对于3d星空在JavaFX中，请使标签保持与查看器透视图齐平

编程问答 2022-08-10

问题描述

注意：我找到了一个解决方案，并编辑了此示例以演示如何执行此操作。我将使用此代码并将其移至更大的应用程序中。

我已经编写了3d恒星制图应用程序，该应用程序接收GAIA恒星数据并为您显示3d表示形式。您可以根据查询查询和绘制一组基于其属性的恒星对象。该应用程序旨在帮助科幻小说家和业余爱好者可视化空间区域中的真实关系。

构建视图时，我绘制了代表星星（半径，颜色等）的球体。

我标记了每颗恒星，以便用户识别感兴趣的恒星。

所以我的问题是，当我旋转视图（实际上是相机）时，标签会旋转，用户会觉得不方便。那么在旋转视图时如何使它们面对相机？

一些细节。我保留两组。一种是绘制所有星星，另一种是绘制标签。星形和标签都绘制在同一点。分开的原因是为了能够独立于星星打开和关闭标签（出于可用性方面的考虑）。

因此，当我旋转视场时，我想拍摄一组标签并将其变换为面向相机。

示例：（茎从赤道平面投影到恒星，网格绘制了赤道平面的透视图）

enter image description here

随着视图的旋转：

enter image description here

这是工作示例。我找到了一个FXyz库示例，并将其更改为可以执行的操作。 FXyz唯一使用的是Mathutils.clamp（...）。

import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Point3D;
import javafx.scene.*;
import javafx.scene.control.Label;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Background;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.paint.PhongMaterial;
import javafx.scene.shape.Shape3D;
import javafx.scene.shape.Sphere;
import javafx.scene.text.Font;
import javafx.scene.transform.Rotate;
import javafx.scene.transform.Translate;
import javafx.stage.Stage;

import java.util.HashMap;
import java.util.Random;

import static org.fxyz3d.geometry.MathUtils.clamp;

/**
 * example for floating labels
 */
public class StarFieldExample extends Application {

    final double sceneWidth = 600;
    final double sceneHeight = 600;

    private double mousePosX;
    private double mousePosY;
    private double mouseOldX;
    private double mouseOldY;
    private double mouseDeltaX;
    private double mouseDeltaY;

    private final Font font = new Font("arial",10);

    // We'll use custom Rotate transforms to manage the coordinate conversions
    private final Rotate rotateX = new Rotate(0,Rotate.X_AXIS);
    private final Rotate rotateY = new Rotate(0,Rotate.Y_AXIS);
    private final Rotate rotateZ = new Rotate(0,Rotate.Z_AXIS);

    private final Group root = new Group();
    private final Group nodeGroup = new Group();  //all 3D nodes in scene
    private final Group labelGroup = new Group(); //all generic 3D labels

    //All shapes and labels linked via hash for easy update during camera movement
    private final HashMap<Shape3D,Label> shape3DToLabel = new HashMap<>();

    private SubScene subScene;

    private final Random random = new Random();

    private final static double RADIUS_MAX = 7;
    private final static double X_MAX = 300;
    private final static double Y_MAX = 300;
    private final static double Z_MAX = 300;

    public Pane createStarField() {

        //attach our custom rotation transforms so we can update the labels dynamically
        nodeGroup.getTransforms().addAll(rotateX,rotateY,rotateZ);

        subScene = new SubScene(nodeGroup,sceneWidth,sceneHeight,true,SceneAntialiasing.BALANCED);
        subScene.setFill(Color.BLACK);

        PerspectiveCamera camera = new PerspectiveCamera(true);
        camera.setNearClip(0.1);
        camera.setFarClip(10000.0);
        camera.setTranslateZ(-1000);

        subScene.setCamera(camera);
        Group sceneRoot = new Group(subScene);
        sceneRoot.getChildren().add(labelGroup);

        generateRandomStars(20);

        subScene.setOnMousePressed((MouseEvent me) -> {
                    mousePosX = me.getSceneX();
                    mousePosY = me.getSceneY();
                    mouseOldX = me.getSceneX();
                    mouseOldY = me.getSceneY();
                }
        );

