/**
* divideCrvsByDeltaTan : Curve[] * double -> LinkedList<Plane>
* REQUIRES: theta > 0
* ENSURES: divideCrvsByDeltaTan(crvs, theta) returns a linked list of planes
* along the curves s.t. there is a plane at every point along
* the curve where the change in the tangent vector between
* two points is greater than theta.
**/
private IEnumerable<Point3d> DivByAngle(Curve crv, double angle)
{
//initialize parameters
double theta = angle;
Interval dom = crv.Domain;
double stepSize = Math.Abs(dom.Length) * Constants.AbsoluteTolerance * Constants.AbsoluteTolerance;
//initialize list
List<Point3d> pts = new List<Point3d>();
Continuity c = Continuity.C1_continuous;
//initialize data
double rover = dom.Min; //steps along the curve by stepSize
//Add plane at start point of curve to list
Point3d pt = crv.PointAt(rover);
pts.Add(pt);
//Increment
Vector3d prevTan = crv.TangentAt(rover);
double oldRover = rover; //stores the previous rover for comparison
rover += stepSize;
while (rover < dom.Max)
{
Vector3d currTan = crv.TangentAt(rover);
//If there is a discontinuity between the oldRover and rover
//then place a point at the discontinuity and update prevTan.
double discontinuity;
bool isDisc = crv.GetNextDiscontinuity(c, oldRover, rover,
out discontinuity);
if (isDisc)
{
pt = crv.PointAt(discontinuity);
pts.Add(pt);
prevTan = crv.TangentAt(discontinuity);
}
//If the change in tangent vector is greater than theta,
//then drop a target at the rover and update prevTan.
double delta = RhinoMath.ToDegrees(Math.Abs(Vector3d.VectorAngle(prevTan, currTan)));
if (delta > theta)
{
pt = crv.PointAt(rover);
pts.Add(pt);
prevTan = currTan;
}
//Increment
oldRover = rover;
rover += stepSize;
}
//Add target at end point of curve
pt = crv.PointAt(dom.Max);
pts.Add(pt);
return pts;
}