TransferFunction.h

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/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
 *
 * This library is open source and may be redistributed and/or modified under
 * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
 * (at your option) any later version.  The full license is in LICENSE file
 * included with this distribution, and on the openscenegraph.org website.
 *
 * This library 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
 * OpenSceneGraph Public License for more details.
*/

#ifndef OSG_TRANSFERFUNCTION
#define OSG_TRANSFERFUNCTION 1

#include <osg/Texture>
#include <osg/Shader>

#include <map>

namespace osg {


class OSG_EXPORT TransferFunction : public osg::Object
{
    public :

        TransferFunction();

        TransferFunction(const TransferFunction& tf, const CopyOp& copyop=CopyOp::SHALLOW_COPY);

        META_Object(osg, TransferFunction)

        
        osg::Image* getImage() { return _image.get(); }

        const osg::Image* getImage() const { return _image.get(); }

    protected:

        virtual ~TransferFunction();

        osg::ref_ptr<osg::Image>    _image;
};

class OSG_EXPORT TransferFunction1D : public osg::TransferFunction
{
    public:

        TransferFunction1D();

        TransferFunction1D(const TransferFunction1D& tf, const CopyOp& copyop=CopyOp::SHALLOW_COPY);

        META_Object(osg, TransferFunction1D)

        
        float getMinimum() const { return _colorMap.empty() ? 0.0f : _colorMap.begin()->first; }

        float getMaximum() const { return _colorMap.empty() ? 0.0f : _colorMap.rbegin()->first; }

        void allocate(unsigned int numImageCells);

        void clear(const osg::Vec4& color = osg::Vec4(1.0f,1.0f,1.0f,1.0f));

        osg::Vec4 getPixelValue(unsigned int i) const
        {
            if (_image.valid() && i<static_cast<unsigned int>(_image->s()))
            {
                return *reinterpret_cast<osg::Vec4*>(_image->data(i));
            }
            else
            {
                return osg::Vec4(1.0f,1.0f,1.0f,1.0f);
            }
        }

        unsigned int getNumberImageCells() const { return _image.valid() ? _image->s() : 0; }

        void setColor(float v, const osg::Vec4& color, bool updateImage=true);

        osg::Vec4 getColor(float v) const;

        typedef std::map<float, osg::Vec4> ColorMap;

        void setColorMap(const ColorMap& vcm) { assign(vcm); }

        ColorMap& getColorMap() { return _colorMap; }

        const ColorMap& getColorMap() const { return _colorMap; }

        void assign(const ColorMap& vcm);

        void updateImage();

    protected:

        ColorMap _colorMap;

        void assignToImage(float lower_v, const osg::Vec4& lower_c, float upper_v, const osg::Vec4& upper_c);
};

}

#endif