DisplayListener

• To: visad-list@xxxxxxxxxxxxxxxx
• Subject: DisplayListener
• From: Desiree Hilbring <hilbring@xxxxxxxxxxxxxxxxxxxx>
• Date: Thu, 27 May 2004 16:05:45 +0200 (MET DST)

Hi Bill and others,

I am using VisAD for creating 3D object content. The object content
represents a terrain surface and is reused in my own Java3D based
3D-GIS-Service. The terrain consists of several parts. Thus I am
creating several objects of the class DEMFeatureProxy3D.
For each DEMFeatureProxy3D the method addSurfacePart is called once.
This method includes the VisAD code, which is creating my terrainpart 
object:

        // VisAD stuff
        //
        eastValues = RealType.getRealType("eastValues");
        northValues = RealType.getRealType("northValues");
        heightValues = RealType.getRealType("heightValues");
        try {
                domain_tuple = new RealTupleType(eastValues, northValues);
                // Create a FunctionType (domain_tuple -> range_tuple);
                func_en_h = new FunctionType(domain_tuple, heightValues);       
                

                domain_set
                        new Linear2DSet(
                                domain_tuple,
                                northMin,
                                northMax,
                                nRows,
                                eastMin,
                                eastMax,
                                nCols);

                double[][] flat_samples = new double[1][nCols * nRows];
                for (int c = 0; c < (nRows); c++) {
                        for (int r = 0; r < (nCols); r++) {
                                // dgm 1 x y z
                                flat_samples[0][c * nCols + r] = height[c
* nCols + r];
                        }
                }

                // Create a FlatField  
                // Use FlatField(FunctionType type, Set domain_set)    
                vals_ff = new FlatField(func_en_h, domain_set);

                // ...and put the values above into it
                // Note the argument false, meaning that the array won't
be copied 
                vals_ff.setSamples(flat_samples, false);

                // Create Display and its maps    
                // A 2D display    
                display = new DisplayImplJ3D("display1");

                // Create the ScalarMaps: latitude to XAxis, longitude to
YAxis and
                // altitude to RGB and temperature to IsoContour
                // Use ScalarMap(ScalarType scalar, DisplayRealType
display_scalar) 
                eastMap = new ScalarMap(eastValues, visad.Display.YAxis);
                northMap = new ScalarMap(northValues,
visad.Display.XAxis);
                heightMap = new ScalarMap(heightValues,
visad.Display.ZAxis);

                eastMap.setRange(-1.0, 1.0);
                northMap.setRange(-1.0, 1.0);
                heightMap.setRange(-1.0, 1.0);

                // Add maps to display
                display.addMap(eastMap);
                display.addMap(northMap);
                display.addMap(heightMap);

                // Create a data reference and set the FlatField as our
data 
                data_ref = new DataReferenceImpl("data_ref");
                data_ref.setData(vals_ff);
                renderer = new DefaultRendererJ3D();

                // Add reference to display
                GraphicsModeControl dispGMC

(GraphicsModeControl) display.getGraphicsModeControl();
                //dispGMC.setScaleEnable(true);
                //dispGMC.setPolygonMode(1);
                dispGMC.setTextureEnable(false);

                display.addReferences(renderer, data_ref);

                //      For DEM part indentification
                display.setName(String.valueOf(partNumber));

                display.addDisplayListener(listener);

        } catch (VisADException ve) {
                System.out.println("VisAd TupleType Exception");
        } catch (RemoteException re) {
                System.out.println("RemoteExcpetion");
        }
                
Add the end the DisplayListener is attached.
I thought the method displayChanged is called when 
VisAD is ready. In displayChanged I am looking for
the object content and transform so that I can reuse
the object geometry for my 3D-Service.

public synchronized void displayChanged(DisplayEvent e) {               

// DEM-Konzept-Test multiple parts of DEM                       
WorldVolume wv2 = null;
if (e.getId() == DisplayEvent.TRANSFORM_DONE) {                 
        DisplayImplJ3D displayInC = (DisplayImplJ3D) e.getDisplay();
        Vector renderers = displayInC.getRenderers();
        if (renderers.size() != 1) {
                System.err.println(
                        "Error: Number of Renderes should be one! Num: "
                                + renderers.size());
        } else {
                DefaultRendererJ3D rendererInC
                        (DefaultRendererJ3D) renderers.elementAt(0);

                // Look for DEM part number
                String pns = displayInC.getName();
                Integer pnI = new Integer(pns);
                int partNumber = pnI.intValue();
                //System.out.println("partNumber " + partNumber);
                BranchGroup branchGroup = rendererInC.getBranch();
                
                try {
                        renderer.clearScene();
                        renderer.clearBranch();
                        display.destroy();
                } catch (VisADException ex) {
                        System.err.println(ex);
                } catch (RemoteException re) {
                        System.err.println(re);
                }

                if (branchGroup != null) {
                        branchGroup.detach();
                        Enumeration enum = branchGroup.getAllChildren();
                        while (enum.hasMoreElements()) {
                        
                                ...
                        }
                }
        }
}
}

Unfortunately sometimes I never come into the displayChanged method.
Say the terrain consists of 9 parts, thus I shoul reach the method 
displayChanged 9 times, but sometimes I reach it only 2 times or
5 times. Thus some parts for my final terrain are missing.

Any ideas?

Thank for your help in advance.

Greetings Desiree





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Desiree Hilbring

Institut fuer Photogrammetrie und Fernerkundung  
Universitaet Karlsruhe, Germany
email: hilbring@xxxxxxxxxxxxxxxxxxxx             
# 0721 6083676                                   
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• Follow-Ups:
  • Re: DisplayListener
    • From: Bill Hibbard