C#•10mo ago

✅ A* Algorithm Get Node where x and y is 1 less (Neigbour)

Any idea how to get the neighbours? ive tried to grab the neighbour pathnode item by subtracting 1 from x. Either im not doing it correctly or the list needs to be formatted better but all the ways i have tried are not seeming to work so help?.

c#
public class PathNode
{
    private double width;
    private double height;
    public double x;
    public double y;
    //private List<double> neighbours;
    private bool closed = false;
    private bool walkable = true;
    public PathNode(double width, double height, double x, double y)
    {
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
    }
    public bool barrierNode()
    {
        return walkable = false;
    }
    public void updateNeighbours(List<PathNode> panelNodes)
    {
        if (x < width - 1 /* Code Here to get the pathnode with x - 1 and y -1*/ )
        {

        }
    }
}

c#
public class PathNode
{
    private double width;
    private double height;
    public double x;
    public double y;
    //private List<double> neighbours;
    private bool closed = false;
    private bool walkable = true;
    public PathNode(double width, double height, double x, double y)
    {
        this.x = x;
        this.y = y;
        this.width = width;
        this.height = height;
    }
    public bool barrierNode()
    {
        return walkable = false;
    }
    public void updateNeighbours(List<PathNode> panelNodes)
    {
        if (x < width - 1 /* Code Here to get the pathnode with x - 1 and y -1*/ )
        {

        }
    }
}

72 Replies

Duath•10mo ago

hi, what does panelNodes argument hold and, whatever it is, is it ordered? not knowing pretty much anything, would "Dictionary" or anything "Hash.."ed be a better (easier) choice?

CamOP•10mo ago

panelNodes holds all the Nodes in the A* Grid. It’s a 1201x601 size Grid with each coordinate being 1 singular instance of the “PathNode” class Given the amount of classes due to the grid size…it’s definitely gonna be a class I don’t call until needed. #performancematters 😂

Duath•10mo ago

so without changing the data and without knowing the order of the nodes a very crude way would be var mx = this.x - 1; var my = this.y - 1; var x_neighbour = panelNodes.FirstOrDefault(n => n.x == mx); var y_neighbour = panelNodes.FirstOrDefault(n => n.y == my); but it will hurst perf hurt*

CamOP•10mo ago

Do you want me to show you the code creating the nodes?

Duath•10mo ago

simplest ways, either change the List<> or change the PathNode class adding pointers to neighours, basically implementing your own "true" list yes, paste it

CamOP•10mo ago

Okay 2 secs

Duath•10mo ago

but the code above will find what you need, or null it doesnt care about duplicates nor anything else basically 😛

CamOP•10mo ago

c#
public class PanelGrid
{
    public double width;
    public double height;
    public double[,] gridArray;
    private Canvas panelImport;
    public List<PathNode> panelNodes = new List<PathNode>();
    public PanelGrid(Canvas panelImport)
    {
        this.panelImport = panelImport;
        width = panelImport.Width;
        height = panelImport.Height;

        gridArray = new double[(int)width, (int)height];

        int i = 0;
        for (int x = 0; x < gridArray.GetLength(0); x++)
        {
            for (int y = 0; y < gridArray.GetLength(1); y++)
            {
                panelNodes.Add(new PathNode(width, height, x, y));
                i++;
            }
        }
    }
}

c#
public class PanelGrid
{
    public double width;
    public double height;
    public double[,] gridArray;
    private Canvas panelImport;
    public List<PathNode> panelNodes = new List<PathNode>();
    public PanelGrid(Canvas panelImport)
    {
        this.panelImport = panelImport;
        width = panelImport.Width;
        height = panelImport.Height;

        gridArray = new double[(int)width, (int)height];

        int i = 0;
        for (int x = 0; x < gridArray.GetLength(0); x++)
        {
            for (int y = 0; y < gridArray.GetLength(1); y++)
            {
                panelNodes.Add(new PathNode(width, height, x, y));
                i++;
            }
        }
    }
}

only use for "Canvas panelImport" is just to get the width and height for the grid also i++ was used for testing i just forgot to remove it 🤣

Duath•10mo ago

yeah that private field is not needed, but it's a very minor point 😛

CamOP•10mo ago

yea i was using it to edit stuff earlier.

c#
       public void updateNeighbours(List<PathNode> panelNodes)
       {
           var mx = x - 1;
           var my = y - 1;
           var panelNeighbour = panelNodes.FirstOrDefault(n => n.x == mx & n.y == my);
           //var yNeighbour = panelNodes.FirstOrDefault(n => n.y == my);
           if (x < width - 1 && !panelNeighbour.barrierNode())
           {

           }
       }

c#
       public void updateNeighbours(List<PathNode> panelNodes)
       {
           var mx = x - 1;
           var my = y - 1;
           var panelNeighbour = panelNodes.FirstOrDefault(n => n.x == mx & n.y == my);
           //var yNeighbour = panelNodes.FirstOrDefault(n => n.y == my);
           if (x < width - 1 && !panelNeighbour.barrierNode())
           {

           }
       }

all things considered. this should get the .barrierNode return value from that list item right? i combined it because i need to get a singular coord

Duath•10mo ago

wait a sec 🙂

CamOP•10mo ago

yes?

