Android Question [Solved] How can I optimise the code in sub AddReachable

[Mark Read]

This is part of my code. I pass the x & y coordinates of a screen pixel to the sub and need to calculate parameters for the surrounding 8 pixels. This code works but as I need to call the sub a few thousand times, I think it could be written easier. A loop would be good to make the code easier to read but would it be quicker?
Many thanks.

Sub Globals
    'These global variables will be redeclared each time the activity is created.
    'These variables can only be accessed from this module.
    

    Type PathType(X As Int, Y As Int, Value1 As Int, Value2 As Int, Value3 As Int, ParentX As Int, ParentY As Int)       
    Dim CurrentCoordinate As PathType        'Store coords + f,g,h, parentx, parenty values
    Dim OpenList, ClosedList As List        '2 lists for pathfinding, sort with OpenList.SortType("Value3", true)
    Dim PixelInterval As Int=4                'Distance between two point on path           

End Sub

Sub Activity_Create(FirstTime As Boolean)
    'Do not forget to load the layout file created with the visual designer. For example:
    'Activity.LoadLayout("Layout1")
 
    BeginPathfinder   
End Sub

Sub BeginPathfinder
    'Here we start pathfinding
    'Define starting point and add start to open list
    CurrentCoordinate.X=x1
    CurrentCoordinate.Y=y1
    CurrentCoordinate.Value1=0
    CurrentCoordinate.Value2=0
    CurrentCoordinate.Value3=0
    CurrentCoordinate.ParentX=x1
    CurrentCoordinate.ParentY=y2
    OpenList.Add(CurrentCoordinate)
   
    'Add the neighbours
    AddReachable(x1,y1)
   
    Dim CurrentCoordinate As PathType    'Reset
    CurrentCoordinate=OpenList.Get(0)
    ClosedList.Add(CurrentCoordinate)    'Add lowest F score to closed list
    OpenList.RemoveAt(0)                'Remove it from open list
   
    cvs.DrawCircle(CurrentCoordinate.X,CurrentCoordinate.Y,2,Colors.blue,False,2)    'draw point
    iv.Invalidate

End Sub

Sub AddReachable(x As Int, y As Int)
    'F=Value1, G=Value2, H=Value3
    'G is path to point from start. Horizontal and vertical border points are 10, diagonals are 14
    'H is the Manhattan distance to the finish point (x2,y2)
    'F=G+H

    'Add the 8 surrounding points to the open list
    Dim CurrentCoordinate As PathType        'Need to redim to clear the old values!
    'Up
    CurrentCoordinate.X=x
    CurrentCoordinate.Y=y-PixelInterval
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=10
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Up and right
    CurrentCoordinate.X=x+PixelInterval
    CurrentCoordinate.Y=y-PixelInterval
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=14
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Right
    CurrentCoordinate.X=x+PixelInterval
    CurrentCoordinate.Y=y
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=10
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Right and down
    CurrentCoordinate.X=x+PixelInterval
    CurrentCoordinate.Y=y+PixelInterval
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=14
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Down
    CurrentCoordinate.X=x
    CurrentCoordinate.Y=y+PixelInterval
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=10
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Down and left
    CurrentCoordinate.X=x-PixelInterval
    CurrentCoordinate.Y=y+PixelInterval
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=14
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Left
    CurrentCoordinate.X=x-PixelInterval
    CurrentCoordinate.Y=y
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=10
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    Dim CurrentCoordinate As PathType
    'Up and left
    CurrentCoordinate.X=x-PixelInterval
    CurrentCoordinate.Y=y-PixelInterval
    CurrentCoordinate.Value3=(Abs(x2-x)+Abs(y2-y))*10
    CurrentCoordinate.Value2=14
    CurrentCoordinate.Value1=CurrentCoordinate.Value2+CurrentCoordinate.Value3
    CurrentCoordinate.ParentX=x
    CurrentCoordinate.ParentY=y
    OpenList.Add(CurrentCoordinate)
   
    OpenList.SortType("Value1",True)        'Sort list according to F, smallest first.
   
End Sub