Best way to MouseDrag multiple objects around a scene.

Question

So I am having a little trouble trying to drag 3 Box's in a scene.
Originally I had it set up where each was relocated to an x,y translated Z and set to a HWD. Then I figured I would, instead of the mouse click on the box itself, be in the root. From there I would look through all of the root.getChildren() then made that see if it contained the x,y position.
Then from knowing which of my root Children I clicked I did root.getChildren.get(current).setOnDragged to figure out which one was dragged.
The code itself worked except for finding which box I was on.
The issue I find is that I onyl have getX, getSceneX, and getScreenX. X, and SceneX produce the same value, and ScreenX is useless. I tried then to do event.getX() - root.getLayoutX() to make the contains function to work, but it wasn't working and would require me to change up more things. getLayoutX() was = 0 since I didn't set the root location, only the locations of the box's.
From there I kept wondering if there was a better way. Then I thought maybe to loop through every element in my root or in an arrayList(Which is what I used, but realized the root.getchildren should work like the original) but the problem is it keeps only registering the last one in the list, so it just loops and that's it.
So what I want to know is, what would be the best way to figure out what object I'm in?
Originally I use the contains(Swing) but Swing is different, and now especially since we can register mouseEvents to each node, shouldn't we know exactly which one we are on, just by looping through each of them? I figure that's easier than having to check every single mouse position contained within, especially if I have 10000 things to check?
Edited by: KonradZuse on Mar 18, 2013 8:05 PM

Answer 1

I slightly modified your code for 3D.
- added a pointlight
- added a phong material
- the rectangle changed to a box
- the circle changed to a sphere
- add scene.setCamera(new PerspectiveCamera(false));
Without the last line it is not working.
I tested it with javafx8.0 build 80 Netbean7.3
import javafx.application.Application;
import javafx.scene.Node;
import javafx.scene.Scene;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Circle;
import javafx.scene.shape.Polygon;
import javafx.scene.shape.Rectangle;
import javafx.stage.Stage;
import javafx.event.EventHandler;
import javafx.scene.Group;
import javafx.scene.PerspectiveCamera;
import javafx.scene.PointLight;
import javafx.scene.paint.PhongMaterial;
import javafx.scene.shape.Box;
import javafx.scene.shape.DrawMode;
import javafx.scene.shape.Sphere;
public class DraggingShapes3D extends Application {
    @Override
    public void start(Stage primaryStage) {
        PointLight pointLight = new PointLight(Color.ANTIQUEWHITE);    
        pointLight.setTranslateX(800);    
        pointLight.setTranslateY(-100);  
        pointLight.setTranslateZ(-1000);
        PhongMaterial material = new PhongMaterial();
        material.setDiffuseColor(Color.LIGHTGRAY);
        material.setSpecularColor(Color.rgb(30, 30, 30));
        Box box = new Box(200, 200, 200);
        box.setMaterial(material);
        box.setTranslateX(100);
        box.setTranslateY(100);
        box.setDrawMode(DrawMode.FILL);
        box.addEventHandler(MouseEvent.ANY, new DragShapeHandler());
        Group root = new Group();
        Sphere sphere = new Sphere(100);
        sphere.setTranslateX(400);
        sphere.setTranslateY(100);
        sphere.setMaterial(material);
        sphere.addEventHandler(MouseEvent.ANY, new DragShapeHandler());
        root.getChildren().addAll(box, sphere);
         root.getChildren().addAll(pointLight);
        Scene scene = new Scene(root, 800, 800, true);
        scene.setCamera(new PerspectiveCamera(false));
        primaryStage.setScene(scene);
        primaryStage.show();
    public static void main(String[] args) {
        launch(args);
    class DragShapeHandler implements EventHandler<MouseEvent> {
        private double sceneAnchorX;
        private double sceneAnchorY;
        @Override
        public void handle(MouseEvent event) {
            if (event.getEventType() == MouseEvent.MOUSE_PRESSED) {
                sceneAnchorX = event.getSceneX();
                sceneAnchorY = event.getSceneY();
            } else if (event.getEventType() == MouseEvent.MOUSE_DRAGGED) {
                double x = event.getSceneX();
                double y = event.getSceneY();
                Node node = (Node) event.getSource();
                node.setTranslateX(node.getTranslateX() + x - sceneAnchorX);
                node.setTranslateY(node.getTranslateY() + y - sceneAnchorY);
                sceneAnchorX = x;
                sceneAnchorY = y;
}