我目前正在JavaFX中编写一个程序，它以3D形式显示图形。用户应该能够翻译和旋转它 因为在3D中移动的常见规则是，移动相机而不是整个图形，我遵循这个规则。
我创建了一个 StackPane ，其中包含两个 Pane （bottomPane和topPane）。 bottomPane包含SubScene，其中显示图表并使用 PerspectiveCamera 。在topPane中，我为特定节点添加了包含 Label 的组。
我做了这个设置，以防止标签被图形隐藏，当它们的相应节点在其他节点或边缘后面时。
为了正确定位标签，我将一个函数绑定到摄像机的translateX / Y / Z属性，相应地更新标签的位置（ rearrangeLabels（））。登记/> 此函数计算节点的屏幕坐标，然后将这些坐标计算回包含标签的组的坐标。
这适用于翻译（例如，向上/向下/向左/向右移动图表）。如果我仅围绕x轴或y轴旋转相机，它也可以工作 但是当我想在两个轴上同时旋转（例如对角线）时，标签不会相应地移动。
我尝试了很多不同的方法并得出结论，这可能是JavaFX中的错误，或者更准确地说是 localToScreen（）或 screenToLocal（）功能。
我附上了一个演示程序，它描述了上述问题 只需按开始并使用主鼠标按钮旋转相机。
所以我的问题是，你是否有人知道，如果这是一个已知的错误？如果是，是否有解决方法？或者我做错了什么？
编辑：我将错误范围缩小为围绕Z轴的旋转。当仅围绕z轴旋转时，会发生奇怪的行为，而仅围绕X轴或Y轴旋转，一切都会按预期移动。
import javafx.application.Application;
import javafx.geometry.Point2D;
import javafx.geometry.Point3D;
import javafx.scene.*;
import javafx.scene.control.Button;
import javafx.scene.control.Label;
import javafx.scene.layout.Pane;
import javafx.scene.layout.StackPane;
import javafx.scene.paint.Color;
import javafx.scene.shape.Cylinder;
import javafx.scene.shape.Sphere;
import javafx.scene.transform.Rotate;
import javafx.scene.transform.Transform;
import javafx.scene.transform.Translate;
import javafx.stage.Stage;
public class RotateCamWithLabel extends Application{
Sphere node1;
Sphere node2;
Cylinder edge;
Label nodeLabel1;
Label nodeLabel2;
Group labelGroup;
Group graphGroup;
Pane topPane;
Pane bottomPane;
PerspectiveCamera cam;
double oldPosX;
double oldPosY;
Transform camTransform = new Rotate();
@Override
public void start(Stage primaryStage) throws Exception {
// Setting up the root of the whole Scene
topPane = new Pane();
topPane.setPickOnBounds(false);
bottomPane = new Pane();
StackPane root = new StackPane();
root.getChildren().addAll(bottomPane, topPane);
Button startButton = new Button("Start");
startButton.setOnAction(event -> {
setUpSubSceneAndCam();
addLabels();
});
topPane.getChildren().add(startButton);
// Starting the Scene
Scene scene = new Scene(root, 700, 500);
primaryStage.setScene(scene);
primaryStage.show();
}
private void setUpSubSceneAndCam() {
createGraph();
SubScene subScene = new SubScene(graphGroup, 700, 500, true, SceneAntialiasing.BALANCED);
subScene.setFill(Color.LIGHTGRAY);
cam = new PerspectiveCamera(true);
cam.setTranslateZ(-1000);
cam.setNearClip(0.1);
cam.setFarClip(Double.MAX_VALUE);
subScene.setCamera(cam);
bottomPane.getChildren().add(subScene);
createCameraLabelBinding();
subScene.setOnMousePressed(event -> {
oldPosX = event.getSceneX();
oldPosY = event.getSceneY();
});
subScene.setOnMouseDragged(event -> {
double deltaX = event.getSceneX() - oldPosX;
double deltaY = event.getSceneY() - oldPosY;
if (event.isPrimaryButtonDown()) {
rotateCamera(deltaX, deltaY);
}
oldPosX = event.getSceneX();
oldPosY = event.getSceneY();
});
}
// Rotation is done by calculating the local camera position in the subscene and out of these,
// the rotation axis is calculated as well as the degree.
