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Thread: [Vb.Net] Pathfinder

  1. #1

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    Super Moderator dday9's Avatar
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    [Vb.Net] Pathfinder

    There has been a major update. See post #4.

    I've been very interested in path finding for a while now and decided to make one myself.

    Features:
    • A panel that draws up a grid. The grid is determined by the NodeHeightCount, NodeWidthCount, and NodeSize.
    • Fills up the nodes by calling the FillPath method
    • Clears the path by calling the ClearPath method


    Drawbacks:
    • A very slow and brutal approach
    • Doesn't allow for "Blocked" nodes


    Plans:
    I plan on studying some other methods of path finding such as the famous A* algorithm and adjusting my code accordingly.

    Notes:
    The way that the program works is it first checks if the current node we are on is the end, if it is, then exit out. Next it checks if we can move up/down or left/right based on where the end node is in relation to the current node. If so, then move accordingly.

    Image:
    Name:  path finder.png
Views: 233
Size:  14.4 KB

    Code:
    Code:
    Public Class Grid
        Inherits Windows.Forms.Panel
    
    #Region "Node Properties"
    
        Private beginning_node As Point = New Point(0, 0)
        Public Property BeginningNode() As Point
            Get
                Return beginning_node
            End Get
            Set(ByVal value As Point)
                If value.X > nodes_left - 1 Then
                    value.X = nodes_left - 1
                    value.Y = value.Y
                ElseIf value.X < 0 Then
                    value.X = 0
                    value.Y = value.Y
                End If
                If value.Y > nodes_height - 1 Then
                    value.Y = nodes_height - 1
                ElseIf value.Y < 0 Then
                    value.Y = 0
                End If
    
                beginning_node = value : Me.Invalidate()
            End Set
        End Property
    
        Private end_node As Point = New Point(1, 1)
        Public Property EndNode() As Point
            Get
                Return end_node
            End Get
            Set(ByVal value As Point)
                If value.X > nodes_left - 1 Then
                    value.X = nodes_left - 1
                    value.Y = value.Y
                ElseIf value.X < 0 Then
                    value.X = 0
                    value.Y = value.Y
                End If
                If value.Y > nodes_height - 1 Then
                    value.Y = nodes_height - 1
                ElseIf value.Y < 0 Then
                    value.Y = 0
                End If
    
                If value = beginning_node Then value = New Point(1, 1)
                end_node = value : Me.Invalidate()
            End Set
        End Property
    
        Private _nodes As New List(Of Point)
        Public ReadOnly Property Nodes() As List(Of Point)
            Get
                Return _nodes
            End Get
        End Property
    
        Private node_default_color As Color = Me.BackColor
        <System.ComponentModel.Description("Node")> Public Property NodeDefaultColor() As Color
            Get
                Return node_default_color
            End Get
            Set(ByVal value As Color)
                node_default_color = value : Me.Invalidate()
            End Set
        End Property
    
        Private nodes_height As Integer = 12
        <System.ComponentModel.Description("Node")> Public Property NodeHeightCount() As Integer
            Get
                Return nodes_height
            End Get
            Set(ByVal value As Integer)
                If value < 1 Then value = 1
                nodes_height = value : Me.Invalidate()
            End Set
        End Property
    
        Private node_selected_color As Color = Me.BackColor
        <System.ComponentModel.Description("Node")> Public Property NodeSelectedColor() As Color
            Get
                Return node_selected_color
            End Get
            Set(ByVal value As Color)
                node_selected_color = value : Me.Invalidate()
            End Set
        End Property
    
        Private node_size As Size = New Size(25, 25)
        <System.ComponentModel.Description("Node")> Public Property NodeSize() As Size
            Get
                Return node_size
            End Get
            Set(ByVal value As Size)
                node_size = value : Me.Invalidate()
            End Set
        End Property
    
        Private nodes_left As Integer = 12
        <System.ComponentModel.Description("Node")> Public Property NodeWidthCount() As Integer
            Get
                Return nodes_left
            End Get
            Set(ByVal value As Integer)
                If value < 1 Then value = 1
                nodes_left = value : Me.Invalidate()
            End Set
        End Property
    
    #End Region
    
    #Region "Methods"
    
