How do I create a triangle using JavaFX?

Question

How can I create a triangle using JavaFX? I have already tried these but I don't know how to fix it exactly :

Polygon triangle = new Polygon();
triangle.getPoints().setAll(
   50, 50,
   60, 60,
   20, 40
);

Answer 1

Replace triangle.getPoints().setAll.. with triangle.getPoints().addAll(

Explanation:

You are adding 3 points, the x0=50,y0=50 then the x0=60,y0=60 and then x0=20,y0=40, those are the vertices of the triangle...

this represents a triangle like this (Be careful of not plotting a line or a weird figure)

The following snippet will generate a polygon like the image below.

public class Main extends Application {
      @Override
      public void start(Stage stage) {
        Group root = new Group();
        Scene scene = new Scene(root, 260, 80);
        stage.setScene(scene);
    
        Group g = new Group();
    
        Polygon polygon = new Polygon();
        polygon.getPoints().addAll(new Double[]{
            0.0, 0.0,
            20.0, 10.0,
            10.0, 20.0 });
        
        g.getChildren().add(polygon);
        
        scene.setRoot(g);
        stage.show();
      }
    
      public static void main(String[] args) {
        launch(args);
      }
    }