Duath•10mo ago

just gimme a sec xD

CamOP•10mo ago

haha your good dw xD

Duath•10mo ago

& is a bit operator, && is a boolean operato, but what you want there is a || iun that lambda

CamOP•10mo ago

facepalm rookie mistake. i didnt even click that i did that lol

Duath•10mo ago

something like that if you want to run once like above - panelNodes.Where(n=> n.x | x.y).ToList(); yyes those are my nemesis as well, misslicks, ctrl+c, ctrl+v.. even ctrl+s can ef you over 😛 but then Where can return null, one or two items.. where two is the expected one 🙂 but im thinking about the second solution i mentioned

CamOP•10mo ago

Duath•10mo ago

where PathNode holsd references to its neighbours*

CamOP•10mo ago

Oh yea so I have that in there already…it’s just commented out. “neighbours” But before you get all “why didn’t you tell me” 😂 I hadn’t created a search into that yet.

Duath•10mo ago

show me then 😛

CamOP•10mo ago

It’s literally just “private list neighbours” Obviously coded correctly

c#
//private List<double> neighbours;

c#
//private List<double> neighbours;

thats inside the "PathNode" class

Duath•10mo ago

how do you create such a list?

CamOP•10mo ago

reason why i havent implemented it is because i dont want to get all the grid members. just the ones surrounding it for better performance

Duath•10mo ago

or you dont? yet 😛

CamOP•10mo ago

yep havent yet

Duath•10mo ago

well it's just a reference, not a value object 😛

CamOP•10mo ago

no point in me piling the whole grid into 7 billion classes when i just want the 8 nodes that are surrounding the node

Duath•10mo ago

you wouldn't, but yes memory would rise, but..

CamOP•10mo ago

oh i know. dont worry i know i havent made it into a new list. i commented it out for that reason because i wasnt sure what i was gonna do with it

Duath•10mo ago

x and y is a tuple.. basically and it is unique, from what i rember about A* right> ?

CamOP•10mo ago

my x and y is in double[,] format but i can switch back to tuple cuz i did have it there earlier. yes the x and y are unique to each cord in the grid sorry x and y are both double type variables. they are not combined in an array by default

Duath•10mo ago

well you can always create your own "tuple" class, but now you dont have to well what dotnet version do yo use? 😉

CamOP•10mo ago

6.0 i believe it is

CamOP•10mo ago

Duath•10mo ago

because (double x, double y) node = (0.1, 0.2);

CamOP•10mo ago

7.0 actually

Duath•10mo ago

which is a new tuple supoprts == and != its a value type though

CamOP•10mo ago

not quite following you

Duath•10mo ago

so i dont know about a performance with dictionaries, but dictionaries 🙂 insdtead of a list

CamOP•10mo ago

what...so switch out my x and y type from double to dictionary? oh instrad of list

Duath•10mo ago

use Dictionary<"tuple", PathNode> ddict than you can find any node in a O(1) time 🙂 in an easy way

CamOP•10mo ago

c#
        public List<PathNode> panelNodes = new List<PathNode>();

c#
        public List<PathNode> panelNodes = new List<PathNode>();

you talking about switching this out?

Duath•10mo ago

yes exactly to a dictionarty with a key including both x and y 🙂 you can use tyuple or new tuples or wrote your won tupe class and overridfe hascode method

CamOP•10mo ago

c#
        public Dictionary<"tuple", PathNode> panelNodes = new Dictionary<"tuple", PathNode>;

c#
        public Dictionary<"tuple", PathNode> panelNodes = new Dictionary<"tuple", PathNode>;

either im stupid and not reading this properly or its just my never used dictionary class before....."tuple" is red underlined

Duath•10mo ago

where: "tuple" is class for axample publis class MyTuple { public int x; public int y; public MyTuple(int argX, int argY) { x = argX; y = argY;}}

