Array question

H

hog

Senior Contributor
Joined
Mar 17, 2003
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I know the content of this is DirectX but the problem I have is the mechanics of the usage of the array hence posting here:)


I don't follow how this code works and hope someone can explain.

Here goes;

Visual Basic: 
Public Function CreateTextures() As Boolean

        Dim Verts As CustomVertex()
        Dim intX As Integer

        Dim strTexturePath As String

        Try

            For intX = 1 To 10

                strTexturePath = Application.StartupPath & "\walk" & CStr(intX) & ".bmp"

                Textures(intX - 1) = TextureLoader.FromFile(m_objDevice, strTexturePath)

            Next

            VertBuffer = New VertexBuffer(GetType(CustomVertex), NUM_VERTS, m_objDevice, Usage.WriteOnly, FVF_CUSTOMVERTEX, Pool.Default)

            Verts = VertBuffer.Lock(0, 0)

            SquareVertices(Verts)

            VertBuffer.Unlock()

            Return True

        Catch objException As Exception

            Return False

        End Try

End Function

Private Function SquareVertices(ByVal Vertices As CUSTOMVERTEX())

        Vertices(0) = CreateFlexVertex(60, 60, 0, 1, 0, 0)
        Vertices(1) = CreateFlexVertex(240, 60, 0, 1, 1, 0)
        Vertices(2) = CreateFlexVertex(60, 240, 0, 1, 0, 1)
        Vertices(3) = CreateFlexVertex(240, 240, 0, 1, 1, 1)

End Function

  Private Function CreateFlexVertex(ByVal X As Single, ByVal Y As Single, ByVal Z As Single, ByVal rhw As Single, _
                                      ByVal tu As Single, ByVal tv As Single) As CUSTOMVERTEX

        CreateFlexVertex.X = X
        CreateFlexVertex.Y = Y
        CreateFlexVertex.Z = Z
        CreateFlexVertex.rhw = rhw
        CreateFlexVertex.tu = tu
        CreateFlexVertex.tv = tv

End Function

In the procedure CreateTextures() Verts is declared as CUSTOMVERTEX() which is a structure. So Verts is an array of structures?

This line, SquareVertices(Verts), passes Verts to the SquareVertices procedure ByVal again an array of structures?

In SquareVertices it assigns values to each array element.

But how come the redim staement is not required? I spent a lot of time trying to get this to work and by trial and error found if I removed the redim line it work??

Duh.....don't get it :(
 
the lines
Visual Basic: 
VertBuffer = New VertexBuffer(GetType(CustomVertex), NUM_VERTS, m_objDevice, Usage.WriteOnly, FVF_CUSTOMVERTEX, Pool.Default)
Verts = VertBuffer.Lock(0,

are creating the array at the correct size
 
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