Box2DX.Collision.CircleShape.TestSegment C# (CSharp) Метод

        public override SegmentCollide TestSegment(XForm transform, out float lambda, out Vec2 normal, Segment segment, float maxLambda)
        {
            lambda = 0f;
            normal = Vec2.Zero;

            Vec2 position = transform.Position + Common.Math.Mul(transform.R, _localPosition);
            Vec2 s = segment.P1 - position;
            float b = Vec2.Dot(s, s) - _radius * _radius;

            // Does the segment start inside the circle?
            if (b < 0.0f)
            {
                lambda = 0f;
                return SegmentCollide.StartInsideCollide;
            }

            // Solve quadratic equation.
            Vec2 r = segment.P2 - segment.P1;
            float c = Vec2.Dot(s, r);
            float rr = Vec2.Dot(r, r);
            float sigma = c * c - rr * b;

            // Check for negative discriminant and short segment.
            if (sigma < 0.0f || rr < Common.Settings.FLT_EPSILON)
            {
                return SegmentCollide.MissCollide;
            }

            // Find the point of intersection of the line with the circle.
            float a = -(c + Common.Math.Sqrt(sigma));

            // Is the intersection point on the segment?
            if (0.0f <= a && a <= maxLambda * rr)
            {
                a /= rr;
                lambda = a;
                normal = s + a * r;
                normal.Normalize();
                return SegmentCollide.HitCollide;
            }

            return SegmentCollide.MissCollide;
        }