        Public Sub FindPath()
            'Clear existing points
            Call ClearPath()
    
            'Get a start node
            Dim start_node As Point = beginning_node
    
            'Get if the path is to the left or to the rigth
            Dim horizontal_movement As Direction
            'Get if the path is to the up or to the down
            Dim vertical_movement As Direction
    
            If beginning_node.X < end_node.X Then
                horizontal_movement = Direction.Right
            ElseIf beginning_node.X > end_node.X Then
                horizontal_movement = Direction.Left
            Else
                horizontal_movement = Direction.None
            End If
    
            If beginning_node.Y < end_node.Y Then
                vertical_movement = Direction.Down
            ElseIf beginning_node.Y > end_node.Y Then
                vertical_movement = Direction.Up
            Else
                vertical_movement = Direction.None
            End If
    
            'If vertical movement or horizontal movement is nothing then we either move only up or only down
            If horizontal_movement = Direction.None Then
                Dim _step As Integer = 1
                If vertical_movement = Direction.Up Then
                    _step = -_step
                End If
    
                For i As Integer = beginning_node.Y To end_node.Y Step _step
                    _nodes.Add(New Point(beginning_node.X, i))
                Next
            ElseIf vertical_movement = Direction.None Then
                Dim _step As Integer = 1
                If horizontal_movement = Direction.Left Then
                    _step = -_step
                End If
    
                For i As Integer = beginning_node.X To end_node.X Step _step
                    _nodes.Add(New Point(i, beginning_node.Y))
                Next
            Else
                Dim temp_nodes As New List(Of Point)
                temp_nodes.Add(New Point(beginning_node.X, beginning_node.Y))
    
                Do Until horizontal_movement = Direction.None AndAlso vertical_movement = Direction.None
                    Dim current_node As Point = temp_nodes.Item(temp_nodes.Count - 1)
    
                    If current_node = end_node Then
                        horizontal_movement = Direction.None
                        vertical_movement = Direction.None
                    Else
                        If current_node.X < end_node.X Then
                            horizontal_movement = Direction.Right
                        ElseIf current_node.X > end_node.X Then
                            horizontal_movement = Direction.Left
                        Else
                            horizontal_movement = Direction.None
                        End If
    
                        If current_node.Y < end_node.Y Then
                            vertical_movement = Direction.Down
                        ElseIf current_node.Y > end_node.Y Then
                            vertical_movement = Direction.Up
                        Else
                            vertical_movement = Direction.None
                        End If
    
                    End If
    
                    If horizontal_movement = Direction.Right Then
                        current_node = New Point(current_node.X + 1, current_node.Y)
                    ElseIf horizontal_movement = Direction.Left Then
                        current_node = New Point(current_node.X - 1, current_node.Y)
                    End If
    
                    If vertical_movement = Direction.Down Then
                        current_node = New Point(current_node.X, current_node.Y + 1)
                    ElseIf vertical_movement = Direction.Up Then
                        current_node = New Point(current_node.X, current_node.Y - 1)
                    End If
    
                    temp_nodes.Add(New Point(current_node.X, current_node.Y))
    
                Loop
    
                _nodes = temp_nodes
    
            End If
    
            Me.Invalidate()
        End Sub
    
        Public Sub ClearPath()
            _nodes.Clear()
            Me.Invalidate()
        End Sub
    
    #End Region
    
        Protected Overrides Sub OnPaint(e As System.Windows.Forms.PaintEventArgs)
            MyBase.OnPaint(e)
    
            For x As Integer = 0 To nodes_left - 1
                For y As Integer = 0 To nodes_height - 1
                    Dim pt As New Point(x, y)
                    If pt = beginning_node OrElse _
                        pt = end_node OrElse _
                        _nodes.Contains(pt) Then
    
                        e.Graphics.FillRectangle(New SolidBrush(node_selected_color), New Rectangle(New Point(pt.X * node_size.Width, pt.Y * node_size.Height), node_size))
                    Else
                        e.Graphics.FillRectangle(New SolidBrush(node_default_color), New Rectangle(New Point(pt.X * node_size.Width, pt.Y * node_size.Height), node_size))
                    End If
                    e.Graphics.DrawRectangle(Pens.Black, New Rectangle(New Point(pt.X * node_size.Width, pt.Y * node_size.Height), node_size))
                Next
            Next
    
