- reinstate the old code for rendering the first portal without stencil

The previous commit fixes the true issue causing the problems - with this back the restriction is not needed anymore.

source/core/rendering/scene/hw_portal.cpp

@@ -118,13 +118,42 @@ bool FPortalSceneState::RenderFirstSkyPortal(int recursion, HWDrawInfo *outer_di
 	HWPortal* best = nullptr;
 	unsigned bestindex = 0;
 
-	if (recursion > 0 || outer_di->Portals.Size() != 1 || !outer_di->Portals[0]->IsSky()) return false;
+	// Find the one with the highest amount of lines.
+	// Normally this is also the one that saves the largest amount
+	// of time by drawing it before the scene itself.
+	auto& portals = outer_di->Portals;
+	for (int i = portals.Size() - 1; i >= 0; --i)
+	{
+		auto p = portals[i];
+		if (p->lines.Size() > 0 && p->IsSky())
+		{
+			// Cannot clear the depth buffer inside a portal recursion
+			if (recursion && p->NeedDepthBuffer()) continue;
 
-	best = outer_di->Portals[0];
-	outer_di->Portals.Clear();
-	RenderPortal(best, state, false, outer_di);
-	delete best;
-	return true;
+			if (!best || p->lines.Size() > best->lines.Size())
+			{
+				best = p;
+				bestindex = i;
+			}
+
+			// If the portal area contains the current camera viewpoint, let's always use it because it's likely to give the largest area.
+			if (p->boundingBox.contains(outer_di->Viewpoint.Pos))
+			{
+				best = p;
+				bestindex = i;
+				break;
+			}
+		}
+	}
+
+	if (best)
+	{
+		portals.Delete(bestindex);
+		RenderPortal(best, state, false, outer_di);
+		delete best;
+		return true;
+	}
+	return false;
 }