Posted by philjord on Jul 10, 2023; 9:53pm
URL: https://forum.jogamp.org/How-to-make-a-multi-line-Text3D-tp4042759p4042762.html

Basti,
You are right there is no comment on how a newline is handled. The code simply treats it like another character, and use the GlyphVector to discover it is 0 wide and 0 high and has no geometry. Obviously this isn't a useful way to treat a newline.

The good news is that creating your own newlines is very straight forward.

The point size on the Text3D is in meters, and the position of it is in meters as well, so you can simply add several Text3D to the same root node and move them up or down by point size amount (plus a little space) to get a reasonable result.

It wouldn't be hard to write a MultiLineText3D class to handle this (extending javax.media.j3d.Group)

Here is the Text3D example from java3d-exmples with 2 lines of Text3D showing nicely.
Note //NEWCODE


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package org.jdesktop.j3d.examples.text3d;

import java.applet.Applet;
import java.awt.BorderLayout;
import java.awt.Button;
import java.awt.Font;
import java.awt.GraphicsConfiguration;
import java.awt.Panel;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;

import javax.media.j3d.Alpha;
import javax.media.j3d.AmbientLight;
import javax.media.j3d.Appearance;
import javax.media.j3d.Background;
import javax.media.j3d.BoundingSphere;
import javax.media.j3d.BranchGroup;
import javax.media.j3d.Canvas3D;
import javax.media.j3d.DirectionalLight;
import javax.media.j3d.Font3D;
import javax.media.j3d.FontExtrusion;
import javax.media.j3d.Material;
import javax.media.j3d.RotationInterpolator;
import javax.media.j3d.Shape3D;
import javax.media.j3d.Text3D;
import javax.media.j3d.Transform3D;
import javax.media.j3d.TransformGroup;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.behaviors.vp.OrbitBehavior;
import com.sun.j3d.utils.universe.SimpleUniverse;
import com.sun.j3d.utils.universe.ViewingPlatform;
import javax.vecmath.Color3f;
import javax.vecmath.Point3d;
import javax.vecmath.Point3f;
import javax.vecmath.Vector3f;

public class Text3DLoad extends Applet implements ActionListener {

    private String fontName = "TestFont";
    private String textString = null;
    private double tessellation = 0.0;

    private SimpleUniverse u;

    private Button button;
    private boolean behaviorsOn = false;
    private OrbitBehavior orbit;

    public BranchGroup createSceneGraph() {
        float sl = textString.length();
        // Create the root of the branch graph
        BranchGroup objRoot = new BranchGroup();

        // Create a Transformgroup to scale all objects so they
        // appear in the scene.
        TransformGroup objScale = new TransformGroup();
        Transform3D t3d = new Transform3D();
        // Assuming uniform size chars, set scale to fit string in view
        t3d.setScale(1.2/sl);
        objScale.setTransform(t3d);
        objRoot.addChild(objScale);

        // Create the transform group node and initialize it to the
        // identity.  Enable the TRANSFORM_WRITE capability so that
        // our behavior code can modify it at runtime.  Add it to the
        // root of the subgraph.
        TransformGroup objTrans = new TransformGroup();
        objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_WRITE);
        objTrans.setCapability(TransformGroup.ALLOW_TRANSFORM_READ);
        objScale.addChild(objTrans);

        Font3D f3d;
        if (tessellation > 0.0) {
            f3d = new Font3D(new Font(fontName, Font.PLAIN, 2),
                             tessellation,
                             new FontExtrusion());
        }
        else {
            f3d = new Font3D(new Font(fontName, Font.PLAIN, 2),
                             new FontExtrusion());
        }
        Text3D txt = new Text3D(f3d, textString,
             new Point3f( -sl/2.0f, -1.f, -1.f));
        Shape3D sh = new Shape3D();
        Appearance app = new Appearance();
        Material mm = new Material();
        mm.setLightingEnable(true);
        app.setMaterial(mm);
        sh.setGeometry(txt);
        sh.setAppearance(app);
        objTrans.addChild(sh);
//////////////////NEW CODE
        Text3D txt2 = new Text3D(f3d, textString,
                     new Point3f( -sl/2.0f, 1.f, -1.f));/// only change from -1 on Y to +1 on Y, these are in meters, same as the point size
        Shape3D sh2 = new Shape3D();
        sh2.setGeometry(txt2);
        sh2.setAppearance(app);
        objTrans.addChild(sh2);
//////////////////NEW CODE

        BoundingSphere bounds =
          new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);

        if (false) {
          Transform3D yAxis = new Transform3D();
          Alpha rotationAlpha = new Alpha(-1, Alpha.INCREASING_ENABLE,
                                          0, 0,
                                          4000, 0, 0,
                                          0, 0, 0);

