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Java3D - How to restrict vertical movement

MrCrawfish
MrCrawfish asked
on
Medium Priority
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Last Modified: 2008-01-09
Below are the samples of the OrientedTest.java and MouseRotateY.java from the Java3D installation.

I would like to use the code with one modification.  When the right and left mouse buttons are pressed the scence can be moved vertically up or down. What is needed to restrict the movement not to go below the xz axis. In other words, I want to view the object from any height above the ground level up, but not allow to go below the images.


1. OrientedTest.java code

import java.applet.Applet;
import java.awt.*;
import java.awt.event.*;
import com.sun.j3d.utils.image.TextureLoader;
import com.sun.j3d.utils.applet.MainFrame;
import com.sun.j3d.utils.geometry.*;
import com.sun.j3d.utils.universe.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.behaviors.mouse.*;

public class OrientedTest extends Applet {

    // setup font stuff
    private String fontName = "TestFont";
    private String textString = "OrientedShape3D";
    float sl = textString.length();

    // paths to texture image files
    private java.net.URL earthImage = null;
    private java.net.URL stoneImage = null;

    private SimpleUniverse u = null;

    public BranchGroup createSceneGraph() {

        // Create the root of the branch graph
        BranchGroup objRoot = new BranchGroup();

        TransformGroup objScale = new TransformGroup();
        Transform3D textMat = new Transform3D();
        // Assuming uniform size chars, set scale to fit string in view
        textMat.setScale(1.2/sl);
        objScale.setTransform(textMat);



        // 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);
        objRoot.addChild(objTrans);

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

        Appearance apText = new Appearance();
        Material m = new Material();
        m.setLightingEnable(true);
        apText.setMaterial(m);


        Appearance apEarth= new Appearance();
        Material mm = new Material();
        mm.setLightingEnable(true);
        apEarth.setMaterial(mm);

        Appearance apStone = new Appearance();
        apStone.setMaterial(mm);

// create 3D text
        Font3D f3d = new Font3D(new Font(fontName, Font.PLAIN, 2),
                                new FontExtrusion());
        Text3D txt = new Text3D(f3d, textString,
             new Point3f( -sl/2.0f, 3.0f, 0.0f));
        OrientedShape3D textShape = new OrientedShape3D();
        textShape.setGeometry(txt);
        textShape.setAppearance(apText);
        textShape.setAlignmentAxis( 0.0f, 1.0f, 0.0f);
        objScale.addChild( textShape );


        // Create a simple shape leaf node, add it to the scene graph.

        Transform3D cubeMat = new Transform3D();
        TransformGroup cubeTrans = new TransformGroup(cubeMat);
        cubeMat.set(new Vector3d(0.9, 0.0, -1.0));
        cubeTrans.setTransform(cubeMat);
        cubeTrans.addChild(new ColorCube(0.3));
        objTrans.addChild(cubeTrans);

        TextureLoader stoneTex = new TextureLoader(stoneImage, new String("RGB"), this);
        if (stoneTex != null) apStone.setTexture(stoneTex.getTexture());

        TextureAttributes texAttr = new TextureAttributes();
        texAttr.setTextureMode(TextureAttributes.MODULATE);
        apStone.setTextureAttributes(texAttr);


        Transform3D coneMat = new Transform3D();
        TransformGroup coneTrans = new TransformGroup(coneMat);
        coneMat.set(new Vector3d(0.0, 0.0, 0.0));
        coneTrans.setTransform(coneMat);
        coneTrans.addChild(new Cone(.2f, 0.8f,Cone.GENERATE_NORMALS |
                                    Cone.GENERATE_TEXTURE_COORDS, apStone));
        objTrans.addChild(coneTrans);

        TextureLoader earthTex = new TextureLoader(earthImage, new String("RGB"), this);
        if (earthTex != null) apEarth.setTexture(earthTex.getTexture());

        apEarth.setTextureAttributes(texAttr);

        Transform3D cylinderMat = new Transform3D();
        TransformGroup cylinderTrans = new TransformGroup(cylinderMat);
        cylinderMat.set(new Vector3d(-0.9, 0.5, -1.0));
        cylinderTrans.setTransform(cylinderMat);
        cylinderTrans.addChild(new Cylinder(.35f, 2.0f,Cylinder.GENERATE_NORMALS |
                                                      Cylinder.GENERATE_TEXTURE_COORDS, apEarth));
        objTrans.addChild(cylinderTrans);

        objTrans.addChild(objScale);




