From bb75bc76ddd99e7d3edaf6e7dbd3719ea332052c Mon Sep 17 00:00:00 2001
From: Mikko Rasa <tdb@tdb.fi>
Date: Thu, 5 Feb 2015 20:02:20 +0200
Subject: [PATCH] Don't diverge from critical blocks

Doing so could confuse the router.
---
 source/libr2c2/trainrouteplanner.cpp | 37 ++++++++++++++++++++--------
 source/libr2c2/trainrouteplanner.h   |  4 ++-
 2 files changed, 30 insertions(+), 11 deletions(-)

diff --git a/source/libr2c2/trainrouteplanner.cpp b/source/libr2c2/trainrouteplanner.cpp
index 9e74eca..a05e97e 100644
--- a/source/libr2c2/trainrouteplanner.cpp
+++ b/source/libr2c2/trainrouteplanner.cpp
@@ -214,6 +214,7 @@ void TrainRoutePlanner::finalize_plan()
 TrainRoutePlanner::TrainRoutingInfo::TrainRoutingInfo(Train &t):
 	train(&t),
 	speed(train->get_maximum_speed()),
+	first_noncritical(train->get_first_noncritical_block().block()),
 	router(train->get_ai_of_type<TrainRouter>()),
 	destination(0),
 	has_duration(false)
@@ -272,6 +273,7 @@ TrainRoutePlanner::OccupiedTrack::~OccupiedTrack()
 
 TrainRoutePlanner::TrainRoutingState::TrainRoutingState(TrainRoutingInfo &inf):
 	info(&inf),
+	critical(true),
 	occupied_tracks(0),
 	state(MOVING),
 	delay(info->router->get_departure_delay()),
@@ -307,6 +309,7 @@ TrainRoutePlanner::TrainRoutingState::TrainRoutingState(const TrainRoutingState
 	info(other.info),
 	track(other.track),
 	path(other.path),
+	critical(other.critical),
 	occupied_tracks(other.occupied_tracks),
 	offset(other.offset),
 	back_offset(other.back_offset),
@@ -361,6 +364,9 @@ bool TrainRoutePlanner::TrainRoutingState::check_arrival()
 			waypoint = -1;
 	}
 
+	if(info->first_noncritical->has_track(*track))
+		critical = false;
+
 	return false;
 }
 
@@ -475,15 +481,26 @@ void TrainRoutePlanner::RoutingStep::create_successors(list<RoutingStep> &new_st
 	train.advance_track(0);
 
 	const TrackType::Endpoint &next_entry_ep = next_track.endpoint();
-	for(unsigned i=0; next_entry_ep.paths>>i; ++i)
-		if(next_entry_ep.has_path(i))
-		{
-			train.path = i;
-			train.update_estimate();
-			next.update_estimate();
-			if(next.is_viable())
-				new_steps.push_back(next);
-		}
+	if(train.critical)
+	{
+		train.path = train.track->get_type().coerce_path(train.track.entry(), train.track->get_active_path());
+		train.update_estimate();
+		next.update_estimate();
+		if(next.is_viable())
+			new_steps.push_back(next);
+	}
+	else
+	{
+		for(unsigned i=0; next_entry_ep.paths>>i; ++i)
+			if(next_entry_ep.has_path(i))
+			{
+				train.path = i;
+				train.update_estimate();
+				next.update_estimate();
+				if(next.is_viable())
+					new_steps.push_back(next);
+			}
+	}
 
 	new_steps.sort();
 	for(list<RoutingStep>::iterator i=new_steps.begin(); ++i!=new_steps.end(); )
@@ -492,7 +509,7 @@ void TrainRoutePlanner::RoutingStep::create_successors(list<RoutingStep> &new_st
 		i->update_estimate();
 	}
 
-	if(next_entry_ep.paths!=next_track->get_type().get_paths())
+	if(next_entry_ep.paths!=next_track->get_type().get_paths() && !train.critical)
 	{
 		RoutingStep wait(this);
 		wait.advance(dt);
diff --git a/source/libr2c2/trainrouteplanner.h b/source/libr2c2/trainrouteplanner.h
index 85a748c..0ed2e11 100644
--- a/source/libr2c2/trainrouteplanner.h
+++ b/source/libr2c2/trainrouteplanner.h
@@ -32,6 +32,7 @@ private:
 	{
 		Train *train;
 		float speed;
+		Block *first_noncritical;
 		TrainRouter *router;
 		const TrackChain *destination;
 		std::vector<const TrackChain *> waypoints;
@@ -69,7 +70,8 @@ private:
 	{
 		TrainRoutingInfo *info;
 		TrackIter track;
-		unsigned path;
+		unsigned char path;
+		bool critical;
 		OccupiedTrack *occupied_tracks;
 		float offset;
 		float back_offset;
-- 
2.45.2