        subScene.setOnMouseDragged((MouseEvent me) -> {
                    mouseOldX = mousePosX;
                    mouseOldY = mousePosY;
                    mousePosX = me.getSceneX();
                    mousePosY = me.getSceneY();
                    mouseDeltaX = (mousePosX - mouseOldX);
                    mouseDeltaY = (mousePosY - mouseOldY);
                    double modifier = 5.0;
                    double modifierFactor = 0.1;

                    if (me.isPrimaryButtonDown()) {
                        if (me.isAltDown()) { //roll
                            rotateZ.setAngle(((rotateZ.getAngle() + mouseDeltaX * modifierFactor * modifier * 2.0) % 360 + 540) % 360 - 180); // +
                        } else {
                            rotateY.setAngle(((rotateY.getAngle() + mouseDeltaX * modifierFactor * modifier * 2.0) % 360 + 540) % 360 - 180); // +
                            rotateX.setAngle(
                                    clamp(
                                            (((rotateX.getAngle() - mouseDeltaY * modifierFactor * modifier * 2.0) % 360 + 540) % 360 - 180),-60,60
                                    )
                            ); // -
                        }
                    }
                    updateLabels();
                }
        );

        // add to the 2D portion of this component
        Pane pane = new Pane();
        pane.setPrefSize(sceneWidth,sceneHeight);
        pane.setMaxSize(Pane.USE_COMPUTED_SIZE,Pane.USE_COMPUTED_SIZE);
        pane.setMinSize(Pane.USE_COMPUTED_SIZE,Pane.USE_COMPUTED_SIZE);
        pane.setBackground(Background.EMPTY);
        pane.getChildren().add(sceneRoot);
        pane.setPickOnBounds(false);

        subScene.widthProperty().bind(pane.widthProperty());
        subScene.heightProperty().bind(pane.heightProperty());
        Platform.runLater(this::updateLabels);
        return (pane);
    }

    public void generateRandomStars(int numberStars) {
        for (int i = 0; i < numberStars; i++) {
            double radius = random.nextDouble() * RADIUS_MAX;
            Color color = randomColor();
            double x = random.nextDouble() * X_MAX * 2 / 3 * (random.nextBoolean() ? 1 : -1);
            double y = random.nextDouble() * Y_MAX * 2 / 3 * (random.nextBoolean() ? 1 : -1);
            double z = random.nextDouble() * Z_MAX * 2 / 3 * (random.nextBoolean() ? 1 : -1);

            String labelText = "Star " + i;
            boolean fadeFlag = random.nextBoolean();
            createSphereLabel(radius,x,y,z,color,labelText);
        }
    }

    private Color randomColor() {
        int r = random.nextInt(255);
        int g = random.nextInt(255);
        int b = random.nextInt(255);
        return Color.rgb(r,g,b);
    }


    private void createSphereLabel(double radius,double x,double y,double z,Color color,String labelText) {
        Sphere sphere = new Sphere(radius);
        sphere.setTranslateX(x);
        sphere.setTranslateY(y);
        sphere.setTranslateZ(z);
        sphere.setMaterial(new PhongMaterial(color));
        //add our nodes to the group that will later be added to the 3D scene
        nodeGroup.getChildren().add(sphere);

        Label label = new Label(labelText);
        label.setTextFill(color);
        label.setFont(font);
        labelGroup.getChildren().add(label);

        //Add to hashmap so updateLabels() can manage the label position
        shape3DToLabel.put(sphere,label);
    }

    private void updateLabels() {
        shape3DToLabel.forEach((node,label) -> {
            Point3D coordinates = node.localToScene(Point3D.ZERO,true);

            //Clipping Logic
            //if coordinates are outside of the scene it could
            //stretch the screen so don't transform them
            double x = coordinates.getX();
            double y = coordinates.getY();

            // is it left of the view?
            if (x < 0) {
                x = 0;
            }

            // is it right of the view?
            if ((x + label.getWidth() + 5) > subScene.getWidth()) {
                x = subScene.getWidth() - (label.getWidth() + 5);
            }

            // is it above the view?
            if (y < 0) {
                y = 0;
            }

            // is it below the view
            if ((y + label.getHeight()) > subScene.getHeight()) {
                y = subScene.getHeight() - (label.getHeight() + 5);
            }

