History: Render Target to QImage [QT]

            {maketoc showhide="y"}

Some times it is necessary to store a image from the current render target (e.g. your Ogre::RenderWindow) to an Image.
This is a short Snippets, that describs the way for Qt.

{CODE(wrap="1", colors="c++")} 
QImage getImageFromRenderTarget(Ogre::RenderTarget* render_target) const
{
    if(render_target == 0)
        return QImage();

    Ogre::DataStreamPtr image_data_stream;
    QImage image_render_view;

    try
    {
        // create PixelBox and get data from target
        Ogre::PixelFormat pf = render_target->suggestPixelFormat();

        unsigned int target_width = render_target->getWidth();
        unsigned int target_height = render_target->getHeight();
        size_t bp_box_size = target_width * target_height * Ogre::PixelUtil::getNumElemBytes(pf);

        unsigned char* ogre_pixel_data = new unsigned char[bp_box_size];
        Ogre::PixelBox pixelbox(target_width, target_height, 1, pf, ogre_pixel_data);

        render_target->copyContentsToMemory(pixelbox);

        // load data into Ogre::Image and encode to bmp
        Ogre::Image ogre_image = Ogre::Image().loadDynamicImage(ogre_pixel_data, target_width, target_height, 1, pf);

        image_data_stream = ogre_image.encode("bmp");

        // get size and data from Ogre::Image
        size_t bmp_buffer_size = size_t image_data_stream->size();

        unsigned char* bmp_data = new unsigned char[bmp_buffer_size];

        image_data_stream->read(bmp_data, bmp_buffer_size);

        //save data into QImage as BMP
        image_render_view = image_render_view.fromData(bmp_data, bmp_buffer_size, "BMP");

        delete[] bmp_data;
        delete[] ogre_pixel_data;
    }
    catch(Ogre::Exception& ex)
    {
        std::stringstream error;

	error << "Could not read FrameBuffer Image: Error Description: " << ex.getFullDescription() << std::ends;
	// post the error to whatever you prefer

        return QImage();
    }
    catch(...)
    {
        std::stringstream error;

	error << "An unknown error occured in getImageFromRenderTarget(Ogre::RenderTarget* render_target)" << std::ends;
	// post the error to whatever you prefer
    }

    return image_render_view;
}
{CODE}