AirspaceIntersectionVector
AirspaceCircle::Intersects(const GeoPoint &start, const GeoPoint &end,
const TaskProjection &projection) const
{
const fixed f_radius = projection.fproject_range(m_center, m_radius);
const FlatPoint f_center = projection.fproject(m_center);
const FlatPoint f_start = projection.fproject(start);
const FlatPoint f_end = projection.fproject(end);
const FlatLine line(f_start, f_end);
FlatPoint f_p1, f_p2;
if (!line.intersect_circle(f_radius, f_center, f_p1, f_p2))
return AirspaceIntersectionVector();
const fixed mag = line.dsq();
if (!positive(mag))
return AirspaceIntersectionVector();
const fixed inv_mag = fixed_one / mag;
const fixed t1 = FlatLine(f_start, f_p1).dot(line);
const fixed t2 = (f_p1 == f_p2) ?
-fixed_one : FlatLine(f_start, f_p2).dot(line);
const bool in_range = (t1 < mag) || (t2 < mag);
// if at least one point is within range, capture both points
AirspaceIntersectSort sorter(start, end, *this);
if ((t1 >= fixed_zero) && in_range)
sorter.add(t1 * inv_mag, projection.funproject(f_p1));
if ((t2 >= fixed_zero) && in_range)
sorter.add(t2 * inv_mag, projection.funproject(f_p2));
return sorter.all();
}
void
AATPoint::set_target(const fixed range, const fixed radial,
const TaskProjection &proj)
{
fixed oldrange = fixed_zero;
fixed oldradial = fixed_zero;
get_target_range_radial(oldrange, oldradial);
const FlatPoint fprev = proj.fproject(get_previous()->get_location_remaining());
const FlatPoint floc = proj.fproject(get_location());
const FlatLine flb (fprev,floc);
const FlatLine fradius (floc,proj.fproject(get_location_min()));
const fixed bearing = fixed_minus_one * flb.angle().value_degrees();
const fixed radius = fradius.d();
fixed swapquadrants = fixed_zero;
if (positive(range) != positive(oldrange))
swapquadrants = fixed(180);
const FlatPoint ftarget1 (fabs(range) * radius *
cos((bearing + radial + swapquadrants)
/ fixed(360) * fixed_two_pi),
fabs(range) * radius *
sin( fixed_minus_one * (bearing + radial + swapquadrants)
/ fixed(360) * fixed_two_pi));
const FlatPoint ftarget2 = floc + ftarget1;
const GeoPoint targetG = proj.funproject(ftarget2);
set_target(targetG, true);
}
void
ThermalLocator::Update(const fixed t_0,
const GeoPoint &location_0,
const SpeedVector wind,
ThermalLocatorInfo &therm)
{
if (n_points < TLOCATOR_NMIN) {
therm.estimate_valid = false;
return; // nothing to do.
}
GeoPoint dloc = FindLatitudeLongitude(location_0, wind.bearing, wind.norm);
TaskProjection projection;
projection.reset(location_0);
projection.update_fast();
// drift points
Drift(t_0, projection, location_0 - dloc);
FlatPoint av = glider_average();
// find thermal center relative to glider's average position
FlatPoint f0(fixed_zero, fixed_zero);
fixed acc = fixed_zero;
for (unsigned i = 0; i < n_points; ++i) {
f0 += (points[i].loc_drift-av)*points[i].lift_weight;
acc += points[i].lift_weight;
}
// if sufficient data, estimate location
if (!positive(acc)) {
therm.estimate_valid = false;
return;
}
f0 = f0 * (fixed_one/acc) + av;
therm.estimate_location = projection.funproject(f0);
therm.estimate_valid = true;
}
