FilterNormal.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 FILTERNORMAL_H
#define FILTERNORMAL_H

#include "Common.h"

#include "FilterBase.h"


// scale constants for normals
const float depthScaleKoef = 255.0;
const float normScaleKoef = float(depthScaleKoef / 2.0);


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

    unsigned short getColor (void) { return m_colIdx; }
    void setColor (unsigned short colIdx);

    float getDepth (void) { return m_depth; }
    void setDepth (float depth);

protected:
    float m_depth;
    float m_depthScale;

    unsigned short m_colIdx;

    template <class SRC> unsigned int tFilter (SRC * src, short x, short y,
        short * size, unsigned int pixSize, unsigned int val = 0)
    {
        // get value of required color
        int actPix = int(VT_C(val,m_colIdx));
        int upPix = actPix;
        int leftPix = actPix;
        // get upper and left pixel from actual pixel
        if (y > 0)
        {
            val = convertPrevious(src - pixSize * size[0], x, y - 1, size, pixSize);
            upPix = VT_C(val,m_colIdx);
        }
        if (x > 0)
        {
            val = convertPrevious(src - pixSize, x - 1, y, size, pixSize);
            leftPix = VT_C(val,m_colIdx);
        }
        // height differences (from blue color)
        float dx = (actPix - leftPix) * m_depthScale;
        float dy = (actPix - upPix) * m_depthScale;
        // normalize vector
        float dz = float(normScaleKoef / sqrt(dx * dx + dy * dy + 1.0));
        dx = dx * dz + normScaleKoef;
        dy = dy * dz + normScaleKoef;
        dz += normScaleKoef;
        // return normal vector converted to color
        VT_RGBA(val, dx, dy, dz, 0xFF);
        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