        // 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(0.1f, 0.1f, 0.1f);
        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);

        apText.setMaterial(mm);

        // Have Java 3D perform optimizations on this scene graph.
        objRoot.compile();

        return objRoot;
    }

    public OrientedTest() {
    }

    public OrientedTest(java.net.URL earthURL, java.net.URL stoneURL) {
        earthImage = earthURL;
        stoneImage = stoneURL;
    }

    public void init() {
        // the paths to the image files for an applet
        if (earthImage == null) {
            try {
                earthImage = new java.net.URL(getCodeBase().toString() +
                                              "../images/earth.jpg");
            }
            catch (java.net.MalformedURLException ex) {
                System.out.println(ex.getMessage());
                System.exit(1);
            }
        }
        if (stoneImage == null) {
          try {
              stoneImage = new java.net.URL(getCodeBase().toString() +
                                            "../images/stone.jpg");
          }
          catch (java.net.MalformedURLException ex) {
              System.out.println(ex.getMessage());
              System.exit(1);
          }
        }
        setLayout(new BorderLayout());
        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();
        u = new SimpleUniverse(c, 4);

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

        // there is a special rotate behavior, so can't use the utility
        // method
        MouseRotateY rotate = new MouseRotateY(MouseRotateY.INVERT_INPUT);
        rotate.setTransformGroup(viewingPlatform.getMultiTransformGroup().
                                   getTransformGroup(0));
        BranchGroup rotateBG = new BranchGroup();
        rotateBG.addChild(rotate);
        viewingPlatform.addChild(rotateBG);
        BoundingSphere bounds =
            new BoundingSphere(new Point3d(0.0,0.0,0.0), 100.0);
        rotate.setSchedulingBounds(bounds);

        MouseZoom zoom =
            new MouseZoom(c, MouseZoom.INVERT_INPUT);
        zoom.setTransformGroup(viewingPlatform.getMultiTransformGroup().
                          getTransformGroup(1));
        zoom.setSchedulingBounds(bounds);
        BranchGroup zoomBG = new BranchGroup();
        zoomBG.addChild(zoom);
        viewingPlatform.addChild(zoomBG);

        MouseTranslate translate =
            new MouseTranslate(c, MouseTranslate.INVERT_INPUT);
        translate.setTransformGroup(viewingPlatform.getMultiTransformGroup().
                                    getTransformGroup(2));
        translate.setSchedulingBounds(bounds);
        BranchGroup translateBG = new BranchGroup();
        translateBG.addChild(translate);
        viewingPlatform.addChild(translateBG);

        // This will move the ViewPlatform back a bit so the
        // objects in the scene can be viewed.
        u.getViewingPlatform().setNominalViewingTransform();

        u.addBranchGraph(scene);
    }

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

    //
    // The following allows OrientedTest to be run as an application
    // as well as an applet
    //
    public static void main(String[] args) {
        java.net.URL earthURL = null;
        java.net.URL stoneURL = null;
        try {
            // the paths to the image files for an application
            earthURL = new java.net.URL("file:../images/earth.jpg");
            stoneURL = new java.net.URL("file:../images/stone.jpg");
        }
        catch (java.net.MalformedURLException ex) {
            System.out.println(ex.getMessage());
            System.exit(1);
        }

        new MainFrame(new OrientedTest(earthURL, stoneURL), 400, 400);
    }
}



2. MouseRotateY  code

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import javax.media.j3d.*;
import javax.vecmath.*;
import com.sun.j3d.utils.behaviors.mouse.*;

/**
 * MouseRotateY is a Java3D behavior object that lets users control the
 * rotation of an object via a mouse.
 * <p>
 * To use this utility, first create a transform group that this
 * rotate behavior will operate on. Then,
 *<blockquote><pre>
 *
 *   MouseRotateY behavior = new MouseRotateY();
 *   behavior.setTransformGroup(objTrans);
 *   objTrans.addChild(behavior);
 *   behavior.setSchedulingBounds(bounds);
 *
 *</pre></blockquote>
 * The above code will add the rotate behavior to the transform
 * group. The user can rotate any object attached to the objTrans.
 */

public class MouseRotateY extends MouseBehavior {
  double  y_angle;
  double  y_factor;

