- moved particle storage into FLevelLocals.

- moved parts of the render setup out of the separate render functions.

Things like particle and polyobject linking were duplicated several times for rendering different things in different renderers.
These things only need to be set up once before the renderer is started so it makes a lot more sense to consolidate them into one place outside the actual rendering code.

src/maploader/polyobjects.cpp

@@ -152,6 +152,7 @@ void MapLoader::SpawnPolyobj (int index, int tag, int type)
 	unsigned int ii;
 	int i;
 	FPolyObj *po = &Level->Polyobjects[index];
+	po->Level = Level;
 
 	for (ii = 0; ii < KnownPolySides.Size(); ++ii)
 	{
@@ -351,10 +352,6 @@ void MapLoader::PO_Init (void)
 	InitSideLists ();
 
 	Level->Polyobjects.Resize(NumPolyobjs);
-	for (auto p : Level->Polyobjects)
-	{
-		p.Level = Level;
-	}
 
 	polyIndex = 0; // index polyobj number
 	// Find the startSpot points, and spawn each polyobj