VisClient/org/hfbk/vis/visnode/VisNodeDraggable.java

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/*
 * Created on 28.04.2008
 *
 */
package org.hfbk.vis.visnode;

import java.awt.event.MouseEvent;

import org.dronus.gl.GLUtil;
import org.dronus.graph.Node;
import org.lwjgl.util.vector.Vector3f;

abstract public class VisNodeDraggable extends VisNodeMousable {

        protected VisNodeDraggable(Node node, Vector3f position) {
                super(node, position);
        }

        Vector3f handle;
        Vector3f vpLast;
        
        boolean hit(Ray mouseray, Vector3f hit) {

                // calculate a flat plane intersection in object space to determine if hit.
                boolean gotHit=super.hit(mouseray, hit);
                
                if  (handle==null) return gotHit; 
                        
                // tie distance to camera to first hit 
                // fix to prevent sliding due to inexact
                // sphere approx. by the tangential plane.
                
                Vector3f projector=(Vector3f)new Vector3f(mouseray.dir).scale(hitDepth);   
                Vector3f.add(mouseray.start, projector, hit);

                return gotHit;                  
        }
        
        
        
        float hitDepth;
        void handleEvent(VisMouseEvent evt) {
                        if (evt.getID()==MouseEvent.MOUSE_DRAGGED){
                                if (handle==null){
                                        //first click, just remember position ("handle")
                                        handle=evt.hit;
                                        hitDepth=GLUtil.getPosition().length();
                                }else{
                                        //moves the object so the handle position matches 
                                        //the current hit position
                                        
                                        Vector3f drag=evt.hit;
                                        Vector3f.sub(drag,handle,drag);
                                        position=traverse(parent, drag);
                                        
                                        Vector3f viewdrag=new Vector3f();
                                        Vector3f.sub(getRoot().client.mouseViewpoint, vpLast, viewdrag);
                                        Vector3f.add(position, viewdrag, position);                                     
                                }
                                vpLast=new Vector3f(getRoot().client.mouseViewpoint);                           
                        }else if (evt.getID()==MouseEvent.MOUSE_MOVED){
                                // no drag, remove handle.
                                handle=null;
                                vpLast=null;
                        }
        }       
}

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