throw unsupported_gl_mode(opts);
SetPixelFormat(dc, pf_index, &pfd);
throw unsupported_gl_mode(opts);
SetPixelFormat(dc, pf_index, &pfd);
priv->context = wglCreateContext(dc);
wglMakeCurrent(dc, priv->context);
priv->context = wglCreateContext(dc);
wglMakeCurrent(dc, priv->context);