A* pathfind algorithm and Grid

[Ichi]

Hi i want to make some findpath app i am using QML and i don't know how to implement this because i don't know how makes node from QML grid. But i have some problems with implement algorithm. Can somebody give me some advices or links.
Thanks

[Ichi]

Any help? i simply don't know how to make from QML grid something like tree or graph and how to sent it to c++ class.

[lanz]

How do you generate grid?

[MarekR22]

the best approach is to use GridView. Data model and A* algorithm I would implement in C++.

[Ichi]

yes i will implement A* algorithm in C++ but have you some source or example ??? It will help me a lot
Thanks for help

[lanz]

What do you need example for?
Try to subdivide your task to a series of simpler task, then you can easily google it/look it up in reference.

1. How to implement A* in C++ (http://code.activestate.com/recipes/...ath-algorithm/).
2. How to expose C++ classes to QML (http://qt-project.org/doc/qt-5.0/qtq...ttributes.html).
3. How to dynamically generate QML elements (http://kunalmaemo.blogspot.ru/2011/0...ically-on.html).

[Ichi]

I want some example how to use A* algorithm with QML GridLayout

[lanz]

OK, I don't think there's particular example or specific component in qt for that.
Try to do it yourself, start with simple QML - C++ calls, then implement graph structure in QML (for example add to your node objects references to neighbors).
Then you can expose these elements to C++, or you can serialize them and send to C++.
After calculating shortest path you can return it as a list of identifiers for example.

Be creative, every complex task is just a number of simple tasks, don't be afraid to write some code!

[Ichi]

Hi yesterday i start code and i do this but i dont know what with walls i dont know how to go back i somebody will look my code and help me i will happy
Code: A-StarTest01.zip

[Ichi]

ok i make it otherwise :

pathFind = false;
    openList.clear();
    QQuickItem *currentItem = start;
    QList<QQuickItem*> path;
    openList.append(start);
    while(!openList.isEmpty())
    {
        findNeighbors(currentItem);
 
        QQuickItem *minimal = openList.first();
        foreach (QQuickItem *item, openList)
        {
            int minF = getF(currentItem, minimal);
            int itemF = getF(currentItem, item);
            if(itemF < minF)
            {
            minimal = item;
 
            }
        }
        openList.removeOne(start);
        closedList.append(currentItem);
        currentItem = minimal;
        path.append(currentItem);
        if(currentItem == finish)
        {
            pathFind = true;
            drawPath(path);
        }
    }
    qDebug() << (pathFind ? "path finded" : "no path");
 
}

pathFind = false;
    openList.clear();
    QQuickItem *currentItem = start;
    QList<QQuickItem*> path;
    openList.append(start);
    while(!openList.isEmpty())
    {
        findNeighbors(currentItem);

        QQuickItem *minimal = openList.first();
        foreach (QQuickItem *item, openList)
        {
            int minF = getF(currentItem, minimal);
            int itemF = getF(currentItem, item);
            if(itemF < minF)
            {
            minimal = item;

            }
        }
        openList.removeOne(start);
        closedList.append(currentItem);
        currentItem = minimal;
        path.append(currentItem);
        if(currentItem == finish)
        {
            pathFind = true;
            drawPath(path);
        }
    }
    qDebug() << (pathFind ? "path finded" : "no path");

}

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but this algorthm dont know how go back