private static bool IsRayIntersectWithBeaconAccuracy(PointF ray, Beacon beacon)
{
if (beacon == null)
return false;
var x = beacon.X;
var y = beacon.Y;
var r = beacon.Accuracy;
return r > Math.Sqrt((ray.X - x) * (ray.X - x) + (ray.Y - y) * (ray.Y - y));
}
private static IEnumerable<PointF> GetCircleCircleIntersections(Beacon b1, Beacon b2)
{
var p1 = new PointF(b1.X, b1.Y);
var p2 = new PointF(b2.X, b2.Y);
var d = GetDistanceBetween(p1, p2);
var r1 = b1.Accuracy;
var r2 = b2.Accuracy;
// if to far away, or self contained - can't be done
if ((d >= (r1 + r2)) || (d <= Math.Abs(r1 - r2))) {
return new List<PointF>();
}
var a = (r1*r1 - r2*r2 + d*d)/(2*d);
var h = Math.Sqrt(r1*r1 - a*a);
var x0 = p1.X + a*(p2.X - p1.X)/d;
var y0 = p1.Y + a*(p2.Y - p1.Y)/d;
var rx = -(p2.Y - p1.Y)*(h/d);
var ry = -(p2.X - p1.X)*(h/d);
return new List<PointF>
{
new PointF((float) (x0 + rx), (float) (y0 - ry)),
new PointF((float) (x0 - rx), (float) (y0 + ry))
};
}
private static bool IsOverBeaconAccuracyRadius(Beacon beacon, float x, float y)
{
var dx = MetersToPixels * beacon.X + ShiftX - x;
var dy = MetersToPixels * beacon.Y + ShiftY - y;
var dist = Math.Sqrt(dx*dx + dy*dy);
var acc = MetersToPixels*beacon.Accuracy;
return Math.Abs(dist - acc) < 12;
}