/// <summary>
/// Computes an intersection of the line and the circle
/// </summary>
public static bool LineCircle(Vector2 lineOrigin, Vector2 lineDirection, Vector2 circleCenter, float circleRadius,
out IntersectionLineCircle intersection)
{
Vector2 originToCenter = circleCenter - lineOrigin;
float centerProjection = Vector2.Dot(lineDirection, originToCenter);
float sqrDistanceToLine = originToCenter.sqrMagnitude - centerProjection * centerProjection;
float sqrDistanceToIntersection = circleRadius * circleRadius - sqrDistanceToLine;
if (sqrDistanceToIntersection < -Geometry.Epsilon)
{
intersection = IntersectionLineCircle.None();
return(false);
}
if (sqrDistanceToIntersection < Geometry.Epsilon)
{
intersection = IntersectionLineCircle.Point(lineOrigin + lineDirection * centerProjection);
return(true);
}
float distanceToIntersection = Mathf.Sqrt(sqrDistanceToIntersection);
float distanceA = centerProjection - distanceToIntersection;
float distanceB = centerProjection + distanceToIntersection;
Vector2 pointA = lineOrigin + lineDirection * distanceA;
Vector2 pointB = lineOrigin + lineDirection * distanceB;
intersection = IntersectionLineCircle.TwoPoints(pointA, pointB);
return(true);
}
/// <summary>
/// Computes an intersection of the line and the circle
/// </summary>
public static bool LineCircle(Line2 line, Circle2 circle, out IntersectionLineCircle intersection)
{
return(LineCircle(line.origin, line.direction, circle.center, circle.radius, out intersection));
}
