/**
* Performs one line of sight calculation between the reference position and a specified grid
* position.
*
* @param gridPosition the grid position.
* @throws InterruptedException if the operation is interrupted.
*/
protected void performIntersection(Position gridPosition) throws InterruptedException {
// Intersect the line between this grid point and the selected position.
Intersection[] intersections = this.terrain.intersect(this.referencePosition, gridPosition);
if (intersections == null || intersections.length == 0) {
// No intersection, so the line goes from the center to the grid point.
this.sightLines.add(new Position[] {this.referencePosition, gridPosition});
return;
}
// Only the first intersection is shown.
Vec4 iPoint = intersections[0].getIntersectionPoint();
Vec4 gPoint =
terrain.getSurfacePoint(
gridPosition.getLatitude(), gridPosition.getLongitude(), gridPosition.getAltitude());
// Check to see whether the intersection is beyond the grid point.
if (iPoint.distanceTo3(this.referencePoint) >= gPoint.distanceTo3(this.referencePoint)) {
// Intersection is beyond the grid point; the line goes from the center to the grid point.
this.addSightLine(this.referencePosition, gridPosition);
return;
}
// Compute the position corresponding to the intersection.
Position iPosition = this.terrain.getGlobe().computePositionFromPoint(iPoint);
// The sight line goes from the user-selected position to the intersection position.
this.addSightLine(this.referencePosition, new Position(iPosition, 0));
// Keep track of the intersection positions.
this.addIntersectionPosition(iPosition);
this.updateProgress();
}
protected void performIntersectionTests(final Position curPos) throws InterruptedException {
// Clear the results lists when the user selects a new location.
this.firstIntersectionPositions.clear();
this.sightLines.clear();
// Raise the selected location and the grid points a little above ground just to show we can.
final double height = 5; // meters
// Form the grid.
double gridRadius = GRID_RADIUS.degrees;
Sector sector =
Sector.fromDegrees(
curPos.getLatitude().degrees - gridRadius, curPos.getLatitude().degrees + gridRadius,
curPos.getLongitude().degrees - gridRadius,
curPos.getLongitude().degrees + gridRadius);
this.grid = buildGrid(sector, height, GRID_DIMENSION, GRID_DIMENSION);
this.numGridPoints = grid.size();
// Compute the position of the selected location (incorporate its height).
this.referencePosition = new Position(curPos.getLatitude(), curPos.getLongitude(), height);
this.referencePoint =
terrain.getSurfacePoint(curPos.getLatitude(), curPos.getLongitude(), height);
// // Pre-caching is unnecessary and is useful only when it occurs before the
// intersection
// // calculations. It will incur extra overhead otherwise. The normal intersection
// calculations
// // cause the same caching, making subsequent calculations on the same area
// faster.
// this.preCache(grid, this.referencePosition);
// On the EDT, show the grid.
SwingUtilities.invokeLater(
new Runnable() {
public void run() {
progressBar.setValue(0);
progressBar.setString(null);
clearLayers();
showGrid(grid, referencePosition);
getWwd().redraw();
}
});
// Perform the intersection calculations.
this.startTime = System.currentTimeMillis();
for (Position gridPos : this.grid) // for each grid point.
{
//noinspection ConstantConditions
if (NUM_THREADS > 0) this.threadPool.execute(new Intersector(gridPos));
else performIntersection(gridPos);
}
}