Very high CPU load when zooming in at North or South edge of Mercator projection

[adamish]

Steps to Reproduce

1. Run the example
2. Zoom into the north edge of the map
3. Keep zooming

Expected behavior: CPU load stays relatively constant

Actual behavior: CPU load increases, application becomes sluggish and unresponsive, number of tiles increases to over 1000

Reproduces how often: 100%

Operating System and Version

Redhat 6u8 with WorlwindWind 2.0.0, also reproduced with 2.1.0

Example to recreate the issue

import java.awt.EventQueue; import java.lang.reflect.Field;

import javax.swing.JFrame;

import gov.nasa.worldwind.BasicModel; import gov.nasa.worldwind.Configuration; import gov.nasa.worldwind.WorldWind; import gov.nasa.worldwind.avlist.AVKey; import gov.nasa.worldwind.awt.WorldWindowGLCanvas; import gov.nasa.worldwind.globes.EarthFlat; import gov.nasa.worldwind.layers.LatLonGraticuleLayer; import gov.nasa.worldwind.layers.ScalebarLayer; import gov.nasa.worldwind.terrain.RectangularTessellator; import gov.nasa.worldwind.terrain.SectorGeometryList; import gov.nasa.worldwind.terrain.ZeroElevationModel; import gov.nasa.worldwind.view.orbit.FlatOrbitView;

public class WorldWindHighCpuLoadExample {

public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
        Configuration.setValue(AVKey.NETWORK_RETRIEVAL_ENABLED, false);
        Configuration.setValue(AVKey.GLOBE_CLASS_NAME, EarthFlat.class.getName());
        Configuration.setValue(AVKey.VIEW_CLASS_NAME, FlatOrbitView.class.getName());
        WorldWind.getNetworkStatus().setOfflineMode(true);
        JFrame frame = new JFrame();

        WorldWindowGLCanvas wwd = new WorldWindowGLCanvas();
        wwd.setPreferredSize(new java.awt.Dimension(1000, 800));
        frame.getContentPane().add(wwd, java.awt.BorderLayout.CENTER);
        frame.pack();

        wwd.setModel(new BasicModel());
        wwd.getModel().getGlobe().setElevationModel(new ZeroElevationModel());
        wwd.getModel().getLayers().clear();
        wwd.getModel().getLayers().add(new LatLonGraticuleLayer());
        wwd.getModel().getLayers().add(new ScalebarLayer());
        frame.setVisible(true);

        new Thread(() -> {
            while (true) {
                try {
                    Field declaredField = RectangularTessellator.class.getDeclaredField("currentTiles");
                    declaredField.setAccessible(true);
                    SectorGeometryList list = (SectorGeometryList) declaredField
                            .get(wwd.getModel().getGlobe().getTessellator());
                    System.out.println(list.size());
                    Thread.sleep(3000);
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();
    });
}

}

[adamish]

Apologies, further testing shows this problem isn't present in 2.1.0