public static extern int ChoosePixelFormat(IntPtr hdc, [In] ref PIXELFORMATDESCRIPTOR ppfd);
static Wgl()
{
// save the current GL context
var prevDC = Wgl.wglGetCurrentDC();
var prevGLRC = Wgl.wglGetCurrentContext();
// register the dummy window class
var wc = new WNDCLASS
{
style = (User32.CS_HREDRAW | User32.CS_VREDRAW | User32.CS_OWNDC),
lpfnWndProc = (WNDPROC)User32.DefWindowProc,
cbClsExtra = 0,
cbWndExtra = 0,
hInstance = Kernel32.CurrentModuleHandle,
hCursor = User32.LoadCursor(IntPtr.Zero, (int)User32.IDC_ARROW),
hIcon = User32.LoadIcon(IntPtr.Zero, (IntPtr)User32.IDI_WINLOGO),
hbrBackground = IntPtr.Zero,
lpszMenuName = null,
lpszClassName = "DummyClass"
};
if (User32.RegisterClass(ref wc) == 0)
{
throw new Exception("Could not register dummy class.");
}
// get the the dummy window bounds
var windowRect = new RECT {
left = 0, right = 8, top = 0, bottom = 8
};
User32.AdjustWindowRectEx(ref windowRect, WindowStyles.WS_SYSMENU, false, User32.WS_EX_CLIENTEDGE);
// create the dummy window
var dummyWND = User32.CreateWindowEx(
User32.WS_EX_CLIENTEDGE,
"DummyClass",
"DummyWindow",
WindowStyles.WS_CLIPSIBLINGS | WindowStyles.WS_CLIPCHILDREN | WindowStyles.WS_SYSMENU,
0, 0,
windowRect.right - windowRect.left, windowRect.bottom - windowRect.top,
IntPtr.Zero, IntPtr.Zero, Kernel32.CurrentModuleHandle, IntPtr.Zero);
if (dummyWND == IntPtr.Zero)
{
User32.UnregisterClass("DummyClass", Kernel32.CurrentModuleHandle);
throw new Exception("Could not create dummy window.");
}
// get the dummy DC
var dummyDC = User32.GetDC(dummyWND);
// get the dummy pixel format
var dummyPFD = new PIXELFORMATDESCRIPTOR();
dummyPFD.nSize = (ushort)Marshal.SizeOf(dummyPFD);
dummyPFD.nVersion = 1;
dummyPFD.dwFlags = Gdi32.PFD_DRAW_TO_WINDOW | Gdi32.PFD_SUPPORT_OPENGL;
dummyPFD.iPixelType = Gdi32.PFD_TYPE_RGBA;
dummyPFD.cColorBits = 32;
dummyPFD.cDepthBits = 24;
dummyPFD.cStencilBits = 8;
dummyPFD.iLayerType = Gdi32.PFD_MAIN_PLANE;
var dummyFormat = Gdi32.ChoosePixelFormat(dummyDC, ref dummyPFD);
Gdi32.SetPixelFormat(dummyDC, dummyFormat, ref dummyPFD);
// get the dummy GL context
var dummyGLRC = Wgl.wglCreateContext(dummyDC);
if (dummyGLRC == IntPtr.Zero)
{
throw new Exception("Could not create dummy GL context.");
}
Wgl.wglMakeCurrent(dummyDC, dummyGLRC);
VersionString = Wgl.GetString(Wgl.GL_VERSION);
// get the extension methods using the dummy context
wglGetExtensionsStringARB = Wgl.wglGetProcAddress <wglGetExtensionsStringARBDelegate>("wglGetExtensionsStringARB");
wglChoosePixelFormatARB = Wgl.wglGetProcAddress <wglChoosePixelFormatARBDelegate>("wglChoosePixelFormatARB");
wglCreatePbufferARB = Wgl.wglGetProcAddress <wglCreatePbufferARBDelegate>("wglCreatePbufferARB");
wglDestroyPbufferARB = Wgl.wglGetProcAddress <wglDestroyPbufferARBDelegate>("wglDestroyPbufferARB");
wglGetPbufferDCARB = Wgl.wglGetProcAddress <wglGetPbufferDCARBDelegate>("wglGetPbufferDCARB");
wglReleasePbufferDCARB = Wgl.wglGetProcAddress <wglReleasePbufferDCARBDelegate>("wglReleasePbufferDCARB");
wglSwapIntervalEXT = Wgl.wglGetProcAddress <wglSwapIntervalEXTDelegate>("wglSwapIntervalEXT");
// destroy the dummy GL context
Wgl.wglMakeCurrent(dummyDC, IntPtr.Zero);
Wgl.wglDeleteContext(dummyGLRC);
// destroy the dummy window
User32.DestroyWindow(dummyWND);
User32.UnregisterClass("DummyClass", Kernel32.CurrentModuleHandle);
// reset the initial GL context
Wgl.wglMakeCurrent(prevDC, prevGLRC);
}
public static extern bool SetPixelFormat(IntPtr hdc, int iPixelFormat, [In] ref PIXELFORMATDESCRIPTOR ppfd);
