Road.Append() InvalidOperationException

[gsus24]

Hi

i tried to read a table with given waypoints and append the new point to the road in a loop, but like you said if an item is attached it throws a exception.

Another try was to create new Roads and add it them the map in a loop, the roads segments are straight and does not link together.

Any suggestion on doing this with undefined number of points? Rather than hardcode and append the points behind each other.

[sk-zk]

If possible, sort your points so you can continuously Append them.

There's no method for attaching two separate polyline items to each other right now, but it's on my list of things I need to add. Until then, you can do it manually. Say you have two roads you'd like to connect:

var road1 = Road.Add(map, new(10, 0, 10), new(30, 0, 10), "ger1");
var road2 = Road.Add(map, new(32, 0, 12), new(50, 0, 30), "ger1");

You can replace the backward node of road2 with the forward node of road1 like this:

// set the forward item to road2
road1.ForwardNode.ForwardItem = road2;

// clear road2's old backward node so it gets ignored when saving the map
road2.Node.BackwardItem = null;
road2.Node.ForwardItem = null;

// replace road2's backward node
road2.Node = road1.ForwardNode;

// optional: recalculate default node rotations
road1.Recalculate();

The two road items are now connected.

[sk-zk]

You can now attach two polyline items with one method call, if they are attachable to each other. Here's the equivalent of the code above:

var road1 = Road.Add(map, new(10, 0, 10), new(30, 0, 10), "ger1");
var road2 = Road.Add(map, new(32, 0, 12), new(50, 0, 30), "ger1");

road1.ForwardNode.Merge(road2.Node);

[gsus24]

It needs some distinction for road order to merge and exception for the first loop, but .Merge() works well for two road variables.

while (!csvParser.EndOfData)
{
    ...
    if(odd)
    {
        road1 = Road.Add(map, new(10, 0, 10), new(30, 0, 10), "ger1");

        if(!firstLoop)
        {
            road2.ForwardNode.Merge(road1.Node);
        }        
    }
    else
    {
        road2 = Road.Add(map, new(10, 0, 10), new(30, 0, 10), "ger1");
        road1.ForwardNode.Merge(road2.Node);        
    }
    ....
}

[gsus24]

To come back to my issue for InvalidOperationException if append segment to road in loop

while (!csvParser.EndOfData)
{
    ...
    road.append(position);
    ...
}

By appending after each other it works

road.append(position0)
    .append(position1); 

Maybe you have a quick explanation why ForwardItem is not null in loop? And i need to debug myself for better understanding. Thanks

[sk-zk]

I think what you seem to be missing is that Append returns the appended segment, so you can append in a loop like this:

var road = Road.Add(map, points[0], points[1], "ger1");
for (int i = 2; i < points.Count; i++)
{
    road = road.Append(points[i]);
}

Remember that the Road class is not a collection; it's just one individual road item with one neighbor in either direction, so you can't append to it more than once because it's already connected to another item.

[gsus24]

workaround to create route https://github.com/gsus24/TruckLib/tree/route/Samples/02-Route/