Draw map on cellphone screen - GTA IV

Public Function getPhoneRenderID() As Integer
        Dim rPhone As New Native.Pointer(GetType(Integer))
        Native.Function.Call("GET_MOBILE_PHONE_RENDER_ID", rPhone)
        Dim ci As Integer = Integer.Parse(String.Concat(rPhone.Value))
        Return ci
    End Function


Dim txdLoad As Int32 = Native.Function.Call(Of Int32)("LOAD_TXD", "race_atob")
    Dim textureLoad As Int32 = Native.Function.Call(Of Int32)("GET_TEXTURE", txdLoad, "race_atob0")
    Dim tmpCenterPos As Vector3 = New Vector3(338, 546, 0)
    Dim tmpXMax As Int16 = 225
    Dim tmpYMax As Int16 = 402

    Dim zoomCoef As Double = 4.3

    Private Sub general_tick(ByVal sender As Object, ByVal e As EventArgs) Handles MyBase.Tick
        Dim phoneID As Integer = getPhoneRenderID() ' you dont need to get phone id in every tick

        Native.Function.Call("SET_TEXT_RENDER_ID", phoneID)

        Dim tmpXDist As Double = tmpCenterPos.X - Player.Character.Position.X
        Dim tmpYDist As Double = Player.Character.Position.Y - tmpCenterPos.Y

        Dim tmpXPercent As Double = tmpXDist * 100 / tmpXMax / 100 + 0.5
        Dim tmpYPercent As Double = (tmpYDist * 100 / tmpYMax / 100 + 0.5)

        Native.Function.Call("DRAW_SPRITE", textureLoad, tmpXPercent, tmpYPercent, 7.15 * zoomCoef, 2.0 * zoomCoef, 180, 255, 255, 255, 175)
        Native.Function.Call("DRAW_RECT", 0.5, 0.5, 0.025, 0.01, 255, 255, 255, 255)

        msgex(phoneID & " > " & tmpXPercent & "  " & tmpYPercent & "    " & tmpXMax & "  " & tmpYMax & "   " & zoomCoef, 100)

        If Game.isKeyPressed(Keys.Add) Then tmpXMax += 5
        If Game.isKeyPressed(Keys.Subtract) Then tmpXMax -= 5
        If Game.isKeyPressed(Keys.Y) Then tmpYMax += 5
        If Game.isKeyPressed(Keys.U) Then tmpYMax -= 5
        If Game.isKeyPressed(Keys.D8) Then zoomCoef += 0.1
        If Game.isKeyPressed(Keys.D9) Then zoomCoef -= 0.1

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