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

procname

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).

'' 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

• Not available in the -lang qb dialect unless referenced with the alias __Screenglproc.
  
  

• Not available for DOS target.
  
  

• New to FreeBASIC
  
  

• Screen (Graphics)
  
• ScreenControl