JavaFX - Multiple lights on a dark background - image

Question

I'm attempting to create something like a minimap with JavaFX, i.e. a (darkened) background image with some circles layered on top of it. Some of these circles need to be able to shed light on the background, revealing a small part of it. The following figure shows what I am aiming at.
I have worked my way forward using this SO solution, but at the moment, I am stuck because it seems that you can only set one instance of javafx.scene.effect.Lighting on the underlying StackPane.
I would really like to keep this as simple as possible and ideally only employ JavaFX. Any help is greatly appreciated :)

Answer 1

I recommend adding together Circles filled with a RadialGradient on a Pane with black background using BlendMode.LIGHTEN and combining this with a ImageView containing the "map" using BlendMode.MULTIPLY:
private Circle circle;
// gradient with yellow in the center and black on the border
private final static RadialGradient GRADIENT = new RadialGradient(0, 0, 0.5, 0.5, 0.5, true, CycleMethod.NO_CYCLE, new Stop(0, Color.YELLOW), new Stop(1, Color.BLACK));
private void newCircle(Pane container) {
circle = new Circle(50, GRADIENT);
circle.setBlendMode(BlendMode.LIGHTEN);
circle.setManaged(false);
container.getChildren().add(circle);
}
private void setCirclePosition(MouseEvent event) {
circle.setCenterX(event.getX());
circle.setCenterY(event.getY());
}
#Override
public void start(Stage primaryStage) {
Image image = new Image(imageURL);
ImageView imageView = new ImageView(image);
Pane mask = new Pane();
mask.setBlendMode(BlendMode.MULTIPLY);
mask.setStyle("-fx-background-color: black;");
mask.setOnMouseMoved(this::setCirclePosition); // move cricle with mouse
newCircle(mask);
// create new circle on mouse click
mask.setOnMouseClicked(evt -> {
newCircle(mask);
setCirclePosition(evt);
});
StackPane root = new StackPane(imageView, mask);
Scene scene = new Scene(root);
primaryStage.setScene(scene);
primaryStage.show();
}