source: downloads/RenderSystems/GL/src/win32/OgreWin32Context.cpp @ 3

/*
-----------------------------------------------------------------------------
This source file is part of OGRE
    (Object-oriented Graphics Rendering Engine)
For the latest info, see http://www.ogre3d.org/

Copyright (c) 2000-2006 Torus Knot Software Ltd
Also see acknowledgements in Readme.html

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU Lesser General Public License as published by the Free Software
Foundation; either version 2 of the License, or (at your option) any later
version.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU Lesser General Public License for more details.

You should have received a copy of the GNU Lesser General Public License along with
this program; if not, write to the Free Software Foundation, Inc., 59 Temple
Place - Suite 330, Boston, MA 02111-1307, USA, or go to
http://www.gnu.org/copyleft/lesser.txt.

You may alternatively use this source under the terms of a specific version of
the OGRE Unrestricted License provided you have obtained such a license from
Torus Knot Software Ltd.
-----------------------------------------------------------------------------
*/

#include "OgreWin32Context.h"
#include "OgreException.h"
#include "OgreGLRenderSystem.h"
#include "OgreRoot.h"

namespace Ogre {

    Win32Context::Win32Context(HDC     HDC,
                 HGLRC   Glrc):
        mHDC(HDC),
        mGlrc(Glrc)
    {
    }
    
    Win32Context::~Win32Context()
    {
                // NB have to do this is subclass to ensure any methods called back
                // are on this subclass and not half-destructed superclass
                GLRenderSystem *rs = static_cast<GLRenderSystem*>(Root::getSingleton().getRenderSystem());
                rs->_unregisterContext(this);
    }
        
    void Win32Context::setCurrent()
    {
         wglMakeCurrent(mHDC, mGlrc);      
    }
        void Win32Context::endCurrent()
        {
                wglMakeCurrent(NULL, NULL);
        }

        String translateError()
        {

                int winError = GetLastError();
                char* errDesc;
                int i;

                errDesc = new char[255];
                // Try windows errors first
                i = FormatMessage(
                        FORMAT_MESSAGE_FROM_SYSTEM |
                        FORMAT_MESSAGE_IGNORE_INSERTS,
                        NULL,
                        winError,
                        MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), // Default language
                        (LPTSTR) errDesc,
                        255,
                        NULL
                        );

                return String(errDesc);
        }
        GLContext* Win32Context::clone() const
        {
                // Create new context based on own HDC
                HGLRC newCtx = wglCreateContext(mHDC);
                
                if (!newCtx)
                {
                        OGRE_EXCEPT(Exception::ERR_INTERNAL_ERROR, 
                                "Error calling wglCreateContext", "Win32Context::clone");
                }

                HGLRC oldrc = wglGetCurrentContext();
                HDC oldhdc = wglGetCurrentDC();
                wglMakeCurrent(NULL, NULL);
                // Share lists with old context
            if (!wglShareLists(mGlrc, newCtx))
                {
                        String errorMsg = translateError();
                        wglDeleteContext(newCtx);
                        OGRE_EXCEPT(Exception::ERR_RENDERINGAPI_ERROR, String("wglShareLists() failed: ") + errorMsg, "Win32Context::clone");
                }
                // restore old context
                wglMakeCurrent(oldhdc, oldrc);
                

                return new Win32Context(mHDC, newCtx);
        }
}