static float32 b2FindMaxSeparation()

in Box2D/Collision/b2CollidePolygon.cpp [59:139]
64 lines of code
13 McCabe index (conditional complexity)

static float32 b2FindMaxSeparation(int32* edgeIndex,
								 const b2PolygonShape* poly1, const b2Transform& xf1,
								 const b2PolygonShape* poly2, const b2Transform& xf2)
{
	int32 count1 = poly1->m_count;
	const b2Vec2* normals1 = poly1->m_normals;

	// Vector pointing from the centroid of poly1 to the centroid of poly2.
	b2Vec2 d = b2Mul(xf2, poly2->m_centroid) - b2Mul(xf1, poly1->m_centroid);
	b2Vec2 dLocal1 = b2MulT(xf1.q, d);

	// Find edge normal on poly1 that has the largest projection onto d.
	int32 edge = 0;
	float32 maxDot = -b2_maxFloat;
	for (int32 i = 0; i < count1; ++i)
	{
		float32 dot = b2Dot(normals1[i], dLocal1);
		if (dot > maxDot)
		{
			maxDot = dot;
			edge = i;
		}
	}

	// Get the separation for the edge normal.
	float32 s = b2EdgeSeparation(poly1, xf1, edge, poly2, xf2);

	// Check the separation for the previous edge normal.
	int32 prevEdge = edge - 1 >= 0 ? edge - 1 : count1 - 1;
	float32 sPrev = b2EdgeSeparation(poly1, xf1, prevEdge, poly2, xf2);

	// Check the separation for the next edge normal.
	int32 nextEdge = edge + 1 < count1 ? edge + 1 : 0;
	float32 sNext = b2EdgeSeparation(poly1, xf1, nextEdge, poly2, xf2);

	// Find the best edge and the search direction.
	int32 bestEdge;
	float32 bestSeparation;
	int32 increment;
	if (sPrev > s && sPrev > sNext)
	{
		increment = -1;
		bestEdge = prevEdge;
		bestSeparation = sPrev;
	}
	else if (sNext > s)
	{
		increment = 1;
		bestEdge = nextEdge;
		bestSeparation = sNext;
	}
	else
	{
		*edgeIndex = edge;
		return s;
	}

	// Perform a local search for the best edge normal.
	for ( ; ; )
	{
		if (increment == -1)
			edge = bestEdge - 1 >= 0 ? bestEdge - 1 : count1 - 1;
		else
			edge = bestEdge + 1 < count1 ? bestEdge + 1 : 0;

		s = b2EdgeSeparation(poly1, xf1, edge, poly2, xf2);

		if (s > bestSeparation)
		{
			bestEdge = edge;
			bestSeparation = s;
		}
		else
		{
			break;
		}
	}

	*edgeIndex = bestEdge;
	return bestSeparation;
}