Function FindNearestCandidate

qCC/ccEnvelopeExtractor.cpp:77–204

Finds the nearest (available) point to an edge \return The nearest point distance (or -1 if no point was found!) **/

/** \return The nearest point distance (or -1 if no point was found!)
**/
static PointCoordinateType FindNearestCandidate(unsigned& minIndex,
												const VertexIterator& itA,
												const VertexIterator& itB,
												const std::vector<Vertex2D>& points,
												const std::vector<HullPointFlags>& pointFlags,
												PointCoordinateType minSquareEdgeLength,
												bool allowLongerChunks = false,
												double minCosAngle = -1.0)
{
	//look for the nearest point in the input set
	PointCoordinateType minDist2 = -1;
	const CCVector2 AB = **itB-**itA;
	const PointCoordinateType squareLengthAB = AB.norm2();
	const unsigned pointCount = static_cast<unsigned>(points.size());

#ifdef CC_CORE_LIB_USES_TBB
	tbb::parallel_for( static_cast<unsigned int>(0), pointCount, [&](unsigned int i) {
		const Vertex2D& P = points[i];
		if (pointFlags[P.index] != POINT_NOT_USED)
			return;

		//skip the edge vertices!
		if (P.index == (*itA)->index || P.index == (*itB)->index)
		{
			return;
		}

		//we only consider 'inner' points
		const CCVector2 AP = P-**itA;
		if (AB.x * AP.y - AB.y * AP.x < 0)
		{
			return;
		}

		//check the angle
		if (minCosAngle > -1.0)
		{
			const CCVector2 PB = **itB - P;
			const PointCoordinateType dotProd = AP.x * PB.x + AP.y * PB.y;
			const PointCoordinateType minDotProd = static_cast<PointCoordinateType>(minCosAngle * std::sqrt(AP.norm2() * PB.norm2()));
			if (dotProd < minDotProd)
			{
				return;
			}
		}

		const PointCoordinateType dot = AB.dot(AP); // = cos(PAB) * ||AP|| * ||AB||
		if (dot >= 0 && dot <= squareLengthAB)
		{
			const CCVector2 HP = AP - AB * (dot / squareLengthAB);
			const PointCoordinateType dist2 = HP.norm2();
			if (minDist2 < 0 || dist2 < minDist2)
			{
				//the 'nearest' point must also be a valid candidate
				//(i.e. at least one of the created edges is smaller than the original one
				//and we don't create too small edges!)
				const PointCoordinateType squareLengthAP = AP.norm2();
				const PointCoordinateType squareLengthBP = (P-**itB).norm2();