ScreenGLProc

Gets the address of an OpenGL procedure

Syntax
   Declare Function ScreenGLProc ( ByRef procname As Const String ) As Any 
   Ptr

Parameters
   procname
      name of the procedure to retrieve the address of

Description
   This function can be used to get the address of any OpenGL procedure, to 
   be used to retrieve the pointers to new functions associated with OpenGL 
   extensions. If given procedure named procname cannot be found, 
   ScreenGLProc will return NULL (0).

Example
   '' include fbgfx.bi for some useful definitions
   #include "fbgfx.bi"

   Dim SwapInterval As Function(ByVal interval As Integer) As Integer
   Dim extensions As String

   '' Setup OpenGL and retrieve supported extensions
   ScreenRes 640, 480, 32,, FB.GFX_OPENGL
   ScreenControl FB.GET_GL_EXTENSIONS, extensions

   If (InStr(extensions, "WGL_EXT_swap_control") <> 0) Then
      '' extension supported, retrieve proc address
      SwapInterval = ScreenGLProc("wglSwapIntervalEXT")
      If (SwapInterval <> 0) Then
         '' Ok, we got it. Set OpenGL to wait for vertical sync on buffer swaps
         SwapInterval(1)
      End If
   End If

Dialect Differences
   * Not available in the -lang qb dialect unless referenced with the 
     alias __Screenglproc.

Platform Differences
   * Not available for DOS target.

Differences from QB
   * New to FreeBASIC

See also
   * Screen (Graphics)
   * ScreenControl

