Suggested GUI tweak

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I find it difficult to see the FPS counter at times, so I wrote a method 
similar to DrawText in SimContext.cpp that draws a contrasting rectangle behind 
the text, eliminating the possibility of a the FPS text being invisible against 
a matching background. I've attached the code.

Original issue reported on code.google.com by Luc4sDre...@gmail.com on 10 Nov 2013 at 10:17

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[deleted comment]

[GoogleCodeExporter]

Seems like the attachment is missing. Here is the code:

    /// Same as DrawText but draw text onto a contrasting rectangle to make it readable on a matching background.
    static void DrawTextOnContrastingRect( const Vector2i& topLeft, const SColor& color, const std::string& msg, IrrlichtDevice_IPtr device )
    {
        Assert( device );

        const std::wstring wMsg = boost::lexical_cast<std::wstring>(msg.c_str());

        // grab the drawing tools we need as well
        irr::gui::IGUIFont* font = device->getGUIEnvironment()->getFont( "common/data/gui/fonthaettenschweiler.bmp" );

        irr::core::dimension2du optionsSize = font->getDimension(wMsg.c_str());

        irr::core::rect<int32_t> msgPos;
        msgPos.UpperLeftCorner.X = topLeft.X;
        msgPos.UpperLeftCorner.Y = topLeft.Y;
        msgPos.LowerRightCorner.X = topLeft.X + optionsSize.Width;
        msgPos.LowerRightCorner.Y = topLeft.Y + optionsSize.Height;

        // Draw a contrasting color rectangle behind the text 
        video::IVideoDriver* driver = device->getVideoDriver();

        irr::core::rect<int32_t> backgroundBox;    
        backgroundBox.UpperLeftCorner.X = msgPos.UpperLeftCorner.X - 1;
        backgroundBox.UpperLeftCorner.Y = msgPos.UpperLeftCorner.Y;
        backgroundBox.LowerRightCorner.X = msgPos.LowerRightCorner.X + 1;
        backgroundBox.LowerRightCorner.Y = msgPos.LowerRightCorner.Y;

        // Draw on either white or black depending on the luminance of the text color.
        u32 luminance = (u32)(0.2126 * color.getRed() + 0.7152 * color.getGreen() + 0.0722 * color.getBlue());
        SColor contrastingColor;
        if (luminance >= 128)
        {
            SColor white(255, 0, 0, 0);
            contrastingColor = white;
        }
        else
        {
            SColor black(255, 255, 255, 255);
            contrastingColor = black;
        }
        driver->draw2DRectangle(contrastingColor, backgroundBox);
        //driver->endScene(); // is this necessary?

        font->draw( wMsg.c_str(), msgPos, color, false, false, 0 );
    }

Original comment by Luc4sDre...@gmail.com on 1 Dec 2013 at 1:38