source: downloads/ogre/RenderSystems/GL/src/OgreWin32RenderTexture.cpp @ 48

/*
-----------------------------------------------------------------------------
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 "OgreRoot.h"
#include "OgreLogManager.h"
#include "OgreRenderSystem.h"
#include "OgreImageCodec.h"
#include "OgreException.h"
#include "OgreStringConverter.h"
#include "OgreWin32RenderTexture.h"
#include "OgreWin32GLSupport.h"
#include "OgreWin32Context.h"

namespace Ogre {

         Win32PBuffer::Win32PBuffer(PixelComponentType format, size_t width, size_t height):
                GLPBuffer(format, width, height),
        mContext(0)
        {
                createPBuffer();

        // Create context
        mContext = new Win32Context(mHDC, mGlrc);
#if 0
                if(mUseBind)
                {
                        // Bind texture
                        glBindTexture(GL_TEXTURE_2D, static_cast<GLTexture*>(mTexture.get())->getGLID());
                        wglBindTexImageARB(mPBuffer, WGL_FRONT_LEFT_ARB);
                }
#endif
        }
         Win32PBuffer::~Win32PBuffer() 
        {
#if 0
                if(mUseBind)
                {
                        // Unbind texture
                        glBindTexture(GL_TEXTURE_2D,
                                static_cast<GLTexture*>(mTexture.get())->getGLID());
                        glBindTexture(GL_TEXTURE_2D,
                                static_cast<GLTexture*>(mTexture.get())->getGLID());
                        wglReleaseTexImageARB(mPBuffer, WGL_FRONT_LEFT_ARB);
                }
#endif
        // Unregister and destroy mContext
        delete mContext;        
           
                // Destroy pbuffer
                destroyPBuffer();
        }
        
        void Win32PBuffer::createPBuffer() 
        {

        // Process format
        int bits=0;
        bool isFloat=false;
#if 0
                bool hasAlpha=true;
#endif
        switch(mFormat)
        {
            case PCT_BYTE:
                bits=8; isFloat=false;
                break;
            case PCT_SHORT:
                bits=16; isFloat=false;
                break;
            case PCT_FLOAT16:
                bits=16; isFloat=true;
                break;
            case PCT_FLOAT32:
                bits=32; isFloat=true;
                break;
            default: break;
        };
                LogManager::getSingleton().logMessage(
                        " Win32PBuffer::Creating PBuffer of format bits="+
                        StringConverter::toString(bits)+
                        " float="+StringConverter::toString(isFloat)
            );


                HDC old_hdc = wglGetCurrentDC();
                HGLRC old_context = wglGetCurrentContext();

                // Bind to RGB or RGBA texture
                int bttype = 0;
#if 0
                if(mUseBind)
                {
                        // Only provide bind type when actually binding
                        bttype = PixelUtil::hasAlpha(mInternalFormat)?
                                WGL_BIND_TO_TEXTURE_RGBA_ARB : WGL_BIND_TO_TEXTURE_RGB_ARB;
                }
                int texformat = hasAlpha?
                        WGL_TEXTURE_RGBA_ARB : WGL_TEXTURE_RGB_ARB;
#endif
                // Make a float buffer?
        int pixeltype = isFloat?
                        WGL_TYPE_RGBA_FLOAT_ARB: WGL_TYPE_RGBA_ARB;
                
                int attrib[] = {
                        WGL_RED_BITS_ARB,bits,
                        WGL_GREEN_BITS_ARB,bits,
                        WGL_BLUE_BITS_ARB,bits,
                        WGL_ALPHA_BITS_ARB,bits,
                        WGL_STENCIL_BITS_ARB,1,
                        WGL_DEPTH_BITS_ARB,15,
                        WGL_DRAW_TO_PBUFFER_ARB,true,
                        WGL_SUPPORT_OPENGL_ARB,true,
                        WGL_PIXEL_TYPE_ARB,pixeltype,
                        //WGL_DOUBLE_BUFFER_ARB,true,
                        //WGL_ACCELERATION_ARB,WGL_FULL_ACCELERATION_ARB, // Make sure it is accelerated
                        bttype,true, // must be last, as bttype can be zero
                        0
                };
                int pattrib_default[] = { 
                        0
                };
#if 0
                int pattrib_bind[] = { 
                        WGL_TEXTURE_FORMAT_ARB, texformat, 
                        WGL_TEXTURE_TARGET_ARB, WGL_TEXTURE_2D_ARB,
                        WGL_PBUFFER_LARGEST_ARB, true,
                        0 
                };
#endif
                int format;
                unsigned int count;

