/// <summary>
/// Intersects a line segment with the shape and returns the intersection point closest to the beginning of the segment.
/// </summary>
/// <param name="segment">The line segment to intersect.</param>
/// <param name="scalar">A value between 0 and 1 indicating how far along the segment the intersection occurs.</param>
/// <param name="p">The point of the intersection closest to the beginning of the line segment.</param>
/// <returns>Returns a value indicating whether there is an intersection.</returns>
public bool Intersect(ref Segment segment, out float scalar, out Vector3 p)
{
Vector3 d, m, n;
float md, nd, dd;
Vector3.Subtract(ref P2, ref P1, out d);
Vector3.Subtract(ref segment.P1, ref P1, out m);
Vector3.Subtract(ref segment.P2, ref segment.P1, out n);
Vector3.Dot(ref d, ref m, out md);
Vector3.Dot(ref d, ref n, out nd);
Vector3.Dot(ref d, ref d, out dd);
if (!(md < 0f && md + nd < 0f) &&
!(md > dd && md + nd > dd))
{
float nn, mn, k;
Vector3.Dot(ref n, ref n, out nn);
Vector3.Dot(ref m, ref n, out mn);
float a = dd * nn - nd * nd;
Vector3.Dot(ref m, ref m, out k);
k -= Radius * Radius;
float c = dd * k - md * md;
if (Math.Abs(a) >= Constants.Epsilon)
{
float b = dd * mn - nd * md;
float discr = b * b - a * c;
if (discr >= 0f)
{
float t = (-b - (float)Math.Sqrt(discr)) / a;
if (t >= 0f && t <= 1f &&
md + t * nd >= 0f &&
md + t * nd <= dd)
{
scalar = t;
Vector3.Multiply(ref n, t, out p);
Vector3.Add(ref segment.P1, ref p, out p);
return true;
}
}
}
}
var cap = new Sphere(P1, Radius);
float s;
scalar = float.MaxValue;
p = Vector3.Zero;
Vector3 v;
if (cap.Intersect(ref segment, out s, out v))
{
scalar = s;
p = v;
}
cap.Center = P2;
if (cap.Intersect(ref segment, out s, out v) && s < scalar)
{
scalar = s;
p = v;
}
return scalar >= 0f && scalar <= 1f;
}
/// <summary>
/// Intersects a line segment with the shape and returns the intersection point closest to the beginning of the segment.
/// </summary>
/// <param name="segment">The line segment to intersect.</param>
/// <param name="scalar">A value between 0 and 1 indicating how far along the segment the intersection occurs.</param>
/// <param name="p">The point of the intersection closest to the beginning of the line segment.</param>
/// <returns>Returns a value indicating whether there is an intersection.</returns>
public bool Intersect(ref Segment segment, out float scalar, out Vector3 p)
{
Vector3 d, m, n;
float md, nd, dd;
Vector3.Subtract(ref P2, ref P1, out d);
Vector3.Subtract(ref segment.P1, ref P1, out m);
Vector3.Subtract(ref segment.P2, ref segment.P1, out n);
Vector3.Dot(ref d, ref m, out md);
Vector3.Dot(ref d, ref n, out nd);
Vector3.Dot(ref d, ref d, out dd);
if (!(md < 0f && md + nd < 0f) &&
!(md > dd && md + nd > dd))
{
float nn, mn, k;
Vector3.Dot(ref n, ref n, out nn);
Vector3.Dot(ref m, ref n, out mn);
float a = dd * nn - nd * nd;
Vector3.Dot(ref m, ref m, out k);
k -= Radius * Radius;
float c = dd * k - md * md;
if (Math.Abs(a) >= Constants.Epsilon)
{
float b = dd * mn - nd * md;
float discr = b * b - a * c;
if (discr >= 0f)
{
float t = (-b - (float)Math.Sqrt(discr)) / a;
if (t >= 0f && t <= 1f &&
md + t * nd >= 0f &&
md + t * nd <= dd)
{
scalar = t;
Vector3.Multiply(ref n, t, out p);
Vector3.Add(ref segment.P1, ref p, out p);
return(true);
}
}
}
}
var cap = new Sphere(P1, Radius);
float s;
scalar = float.MaxValue;
p = Vector3.Zero;
Vector3 v;
if (cap.Intersect(ref segment, out s, out v))
{
scalar = s;
p = v;
}
cap.Center = P2;
if (cap.Intersect(ref segment, out s, out v) && s < scalar)
{
scalar = s;
p = v;
}
return(scalar >= 0f && scalar <= 1f);
}
/// <summary>
/// Intersects a segment with this collision skin part and returns the intersection point that is nearest to the
/// beginning of the segment.
/// </summary>
/// <param name="segment">The segment to intersect with.</param>
/// <param name="scalar">Returns a value between 0 and 1 indicating where on the segment the first intersection occurs.</param>
/// <param name="point">Returns the point of the first intersection.</param>
/// <returns>Returns a value indicating whether the segment intersects with the part.</returns>
public override bool Intersect(ref Segment segment, out float scalar, out Vector3 point)
{
return(World.Intersect(ref segment, out scalar, out point));
}