            For Each node As Point In _nodes
                e.Graphics.FillRectangle(New SolidBrush(node_selected_color), New Rectangle(New Point(node.X * node_size.Width, node.Y * node_size.Height), node_size))
                e.Graphics.DrawRectangle(Pens.Black, New Rectangle(New Point(node.X * node_size.Width, node.Y * node_size.Height), node_size))
            Next
        End Sub
    
        Private Enum Direction
            Up
            Down
            Left
            Right
            None
        End Enum
    
    End Class

  2. #2
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    Re: [Vb.Net] Pathfinder

    So this would be used for say a game sprite finding a path to food on the other side right? interesting, i always wonder how things like this are done.
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  3. #3

    Thread Starter
    Super Moderator dday9's Avatar
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    Re: [Vb.Net] Pathfinder

    This is really a brute force method and doesn't allow for blocked nodes, but it's a start. I want to learn the A*(pronounced "A Star") algorithm which is the foundation of path finding in game programming.

  4. #4

    Thread Starter
    Super Moderator dday9's Avatar
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    Re: [Vb.Net] Pathfinder

    UPDATE!

    Here is a major update in the Path Finding. I've created my version of the Dijkstra Algorithm in Vb.Net.

    Features
    1. A control that draws up a grid.
    2. There are a start and end node. I reference those as Cap Nodes.
    3. You can also add blocked nodes where the path may not pass through.
    4. Fills up the nodes by calling the GetPath method
    5. Clears the path by calling the ClearPath method


    Drawbacks:
    Dijkstra's algorithm fails if there is a negative edge weight. In the hypothetical situation where Nodes A, B, and C form a connected undirected graph with edges AB = 3, AC = 4, and BC = −2, the optimal path from A to C costs 1, and the optimal path from A to B costs 2. Dijkstra's Algorithm starting from A will first examine B, as that is the closest. It will assign a cost of 3 to it, and mark it closed, meaning that its cost will never be reevaluated. Therefore, Dijkstra's cannot evaluate negative edge weights. However, since for many practical purposes there will never be a negative edgeweight, Dijkstra's algorithm is largely suitable for the purpose of pathfinding. Found here.

    Code:
    Code:
    Public Class Dijkstra
        Inherits System.Windows.Forms.Control
    
    #Region "Properties"
    
        Private bColor As Color
        <System.ComponentModel.Description("Gets/Sets the fill color of nodes that are impassable.")> _
        Public Property BlockedColor() As Color
            Get
                Return bColor
            End Get
            Set(ByVal value As Color)
                bColor = value : Me.Invalidate()
            End Set
        End Property
    
        Private bNodes As List(Of Rectangle)
        <System.ComponentModel.Description("Gets/Sets the collection of nodes that are impassable.")> _
        Public Property BlockedNodes() As List(Of Rectangle)
            Get
                Return bNodes
            End Get
            Set(ByVal value As List(Of Rectangle))
                bNodes = value : Me.Invalidate()
            End Set
        End Property
    
        Private cColor As Color
        <System.ComponentModel.Description("Gets/Sets the fill color of the beginning and end nodes.")> _
        Public Property CapColor() As Color
            Get
                Return cColor
            End Get
            Set(ByVal value As Color)
                cColor = value : Me.Invalidate()
            End Set
        End Property
    
        Private eNode As Rectangle
        <System.ComponentModel.Description("Gets/Sets the node at the end of the path.")> _
        Public Property EndNode() As Rectangle
            Get
                Return eNode
            End Get
            Set(ByVal value As Rectangle)
                eNode = value : Me.Invalidate()
            End Set
        End Property
    
        Private n As List(Of Rectangle)
        <System.ComponentModel.Description("Gets all the nodes in the grid.")> _
        Public ReadOnly Property Nodes() As List(Of Rectangle)
            Get
                Return n
            End Get
        End Property
    
        Private nSize As Size
        <System.ComponentModel.Description("Gets/Sets the size of the nodes in the grid.")> _
        Public Property NodeSize() As Size
            Get
                Return nSize
            End Get
            Set(ByVal value As Size)
                nSize = value : Me.Invalidate()
            End Set
        End Property
    