// Then the camera is repositioned on the pivot point, turned based on the axis and degree, and put
// back along its local backwards vector based on the starting ditance between the camera and the pivot point
private void rotateCamera(double deltaX, double deltaY) {
// Calculate rotation-axis
Point3D leftVec = getCamLeftVector().multiply(deltaX);
Point3D upVec = getCamUpVector().multiply(deltaY);
Point3D dragVec = leftVec.add(upVec).multiply(-1);
Point3D backVec = getCamBackwardVector();
Point3D axis = dragVec.crossProduct(backVec);
//Point3D axis = Rotate.Z_AXIS; //Does not work
//Point3D axis = Rotate.Y_AXIS; //Works
//Point3D axis = Rotate.X_AXIS; //Works
Rotate r = new Rotate(dragVec.magnitude(), axis);
// set camera on pivot point
Point3D pivot = Point3D.ZERO;
Point3D camCurrent = new Point3D(cam.getTranslateX(), cam.getTranslateY(), cam.getTranslateZ());
Point3D camPivVec = pivot.subtract(camCurrent);
setCameraPosition(pivot);
// rotate camera
camTransform = r.createConcatenation(camTransform);
cam.getTransforms().setAll(camTransform);
// put camera back along the local backwards vector
double length = camPivVec.magnitude();
setCameraPosition(getCamBackwardVector().multiply(length).add(pivot));
}
private void addLabels() {
if (labelGroup != null) {
labelGroup.getChildren().remove(nodeLabel1);
labelGroup.getChildren().remove(nodeLabel2);
}
labelGroup = new Group();
topPane.getChildren().add(labelGroup);
nodeLabel1 = new Label("Hello");
nodeLabel2 = new Label("Bye");
labelGroup.getChildren().addAll(nodeLabel1, nodeLabel2);
rearrangeLabels();
}
private void createCameraLabelBinding() {
cam.translateXProperty().addListener((observable, oldValue, newValue) -> rearrangeLabels());
cam.translateYProperty().addListener((observable, oldValue, newValue) -> rearrangeLabels());
cam.translateZProperty().addListener((observable, oldValue, newValue) -> rearrangeLabels());
}
// TODO: Here is probably a bug
// I calculate the screen coordinates of the nodes, then turn them back to local positions
// in the label-group
private void rearrangeLabels() {
Point2D screenCoord1 = node1.localToScreen(Point2D.ZERO);
Point2D screenCoord2 = node2.localToScreen(Point2D.ZERO);
Point2D groupCoord1 = labelGroup.screenToLocal(screenCoord1);
Point2D groupCoord2 = labelGroup.screenToLocal(screenCoord2);
nodeLabel1.setTranslateX(groupCoord1.getX());
nodeLabel1.setTranslateY(groupCoord1.getY());
nodeLabel2.setTranslateX(groupCoord2.getX());
nodeLabel2.setTranslateY(groupCoord2.getY());
}
private void createGraph() {
graphGroup = new Group();
node1 = new Sphere(5);
node2 = new Sphere(5);
node1.setTranslateX(-50);
node1.setTranslateY(-50);
node2.setTranslateX(150);
node2.setTranslateY(50);
edge = new Cylinder(2, 10);
connectNodesWithEdge(new Point3D(node1.getTranslateX(), node1.getTranslateY(), node1.getTranslateZ()),
new Point3D(node2.getTranslateX(), node2.getTranslateY(), node2.getTranslateZ()));
graphGroup.getChildren().addAll(node1, node2, edge);
}
private void connectNodesWithEdge(Point3D origin, Point3D target) {
Point3D yAxis = new Point3D(0, 1, 0);
Point3D diff = target.subtract(origin);
double height = diff.magnitude();
Point3D mid = target.midpoint(origin);
Translate moveToMidpoint = new Translate(mid.getX(), mid.getY(), mid.getZ());
Point3D axisOfRotation = diff.crossProduct(yAxis);
double angle = Math.acos(diff.normalize().dotProduct(yAxis));
Rotate rotateAroundCenter = new Rotate(-Math.toDegrees(angle), axisOfRotation);
this.edge.setHeight(height);
edge.getTransforms().addAll(moveToMidpoint, rotateAroundCenter);
}
private Point3D getCamLeftVector() {
Point3D left = cam.localToScene(-1, 0, 0);
Point3D current = cam.localToScene(0, 0, 0);
return left.subtract(current);
}
private Point3D getCamUpVector() {
Point3D up = cam.localToScene(0, -1, 0);
Point3D current = cam.localToScene(0, 0, 0);
return up.subtract(current);
}
private Point3D getCamBackwardVector() {
Point3D backward = cam.localToScene(0, 0, -1);
Point3D current = cam.localToScene(0, 0, 0);
return backward.subtract(current);
}
private void setCameraPosition(Point3D position) {
cam.setTranslateX(position.getX());
cam.setTranslateY(position.getY());
cam.setTranslateZ(position.getZ());
}
public static void main(String[] args) {
launch(args);
}
}