CamOP•10mo ago

2 secs

Duath•10mo ago

and use it both as a composite field in the PathNode class

CamOP•10mo ago

c#
namespace Birds_Eye.Views.Resources.Functions
{
    public class PanelGrid
    {
        public double width;
        public double height;
        public double[,] gridArray;
        private Canvas panelImport;
        public Dictionary<panelTuple, PathNode> panelNodes = new Dictionary<panelTuple, PathNode>();
        public PanelGrid(Canvas panelImport)
        {
            this.panelImport = panelImport;
            width = panelImport.Width;
            height = panelImport.Height;

            gridArray = new double[(int)width, (int)height];

            for (int x = 0; x < gridArray.GetLength(0); x++)
            {
                for (int y = 0; y < gridArray.GetLength(1); y++)
                {
                    panelNodes.Add(new PathNode(width, height, x, y));
                }
            }
        }
    }
}

namespace Birds_Eye.Views.Resources.Functions
{
    public class panelTuple
    {
        public int x;
        public int y;
        public panelTuple(int x, int y)
        {
            this.x = x;
            this.y = y;
        }
    }
}

c#
namespace Birds_Eye.Views.Resources.Functions
{
    public class PanelGrid
    {
        public double width;
        public double height;
        public double[,] gridArray;
        private Canvas panelImport;
        public Dictionary<panelTuple, PathNode> panelNodes = new Dictionary<panelTuple, PathNode>();
        public PanelGrid(Canvas panelImport)
        {
            this.panelImport = panelImport;
            width = panelImport.Width;
            height = panelImport.Height;

            gridArray = new double[(int)width, (int)height];

            for (int x = 0; x < gridArray.GetLength(0); x++)
            {
                for (int y = 0; y < gridArray.GetLength(1); y++)
                {
                    panelNodes.Add(new PathNode(width, height, x, y));
                }
            }
        }
    }
}

namespace Birds_Eye.Views.Resources.Functions
{
    public class panelTuple
    {
        public int x;
        public int y;
        public panelTuple(int x, int y)
        {
            this.x = x;
            this.y = y;
        }
    }
}

i got you now.

Duath•10mo ago

do not forget to overridre hashcode method in that tuple class use this one 🙂 HashCode.Combine you can store it as a private field (the hashCode) but do not persist it, cause of problems 😛 Add method you ned to provide a key and a value check its header 🙂

CamOP•10mo ago

i need to do some reading on dictionaries and tuples...god damn. sorry can you show me the method lol i know its public override

Duath•10mo ago

wait a sec public class MyTuple { private int _hashCode; public MyTuple(...) { // your code _hashCode = HashCode.Combine<int, int>(x, y); } //somewhere down there public override GetHashCode() { return _hashCode; } } for (int y = 0; y < gridArray.GetLength(1); y++) { panelNodes.Add(new MyTuple(x, y), new PathNode(width, height, x, y)); } this part is in a Grid class 😛 then in : public void updateNeighbours(List<PathNode> panelNodes) { var mx = x - 1; var my = y - 1; MyTuple predicate = new(x-1, y-1); if (panelNodes.CintainsKey(predicate)) { // access it by panelNodes[predicate] } } do not store _hashCode anywhere outside of the memory 😛 public override INT GetHashCode() * 😛

CamOP•10mo ago

c#
MyTuple predicate = new(x-1, y-1);

c#
MyTuple predicate = new(x-1, y-1);

doesnt work nor when i change to

c#
MyTuple predicate = new MyTuple(x-1, y-1);

c#
MyTuple predicate = new MyTuple(x-1, y-1);

Duath•10mo ago

doesnt comple the not working part.. some details? 😛

CamOP•10mo ago

double needed to be casted to int lol

Duath•10mo ago

aaa my bnad

CamOP•10mo ago

c#
            panelTuple predicate = new panelTuple((int)x - 1,(int) y - 1);

c#
            panelTuple predicate = new panelTuple((int)x - 1,(int) y - 1);

Duath•10mo ago

change it to double of course wherever i use int

CamOP•10mo ago

got it tho

Duath•10mo ago

mybad 😛

CamOP•10mo ago

haha alg casting is annoying and easy to forget

Duath•10mo ago

no dont cast it it a waste of tie and memory 😛 in this case just use double as types bouth in mytupel and in dictionery's key where dicts key is ourt calss so you dont have to 😛 i should have done it

CamOP•10mo ago

oh right i can just change the tuple x type. im an egg

Duath•10mo ago

yes you have the power here 😛 you are the captain now 😄 HashCode.Combine<double, double> as well

