/// <summary>
/// Computes an intersection of the line and the sphere
/// </summary>
public static bool LineSphere(Vector3 lineOrigin, Vector3 lineDirection, Vector3 sphereCenter, float sphereRadius,
out IntersectionLineSphere intersection)
{
Vector3 originToCenter = sphereCenter - lineOrigin;
float centerProjection = Vector3.Dot(lineDirection, originToCenter);
float sqrDistanceToLine = originToCenter.sqrMagnitude - centerProjection * centerProjection;
float sqrDistanceToIntersection = sphereRadius * sphereRadius - sqrDistanceToLine;
if (sqrDistanceToIntersection < -Geometry.Epsilon)
{
intersection = IntersectionLineSphere.None();
return(false);
}
if (sqrDistanceToIntersection < Geometry.Epsilon)
{
intersection = IntersectionLineSphere.Point(lineOrigin + lineDirection * centerProjection);
return(true);
}
float distanceToIntersection = Mathf.Sqrt(sqrDistanceToIntersection);
float distanceA = centerProjection - distanceToIntersection;
float distanceB = centerProjection + distanceToIntersection;
Vector3 pointA = lineOrigin + lineDirection * distanceA;
Vector3 pointB = lineOrigin + lineDirection * distanceB;
intersection = IntersectionLineSphere.TwoPoints(pointA, pointB);
return(true);
}