protected override void Dispose(bool disposing)
{
if (!IsDisposed)
{
if (disposing)
{
MakeCurrent(null);
if (_windowHandle != IntPtr.Zero)
{
Win32.Win32.DestroyWindow(_windowHandle);
}
WGL.DeleteContext(ContextHandle);
}
IsDisposed = true;
}
}
private static void EnsureInit()
{
if (!_isInit)
{
// Because WGL is terrible, we need to first create a context that will allow us to check extensions and query functions to create our contexes.
IntPtr dummyWindow = Win32Helper.CreateNativeWindow(WindowStylesEx.WS_EX_OVERLAPPEDWINDOW,
WindowStyles.WS_CLIPSIBLINGS | WindowStyles.WS_CLIPCHILDREN,
"SPB intermediary context",
0, 0, 1, 1);
if (dummyWindow == IntPtr.Zero)
{
throw new PlatformException($"CreateWindowEx failed: {Marshal.GetLastWin32Error()}");
}
// Enforce hidden (this is a hack around possible ShowWindow being ignored when started with a STARTUPINFO)
ShowWindow(dummyWindow, ShowWindowFlag.SW_HIDE);
IntPtr dummyWindowDC = GetDC(dummyWindow);
PixelFormatDescriptor pfd = PixelFormatDescriptor.Create();
pfd.Flags = PixelFormatDescriptorFlags.PFD_DRAW_TO_WINDOW |
PixelFormatDescriptorFlags.PFD_SUPPORT_OPENGL |
PixelFormatDescriptorFlags.PFD_DOUBLEBUFFER;
pfd.PixelType = PixelType.PFD_TYPE_RGBA;
pfd.ColorBits = 24;
int res = SetPixelFormat(dummyWindowDC, ChoosePixelFormat(dummyWindowDC, ref pfd), ref pfd);
if (res == 0)
{
throw new PlatformException($"SetPixelFormat failed for dummy context: {Marshal.GetLastWin32Error()}");
}
IntPtr dummyContext = WGL.CreateContext(dummyWindowDC);
if (dummyContext == IntPtr.Zero)
{
throw new PlatformException($"WGL.CreateContext failed for dummy context: {Marshal.GetLastWin32Error()}");
}
IntPtr oldDC = WGL.GetCurrentDC();
IntPtr oldContext = WGL.GetCurrentContext();
if (!WGL.MakeCurrent(dummyWindowDC, dummyContext))
{
// Ensure the previous context is restored and free the new context.
WGL.MakeCurrent(oldDC, oldContext);
WGL.DeleteContext(dummyContext);
throw new PlatformException($"WGL.MakeCurrent failed for dummy context: {Marshal.GetLastWin32Error()}");
}
// Now that we have a context, query everything we need.
IntPtr getExtensionsPtr = WGL.GetProcAddress("wglGetExtensionsStringEXT");
if (getExtensionsPtr == IntPtr.Zero)
{
getExtensionsPtr = WGL.GetProcAddress("wglGetExtensionsStringARB");
}
GetExtensionsString = Marshal.GetDelegateForFunctionPointer <wglGetExtensionsString>(getExtensionsPtr);
Extensions = GetExtensionsString().Split(" ");
// Ensure that all extensions that we are requiring are present.
EnsureExtensionPresence("WGL_ARB_create_context");
EnsureExtensionPresence("WGL_ARB_create_context_profile");
EnsureExtensionPresence("WGL_ARB_pixel_format"); // TODO: do not enforce this extension as we can use legacy PFDs too.
EnsureExtensionPresence("WGL_EXT_swap_control");
CreateContextAttribsArb = Marshal.GetDelegateForFunctionPointer <wglCreateContextAttribsARBDelegate>(WGL.GetProcAddress("wglCreateContextAttribsARB"));
ChoosePixelFormatArb = Marshal.GetDelegateForFunctionPointer <wglChoosePixelFormatARBDelegate>(WGL.GetProcAddress("wglChoosePixelFormatARB"));
GetPixelFormatAttribivARB = Marshal.GetDelegateForFunctionPointer <wglGetPixelFormatAttribivARB>(WGL.GetProcAddress("wglGetPixelFormatAttribivARB"));
SwapInterval = Marshal.GetDelegateForFunctionPointer <wglSwapIntervalEXTDelegate>(WGL.GetProcAddress("wglSwapIntervalEXT"));
GetSwapInterval = Marshal.GetDelegateForFunctionPointer <wglGetSwapIntervalEXTDelegate>(WGL.GetProcAddress("wglGetSwapIntervalEXT"));
// We got everything we needed, clean up!
WGL.MakeCurrent(oldDC, oldContext);
WGL.DeleteContext(dummyContext);
DestroyWindow(dummyWindow);
_opengl32Handle = NativeLibrary.Load("opengl32.dll");
_isInit = true;
}
}