CHG 2/2: RenderMesh() implements new 'prunning' parameter (to

	centreOffsets[(unsigned)fileNo]=(int)mask.GetIndex(x,y,z);

	//save the mask image, finally (might have some pixels removed)

	//NB: if there is prunning[""] == 0.0 then this saving is redundant...

	mask.SaveImage(fileName);

	//start processing the prunnings...

	std::map<std::string, float>::const_iterator pruningIter = pruning.begin();

	while (pruningIter != pruning.end())

	{

		//over all tips/filopodia:

		//check their lengths and wipe them out if necessary

		tipIter=tipOffsets.begin();

		while (tipIter != tipOffsets.end())

		{

			if (tipLengths[tipIter->first].at((unsigned)fileNo) < pruningIter->second)

				RemoveFromMask(mask, (i3d::GRAY16)tipIter->first);

			++tipIter;

		}

		//save the "updated" mask

		std::cout << "exporting mask #" << fileNo << "\n";

		sprintf(fileName,"%s/ID%d_afterTM/mask_t%03d%s.tif",path,ID,fileNo,pruningIter->first.c_str());

		mask.SaveImage(fileName);

		++pruningIter;

	}

	return(0);

}