static bool TryAdvanceThroughJunction(Junction junction, RoadNetworkDescription network,
ref TraversalState state, bool allowLooping = false)
{
var roadId = state.RoadId.ToString();
// TODO: This search currently terminates on the first found linked road/lane, but we may want to find
// all of them first and then select one based on some criteria
foreach (var connection in junction.connections)
{
if (roadId == connection.incomingRoadId)
{
if (!allowLooping && state.AllRoadIds.HasBeenTraversed(new NativeString64(connection.incomingRoadId)))
{
return(false);
}
foreach (var link in connection.laneLinks)
{
if (link.laneIdFrom != state.LaneId)
{
continue;
}
var direction = DetermineNewDirection(connection.contactPoint);
var idx = direction == TraversalDirection.Forward
? 0
: network.GetRoadById(connection.connectingRoadId).laneSections.Count - 1;
state.SetNewLocation(new NativeString64(connection.connectingRoadId), idx, link.laneIdTo, direction);
return(true);
}
}
else if (roadId == connection.connectingRoadId)
{
if (!allowLooping && state.AllRoadIds.HasBeenTraversed(new NativeString64(connection.connectingRoadId)))
{
return(false);
}
foreach (var link in connection.laneLinks)
{
if (link.laneIdTo != state.LaneId)
{
continue;
}
var nextRoad = network.GetRoadById(connection.incomingRoadId);
var sectionIdx = nextRoad.laneSections.Count - 1;
state.SetNewLocation(new NativeString64(connection.incomingRoadId), sectionIdx, link.laneIdFrom, TraversalDirection.Backward);
return(true);
}
}
}
return(false);
}
// Each non-junction road is effectively a segment of a graph edge - this function identifies which roads
// belong on the same edge as the input graph edge and return the information necessary to query this edge
internal static RoadGroup IdentifyGraphEdgeGroup(RoadNetworkDescription roadNetwork,
TraversalState state, NativeString64 roadId)
{
if (roadNetwork.GetRoadById(roadId).junction != "-1")
{
throw new ArgumentException(
"Cannot collect graph edge group for a road inside a junction - roads inside junctions" +
"are part of a graph node.");
}
// Because we want to limit traversal to this graph edge, we will always stop at junctions (nodes)
const bool stopAtJunctions = true;
var param = new TraversalParameters(roadNetwork, stopAtJunctions);
// Count how many Road elements are in this group, including the starting road
var numRoads = 1;
state.SetNewLocation(roadId, 0, 0, TraversalDirection.Backward);
while (TryAdvanceOneRoad(param, state))
{
numRoads++;
}
// We've moved all the way to the "front" of this collection of roads - store it as the starting location
var startingRoadId = state.RoadId;
// To get from the first Road to the second, we need to travel in the opposite direction we traversed to
// reach the first Road
var startDirection = (TraversalDirection)(-(int)state.Direction);
// Traverse forward to ensure we mark all the roads in this group as traversed
state.SetNewLocation(roadId, 0, 0, TraversalDirection.Forward);
while (TryAdvanceOneRoad(param, state))
{
numRoads++;
}
return(new RoadGroup(startDirection, startingRoadId, numRoads));
}
// NOTE: Because this method advances by ROAD, any LANE information will be lost on traversal (reset to 0)
// Use TryAdvanceOneLaneSection to move along a selected lane
internal static bool TryAdvanceOneRoad(TraversalParameters traversalParam, TraversalState traversalState)
{
var roadCurrent = traversalParam.roadNetwork.GetRoadById(traversalState.RoadId);
var link = GetLinkToNextRoad(roadCurrent, traversalState.Direction);
if (link.linkType == RoadLinkType.None || traversalParam.shouldStopAtJunctions &&
!IsLinkOnGraphEdge(traversalParam.roadNetwork, link))
{
return(false);
}
var directionNext = DetermineNewDirection(link.contactPoint);
traversalState.SetNewLocation(new NativeString64(link.nodeId), 0, 0, directionNext);
return(true);
}
