我正在尝试创建一个 3D 子场景，其中使用 2D 叠加层中的 Label 对象标记对象。我在这个主题上看到过类似的问题，它们都指向在要在 3D 空间中标记的节点上使用 Node.localToScene 方法。但这似乎不适用于我的情况。我在这里的 FXyz FloatingLabels 示例中获取了示例代码：
Label 对象需要将其位置更新为修改后的 3D 场景，我已经这样做了，但是当我打印出 Node.localToScene 方法返回的坐标时，它们太大而无法在应用程序场景中，并且所以标签在场景中永远不可见。我编写了一个示例程序来说明该问题，其设置与 FXyz 示例代码非常相似，但我创建了一个额外的 SubScene 对象来保存 2D 和 3D SubScene 对象，以便将它们植入带有滑块的更大的应用程序窗口中控制。3D 场景使用透视相机，显示了一个大球体，沿 x/y/z 轴有彩色球体，表面上有一些额外的小块供参考：
import javafx.application.Application;
import javafx.application.Platform;
import javafx.scene.Group;
import javafx.scene.Node;
import javafx.scene.PerspectiveCamera;
import javafx.scene.SubScene;
import javafx.scene.Scene;
import javafx.scene.SceneAntialiasing;
import javafx.scene.AmbientLight;
import javafx.scene.PointLight;
import javafx.scene.control.Label;
import javafx.scene.control.Slider;
import javafx.scene.control.ToolBar;
import javafx.scene.layout.GridPane;
import javafx.scene.layout.StackPane;
import javafx.scene.layout.Priority;
import javafx.scene.shape.Sphere;
import javafx.scene.paint.Color;
import javafx.scene.paint.PhongMaterial;
import javafx.scene.transform.Rotate;
import javafx.scene.transform.Translate;
import javafx.stage.Stage;
import javafx.geometry.Point3D;
import java.util.Map;
import java.util.HashMap;
public class LabelTest extends Application {
private Map<Node, Label> nodeToLabelMap;
@Override
public void start (Stage stage) {
// Create main scene graph
var objects3d = new Group();
Rotate xRotate = new Rotate (0, 0, 0, 0, Rotate.X_AXIS);
Rotate yRotate = new Rotate (0, 0, 0, 0, Rotate.Y_AXIS);
objects3d.getTransforms().addAll (
xRotate,
yRotate
);
var root3d = new Group();
root3d.getChildren().add (objects3d);
var camera = new PerspectiveCamera (true);
camera.setTranslateZ (-25);
var scene3d = new SubScene (root3d, 500, 500, true, SceneAntialiasing.BALANCED);
scene3d.setFill (Color.rgb (20, 20, 80));
scene3d.setCamera (camera);
var sceneRoot = new Group (scene3d);
var objects2d = new Group();
sceneRoot.getChildren().add (objects2d);
var viewScene = new SubScene (sceneRoot, 500, 500);
scene3d.widthProperty().bind (viewScene.widthProperty());
scene3d.heightProperty().bind (viewScene.heightProperty());
// Add lights and objects
var ambient = new AmbientLight (Color.color (0.7, 0.7, 0.7));
var point = new PointLight (Color.color (0.3, 0.3, 0.3));
point.setTranslateX (-25);
point.setTranslateY (-25);
point.setTranslateZ (-50);
root3d.getChildren().addAll (ambient, point);
var globe = new Sphere (5);
globe.setMaterial (new PhongMaterial (Color.color (0.3, 0.3, 0.3)));
var xSphere = new Sphere (0.5);
xSphere.setMaterial (new PhongMaterial (Color.RED));
xSphere.setTranslateX (5);
var ySphere = new Sphere (0.5);
ySphere.setMaterial (new PhongMaterial (Color.GREEN));
ySphere.setTranslateY (5);
var zSphere = new Sphere (0.5);
zSphere.setMaterial (new PhongMaterial (Color.BLUE));
zSphere.setTranslateZ (5);
objects3d.getChildren().addAll (globe, xSphere, ySphere, zSphere);
var nubMaterial = new PhongMaterial (Color.color (0.2, 0.2, 0.2));
for (int i = 0; i < 200; i++) {
var nub = new Sphere (0.125);
