102 lines
3.2 KiB
C++
102 lines
3.2 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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#ifndef OSG_TRANSFERFUNCTION
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#define OSG_TRANSFERFUNCTION 1
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#include <osg/Texture>
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#include <osg/Shader>
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#include <map>
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namespace osg {
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/** TransferFunction is a class that provide a 1D,2D or 3D colour look up table
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* that can be used on the GPU as a 1D, 2D or 3D texture.
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* Typically uses include mapping heights to colours when contouring terrain,
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* or mapping intensities to colours when volume rendering.
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*/
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class OSG_EXPORT TransferFunction : public osg::Referenced
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{
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public :
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TransferFunction();
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osg::Image* getImage() { return _image.get(); }
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const osg::Image* getImage() const { return _image.get(); }
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protected:
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virtual ~TransferFunction();
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typedef std::vector<osg::Vec4> Colors;
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Colors _colors;
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osg::ref_ptr<osg::Image> _image;
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};
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/** 1D variant of TransferFunction. */
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class OSG_EXPORT TransferFunction1D : public osg::TransferFunction
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{
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public:
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TransferFunction1D();
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void setInputRange(float minimum, float maximum);
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void setMinimum(float value) { _minimum = value; }
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float getMinimum() const { return _minimum; }
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void setMaximum(float value) { _maximum = value; }
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float getMaximum() const { return _maximum; }
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void allocate(unsigned int numX);
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void clear(const osg::Vec4& color = osg::Vec4(1.0f,1.0f,1.0f,1.0f));
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unsigned int getNumberCellsX() const { return _colors.size(); }
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void setValue(unsigned int i, const osg::Vec4& color) { _colors[i] = color; if (_image.valid()) _image->dirty(); }
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const osg::Vec4& getValue(unsigned int i) const { return _colors[i]; }
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osg::Vec4 getInterpolatedValue(float v) const
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{
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float iPos = (v-_minimum)*float(_colors.size()-1)/(_maximum-_minimum);
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if (iPos<0.0) return _colors[0];
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if (iPos>float(_colors.size()-1)) return _colors[_colors.size()-1];
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unsigned int iLower = (unsigned int)(iPos);
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unsigned int iUpper = iLower+1;
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if (iUpper>=_colors.size()) return _colors[iLower];
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float r = iPos-floorf(iLower);
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const osg::Vec4& cLower = _colors[iLower];
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const osg::Vec4& cUpper = _colors[iUpper];
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return cLower + (cUpper-cLower)*r;
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}
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typedef std::map<float, osg::Vec4> ValueMap;
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void assign(const ValueMap& vcm, bool updateMinMaxRange);
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protected:
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float _minimum;
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float _maximum;
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};
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}
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#endif
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