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

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

			float lower = 0.0f, upper = maxLambda;

			Vec2 p1 = Common.Math.MulT(xf.R, segment.P1 - xf.Position);
			Vec2 p2 = Common.Math.MulT(xf.R, segment.P2 - xf.Position);
			Vec2 d = p2 - p1;
			int index = -1;

			for (int i = 0; i < _vertexCount; ++i)
			{
				// p = p1 + a * d
				// dot(normal, p - v) = 0
				// dot(normal, p1 - v) + a * dot(normal, d) = 0
				float numerator = Vec2.Dot(_normals[i], _vertices[i] - p1);
				float denominator = Vec2.Dot(_normals[i], d);

				if (denominator == 0.0f)
				{
					if (numerator < 0.0f)
					{
						return SegmentCollide.MissCollide;
					}
				}
				else
				{
					// Note: we want this predicate without division:
					// lower < numerator / denominator, where denominator < 0
					// Since denominator < 0, we have to flip the inequality:
					// lower < numerator / denominator <==> denominator * lower > numerator.
					if (denominator < 0.0f && numerator < lower * denominator)
					{
						// Increase lower.
						// The segment enters this half-space.
						lower = numerator / denominator;
						index = i;
					}
					else if (denominator > 0.0f && numerator < upper * denominator)
					{
						// Decrease upper.
						// The segment exits this half-space.
						upper = numerator / denominator;
					}
				}

				if (upper < lower)
				{
					return SegmentCollide.MissCollide;
				}
			}

			Box2DXDebug.Assert(0.0f <= lower && lower <= maxLambda);

			if (index >= 0)
			{
				lambda = lower;
				normal = Common.Math.Mul(xf.R, _normals[index]);
				return SegmentCollide.HitCollide;
			}

			lambda = 0f;
			return SegmentCollide.StartInsideCollide;
		}