nub.setMaterial (nubMaterial);
var phi = 2*Math.PI*Math.random();
var theta = Math.acos (2*Math.random() - 1);
var z = -5 * Math.sin (theta) * Math.cos (phi);
var x = 5 * Math.sin (theta) * Math.sin (phi);
var y = -5 * Math.cos (theta);
nub.setTranslateX (x);
nub.setTranslateY (y);
nub.setTranslateZ (z);
objects3d.getChildren().add (nub);
} // for
// Add labels
var xLabel = new Label ("X axis");
xLabel.setTextFill (Color.RED);
var yLabel = new Label ("Y axis");
yLabel.setTextFill (Color.GREEN);
var zLabel = new Label ("Z axis");
zLabel.setTextFill (Color.BLUE);
objects2d.getChildren().addAll (xLabel, yLabel, zLabel);
nodeToLabelMap = new HashMap<>();
nodeToLabelMap.put (xSphere, xLabel);
nodeToLabelMap.put (ySphere, yLabel);
nodeToLabelMap.put (zSphere, zLabel);
xRotate.angleProperty().addListener ((obs, oldVal, newVal) -> updateLabels());
yRotate.angleProperty().addListener ((obs, oldVal, newVal) -> updateLabels());
camera.translateZProperty().addListener ((obs, oldVal, newVal) -> updateLabels());
Platform.runLater (() -> updateLabels());
// Create main pane
var gridPane = new GridPane();
var stackPane = new StackPane (viewScene);
viewScene.heightProperty().bind (stackPane.heightProperty());
viewScene.widthProperty().bind (stackPane.widthProperty());
viewScene.setManaged (false);
gridPane.add (stackPane, 0, 0);
gridPane.setVgrow (stackPane, Priority.ALWAYS);
gridPane.setHgrow (stackPane, Priority.ALWAYS);
// Add controls
var xSlider = new Slider (-90, 90, 0);
xRotate.angleProperty().bind (xSlider.valueProperty());
var ySlider = new Slider (-180, 180, 0);
yRotate.angleProperty().bind (ySlider.valueProperty());
var zSlider = new Slider (-60, -25, -25);
camera.translateZProperty().bind (zSlider.valueProperty());
ToolBar toolbar = new ToolBar (
new Label ("X rotation:"),
xSlider,
new Label ("Y rotation:"),
ySlider,
new Label ("Z position:"),
zSlider
);
gridPane.add (toolbar, 0, 1);
// Start the show
stage.setTitle ("Label Test");
stage.setScene (new Scene (gridPane, 800, 600));
stage.show();
} // start
private void updateLabels () {
nodeToLabelMap.forEach ((node, label) -> {
var coord = node.localToScene (Point3D.ZERO, true);
System.out.println ("label = " + label.getText() + ", coord = " + coord);
label.getTransforms().setAll (new Translate(coord.getX(), coord.getY()));
});
} // updateLabels
public static void main (String[] args) {
launch (args);
} // main
} // LabelTest class
您可以使用此脚本编译和运行 LabelTest.java 程序（我在 Mac 上使用 JavaFX 14 和 JDK 14.0.2）：
#!/bin/sh
set -x
export PATH_TO_FX=javafx-sdk-14/lib
javac --module-path $PATH_TO_FX --add-modules javafx.controls LabelTest.java
if [ $? -ne 0 ] ; then
exit 1
fi
java -cp . --module-path $PATH_TO_FX --add-modules javafx.controls LabelTest
我的测试程序输出包含非常大的标签坐标，它们不代表彩色轴球体的位置，例如：
label = Y axis, coord = Point3D [x = 17448.00808897467, y = 21535.846392310217, z = 0.0]
label = X axis, coord = Point3D [x = 26530.33870777918, y = 12453.515773505665, z = 0.0]
label = Z axis, coord = Point3D [x = 17448.008088974653, y = 12453.515773505665, z = 0.0]
我的显示如下所示：
它应该看起来更像来自 FXyz 的示例，在轴球体旁边带有标签：
