//3d
//Same math as in 2d case
public static MyVector3 GetClosestPointOnLine(Edge3 e, MyVector3 p, bool withinSegment)
{
MyVector3 a = e.p1;
MyVector3 b = e.p2;
//Assume the line goes from a to b
MyVector3 ab = b - a;
//Vector from start of the line to the point outside of line
MyVector3 ap = p - a;
//The normalized "distance" from a to the closest point, so [0,1] if we are within the line segment
float distance = MyVector3.Dot(ap, ab) / MyVector3.SqrMagnitude(ab);
///This point may not be on the line segment, if so return one of the end points
float epsilon = MathUtility.EPSILON;
if (withinSegment && distance < 0f - epsilon)
{
return(a);
}
else if (withinSegment && distance > 1f + epsilon)
{
return(b);
}
else
{
//This works because a_b is not normalized and distance is [0,1] if distance is within ab
return(a + ab * distance);
}
}