Nsryjdtyk

I want to write my snake game procedurally, using as much windows call as I can so as to practice. Looking into GetAsyncKeyState to capture keyboard inputs and play sound functions. Also making a sweet user interface. Fun!

Also shout to bytecomb for providing example as to how to traverse the array structure, used his code function to find ptr to element in array!!

API CALLS

Option Explicit



Private Declare PtrSafe Function VarPtrArray Lib "VBE7" Alias "VarPtr" _

        (ByRef Var() As Any) As LongPtr



Private Declare PtrSafe Sub CopyMemoryI Lib "kernel32.dll" Alias "RtlMoveMemory" _

        (ByVal dst As LongPtr, ByVal src As LongPtr, ByVal Length As Long)



Private Declare PtrSafe Sub CopyMemoryII Lib "kernel32.dll" Alias "RtlMoveMemory" _

        (ByRef dst As SAFEARRAY, ByVal src As LongPtr, ByVal Length As Long)



Private Declare PtrSafe Function GetAsyncKeyState Lib "user32" _

        (ByVal vKey As Long) As Boolean

DATA STRUCTS

Private Type SAFEARRAY_BOUND

    cElements    As Long

    lLbound      As Long

End Type



Private Type SAFEARRAY

    cDims        As Integer

    fFeatures    As Integer

    cbElements   As Long

    cLocks       As Long

    pvData       As LongPtr

    rgsabound(0) As SAFEARRAY_BOUND

End Type



Private Type SnakePart

    Column       As Long

    Row          As Long

End Type



Private Const SNAKEPART_BYTELENGTH = 8

FUNCTIONS

Private Function ArrayPush(ByRef ArrayOriginal() As SnakePart, ByRef ElementToAdd As SnakePart) As SnakePart()

Dim NewLength      As Long

Dim CopiedBytes    As Long

Dim NewBytes       As Long



    NewLength = UBound(ArrayOriginal) + 1

    ReDim ArrayPush(NewLength)



    CopiedBytes = NewLength * SNAKEPART_BYTELENGTH

    NewBytes = SNAKEPART_BYTELENGTH



    CopyMemoryI ArrayElementGetPointer(ArrayPush, 0, SNAKEPART_BYTELENGTH), ArrayElementGetPointer(ArrayOriginal, 0, SNAKEPART_BYTELENGTH), CopiedBytes

    CopyMemoryI ArrayElementGetPointer(ArrayPush, NewLength, SNAKEPART_BYTELENGTH), VarPtr(ElementToAdd), NewBytes

End Function



Private Function ArrayPop(ByRef ArrayOriginal() As SnakePart) As SnakePart()

Dim NewLength      As Long

Dim CopiedBytes    As Long



    NewLength = UBound(ArrayOriginal) - 1

    ReDim ArrayPop(NewLength)



    CopiedBytes = UBound(ArrayOriginal) * SNAKEPART_BYTELENGTH



    CopyMemoryI ArrayElementGetPointer(ArrayPop, 0, SNAKEPART_BYTELENGTH), ArrayElementGetPointer(ArrayOriginal(), 0, SNAKEPART_BYTELENGTH), CopiedBytes

End Function



Private Function ArrayShift(ByRef ArrayOriginal() As SnakePart, ByRef ElementToAdd As SnakePart) As SnakePart()

Dim NewLength      As Long

Dim CopiedBytes    As Long

Dim NewBytes       As Long



    NewLength = UBound(ArrayOriginal) + 1

    ReDim ArrayShift(NewLength)



    CopiedBytes = NewLength * SNAKEPART_BYTELENGTH

    NewBytes = SNAKEPART_BYTELENGTH



    CopyMemoryI ArrayElementGetPointer(ArrayShift, 1, SNAKEPART_BYTELENGTH), ArrayElementGetPointer(ArrayOriginal, 0, SNAKEPART_BYTELENGTH), CopiedBytes

    CopyMemoryI ArrayElementGetPointer(ArrayShift, 0, SNAKEPART_BYTELENGTH), VarPtr(ElementToAdd), NewBytes

End Function



Private Function ArrayUnshift(ByRef ArrayOriginal() As SnakePart) As SnakePart()

Dim NewLength      As Long

Dim CopiedBytes    As Long



    NewLength = UBound(ArrayOriginal) - 1

    ReDim ArrayUnshift(NewLength)



    CopiedBytes = UBound(ArrayOriginal) * SNAKEPART_BYTELENGTH



    CopyMemoryI ArrayElementGetPointer(ArrayUnshift, 0, SNAKEPART_BYTELENGTH), ArrayElementGetPointer(ArrayOriginal, 1, SNAKEPART_BYTELENGTH), CopiedBytes

End Function



Private Function ArrayElementGetPointer(ByRef Arr() As SnakePart, ByVal ElementIndex As Long, ByVal ElementByteLength As Long) As LongPtr

Dim ptrToArrayVar  As LongPtr

Dim ptrToSafeArray As LongPtr

Dim ptrToArrayData As LongPtr

Dim ptrCursor      As LongPtr

Dim uSAFEARRAY     As SAFEARRAY



    ' Get Pointer To Array *Variable*

    ptrToArrayVar = VarPtrArray(Arr)

    ' Get Pointer To Array Variable *SAFEARRAY* By Directly Reading Array Variable

    CopyMemoryI VarPtr(ptrToSafeArray), ptrToArrayVar, 8

    ' Read The SAFEARRAY Structure

    CopyMemoryII uSAFEARRAY, ptrToSafeArray, LenB(uSAFEARRAY)

    ' Get Pointer To Array Data

    ptrToArrayData = uSAFEARRAY.pvData

    ' Get Pointer To Array Element

    ptrCursor = ptrToArrayData + (ElementIndex * ElementByteLength)

    ArrayElementGetPointer = ptrCursor

End Function

TESTS

Private Sub test()



    Dim x(3) As SnakePart

    Dim sp As SnakePart



    sp.Column = 1

    sp.Row = 1



    x(0) = sp

    x(1) = sp

    x(2) = sp

    x(3) = sp



    ' expect all 1s

    Debug.Print x(0).Column

    Debug.Print x(1).Column

    Debug.Print x(2).Column

    Debug.Print x(3).Column

    Debug.Print "_______________________"



    sp.Column = 2



    Dim temparry() As SnakePart

    temparry = x

    temparry = ArrayPush(temparry, sp)



    Debug.Print "expect 2 at end"

    Debug.Print temparry(0).Column

    Debug.Print temparry(1).Column

    Debug.Print temparry(2).Column

    Debug.Print temparry(3).Column

    Debug.Print temparry(4).Column

    Debug.Print "_______________________"



    temparry = ArrayPop(temparry)



    Debug.Print "expect all 1"

    Debug.Print temparry(0).Column

    Debug.Print temparry(1).Column

    Debug.Print temparry(2).Column

    Debug.Print temparry(3).Column

    Debug.Print "_______________________"



    temparry = ArrayShift(temparry, sp)



    Debug.Print "expect 2 at start"

    Debug.Print temparry(0).Column

    Debug.Print temparry(1).Column

    Debug.Print temparry(2).Column

    Debug.Print temparry(3).Column

    Debug.Print temparry(4).Column

    Debug.Print "_______________________"



    temparry = ArrayUnshift(temparry)



    Debug.Print "expect all 1"

    Debug.Print temparry(0).Column

    Debug.Print temparry(1).Column

    Debug.Print temparry(2).Column

    Debug.Print temparry(3).Column

End Sub