protected Vec4 computeReferencePoint(DrawContext dc) {
if (dc.getViewportCenterPosition() != null)
return dc.getGlobe().computePointFromPosition(dc.getViewportCenterPosition());
java.awt.geom.Rectangle2D viewport = dc.getView().getViewport();
int x = (int) viewport.getWidth() / 2;
for (int y = (int) (0.5 * viewport.getHeight()); y >= 0; y--) {
Position pos = dc.getView().computePositionFromScreenPoint(x, y);
if (pos == null) continue;
return dc.getGlobe().computePointFromPosition(pos.getLatitude(), pos.getLongitude(), 0d);
}
return null;
}
protected static boolean isTileVisible(
DrawContext dc, Tile tile, double minDistanceSquared, double maxDistanceSquared) {
if (!tile.getSector().intersects(dc.getVisibleSector())) return false;
View view = dc.getView();
Position eyePos = view.getEyePosition();
if (eyePos == null) return false;
Angle lat =
clampAngle(
eyePos.getLatitude(),
tile.getSector().getMinLatitude(),
tile.getSector().getMaxLatitude());
Angle lon =
clampAngle(
eyePos.getLongitude(),
tile.getSector().getMinLongitude(),
tile.getSector().getMaxLongitude());
Vec4 p = dc.getGlobe().computePointFromPosition(lat, lon, 0d);
double distSquared = dc.getView().getEyePoint().distanceToSquared3(p);
//noinspection RedundantIfStatement
if (minDistanceSquared > distSquared || maxDistanceSquared < distSquared) return false;
return true;
}
protected void requestTile(DrawContext dc, Tile tile) {
Vec4 centroid = dc.getGlobe().computePointFromPosition(tile.getSector().getCentroid(), 0);
if (this.getReferencePoint() != null)
tile.setPriority(centroid.distanceTo3(this.getReferencePoint()));
RequestTask task = new RequestTask(tile, this);
this.getRequestQ().add(task);
}
protected static boolean isNameVisible(
DrawContext dc, PlaceNameService service, Position namePosition) {
double elevation = dc.getVerticalExaggeration() * namePosition.getElevation();
Vec4 namePoint =
dc.getGlobe()
.computePointFromPosition(
namePosition.getLatitude(), namePosition.getLongitude(), elevation);
Vec4 eyeVec = dc.getView().getEyePoint();
double dist = eyeVec.distanceTo3(namePoint);
return dist >= service.getMinDisplayDistance() && dist <= service.getMaxDisplayDistance();
}
/**
* Compute the lat/lon position of the view center
*
* @param dc the current DrawContext
* @param view the current View
* @return the ground position of the view center or null
*/
protected Position computeGroundPosition(DrawContext dc, View view) {
if (view == null) return null;
Position groundPos =
view.computePositionFromScreenPoint(
view.getViewport().getWidth() / 2, view.getViewport().getHeight() / 2);
if (groundPos == null) return null;
double elevation =
dc.getGlobe().getElevation(groundPos.getLatitude(), groundPos.getLongitude());
return new Position(
groundPos.getLatitude(),
groundPos.getLongitude(),
elevation * dc.getVerticalExaggeration());
}
/**
* 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;
}
protected boolean isNavSectorVisible(
DrawContext dc, double minDistanceSquared, double maxDistanceSquared) {
if (!navSector.intersects(dc.getVisibleSector())) return false;
View view = dc.getView();
Position eyePos = view.getEyePosition();
if (eyePos == null) return false;
// check for eyePos over globe
if (Double.isNaN(eyePos.getLatitude().getDegrees())
|| Double.isNaN(eyePos.getLongitude().getDegrees())) return false;
Angle lat =
clampAngle(eyePos.getLatitude(), navSector.getMinLatitude(), navSector.getMaxLatitude());
Angle lon =
clampAngle(
eyePos.getLongitude(), navSector.getMinLongitude(), navSector.getMaxLongitude());
Vec4 p = dc.getGlobe().computePointFromPosition(lat, lon, 0d);
double distSquared = dc.getView().getEyePoint().distanceToSquared3(p);
//noinspection RedundantIfStatement
if (minDistanceSquared > distSquared || maxDistanceSquared < distSquared) return false;
return true;
}
