public static NearestPointResult NearestPointOnCurve(Vector2[] b, Vector2 p)
{
// convert points to bezier form
if (b.Length != 4)
{
throw new ArgumentException();
}
/* Convert problem to 5th-degree Bezier form */
Vector2[] w = ConvertToBezierForm(p, b);
/* Find all possible roots of 5th-degree equation */
double[] t_candidate = new double[W_DEGREE];
int n_soln = FindRoots(w, W_DEGREE, t_candidate, 0);
/* Compare distances of P to all candidates, and to t=0, and t=1 */
double t;
double dist, new_dist;
Vector2 p1;
/* Check distance to beginning of curve, where t = 0 */
dist = (p - b[0]).VectorLength2;
t = 0;
/* Find distances for candidate points */
for (int i = 0; i < n_soln; i++)
{
p1 = Bezier(b, DEGREE, t_candidate[i], null, null);
new_dist = (p - p1).VectorLength2;
if (new_dist < dist)
{
dist = new_dist;
t = t_candidate[i];
}
}
/* Finally, look at distance to end point, where t = 1.0 */
new_dist = (p - b[DEGREE]).VectorLength2;
if (new_dist < dist)
{
dist = new_dist;
t = 1;
}
/* Return the point on the curve at parameter value t */
NearestPointResult r = new NearestPointResult();
r.NearestPoint = Bezier(b, DEGREE, t, null, null);
r.tval = t;
return(r);
}
public static NearestPointResult NearestPointOnCurve(Vector2[] b, Vector2 p)
{
// convert points to bezier form
if (b.Length != 4)
throw new ArgumentException();
/* Convert problem to 5th-degree Bezier form */
Vector2[] w = ConvertToBezierForm(p, b);
/* Find all possible roots of 5th-degree equation */
double[] t_candidate = new double[W_DEGREE];
int n_soln = FindRoots(w, W_DEGREE, t_candidate, 0);
/* Compare distances of P to all candidates, and to t=0, and t=1 */
double t;
double dist, new_dist;
Vector2 p1;
/* Check distance to beginning of curve, where t = 0 */
dist = (p - b[0]).VectorLength2;
t = 0;
/* Find distances for candidate points */
for (int i = 0; i < n_soln; i++) {
p1 = Bezier(b, DEGREE, t_candidate[i], null, null);
new_dist = (p - p1).VectorLength2;
if (new_dist < dist) {
dist = new_dist;
t = t_candidate[i];
}
}
/* Finally, look at distance to end point, where t = 1.0 */
new_dist = (p - b[DEGREE]).VectorLength2;
if (new_dist < dist) {
dist = new_dist;
t = 1;
}
/* Return the point on the curve at parameter value t */
NearestPointResult r = new NearestPointResult();
r.NearestPoint = Bezier(b, DEGREE, t, null, null);
r.tval = t;
return r;
}