src.gov.nasa.worldwind.render.SurfacePolylines Maven / Gradle / Ivy
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World Wind is a collection of components that interactively display 3D geographic information within Java applications or applets.
/*
* Copyright (C) 2012 United States Government as represented by the Administrator of the
* National Aeronautics and Space Administration.
* All Rights Reserved.
*/
package gov.nasa.worldwind.render;
import gov.nasa.worldwind.cache.GpuResourceCache;
import gov.nasa.worldwind.geom.*;
import gov.nasa.worldwind.globes.Globe;
import gov.nasa.worldwind.util.*;
import javax.media.opengl.*;
import java.util.*;
/**
* This class renders fast multiple surface polylines in one pass. It relies on a {@link CompoundVecBuffer}.
*
* @author Dave Collins
* @author Patrick Murris
* @version $Id: SurfacePolylines.java 1171 2013-02-11 21:45:02Z dcollins $
*/
public class SurfacePolylines extends AbstractSurfaceShape
{
protected List sectors;
protected CompoundVecBuffer buffer;
protected boolean needsOutlineTessellation = true;
protected boolean crossesDateLine = false;
protected Object outlineDisplayListCacheKey = new Object();
public SurfacePolylines(CompoundVecBuffer buffer)
{
if (buffer == null)
{
String message = Logging.getMessage("nullValue.BufferIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
this.buffer = buffer;
}
public SurfacePolylines(Sector sector, CompoundVecBuffer buffer)
{
if (sector == null)
{
String message = Logging.getMessage("nullValue.SectorIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
if (buffer == null)
{
String message = Logging.getMessage("nullValue.BufferIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
this.sectors = Arrays.asList(sector);
this.buffer = buffer;
}
/**
* Get the underlying {@link CompoundVecBuffer} describing the geometry.
*
* @return the underlying {@link CompoundVecBuffer}.
*/
public CompoundVecBuffer getBuffer()
{
return this.buffer;
}
@Override
public List getSectors(DrawContext dc)
{
if (dc == null)
{
String message = Logging.getMessage("nullValue.DrawContextIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
// SurfacePolylines does not interpolate between caller specified positions, therefore it has no path type.
if (this.sectors == null)
this.sectors = this.computeSectors(dc);
return this.sectors;
}
public Iterable getLocations(Globe globe)
{
if (globe == null)
{
String message = Logging.getMessage("nullValue.GlobeIsNull");
Logging.logger().severe(message);
throw new IllegalArgumentException(message);
}
return this.getLocations();
}
protected List> createGeometry(Globe globe, SurfaceTileDrawContext sdc)
{
// SurfacePolylines does not invoke this method, so return null indicating this method is not supported.
// We avoid invoking computeGeometry by overriding determineActiveGeometry below.
return null;
}
public Iterable getLocations()
{
return this.buffer.getLocations();
}
@SuppressWarnings({"UnusedDeclaration"})
public void setLocations(Iterable iterable)
{
throw new UnsupportedOperationException();
}
public Position getReferencePosition()
{
Iterator iterator = this.getLocations().iterator();
if (iterator.hasNext())
return new Position(iterator.next(), 0);
return null;
}
/** {@inheritDoc} Overridden to treat the polylines as open paths rather than closed polygons. */
@Override
protected boolean canContainPole()
{
return false;
}
protected void doMoveTo(Position oldReferencePosition, Position newReferencePosition)
{
for (int i = 0; i < this.buffer.size(); i++)
{
VecBuffer vb = this.buffer.subBuffer(i);
for (int pos = 0; pos < vb.getSize(); pos++)
{
LatLon ll = vb.getLocation(pos);
Angle heading = LatLon.greatCircleAzimuth(oldReferencePosition, ll);
Angle pathLength = LatLon.greatCircleDistance(oldReferencePosition, ll);
vb.putLocation(pos, LatLon.greatCircleEndPosition(newReferencePosition, heading, pathLength));
}
}
this.onGeometryChanged();
}
protected void onGeometryChanged()
{
this.sectors = null;
this.needsOutlineTessellation = true;
super.onShapeChanged();
}
protected void determineActiveGeometry(DrawContext dc, SurfaceTileDrawContext sdc)
{
// Intentionally left blank in order to override the superclass behavior with nothing.
