;
import javafx.scene.text.Text;
import javafx.stage.Stage;

public class MainLoop extends Application {

   //size in pixels of the main game canvas
   private final int SIZE_W = 800;
   private final int SIZE_H = 600;
   //one second in nanoseconds
   private final long ONE_SECOND = 1000000000;
   //used to store the current time to calculate fps
   private long currentTime = 0;
   //used to store the last time to calculate fps
   private long lastTime = 0;
   //fps counter
   private int fps = 0;
   //acumulated difference between current time and last time
   private double delta = 0;
   //text to display fps
   private Text tFPS;
   //the game loop timer
   private AnimationTimer mainLoop;
   //the shape to test the main loop
   private Polygon star;
   //direction x,y of the star shape 
   private int dirx = 1;
   private int diry = 1;
   
   
   @Override
   public void start(Stage stage) throws Exception {
      
      //main game canvas
      Pane root = new Pane();
      root.setPrefSize(SIZE_W, SIZE_H);
      root.setBackground(new Background(new BackgroundFill(Color.BLACK, null, null)));
      
      //initialize all objects of the main loop
      initNodes(root.getChildren());
      //define the main loop
      initMainLoop(root.getChildren());
      //main scene
      Scene scene = new Scene(root);
      //the main window
      stage.setScene(scene);
      stage.setResizable(false);
      stage.setOnCloseRequest(event -> {
         mainLoop.stop();
         System.exit(0);
      });
      stage.show();
      //start the main loop
      mainLoop.start();
      
      
   }
   
   public void initNodes(ObservableList<Node> rootPane){
      tFPS = new Text("FPS : ");
      tFPS.setTranslateX(SIZE_W-180);
      tFPS.setTranslateY(60);
      tFPS.setFill(Color.WHITE);
      tFPS.setFont(new Font(40));
      rootPane.add(tFPS);
      initAnimation(rootPane);
   }
   
   public void initAnimation(ObservableList<Node> rootPane){
      star = new Polygon();
      Double[] starCoord = new Double[]{ 
            35.0, 120.5, 37.9, 129.1, 46.9, 129.1, 39.7, 134.5, 42.3,
            143.1, 35.0 , 139.0, 27.7, 143.1, 30.3, 134.5, 23.1, 129.1,
            32.1,129.1};
      star.getPoints().addAll(starCoord);
      star.setTranslateX(100);
      star.setTranslateY(100);
      star.setFill(Color.RED);
      rootPane.add(star);

   }
   
   public void initMainLoop(ObservableList<Node> rootPane){
      lastTime = System.nanoTime();
      mainLoop = new AnimationTimer() {
         
         @Override
         public void handle(long now) {
            currentTime = now;
            fps++;
            delta += currentTime-lastTime;
            
            updateAnimation(rootPane);
            
            if(delta > ONE_SECOND){
               tFPS.setText("FPS : "+fps);
               delta -= ONE_SECOND;
               fps = 0;
            }
            
            lastTime = currentTime;
         }
      };
   }
   
   public void updateAnimation(ObservableList<Node> rootPane){
      Bounds starbounds = star.getBoundsInParent();
      
      double posx = star.getTranslateX();
      double posy = star.getTranslateY();

      if((starbounds.getMaxX() >= SIZE_W) || (starbounds.getMinX() <= 0.0)){
         dirx = -dirx;
         star.setScaleX(1);
         star.setScaleY(1);
      }
      if((starbounds.getMaxY() >= SIZE_H) || (starbounds.getMinY() <= 0.0)){
         diry = -diry;
         star.setScaleX(1);
         star.setScaleY(1);
      }
      star.setTranslateX(posx+(3*dirx));
      star.setTranslateY(posy+(3*diry));
      star.setScaleX(star.getScaleX()+0.1);
      star.setScaleY(star.getScaleY()+0.1);

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

}

more info here:

http://blog.netopyr.com/2012/06/14/using-the-javafx-animationtimer/#comments

hope somebody found this usefull.