/// <summary>
/// Determine the closest point on a segmentwise-defined line to a test point
/// </summary>
/// <param name="point">The test point</param>
/// <param name="linePointList">List of points defining the line</param>
/// <param name="extrusionAmountAbs">Absolute value of the extrusion distance</param>
/// <param name="closestSegmentDifference">Start-to-end vector of the segment containing the closest point</param>
/// <param name="getPoint">Deleate to return the position <see cref="Vector2"/> from the point type <typeparamref name="T"/></param>
/// <param name="average">Delegate to average two points of type <typeparamref name="T"/></param>
private static T ClosestPointAlongSegmentwiseLine <T>(Vector2 point, SegmentwisePointList <T> linePointList, float extrusionAmountAbs, Func <T, Vector2> getPoint, Func <T, T, float, T> average, out float fractionAlongClosestSegment, out Vector2 closestSegmentDifference, out int closestSegmentIndex) where T : struct
{
var linePoints = linePointList.Points;
var linePointsMaximumDelta = linePointList.MaxSegmentDistance;
var numSegments = linePoints.Count - 1;
float minDistanceSquared = float.MaxValue;
T closestPoint = new T();
closestSegmentDifference = Vector2.zero;
closestSegmentIndex = 0;
fractionAlongClosestSegment = 0f;
//We'll look every *numSteps* points to see what's closest. We will increase it if the line point is much further away than the extrusion distance.
int numSteps = 1;
for (int i = 0; i < numSegments; i += numSteps)
{
float distanceSquaredToSegment;
var segmentStart = linePoints[i];
var segmentEnd = linePoints[i + 1];
Vector2 startVector = getPoint(segmentStart);
Vector2 endVector = getPoint(segmentEnd);
var currentClosestFractionToSegment = LineSegmentUtil.ClosestFractionAlongSegment(startVector, endVector, point, out distanceSquaredToSegment);
if (distanceSquaredToSegment < minDistanceSquared)
{
minDistanceSquared = distanceSquaredToSegment;
closestPoint = average(segmentStart, segmentEnd, currentClosestFractionToSegment);
fractionAlongClosestSegment = currentClosestFractionToSegment;
closestSegmentDifference = endVector - startVector;
closestSegmentIndex = i;
}
var distanceDiff = Math.Max(Math.Sqrt(distanceSquaredToSegment) - extrusionAmountAbs, 0);
numSteps = Mathf.FloorToInt(Mathf.Max(1f, (float)distanceDiff / linePointsMaximumDelta));
}
return(closestPoint);
}
/// <summary>
/// Determines if an extruded point is closer to a line (on a segment-by-segment basis) than the extrusion amount.
/// </summary>
/// <param name="extrudedPoint">Extruded test point</param>
/// <param name="linePointList">List of points defining the line</param>
/// <param name="extrusionAmount">The extrusion amount</param>
internal static bool IsCloserThanExtrusionDistance_Segmentwise(ExtrudedPointUV extrudedPoint, SegmentwiseLinePointListUV linePointList, float extrusionAmount)
{
var linePoints = linePointList.Points;
var linePointsMaximumDelta = linePointList.MaxSegmentDistance;
var numSegments = linePoints.Count - 1;
Vector2 point = extrudedPoint.Point;
var segmentIndex = Math.Max(0, Math.Min(numSegments - 1, extrudedPoint.LinePointSegmentIndex));
var segmentIndex2 = Math.Max(0, Math.Min(numSegments - 1, extrudedPoint.LinePointSegmentIndex2));
bool isCloser = false;
var extrusionAmountAbs = Mathf.Abs(extrusionAmount);
var extrusionAmountSquared = extrusionAmount * extrusionAmount;
//We'll look every *numSteps* points to see what's closest. We will increase it if the line point is much further away than the extrusion distance.
int numSteps = 1;
for (int i = 0; i < numSegments; i += numSteps)
{
if (i != segmentIndex && i != segmentIndex2)
{
isCloser = LineSegmentUtil.IsPointWithinDistanceOfSegment(linePoints[i].Point, linePoints[i + 1].Point, point, extrusionAmountSquared);
}
if (isCloser)
{
break;
}
else
{
var distanceDiff = (linePoints[i].Point - point).magnitude - extrusionAmountAbs;
numSteps = Mathf.FloorToInt(Mathf.Max(1f, distanceDiff / linePointsMaximumDelta));
}
}
return(isCloser);
}
