Duke: lower the coordinate precision for calculating the sector's cen…

…ter for ST09 to original Build.

This is needed so that some maps with not quite correct setups still work. Found in Roch3.

source/games/duke/src/sectors.cpp

@@ -566,15 +566,15 @@ static void handle_st09(sectortype* sptr, DDukeActor* actor)
 
 	sp = (sptr->extra >> 4) / 16.;
 
-	//first find center point by averaging all points
-	dax = 0, day = 0;
+	//first find center point by averaging all points (in Build coordinate system to ensure the higher precision does not affect the result)
+	int idax = 0, iday = 0;
 	for (auto& wal : sptr->walls)
 	{
-		dax += wal.pos.X;
-		day += wal.pos.Y;
+		idax += int(wal.pos.X * 16);
+		iday += int(wal.pos.Y * 16);
 	}
-	dax /= sptr->walls.Size();
-	day /= sptr->walls.Size();
+	dax = (idax / (int)sptr->walls.Size()) / 16.;
+	day = (iday / (int)sptr->walls.Size()) / 16.;
 
 	//find any points with either same x or same y coordinate
 	//  as center (dax, day) - should be 2 points found.
@@ -598,7 +598,7 @@ static void handle_st09(sectortype* sptr, DDukeActor* actor)
 		auto prevwall = wal - 1;
 		if (prevwall < sptr->walls.Data()) prevwall += sptr->walls.Size();
 
-		if ((wal->pos.X == dax) && (wal->pos.Y == day))
+		if (abs(wal->pos.X - dax) <= (1 / 32.) && abs(wal->pos.Y - day) <= (1 / 32.))
 		{
 			dax2 = ((prevwall->pos.X + wal->point2Wall()->pos.X) * 0.5) - wal->pos.X;
 			day2 = ((prevwall->pos.Y + wal->point2Wall()->pos.Y) * 0.5) - wal->pos.Y;