private MinDistanceAtTPair GetClosestTParameter(BezierTParameterRequest request, MinDistanceAtTPair _minDistanceAtT)
{
float mid = (request.startingT + request.endT) / 2.0f;
// Base case for recursion.
if ((request.endT - request.startingT) < request.thresholdT)
{
_minDistanceAtT.tParameter = mid;
return(_minDistanceAtT);
}
// The two halves have param range [start, mid] and [mid, end]. We decide which one to use by using a midpoint param calculation for each section.
float paramA = (request.startingT + mid) / 2.0f;
float paramB = (mid + request.endT) / 2.0f;
Vector3 posA = GetPoint(paramA);
Vector3 posB = GetPoint(paramB);
float distASq = (posA - request.pointToCheck).sqrMagnitude;
float distBSq = (posB - request.pointToCheck).sqrMagnitude;
if (distASq < distBSq)
{
request.endT = mid;
_minDistanceAtT.minSqrDistance = distASq;
}
else
{
request.startingT = mid;
_minDistanceAtT.minSqrDistance = distBSq;
}
// The (tail) recursive call.
return(GetClosestTParameter(request, _minDistanceAtT));
}
public float GetTParameter(Vector3 _pointToCheck)
{
MinDistanceAtTPair result = new MinDistanceAtTPair(float.NaN, float.NaN);
for (int i = 0; i < Spline.ControlPointCount - 1; i += 3)
{
BezierTParameterRequest request = new BezierTParameterRequest(_pointToCheck);
result = GetClosestTParameter(request, result);
}
return(result.tParameter);
}
