protected List<Position> computePathPositions(
Position startPosition, Position endPosition, Angle delta) {
Angle dist = LatLon.greatCircleDistance(startPosition, endPosition);
dist = dist.multiply(0.6);
Angle azimuth = LatLon.greatCircleAzimuth(startPosition, endPosition);
LatLon locA = LatLon.greatCircleEndPosition(startPosition, azimuth.add(delta), dist);
dist = dist.multiply(0.9);
LatLon locB = LatLon.greatCircleEndPosition(startPosition, azimuth.subtract(delta), dist);
return Arrays.asList(startPosition, new Position(locA, 0), new Position(locB, 0), endPosition);
}
/**
* Compute the view range footprint on the globe.
*
* @param dc the current <code>DrawContext</code>
* @param steps the number of steps.
* @return an array list of <code>LatLon</code> forming a closed shape.
*/
protected ArrayList<LatLon> computeViewFootPrint(DrawContext dc, int steps) {
ArrayList<LatLon> positions = new ArrayList<LatLon>();
Position eyePos = dc.getView().getEyePosition();
Angle distance =
Angle.fromRadians(
Math.asin(
dc.getView().getFarClipDistance()
/ (dc.getGlobe().getRadius() + eyePos.getElevation())));
if (distance.degrees > 10) {
double headStep = 360d / steps;
Angle heading = Angle.ZERO;
for (int i = 0; i <= steps; i++) {
LatLon p = LatLon.greatCircleEndPosition(eyePos, heading, distance);
positions.add(p);
heading = heading.addDegrees(headStep);
}
return positions;
} else return null;
}
/** {@inheritDoc} */
@Override
protected void determineLabelPositions(DrawContext dc) {
Position center = this.getReferencePosition();
if (center == null) return;
// Position the labels along a line radiating out from the center of the circle. The angle (60
// degrees) is
// chosen to match the graphic template defined by MIL-STD-2525C, pg. 613.
double globeRadius = dc.getGlobe().getRadius();
Angle labelAngle = this.getLabelAngle();
int i = 0;
for (SurfaceCircle ring : this.rings) {
double radius = ring.getRadius();
LatLon ll = LatLon.greatCircleEndPosition(center, labelAngle.radians, radius / globeRadius);
this.labels.get(i).setPosition(new Position(ll, 0));
i += 1;
}
}