                // Choose suitable pixel format
                wglChoosePixelFormatARB(old_hdc,attrib,NULL,1,&format,&count);
                if(count == 0)
                        OGRE_EXCEPT(Exception::ERR_RENDERINGAPI_ERROR, "wglChoosePixelFormatARB() failed", " Win32PBuffer::createPBuffer");

                // Analyse pixel format
                const int piAttributes[]={
                                WGL_RED_BITS_ARB,WGL_GREEN_BITS_ARB,WGL_BLUE_BITS_ARB,WGL_ALPHA_BITS_ARB,
                                WGL_DEPTH_BITS_ARB,WGL_STENCIL_BITS_ARB
                };
                int piValues[sizeof(piAttributes)/sizeof(const int)];
                wglGetPixelFormatAttribivARB(old_hdc,format,0,sizeof(piAttributes)/sizeof(const int),piAttributes,piValues);

        StringUtil::StrStreamType str;
        str << " Win32PBuffer::PBuffer -- Chosen pixel format rgba="
            << piValues[0] << ","  
            << piValues[1] << ","  
            << piValues[2] << ","  
            << piValues[3] 
            << " depth=" << piValues[4]
            << " stencil=" << piValues[5];
                LogManager::getSingleton().logMessage(
                        LML_NORMAL, str.str());

                mPBuffer = wglCreatePbufferARB(old_hdc,format,mWidth,mHeight,pattrib_default);
                if(!mPBuffer)
                        OGRE_EXCEPT(Exception::ERR_RENDERINGAPI_ERROR, "wglCreatePbufferARB() failed", " Win32PBuffer::createPBuffer");

                mHDC = wglGetPbufferDCARB(mPBuffer);
                if(!mHDC) {
                        wglDestroyPbufferARB(mPBuffer);
                        OGRE_EXCEPT(Exception::ERR_RENDERINGAPI_ERROR, "wglGetPbufferDCARB() failed", " Win32PBuffer::createPBuffer");
                }
                        
                mGlrc = wglCreateContext(mHDC);
                if(!mGlrc) {
                        wglReleasePbufferDCARB(mPBuffer,mHDC);
                        wglDestroyPbufferARB(mPBuffer);
                        OGRE_EXCEPT(Exception::ERR_RENDERINGAPI_ERROR, "wglCreateContext() failed", " Win32PBuffer::createPBuffer");
                }

                if(!wglShareLists(old_context,mGlrc)) {
                        wglDeleteContext(mGlrc);
                        wglReleasePbufferDCARB(mPBuffer,mHDC);
                        wglDestroyPbufferARB(mPBuffer);
                        OGRE_EXCEPT(Exception::ERR_RENDERINGAPI_ERROR, "wglShareLists() failed", " Win32PBuffer::createPBuffer");
                }
                                
                // Query real width and height
                int iWidth, iHeight;
                wglQueryPbufferARB(mPBuffer, WGL_PBUFFER_WIDTH_ARB, &iWidth);
                wglQueryPbufferARB(mPBuffer, WGL_PBUFFER_HEIGHT_ARB, &iHeight);
                mWidth = iWidth;  
                mHeight = iHeight;
                str.str(StringUtil::BLANK);
        str << "Win32RenderTexture::PBuffer created -- Real dimensions "
            << mWidth << "x" << mHeight;
                LogManager::getSingleton().logMessage(LML_NORMAL, str.str());
        }
        void Win32PBuffer::destroyPBuffer() 
        {
                wglDeleteContext(mGlrc);
                wglReleasePbufferDCARB(mPBuffer,mHDC);
                wglDestroyPbufferARB(mPBuffer);
        }


}