        Private pColor As Color
        <System.ComponentModel.Description("Gets the color of the collection of nodes that make up the path.")> _
        Public Property PathColor() As Color
            Get
                Return pColor
            End Get
            Set(ByVal value As Color)
                pColor = value : Me.Invalidate()
            End Set
        End Property
    
        Private pNodes As List(Of Rectangle)
        <System.ComponentModel.Description("Gets the collection of nodes that make up the path using Dijkstra Algorithm.")> _
        Public ReadOnly Property PathNodes() As List(Of Rectangle)
            Get
                Return pNodes
            End Get
        End Property
    
        Private sNode As Rectangle
        <System.ComponentModel.Description("Gets/Sets the node at the beginning of the path.")> _
        Public Property StartNode() As Rectangle
            Get
                Return sNode
            End Get
            Set(ByVal value As Rectangle)
                sNode = value : Me.Invalidate()
            End Set
        End Property
    
    #End Region
    
    #Region "Methods"
    
        Private Function CalculateHScore(ByVal node As Rectangle) As Integer
            'Manhattan method
            Dim h As Integer = (Me.EndNode.X - node.X) \ 25 + (Me.EndNode.Y - node.Y) \ 25
            If h < 0 Then
                h = -h
            End If
            Return h
        End Function
    
        <System.ComponentModel.Description("Clears the PathNodes property.")> _
        Public Sub ClearPath()
            If pNodes IsNot Nothing Then
                pNodes.Clear()
                Me.Invalidate()
            End If
        End Sub
    
        <System.ComponentModel.Description("Gets the nodes that make up the PathNodes property and draws the nodes too.")> _
        Public Sub GetPath()
            pNodes = New List(Of Rectangle)
    
            'The algorithm begins with a start node and an open set of candidate nodes
            Dim openSet As List(Of List(Of Rectangle)) = New List(Of List(Of Rectangle))
    
            'Add a new list with just the start node
            openSet.AddRange(NewNodeList(Nothing))
    
            'Loop until the path is populated or there are no other paths available
            Do
                Dim possibleWinners As List(Of List(Of Rectangle)) = New List(Of List(Of Rectangle))
                For i As Integer = openSet.Count - 1 To 0 Step -1
                    If HitBlocked(openSet.Item(i).Last) OrElse HitWall(openSet.Item(i).Last) Then
                        openSet.RemoveAt(i)
                    ElseIf HitEnd(openSet.Item(i).Last) Then
                        possibleWinners.Add(openSet.Item(i))
                    Else
                        openSet.AddRange(NewNodeList(openSet.Item(i)))
                        openSet.RemoveAt(i)
                    End If
    
                    If possibleWinners.Count > 0 Then
                        Dim winner As List(Of Rectangle) = Nothing
                        For Each win As List(Of Rectangle) In possibleWinners
                            If winner IsNot Nothing Then
                                If win.Count < winner.Count Then
                                    winner = win
                                End If
                            Else
                                winner = win
                            End If
                        Next
    
                        pNodes = winner
                    End If
                Next
            Loop Until pNodes.Count > 0 OrElse openSet.Count = 0
    
            Me.Invalidate()
        End Sub
    
        Private Function HitBlocked(ByVal node As Rectangle) As Boolean
            Return bNodes.Contains(node)
        End Function
    
        Private Function HitWall(ByVal node As Rectangle) As Boolean
            If node.Left < 0 Then
                Return True
            ElseIf node.Right > Me.Width Then
                Return True
            ElseIf node.Top < 0 Then
                Return True
            ElseIf node.Bottom > Me.Height Then
                Return True
            Else
                Return False
            End If
        End Function
    
        Private Function HitEnd(ByVal node As Rectangle) As Boolean
            Return node = eNode
        End Function
    
        Private Function NewNodeList(ByVal priorList As List(Of Rectangle)) As List(Of Rectangle)()
            Dim foo As List(Of List(Of Rectangle)) = New List(Of List(Of Rectangle))
    
