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Tutorial 1 problem

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Started by enigma555 February 25, 2006 09:56 PM

4 comments, last by gan 18 years, 4 months ago

enigma555

178

Author

February 25, 2006 09:56 PM

Hi all, I'm trying to advance my C++ skills past the "Intro" books, and decided to give the NeHe tutorials a try. I typed up the first tutorial, compiled, linked, and built it. Then when I run the program one of the error catchers trips. "Can't create a GL rendering context." from this code:

	if (!(hRC=wglCreateContext(hDC))) // Are we able to get a rendering context?
	{
		KillGLWindow(); //Reset the display
		MessageBox(NULL,"Can't create a GL rendering context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);
		return FALSE;
	}

Can anyone explain what's going on and how to fix it? Thanks

gan

166

February 25, 2006 10:13 PM

Quote: Original post by enigma555

"Can't create a GL rendering context."

from this code:

	if (!(hRC=wglCreateContext(hDC))) // Are we able to get a rendering context?	{		KillGLWindow(); //Reset the display		MessageBox(NULL,"Can't create a GL rendering context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);		return FALSE;	}

Thanks

I think it's because : (hRC=wglCreateContext(hDC))= false, this happened could be a lot of reason, maybe you need to get the last error.
wglCreateContext
GetLastError

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enigma555

178

Author

February 25, 2006 11:08 PM

Thanks for helping!

OK. I added in a GetLastError() line and with a breakpoint got error# 2000 which says that the pixel format is invalid.

Here is the code relating to that section.

	static PIXELFORMATDESCRIPTOR pfd= //pfd tells windows how we want things to be	{		sizeof(PIXELFORMATDESCRIPTOR), // size of this pixel format descriptor			1, // Version number			PFD_DRAW_TO_WINDOW | //Format must support window			PFD_SUPPORT_OPENGL | //Format must support OpenGL			PFD_DOUBLEBUFFER, //Must support double buffering			PFD_TYPE_RGBA, //Request an RGBA format			bits, //select our 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, //Accumulation bits ignored			16, //16Bit Z-Buffer (Depth Buffer)			0, //No Stencil buffer			0, //No auxiliary buffer			PFD_MAIN_PLANE, //Main drawing layer			0, //Reserved			0, 0, 0 //Layer Masks Ignored	};	if (!(hDC=GetDC(hWnd))) //Did we get a device context?	{		KillGLWindow(); //Reset the display		MessageBox(NULL,"Can't create a GL device context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);		return FALSE;	}	if (!(PixelFormat=ChoosePixelFormat(hDC, &pfd))) //Did windows find a matching pixel format?	{		KillGLWindow(); //Reset the display		MessageBox(NULL,"Can't set the PixelFormat.", "ERROR", MB_OK | MB_ICONEXCLAMATION);		return FALSE;	}	if (!(hRC=wglCreateContext(hDC))) // Are we able to get a rendering context?	{		ertest=GetLastError();		KillGLWindow(); //Reset the display		MessageBox(NULL,"Can't create a GL rendering context.", "ERROR", MB_OK | MB_ICONEXCLAMATION);		return FALSE;	}

How do I get the scrollable window?

enigma555

178

Author

February 25, 2006 11:20 PM

Bleh. Found the problem. I must have looked right past the part of code where it set the pixel format.

Thanks for showing me that error checking command! I appreciate it!