bool b2AABB::RayCast()

in Box2D/Collision/b2Collision.cpp [130:195]

• 49 lines of code
• 10 McCabe index (conditional complexity)

bool b2AABB::RayCast(b2RayCastOutput* output, const b2RayCastInput& input) const
{
	float32 tmin = -b2_maxFloat;
	float32 tmax = b2_maxFloat;

	b2Vec2 p = input.p1;
	b2Vec2 d = input.p2 - input.p1;
	b2Vec2 absD = b2Abs(d);

	b2Vec2 normal;

	for (int32 i = 0; i < 2; ++i)
	{
		if (absD(i) < b2_epsilon)
		{
			// Parallel.
			if (p(i) < lowerBound(i) || upperBound(i) < p(i))
			{
				return false;
			}
		}
		else
		{
			float32 inv_d = 1.0f / d(i);
			float32 t1 = (lowerBound(i) - p(i)) * inv_d;
			float32 t2 = (upperBound(i) - p(i)) * inv_d;

			// Sign of the normal vector.
			float32 s = -1.0f;

			if (t1 > t2)
			{
				b2Swap(t1, t2);
				s = 1.0f;
			}

			// Push the min up
			if (t1 > tmin)
			{
				normal.SetZero();
				normal(i) = s;
				tmin = t1;
			}

			// Pull the max down
			tmax = b2Min(tmax, t2);

			if (tmin > tmax)
			{
				return false;
			}
		}
	}

	// Does the ray start inside the box?
	// Does the ray intersect beyond the max fraction?
	if (tmin < 0.0f || input.maxFraction < tmin)
	{
		return false;
	}

	// Intersection.
	output->fraction = tmin;
	output->normal = normal;
	return true;
}