            If priorList IsNot Nothing Then
                Dim lastRect As Rectangle = priorList.Last
                'Get the surrounding nodes.
                'UL = Upper Left
                'UT = Upper Top
                'UR = Upper Right
                'ML = Middle Left
                'MR = Middle Right
                'LL = Lower Left
                'LB = Lower Bottom
                'LR = Lower Right
                Dim ulRect As Rectangle = New Rectangle(lastRect.X - nSize.Width, lastRect.Y - nSize.Height, nSize.Width, nSize.Height)
                Dim utRect As Rectangle = New Rectangle(lastRect.X, lastRect.Y - nSize.Height, nSize.Width, nSize.Height)
                Dim urRect As Rectangle = New Rectangle(lastRect.X + nSize.Width, lastRect.Y - nSize.Height, nSize.Width, nSize.Height)
                Dim mlRect As Rectangle = New Rectangle(lastRect.X - nSize.Width, lastRect.Y, nSize.Width, nSize.Height)
                Dim mrRect As Rectangle = New Rectangle(lastRect.X + nSize.Width, lastRect.Y, nSize.Width, nSize.Height)
                Dim llRect As Rectangle = New Rectangle(lastRect.X - nSize.Width, lastRect.Y + nSize.Height, nSize.Width, nSize.Height)
                Dim lbRect As Rectangle = New Rectangle(lastRect.X, lastRect.Y + nSize.Height, nSize.Width, nSize.Height)
                Dim lrRect As Rectangle = New Rectangle(lastRect.X + nSize.Width, lastRect.Y + nSize.Height, nSize.Width, nSize.Height)
    
    
                If priorList.Contains(ulRect) = False AndAlso HitBlocked(ulRect) = False AndAlso HitWall(ulRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(ulRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(ulRect)
                    foo.Add(n)
                End If
                If priorList.Contains(utRect) = False AndAlso HitBlocked(utRect) = False AndAlso HitWall(utRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(utRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(utRect)
                    foo.Add(n)
                End If
                If priorList.Contains(urRect) = False AndAlso HitBlocked(urRect) = False AndAlso HitWall(urRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(urRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(urRect)
                    foo.Add(n)
                End If
                If priorList.Contains(mlRect) = False AndAlso HitBlocked(mlRect) = False AndAlso HitWall(mlRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(mlRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(mlRect)
                    foo.Add(n)
                End If
                If priorList.Contains(mrRect) = False AndAlso HitBlocked(mrRect) = False AndAlso HitWall(mrRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(mrRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(mrRect)
                    foo.Add(n)
                End If
                If priorList.Contains(llRect) = False AndAlso HitBlocked(llRect) = False AndAlso HitWall(llRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(llRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(llRect)
                    foo.Add(n)
                End If
                If priorList.Contains(lbRect) = False AndAlso HitBlocked(lbRect) = False AndAlso HitWall(lbRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(lbRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(lbRect)
                    foo.Add(n)
                End If
                If priorList.Contains(lrRect) = False AndAlso HitBlocked(lrRect) = False AndAlso HitWall(lrRect) = False AndAlso Me.CalculateHScore(lastRect) > Me.CalculateHScore(lrRect) Then
                    Dim n As List(Of Rectangle) = New List(Of Rectangle)
                    n.AddRange(priorList)
                    n.Add(lrRect)
                    foo.Add(n)
                End If
            Else
                Dim n As List(Of Rectangle) = New List(Of Rectangle)
                n.Add(sNode)
                foo.Add(n)
            End If
    
            Return foo.ToArray
        End Function
    
    #End Region
    
    #Region "Events"
    
        Protected Overrides Sub OnPaint(ByVal e As System.Windows.Forms.PaintEventArgs)
            MyBase.OnPaint(e)
    
            Using rBrush As SolidBrush = New SolidBrush(bColor)
                Using gBrush As SolidBrush = New SolidBrush(pColor)
                    Using cBrush As SolidBrush = New SolidBrush(cColor)
                        Using bPen As Pen = New Pen(Color.Black, 1)
                            For Each r As Rectangle In n
                                If bNodes.Contains(r) Then
                                    e.Graphics.FillRectangle(rBrush, r)
                                ElseIf pNodes IsNot Nothing AndAlso pNodes.Contains(r) AndAlso r <> sNode AndAlso r <> eNode Then
                                    e.Graphics.FillRectangle(gBrush, r)
                                ElseIf r = sNode OrElse r = eNode Then
                                    e.Graphics.FillRectangle(cBrush, r)
                                End If
                                e.Graphics.DrawRectangle(bPen, r)
                            Next
                        End Using
                    End Using
                End Using
            End Using
    
