wglCreateContext and ERROR_INSUFFICIENT_BUFFER

• Wednesday, June 20, 2012 9:43 PM

   

   
  

  0

  I have an application that uses three separate OpenGL contexts embedded in Windows forms.  The first two are of identical size and initialize and run normally.  The third is smaller and I cannot create a context on Windows XP SP3.  All three use identical context creation method.
  

  	PIXELFORMATDESCRIPTOR pfd = { 
  		sizeof(PIXELFORMATDESCRIPTOR),   // size of this pfd  
  		1,                     // version number  
  		PFD_DRAW_TO_WINDOW |   // support window  
  		PFD_SUPPORT_OPENGL |   // support OpenGL  
  		PFD_DOUBLEBUFFER,      // double buffered  
  		PFD_TYPE_RGBA,         // RGBA type  
  		24,                    // 24-bit color depth  
  		0, 0, 0, 0, 0, 0,      // color bits ignored  
  		0,                     // no alpha buffer  
  		0,                     // shift bit ignored  
  		0,                     // no accumulation buffer  
  		0, 0, 0, 0,            // accum bits ignored  
  		32,                    // 32-bit z-buffer  
  		0,                     // no stencil buffer  
  		0,                     // no auxiliary buffer  
  		PFD_MAIN_PLANE,        // main layer  
  		0,                     // reserved  
  		0, 0, 0                // layer masks ignored  
  	}; 
  
  
  	GLuint pixelFormat = ::ChoosePixelFormat(mDc, &pfd);
  	if (!pixelFormat)
  	{
  		CxDebugLastError();
  		CxThrow(CxErrorOpenGL);
  	}
  	
  	bool validPixelFormat = ::SetPixelFormat(mDc, pixelFormat, &pfd);
  	if (!validPixelFormat)
  	{
  		CxDebugLastError();
  		CxThrow(CxErrorOpenGL);
  	}
  	
  	mContext = ::wglCreateContext(mDc);
  	if (!mContext)
  	{
  		CxDebugLastError();
  		CxThrow(CxErrorOpenGL);
  	}
  

  
  

  mDc is fetched from an HWND passed into the method, and is valid. 

  mContext is a HGLRC stored in the class.  It has the address of 0x00010002 after the call to wglCreateContext for the aforementioned issue, thus the "if (!mContext)" fails.  I had to move "CxDebugLastError()" outside the if-check to see that I was getting ERROR_INSUFFICIENT_BUFFER.

  1) Why is this failing on Windows XP SP3, but working fine on Windows 7?

  2) Why does wglCreateContext not return NULL when it fails in this case as the documentation states it should?

  • Moved by Jesse JiangMicrosoft Contingent Staff Friday, June 22, 2012 8:02 AM (From:Visual C++ Language)
  •  
  • Reply
  • Quote