  /**
   * Creates a rotate behavior given the transform group.
   * @param transformGroup The transformGroup to operate on.
   */
  public MouseRotateY(TransformGroup transformGroup) {
    super(transformGroup);
  }

  /**
   * Creates a default mouse rotate behavior.
   **/
  public MouseRotateY() {
      super(0);
   }

  /**
   * Creates a rotate behavior.
   * Note that this behavior still needs a transform
   * group to work on (use setTransformGroup(tg)) and
   * the transform group must add this behavior.
   * @param flags interesting flags (wakeup conditions).
   */
  public MouseRotateY(int flags) {
      super(flags);
   }

  public void initialize() {
    super.initialize();
    y_angle = 0;
    y_factor = .03;
    if ((flags & INVERT_INPUT) == INVERT_INPUT) {
       invert = true;
       y_factor *= -1;
    }
  }

  public double getYFactor() {
    return y_factor;
  }

  public void setFactor( double factor) {
    y_factor = factor;

  }


  public void processStimulus (Enumeration criteria) {
      WakeupCriterion wakeup;
      AWTEvent[] event;
      int id;
      int  dx;

      while (criteria.hasMoreElements()) {
         wakeup = (WakeupCriterion) criteria.nextElement();
         if (wakeup instanceof WakeupOnAWTEvent) {
            event = ((WakeupOnAWTEvent)wakeup).getAWTEvent();
            for (int i=0; i<event.length; i++) {
              processMouseEvent((MouseEvent) event[i]);

              if (((buttonPress)&&((flags & MANUAL_WAKEUP) == 0)) ||
                  ((wakeUp)&&((flags & MANUAL_WAKEUP) != 0))){

                id = event[i].getID();
                if ((id == MouseEvent.MOUSE_DRAGGED) &&
                    !((MouseEvent)event[i]).isMetaDown() &&
                    !((MouseEvent)event[i]).isAltDown()){

                  x = ((MouseEvent)event[i]).getX();

                  dx = x - x_last;

                  if (!reset){
                    y_angle = dx * y_factor;

                    transformY.rotY(y_angle);

                    transformGroup.getTransform(currXform);

                    //Vector3d translation = new Vector3d();
                    //Matrix3f rotation = new Matrix3f();
                    Matrix4d mat = new Matrix4d();

                    // Remember old matrix
                    currXform.get(mat);

                    // Translate to origin
                    currXform.setTranslation(new Vector3d(0.0,0.0,0.0));
                    if (invert) {
                        currXform.mul(currXform, transformX);
                        currXform.mul(currXform, transformY);
                    } else {
                        currXform.mul(transformX, currXform);
                        currXform.mul(transformY, currXform);
                    }

                    // Set old translation back
                    Vector3d translation = new
                      Vector3d(mat.m03, mat.m13, mat.m23);
                    currXform.setTranslation(translation);

                    // Update xform
                    transformGroup.setTransform(currXform);
                  }
                  else {
                    reset = false;
                  }

                  x_last = x;
               }
               else if (id == MouseEvent.MOUSE_PRESSED) {
                  x_last = ((MouseEvent)event[i]).getX();
               }
              }
            }
         }
      }

      wakeupOn (mouseCriterion);

   }
}
 
Comment
Watch Question

CERTIFIED EXPERT
Top Expert 2016
Commented:
Set the position to (position % maxHeight)

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Ask the Experts
CERTIFIED EXPERT
Top Expert 2016

Commented:
Sorry. Should have said

if (position > maxHeight) {
    position = maxHeight;
}

Author

Commented:
Where exactly in the code should this go..use code above.
CERTIFIED EXPERT
Top Expert 2016

Commented:
That's a 'notional' answer. I don't know the API, so can't advise on the location of that principle. You need to put it wherever the new position is being set and calculate the maximum dimension based on your limit

Author

Commented:
I am looking for an answer using the Java3D api that relate to WakeCondition MouseDragged or equivalent that would know where in the code "supplied" that this function could be restricted to above xz movement.

Commented:
i've skim thru the code and the code should be in somewhere in processStimulus() function
btw, i do not understand your last comment...
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