        End Sub
    
        Private Sub Dijkstra_SizeChanged(ByVal sender As Object, ByVal e As System.EventArgs) Handles Me.SizeChanged
            n.Clear()
            For x As Integer = 0 To Me.Width - nSize.Width Step nSize.Width
                For y As Integer = 0 To Me.Height - nSize.Height Step nSize.Height
                    n.Add(New Rectangle(New Point(x, y), nSize))
                Next
            Next
        End Sub
    
    #End Region
    
    #Region "New Constructors"
    
        Public Sub New()
            bColor = Color.Red
            bNodes = New List(Of Rectangle)
            cColor = Color.Blue
            nSize = New Size(25, 25)
            eNode = New Rectangle(0, 0, nSize.Width, nSize.Height)
            pColor = Color.Green
            sNode = New Rectangle(0, 0, nSize.Width, nSize.Height)
            n = New List(Of Rectangle)
        End Sub
    
    #End Region
    
    End Class
    Image:
    Name:  Dijkstra.png
Views: 74
Size:  16.0 KB

  5. #5

    Thread Starter
    Super Moderator dday9's Avatar
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    Mar 2011
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    South Louisiana
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    Re: [Vb.Net] Pathfinder

    Here is the code I used in my Form in the image above for the Dijkstra algorithm(to much for the last post):
    Code:
    Option Strict On
    Option Explicit On
    Public Class Form1
    
        Private selectingBlocked As Boolean
        Private selectingEnd As Boolean
        Private selectingStart As Boolean
    
        Private Sub btnStart_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnStart.Click
            selectingBlocked = False
            selectingEnd = False
            selectingStart = True
            Dijkstra1.Cursor = Cursors.Cross
        End Sub
    
        Private Sub btnEnd_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnEnd.Click
            selectingBlocked = False
            selectingEnd = True
            selectingStart = False
            Dijkstra1.Cursor = Cursors.Cross
        End Sub
    
        Private Sub btnBlocked_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnBlocked.Click
            selectingBlocked = True
            selectingEnd = False
            selectingStart = False
            Dijkstra1.Cursor = Cursors.Cross
        End Sub
    
        Private Sub btnClear_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnClear.Click
            Dijkstra1.ClearPath()
        End Sub
    
        Private Sub btnFind_Click(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles btnFind.Click
            Dijkstra1.GetPath()
        End Sub
    
        Private Sub Dijkstra1_MouseClick(ByVal sender As System.Object, ByVal e As System.Windows.Forms.MouseEventArgs) Handles Dijkstra1.MouseClick
            Dim x As Integer = e.Location.X
            Dim y As Integer = e.Location.Y
    
            Dim selectedNode As Rectangle
    
            For Each r As Rectangle In Dijkstra1.Nodes
                If r.IntersectsWith(New Rectangle(x, y, 1, 1)) Then
                    selectedNode = r
                    Exit For
                End If
            Next
    
            If selectingEnd = True Then
                Dijkstra1.EndNode = selectedNode
            ElseIf selectingStart = True Then
                Dijkstra1.StartNode = selectedNode
            ElseIf selectingBlocked Then
                If Dijkstra1.BlockedNodes.Contains(selectedNode) = False Then
                    Dijkstra1.BlockedNodes.Add(selectedNode)
                    Dijkstra1.Invalidate()
                Else
                    Dijkstra1.BlockedNodes.Remove(selectedNode)
                    Dijkstra1.Invalidate()
                End If
            End If
        End Sub
    
        Private Sub Form1_Load(ByVal sender As System.Object, ByVal e As System.EventArgs) Handles MyBase.Load
            selectingBlocked = False
            selectingEnd = False
            selectingStart = False
            selectingBlocked = False
        End Sub
    
    End Class

  6. #6
    WiggleWiggle dclamp's Avatar
    Join Date
    Aug 2006
    Posts
    3,279

    Re: [Vb.Net] Pathfinder

    *Choose*

  7. #7

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