FilterBlueScreen.h

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/*
-----------------------------------------------------------------------------
This source file is part of blendTex library

Copyright (c) 2007 The Zdeno Ash Miklas

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.
-----------------------------------------------------------------------------
*/

#if !defined FILTERBLUESCREEN_H
#define FILTERBLUESCREEN_H

#include "Common.h"

#include "FilterBase.h"


class FilterBlueScreen : public FilterBase
{
public:
    FilterBlueScreen (void);
    virtual ~FilterBlueScreen (void) {}

    unsigned char * getColor (void) { return m_color; }
    void setColor (unsigned char red, unsigned char green, unsigned char blue);

    unsigned short * getLimits (void) { return m_limits; }
    void setLimits (unsigned short minLimit, unsigned short maxLimit);

protected:
    unsigned char m_color[3];
    unsigned short m_limits[2];
    unsigned int m_squareLimits[2];
    unsigned int m_limitDist;

    template <class SRC> unsigned int tFilter (SRC src, short x, short y,
        short * size, unsigned int pixSize, unsigned int val)
    {
        // calculate differences
        int difRed = int(VT_R(val)) - int(m_color[0]);
        int difGreen = int(VT_G(val)) - int(m_color[1]);
        int difBlue = int(VT_B(val)) - int(m_color[2]);
        // calc distance from "blue screen" color
        unsigned int dist = (unsigned int)(difRed * difRed + difGreen * difGreen
            + difBlue * difBlue);
        // condition for fully transparent color
        if (m_squareLimits[0] >= dist) 
            // return color with zero alpha
            VT_A(val) = 0;
        // condition for fully opaque color
        else if (m_squareLimits[1] <= dist)
            // return normal color
            VT_A(val) = 0xFF;
        // otherwise calc alpha
        else
            VT_A(val) = (((dist - m_squareLimits[0]) << 8) / m_limitDist);
        return val;
    }

    virtual unsigned int filter (unsigned char * src, short x, short y,
        short * size, unsigned int pixSize, unsigned int val = 0)
    { return tFilter(src, x, y, size, pixSize, val); }
    virtual unsigned int filter (unsigned int * src, short x, short y,
        short * size, unsigned int pixSize, unsigned int val = 0)
    { return tFilter(src, x, y, size, pixSize, val); }
};


#endif