}
protected void drawInterior(DrawContext dc, SurfaceTileDrawContext sdc)
{
// Intentionally left blank; SurfacePolylines does not render an interior.
}
protected void drawOutline(DrawContext dc, SurfaceTileDrawContext sdc)
{
// Exit immediately if the Polyline has no coordinate data.
if (this.buffer.size() == 0)
return;
Position referencePos = this.getReferencePosition();
if (referencePos == null)
return;
int hemisphereSign = (int) Math.signum(sdc.getSector().getCentroid().getLongitude().degrees);
// Attempt to tessellate the Polyline's outline if the Polyline's outline display list is uninitialized, or if
// the Polyline is marked as needing tessellation.
int[] dlResource = (int[]) dc.getGpuResourceCache().get(this.outlineDisplayListCacheKey);
if (dlResource == null || this.needsOutlineTessellation)
dlResource = this.tessellateOutline(dc, referencePos);
// Exit immediately if the Polyline's interior failed to tessellate. The cause has already been logged by
// tessellateInterior.
if (dlResource == null)
return;
GL2 gl = dc.getGL().getGL2(); // GL initialization checks for GL2 compatibility.
this.applyOutlineState(dc, this.getActiveAttributes());
gl.glCallList(dlResource[0]);
if (this.crossesDateLine)
{
gl.glPushMatrix();
try
{
// Apply hemisphere offset and draw again
gl.glTranslated(360 * hemisphereSign, 0, 0);
gl.glCallList(dlResource[0]);
}
finally
{
gl.glPopMatrix();
}
}
}
protected int[] tessellateOutline(DrawContext dc, LatLon referenceLocation)
{
GL2 gl = dc.getGL().getGL2(); // GL initialization checks for GL2 compatibility.
this.crossesDateLine = false;
int[] dlResource = new int[] {gl.glGenLists(1), 1};
gl.glNewList(dlResource[0], GL2.GL_COMPILE);
try
{
// Tessellate each part, note if crossing date line
for (int i = 0; i < this.buffer.size(); i++)
{
VecBuffer subBuffer = this.buffer.subBuffer(i);
if (this.tessellatePart(gl, subBuffer, referenceLocation))
this.crossesDateLine = true;
}
}
finally
{
gl.glEndList();
}
this.needsOutlineTessellation = false;
int numBytes = this.buffer.size() * 3 * 4; // 3 float coords
dc.getGpuResourceCache().put(this.outlineDisplayListCacheKey, dlResource, GpuResourceCache.DISPLAY_LISTS,
numBytes);
return dlResource;
}
protected boolean tessellatePart(GL2 gl, VecBuffer vecBuffer, LatLon referenceLocation)
{
Iterable iterable = vecBuffer.getCoords(3);
boolean dateLineCrossed = false;
gl.glBegin(GL2.GL_LINE_STRIP);
try
{
int sign = 0; // hemisphere offset direction
double previousLongitude = 0;
for (double[] coords : iterable)
{
if (Math.abs(previousLongitude - coords[0]) > 180)
{
// Crossing date line, sum departure point longitude sign for hemisphere offset
sign += (int) Math.signum(previousLongitude);
dateLineCrossed = true;
}
previousLongitude = coords[0];
double lonDegrees = coords[0] - referenceLocation.getLongitude().degrees;
double latDegrees = coords[1] - referenceLocation.getLatitude().degrees;
lonDegrees += sign * 360; // apply hemisphere offset
gl.glVertex3f((float) lonDegrees, (float) latDegrees, 0);
}
}
finally
{
gl.glEnd();
}
return dateLineCrossed;
}
}