Why I cannot check OpenGL version in this fake OpenGL context? - c++

Question

I'm trying to check OpenGL version creating a fake OpenGL context, but always I'm getting version 0. I create a fake context with this code:
PIXELFORMATDESCRIPTOR pfd;
ZeroMemory( &pfd, sizeof( pfd ) );
pfd.nSize = sizeof( pfd );
pfd.nVersion = 1;
pfd.dwFlags = PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL |
PFD_DOUBLEBUFFER;
pfd.iPixelType = PFD_TYPE_RGBA;
pfd.cColorBits = 24;
pfd.cDepthBits = 16;
pfd.iLayerType = PFD_MAIN_PLANE;
WINDOWINFO info;
HWND mHWND;
info.cbSize = sizeof(WINDOWINFO);
GetWindowInfo(mHWND,&info);
HDC mDC;
mDC = GetDC(mHWND);
int fmt = ChoosePixelFormat( mDC, &pfd );
SetPixelFormat( mDC, fmt, &pfd );
HGLRC mOGLCtx;
mOGLCtx = wglCreateContext( mDC );
wglMakeCurrent(mDC, mOGLCtx);
And try to check version with this:
glGetString(GL_VERSION)

Answer 1

Try to get (GetActiveWindow, GetForegroundWindow) or create (CreateWindowEx) window handle before getting its DC or try to GetDC(0).

Answer 2

Can create minimal OpenGL context with that:
HWND wnd = CreateWindow(
"STATIC",
"GL",
WS_OVERLAPPEDWINDOW | WS_CLIPSIBLINGS | WS_CLIPCHILDREN,
0, 0, 16, 16,
NULL, NULL,
NULL, NULL );
HDC dc = GetDC( wnd );
PIXELFORMATDESCRIPTOR pfd = {
sizeof(PIXELFORMATDESCRIPTOR), 1,
PFD_DRAW_TO_WINDOW | PFD_SUPPORT_OPENGL,
PFD_TYPE_RGBA, 32,
0, 0, 0, 0, 0, 0,
0, 0, 0, 0, 0, 0, 0,
16, 0,
0, PFD_MAIN_PLANE, 0, 0, 0, 0
};
int fmt = ChoosePixelFormat( dc, &pfd );
SetPixelFormat( dc, fmt, &pfd );
HGLRC rc = wglCreateContext( dc );
wglMakeCurrent( dc, rc );
Check OpenGL version with the same manner:
glGetString(GL_VERSION)
To be more efficient, after all:
// Clean GL context
wglDeleteContext( rc );
ReleaseDC( wnd, dc );
DestroyWindow( wnd );