Function getzrange

source/core/gamefuncs.cpp:943–1041

//==========================================================================

void getzrange(const DVector3& pos, sectortype* sect, double* ceilz, CollisionBase& ceilhit, double* florz, CollisionBase& florhit, double maxdist, uint32_t cliptype)
{
	if (sect == nullptr)
	{
		*ceilz = -FLT_MAX; ceilhit.setVoid();
		*florz = FLT_MAX; florhit.setVoid();
		return;
	}

	const EWallFlags dawalclipmask = EWallFlags::FromInt(cliptype & 65535);
	const ESpriteFlags dasprclipmask = ESpriteFlags::FromInt(cliptype >> 16);

	auto closest = pos.XY();
	if (enginecompatibility_mode == ENGINECOMPATIBILITY_NONE)
		SquareDistToSector(closest.X, closest.Y, sect, &closest);

	calcSlope(sect, closest, ceilz, florz);
	ceilhit.setSector(sect);
	florhit.setSector(sect);

	double theZs[2];

	BFSSectorSearch search(sect);
	while (auto sec = search.GetNext())
	{
		for (auto& wal : sec->walls)
		{
			if (checkRangeOfWall(&wal, EWallFlags::FromInt(dawalclipmask), pos, maxdist + 1 / 16., theZs))
			{
				auto nsec = wal.nextSector();
				search.Add(nsec);
				if (/*(pos.Z > theZs[0]) &&*/ (theZs[0] > *ceilz))
				{
					*ceilz = theZs[0];
					ceilhit.setSector(nsec);
				}

				if (/*(pos.Z < theZs[1]) &&*/ (theZs[1] < *florz))
				{
					*florz = theZs[1];
					florhit.setSector(nsec);
				}
			}
			else if (checkRangeOfWall(&wal, EWallFlags::FromInt(dawalclipmask), pos, maxdist + 64., theZs))
			{
				// extend the search distance for neighboring sectors a bit further so that we can find sprites outside the search range extending to our position.
				auto nsec = wal.nextSector();
				search.Add(nsec);
			}
		}
	}

	if (dasprclipmask)
	{
		search.Rewind();
		while (auto sec = search.GetNext())
		{
			TSectIterator<DCoreActor> it(sec);