            //update the local transform of the label.
            label.getTransforms().setAll(new Translate(x,y));
        });
    }

    //////////////////////////////////

    @Override
    public void start(Stage primaryStage) throws Exception {
        Pane pane = createStarField();
        root.getChildren().add(pane);
        Scene scene = new Scene(root,sceneHeight);
        primaryStage.setTitle("2D Labels over 3D SubScene");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }

}

解决方法

正如Kleopatra所建议的那样，我将此处的代码作为答案。

因此，我环顾四周，并在FXyz库包中找到了类似的解决方案。我对其进行了修改以适合我的需求，现在我有了想要的工作版本。 我从FXyz中包含的唯一部分是MathUtils钳制静态方法。

import javafx.application.Application;
import javafx.application.Platform;
import javafx.geometry.Point3D;
import javafx.scene.*;
import javafx.scene.control.Label;
import javafx.scene.input.MouseEvent;
import javafx.scene.layout.Background;
import javafx.scene.layout.Pane;
import javafx.scene.paint.Color;
import javafx.scene.paint.PhongMaterial;
import javafx.scene.shape.Shape3D;
import javafx.scene.shape.Sphere;
import javafx.scene.text.Font;
import javafx.scene.transform.Rotate;
import javafx.scene.transform.Translate;
import javafx.stage.Stage;

import java.util.HashMap;
import java.util.Random;

import static org.fxyz3d.geometry.MathUtils.clamp;

/**
 * example for flat labels
 */
public class StarFieldExample extends Application {

    final double sceneWidth = 600;
    final double sceneHeight = 600;

    private double mousePosX;
    private double mousePosY;
    private double mouseOldX;
    private double mouseOldY;
    private double mouseDeltaX;
    private double mouseDeltaY;

    private final Font font = new Font("arial",10);

    // We'll use custom Rotate transforms to manage the coordinate conversions
    private final Rotate rotateX = new Rotate(0,Rotate.X_AXIS);
    private final Rotate rotateY = new Rotate(0,Rotate.Y_AXIS);
    private final Rotate rotateZ = new Rotate(0,Rotate.Z_AXIS);

    private final Group root = new Group();
    private final Group nodeGroup = new Group();  //all 3D nodes in scene
    private final Group labelGroup = new Group(); //all generic 3D labels

    //All shapes and labels linked via hash for easy update during camera movement
    private final HashMap<Shape3D,Label> shape3DToLabel = new HashMap<>();

    private SubScene subScene;

    private final Random random = new Random();

    private final static double RADIUS_MAX = 7;
    private final static double X_MAX = 300;
    private final static double Y_MAX = 300;
    private final static double Z_MAX = 300;

    public Pane createStarField() {

        //attach our custom rotation transforms so we can update the labels dynamically
        nodeGroup.getTransforms().addAll(rotateX,rotateY,rotateZ);

        subScene = new SubScene(nodeGroup,sceneWidth,sceneHeight,true,SceneAntialiasing.BALANCED);
        subScene.setFill(Color.BLACK);

        PerspectiveCamera camera = new PerspectiveCamera(true);
        camera.setNearClip(0.1);
        camera.setFarClip(10000.0);
        camera.setTranslateZ(-1000);

        subScene.setCamera(camera);
        Group sceneRoot = new Group(subScene);
        sceneRoot.getChildren().add(labelGroup);

        generateRandomStars(20);

        subScene.setOnMousePressed((MouseEvent me) -> {
                    mousePosX = me.getSceneX();
                    mousePosY = me.getSceneY();
                    mouseOldX = me.getSceneX();
                    mouseOldY = me.getSceneY();
                }
        );

        subScene.setOnMouseDragged((MouseEvent me) -> {
                    mouseOldX = mousePosX;
                    mouseOldY = mousePosY;
                    mousePosX = me.getSceneX();
                    mousePosY = me.getSceneY();
                    mouseDeltaX = (mousePosX - mouseOldX);
                    mouseDeltaY = (mousePosY - mouseOldY);
                    double modifier = 5.0;
                    double modifierFactor = 0.1;

                    if (me.isPrimaryButtonDown()) {
                        if (me.isAltDown()) { //roll
                            rotateZ.setAngle(((rotateZ.getAngle() + mouseDeltaX * modifierFactor * modifier * 2.0) % 360 + 540) % 360 - 180); // +
                        } else {
                            rotateY.setAngle(((rotateY.getAngle() + mouseDeltaX * modifierFactor * modifier * 2.0) % 360 + 540) % 360 - 180); // +
                            rotateX.setAngle(
                                    clamp(
                                            (((rotateX.getAngle() - mouseDeltaY * modifierFactor * modifier * 2.0) % 360 + 540) % 360 - 180),-60,60
                                    )
                            ); // -
                        }
                    }
                    updateLabels();
                }
        );

