예제 #1
0
        public LineSegmentCircleIntersect(LineSegment segment, Vector3 circleCenter, float circleRadius)
        {
            Vector3 a = segment.A;
            Vector3 b = segment.B;
            Vector3 c = circleCenter;

            // Compute a normal perpendicular to the line and pointing to the point
            Vector3 up = Vector3.Cross(segment.A - circleCenter, segment.A - segment.B); // This points up from the line
            Vector3 normal = Vector3.Cross(up, segment.A - segment.B);
            float distanceToLine = 0.0f;
            if (normal.Length > 0.0f)
            {
                distanceToLine = Math.Abs(new Plane(normal, segment.A).Distance(circleCenter));
            }

            if (distanceToLine >= circleRadius)
            {
                intersectType = IntersectType.None;
                return;
            }
            if (distanceToLine == float.NaN)
            {
            }

            float along = (float)Math.Sqrt(Math.Pow(circleRadius, 2) - Math.Pow(distanceToLine, 2));

            Plane plane = new Plane(b - a, a);

            float toA = 0.0f;
            float toB = plane.Distance(b);
            float toC = plane.Distance(c);

            float toP1 = toC - along;
            float toP2 = toC + along;

            if (toP2 < toA || toP1 > toB)
            {
                intersectType = IntersectType.None;
                return;
            }

            if (toP1 > toA)
            {
                beginNoIntersect = new LineSegment(a, a + toA * plane.Normal);
            }
            if (toP2 < toB)
            {
                endNoIntersect = new LineSegment(a + toP2 * plane.Normal, a + toB * plane.Normal);
            }

            toP1 = Math.Min(Math.Max(toP1, toA), toB);
            toP2 = Math.Min(Math.Max(toP2, toA), toB);

            intersectType = IntersectType.Segment;
            intersectSegment = new LineSegment(a + plane.Normal * toP1, a + plane.Normal * toP2);
        }
예제 #2
0
        /// <summary>
        /// Subtract another line segment from this one.
        /// It's assumed that the other segment lies on the same line as this one.
        /// </summary>
        /// <param name="other"></param>
        public List<LineSegment> Subtract(LineSegment other)
        {
            //Vector3 n = b - a;
            //n.Normalize();

            Plane plane = new Plane(b - a, a);
            float toB = plane.Distance(b);

            float toOtherA = plane.Distance(other.a);
            float toOtherB = plane.Distance(other.b);

            if (toOtherA > toOtherB)
            {
                float temp = toOtherA;
                toOtherA = toOtherB;
                toOtherB = temp;
            }
            else
            {
            }

            List<LineSegment> remainingSegments = new List<LineSegment>();

            // Check for no overlap
            if (toOtherA >= toB || toOtherB <= 0.0f)
            {
                remainingSegments.Add(new LineSegment(a, b));
                return remainingSegments;
            }

            if (toOtherA > 0)
            {
                Vector3 p1 = a;
                remainingSegments.Add(new LineSegment(a, a + plane.Normal * toOtherA));
            }

            if (toOtherB < toB)
            {
                remainingSegments.Add(new LineSegment(a + plane.Normal * toOtherB, b));
            }

            return remainingSegments;
        }