CamOP•10mo ago

yep changed that

Duath•10mo ago

casting int to double looses data, so it would not work anyway

CamOP•10mo ago

c#
namespace Birds_Eye.Views.Resources.Functions
{ 
    public class PathNode
    {
        private double width;
        private double height;
        public double x;
        public double y;
        //private List<double> neighbours;
        private bool closed = false;
        private bool walkable = true;
        public PathNode(double width, double height, double x, double y)
        {
            this.x = x;
            this.y = y;
            this.width = width;
            this.height = height;
        }
        public double[,] getPosition()
        {
            return new double[(int)x, (int)y];
        }
        public bool isClosed()
        {
            return closed = true;
        }
        public bool isOpen()
        {
            return closed = false;
        }
        public void closeNode()
        {
            closed = true;
        }
        public void openNode()
        {
            closed = false;
        }
        public bool barrierNode()
        {
            return walkable = false;
        }
        public void updateNeighbours(Dictionary<panelTuple, PathNode> panelNodes)
        {
            var mx = x - 1;
            var my = y - 1;
            panelTuple predicate = new panelTuple(x - 1, y - 1);    
            if (panelNodes.ContainsKey(predicate))
            {
                if (x < width - 1 && panelNodes[predicate].barrierNode())
                {

                }
            }
        }
    }
}

namespace Birds_Eye.Views.Resources.Functions
{
    public class PanelGrid
    {
        private double width;
        private double height;
        private double[,] gridArray;
        public Dictionary<panelTuple, PathNode> panelNodes = new Dictionary<panelTuple, PathNode>();
        public PanelGrid(Canvas panelImport)
        {
            width = panelImport.Width;
            height = panelImport.Height;

            gridArray = new double[(int)width, (int)height];

            for (int x = 0; x < gridArray.GetLength(0); x++)
            {
                for (int y = 0; y < gridArray.GetLength(1); y++)
                {
                    panelNodes.Add(new panelTuple(x, y), new PathNode(width, height, x, y));
                }
            }
        }
    }
}

namespace Birds_Eye.Views.Resources.Functions
{
    public class panelTuple
    {
        public double x;
        public double y;
        private int _hashCode;
        public panelTuple(double x, double y)
        {
            this.x = x;
            this.y = y;
            _hashCode = HashCode.Combine(x, y);
        }
        public override int GetHashCode()
        {
            return _hashCode;
        }
    }
}

c#
namespace Birds_Eye.Views.Resources.Functions
{ 
    public class PathNode
    {
        private double width;
        private double height;
        public double x;
        public double y;
        //private List<double> neighbours;
        private bool closed = false;
        private bool walkable = true;
        public PathNode(double width, double height, double x, double y)
        {
            this.x = x;
            this.y = y;
            this.width = width;
            this.height = height;
        }
        public double[,] getPosition()
        {
            return new double[(int)x, (int)y];
        }
        public bool isClosed()
        {
            return closed = true;
        }
        public bool isOpen()
        {
            return closed = false;
        }
        public void closeNode()
        {
            closed = true;
        }
        public void openNode()
        {
            closed = false;
        }
        public bool barrierNode()
        {
            return walkable = false;
        }
        public void updateNeighbours(Dictionary<panelTuple, PathNode> panelNodes)
        {
            var mx = x - 1;
            var my = y - 1;
            panelTuple predicate = new panelTuple(x - 1, y - 1);    
            if (panelNodes.ContainsKey(predicate))
            {
                if (x < width - 1 && panelNodes[predicate].barrierNode())
                {

                }
            }
        }
    }
}

namespace Birds_Eye.Views.Resources.Functions
{
    public class PanelGrid
    {
        private double width;
        private double height;
        private double[,] gridArray;
        public Dictionary<panelTuple, PathNode> panelNodes = new Dictionary<panelTuple, PathNode>();
        public PanelGrid(Canvas panelImport)
        {
            width = panelImport.Width;
            height = panelImport.Height;

            gridArray = new double[(int)width, (int)height];

            for (int x = 0; x < gridArray.GetLength(0); x++)
            {
                for (int y = 0; y < gridArray.GetLength(1); y++)
                {
                    panelNodes.Add(new panelTuple(x, y), new PathNode(width, height, x, y));
                }
            }
        }
    }
}

namespace Birds_Eye.Views.Resources.Functions
{
    public class panelTuple
    {
        public double x;
        public double y;
        private int _hashCode;
        public panelTuple(double x, double y)
        {
            this.x = x;
            this.y = y;
            _hashCode = HashCode.Combine(x, y);
        }
        public override int GetHashCode()
        {
            return _hashCode;
        }
    }
}

Much better 🙂 couple bits of garbage now to clean up but now i have the neighbour and more importantly can access their return method functions 🙂

Duath•10mo ago

its actually quite fast as well no boxing issues i think 😛

CamOP•10mo ago

legendary man. i added you......in case i have more errors....... but thank you for that.

Duath•10mo ago

should do the job no prob

CamOP•10mo ago

ill let you know how it goes. Thanks bro 🙂

Duath•10mo ago

"return walkable = false;" will assign false to walkable and then return false always 😛

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✅ A* Algorithm Get Node where x and y is 1 less (Neigbour)