/// <summary>
/// Gets the distance from a point p to its projection on a segment</summary>
/// <param name="seg">Segment</param>
/// <param name="p">Point to project</param>
/// <returns>Distance from point p to its projection on segment</returns>
public static float DistanceToSegment(Seg2F seg, Vec2F p)
{
Vec2F projection = Project(seg, p);
float d = Vec2F.Distance(p, projection);
return(d);
}
/// <summary>
/// Picks the specified curve</summary>
/// <param name="curve">Curve</param>
/// <param name="p">Picking point</param>
/// <param name="tolerance">Pick tolerance</param>
/// <param name="hitPoint">Hit point</param>
/// <returns>True if curve found; false otherwise</returns>
public static bool Pick(BezierCurve2F curve, Vec2F p, float tolerance, ref Vec2F hitPoint)
{
Queue <BezierCurve2F> curves = new Queue <BezierCurve2F>();
curves.Enqueue(curve);
float dMin = float.MaxValue;
Vec2F closestPoint = new Vec2F();
while (curves.Count > 0)
{
BezierCurve2F current = curves.Dequeue();
// project p onto segment connecting curve endpoints
Seg2F seg = new Seg2F(current.P1, current.P4);
Vec2F projection = Seg2F.Project(seg, p);
float d = Vec2F.Distance(p, projection);
// reject - point not near enough to segment, expanded by curve "thickness"
float flatness = current.Flatness;
if (d - flatness > tolerance)
{
continue;
}
// accept - point within tolerance of curve
if (flatness <= tolerance)
{
if (d < dMin)
{
dMin = d;
closestPoint = projection;
}
}
else
{
BezierCurve2F left, right;
current.Subdivide(0.5f, out left, out right);
curves.Enqueue(left);
curves.Enqueue(right);
}
}
if (dMin < tolerance)
{
hitPoint = closestPoint;
return(true);
}
return(false);
}
/// <summary>
/// Constructs the circle containing 3 points</summary>
/// <param name="p1">Point 1</param>
/// <param name="p2">Point 2</param>
/// <param name="p3">Point 3</param>
public CircleF(Vec2F p1, Vec2F p2, Vec2F p3)
{
Vec2F o1 = Vec2F.Add(p1, p2); o1 *= 0.5f;
Vec2F o2 = Vec2F.Add(p3, p2); o2 *= 0.5f;
Vec2F d1 = Vec2F.Sub(p2, p1); d1 = d1.Perp;
Vec2F d2 = Vec2F.Sub(p3, p2); d2 = d2.Perp;
double t1 = 0;
double t2 = 0;
if (Ray2F.Intersect(new Ray2F(o1, d1), new Ray2F(o2, d2), ref t1, ref t2))
{
Center = o1 + d1 * (float)t1;
Radius = Vec2F.Distance(Center, p1);
}
else
{
Center = new Vec2F(float.PositiveInfinity, float.PositiveInfinity);
Radius = float.PositiveInfinity;
}
}