        // add to the 2D portion of this component
        Pane pane = new Pane();
        pane.setPrefSize(sceneWidth,sceneHeight);
        pane.setMaxSize(Pane.USE_COMPUTED_SIZE,Pane.USE_COMPUTED_SIZE);
        pane.setMinSize(Pane.USE_COMPUTED_SIZE,Pane.USE_COMPUTED_SIZE);
        pane.setBackground(Background.EMPTY);
        pane.getChildren().add(sceneRoot);
        pane.setPickOnBounds(false);

        subScene.widthProperty().bind(pane.widthProperty());
        subScene.heightProperty().bind(pane.heightProperty());
        Platform.runLater(this::updateLabels);
        return (pane);
    }

    public void generateRandomStars(int numberStars) {
        for (int i = 0; i < numberStars; i++) {
            double radius = random.nextDouble() * RADIUS_MAX;
            Color color = randomColor();
            double x = random.nextDouble() * X_MAX * 2 / 3 * (random.nextBoolean() ? 1 : -1);
            double y = random.nextDouble() * Y_MAX * 2 / 3 * (random.nextBoolean() ? 1 : -1);
            double z = random.nextDouble() * Z_MAX * 2 / 3 * (random.nextBoolean() ? 1 : -1);

            String labelText = "Star " + i;
            boolean fadeFlag = random.nextBoolean();
            createSphereLabel(radius,x,y,z,color,labelText);
        }
    }

    private Color randomColor() {
        int r = random.nextInt(255);
        int g = random.nextInt(255);
        int b = random.nextInt(255);
        return Color.rgb(r,g,b);
    }


    private void createSphereLabel(double radius,double x,double y,double z,Color color,String labelText) {
        Sphere sphere = new Sphere(radius);
        sphere.setTranslateX(x);
        sphere.setTranslateY(y);
        sphere.setTranslateZ(z);
        sphere.setMaterial(new PhongMaterial(color));
        //add our nodes to the group that will later be added to the 3D scene
        nodeGroup.getChildren().add(sphere);

        Label label = new Label(labelText);
        label.setTextFill(color);
        label.setFont(font);
        labelGroup.getChildren().add(label);

        //Add to hashmap so updateLabels() can manage the label position
        shape3DToLabel.put(sphere,label);
    }

    private void updateLabels() {
        shape3DToLabel.forEach((node,label) -> {
            Point3D coordinates = node.localToScene(Point3D.ZERO,true);

            //Clipping Logic
            //if coordinates are outside of the scene it could
            //stretch the screen so don't transform them
            double x = coordinates.getX();
            double y = coordinates.getY();

            // is it left of the view?
            if (x < 0) {
                x = 0;
            }

            // is it right of the view?
            if ((x + label.getWidth() + 5) > subScene.getWidth()) {
                x = subScene.getWidth() - (label.getWidth() + 5);
            }

            // is it above the view?
            if (y < 0) {
                y = 0;
            }

            // is it below the view
            if ((y + label.getHeight()) > subScene.getHeight()) {
                y = subScene.getHeight() - (label.getHeight() + 5);
            }

            //update the local transform of the label.
            label.getTransforms().setAll(new Translate(x,y));
        });
    }

    //////////////////////////////////

    @Override
    public void start(Stage primaryStage) throws Exception {
        Pane pane = createStarField();
        root.getChildren().add(pane);
        Scene scene = new Scene(root,sceneHeight);
        primaryStage.setTitle("2D Labels over 3D SubScene");
        primaryStage.setScene(scene);
        primaryStage.show();
    }

    public static void main(String[] args) {
        launch(args);
    }

}
javajavajavafxjavafx-11openjfx

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