          RotationInterpolator rotator =
              new RotationInterpolator(rotationAlpha, objTrans, yAxis,
                                       0.0f, (float) Math.PI*2.0f);
          rotator.setSchedulingBounds(bounds);
          objTrans.addChild(rotator);
        }

        // Set up the background
        Color3f bgColor = new Color3f(0.05f, 0.05f, 0.5f);
        Background bgNode = new Background(bgColor);
        bgNode.setApplicationBounds(bounds);
        objRoot.addChild(bgNode);

        // Set up the ambient light
        Color3f ambientColor = new Color3f(0.3f, 0.3f, 0.3f);
        AmbientLight ambientLightNode = new AmbientLight(ambientColor);
        ambientLightNode.setInfluencingBounds(bounds);
        objRoot.addChild(ambientLightNode);
       
        // Set up the directional lights
        Color3f light1Color = new Color3f(1.0f, 1.0f, 0.9f);
        Vector3f light1Direction  = new Vector3f(1.0f, 1.0f, 1.0f);
        Color3f light2Color = new Color3f(1.0f, 1.0f, 0.9f);
        Vector3f light2Direction  = new Vector3f(-1.0f, -1.0f, -1.0f);
       
        DirectionalLight light1
            = new DirectionalLight(light1Color, light1Direction);
        light1.setInfluencingBounds(bounds);
        objRoot.addChild(light1);
       
        DirectionalLight light2
            = new DirectionalLight(light2Color, light2Direction);
        light2.setInfluencingBounds(bounds);
        objRoot.addChild(light2);

        return objRoot;
    }

    private void usage()
    {
      System.out.println(
        "Usage: java Text3DLoad [-f fontname] [-t tessellation] [<text>]");
      System.exit(0);
    } // End of usage

    public Text3DLoad() {}

    public Text3DLoad(String args[]) {

        if (args.length == 0) {
//  usage();
          textString = "Java3D";
        }
        else {
            for (int i = 0 ; i < args.length ; i++) {
                if (args[i].startsWith("-")) {
                    if (args[i].equals("-f")) {
                        if (i < args.length - 1) {
                            fontName = args[++i];
                        }
                        else {
                            usage();
                        }
                    }
                    else if (args[i].equals("-t")) {
                        if (i < args.length - 1) {
                            tessellation = Double.parseDouble(args[++i]);
                        }
                        else {
                            usage();
                        }
                    }
                    else {
                        System.err.println("Argument '" + args[i] +
                                           "' ignored.");
                    }
                }
                else {
                    textString = args[i];
                }
            }
        }

        if (textString == null) {
          usage();
        }

    }

    public void init() {System.setProperty("sun.awt.noerasebackground", "true");

        if (textString == null) {
            textString = "Java3D";
        }
        setLayout(new BorderLayout());

        button = new Button("remove behaviors");
        button.addActionListener(this);
        Panel p = new Panel();
        p.add(button);
        add("South", p);
       
        GraphicsConfiguration config =
           SimpleUniverse.getPreferredConfiguration();

        Canvas3D c = new Canvas3D(config);
        add("Center", c);

        // Create a simple scene and attach it to the virtual universe
        BranchGroup scene = createSceneGraph();
       
        // create a SimpleUniverse with 4 TransformGroups for the mouse
        // behaviors
        u = new SimpleUniverse(c);

        // add the behaviors to the ViewingPlatform
        ViewingPlatform viewingPlatform = u.getViewingPlatform();
       
  viewingPlatform.setNominalViewingTransform();

        // add orbit behavior to ViewingPlatform
        orbit = new OrbitBehavior(c, OrbitBehavior.REVERSE_ALL |
                                  OrbitBehavior.STOP_ZOOM);
        BoundingSphere bounds =
            new BoundingSphere(new Point3d(0.0, 0.0, 0.0), 100.0);
        orbit.setSchedulingBounds(bounds);
        viewingPlatform.setViewPlatformBehavior(orbit);

        behaviorsOn = true;

       
        u.addBranchGraph(scene);
    }

  public void destroy() {
      u.cleanup();
  }

    public void actionPerformed(ActionEvent e) {
        if (e.getSource() == button) {
            ViewingPlatform v = u.getViewingPlatform();
            if (behaviorsOn) {
                v.setViewPlatformBehavior(null);
                button.setLabel("add behaviors");
                behaviorsOn = false;
            }
            else {
                v.setViewPlatformBehavior(orbit);
                button.setLabel("remove behaviors");
                behaviorsOn = true;
            }
        }
    }

    //
    // The following allows Text3DLoad to be run as an application
    // as well as an applet
    //
    public static void main(String[] args) {System.setProperty("sun.awt.noerasebackground", "true");
        new MainFrame(new Text3DLoad(args), 700, 700);
    }
}