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javajavafxjavafx-8perspectivecamera

How to set up and transform a Camera in a SubScene?

I am trying to get an isometric view of a grid. The grid is only part of the main scene so I created a subscene and I want add a camera to it. I will want to be able to zoom the camera in and out and pan it around preserving the viewing angle throughout all these operation.

Here is what I have without the camera:

public class MyApp extends Application {

    @Override
    public void start(Stage stage) throws Exception {

        Button actionButton = new Button("Placeholder\t\t\t\t\t\t\t\t\t\t\t\t");
        HBox hbox = new HBox(actionButton);

        BorderPane mainPane = new BorderPane(new MyView(), null, null, hbox, null);

        Scene scene = new Scene(mainPane);
        stage.setScene(scene);
        stage.show();
    }

    private class MyView extends Group {

        MyView() {

            super();

            GridPane grid = new GridPane();
            for (int i = 0; i < 64; i++) {
                Rectangle tile = new Rectangle(30, 30, Color.GREEN);
                BorderPane pane = new BorderPane(tile);
                pane.setBorder(new Border(new BorderStroke(null, BorderStrokeStyle.SOLID,
                                                           null, null, null)));
                grid.add(pane, i / 8, i % 8);
            }

            Group root = new Group();
            root.getChildren().add(grid);

            SubScene scene = new SubScene(root, 300, 300, true, SceneAntialiasing.BALANCED);
            scene.setFill(Color.DARKCYAN); // just to see the area

            getChildren().add(scene);
        }
    }

    public static void main(String[] args) throws Exception {

        launch(args);
    }
}

enter image description here

Now I add the camera like this in the MyView constructor:

Camera camera = new PerspectiveCamera(true);
scene.setCamera(camera);

and the grid disappears.

enter image description here

I didn't even do any transformation yet (i would do camera.getTransforms().addAll(new Rotate(-15, Rotate.Y_AXIS));). What am i doing wrong?

also, how can I tell the subscene to take whatever space is available? I don't want to need to specify specific size because the program can run on all sorts of screens.

Solution

  • Your camera is positioned at the same z coordinates as the Group. However you have to make sure it's at a distance between farClip and nearClip:

    PerspectiveCamera camera = new PerspectiveCamera(true);
camera.setTranslateZ(-100);
camera.setFieldOfView(120);

    Furthermore for isometric views PerspectiveCamera is the wrong Camera to use. Use ParallelCamera instead:

    Camera camera = new ParallelCamera();
//camera.setRotationAxis(new Point3D(1, 1, 0));
//camera.setRotate(30);
scene.setCamera(camera);

    also, how can I tell the subscene to take whatever space is available?

    Change the type extended by MyView to something that is resizable and bind the size of the SubScene to the size of MyView:

    private class MyView extends Pane {

    MyView() {
        ...
        setPrefSize(300, 300);
        scene.widthProperty().bind(widthProperty());
        scene.heightProperty().bind(heightProperty());
    }