2007-03-10 19:53:31 +08:00
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/* -*-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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2008-09-13 17:09:51 +08:00
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#include <map>
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2007-03-10 19:53:31 +08:00
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namespace osg {
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2007-07-12 16:29:39 +08:00
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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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2009-02-01 20:38:55 +08:00
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class OSG_EXPORT TransferFunction : public osg::Object
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2007-03-10 19:53:31 +08:00
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{
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public :
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TransferFunction();
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2009-02-01 20:38:55 +08:00
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/** Copy constructor using CopyOp to manage deep vs shallow copy.*/
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TransferFunction(const TransferFunction& tf, const CopyOp& copyop=CopyOp::SHALLOW_COPY);
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META_Object(osg, TransferFunction)
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2009-02-02 22:43:27 +08:00
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/** Get the image that is used for passing the transfer function data to the GPU.*/
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2007-03-10 19:53:31 +08:00
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osg::Image* getImage() { return _image.get(); }
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/** Get the const image that is used for passing the transfer function data to the GPU.*/
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2007-03-10 19:53:31 +08:00
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const osg::Image* getImage() const { return _image.get(); }
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protected:
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2007-03-22 00:34:04 +08:00
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virtual ~TransferFunction();
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2007-03-10 19:53:31 +08:00
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osg::ref_ptr<osg::Image> _image;
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};
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2007-07-12 16:29:39 +08:00
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/** 1D variant of TransferFunction. */
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2007-03-10 19:53:31 +08:00
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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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2009-02-01 20:38:55 +08:00
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/** Copy constructor using CopyOp to manage deep vs shallow copy.*/
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TransferFunction1D(const TransferFunction1D& tf, const CopyOp& copyop=CopyOp::SHALLOW_COPY);
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META_Object(osg, TransferFunction1D)
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2007-04-03 23:39:05 +08:00
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2009-02-02 22:43:27 +08:00
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/** Get the mnimum transfer function value.*/
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float getMinimum() const { return _colorMap.empty() ? 0.0f : _colorMap.begin()->first; }
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2007-04-03 23:39:05 +08:00
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2009-02-02 22:43:27 +08:00
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/** Get the maximum transfer function value.*/
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float getMaximum() const { return _colorMap.empty() ? 0.0f : _colorMap.rbegin()->first; }
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2007-03-10 19:53:31 +08:00
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2009-02-02 22:43:27 +08:00
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/** allocate the osg::Image with specified dimension. The Image tracks the color map, and is used to represent the
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* transfer function when download to GPU.*/
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void allocate(unsigned int numImageCells);
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2007-03-10 19:53:31 +08:00
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2009-02-02 22:43:27 +08:00
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/** Clear the whole range to just represet a single color.*/
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2007-03-10 19:53:31 +08:00
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void clear(const osg::Vec4& color = osg::Vec4(1.0f,1.0f,1.0f,1.0f));
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2009-02-02 22:43:27 +08:00
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/** Get pixel value from the image. */
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osg::Vec4 getPixelValue(unsigned int i) const
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{
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if (_image.valid() && i<static_cast<unsigned int>(_image->s()))
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{
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return *reinterpret_cast<osg::Vec4*>(_image->data(i));
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}
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else
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{
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return osg::Vec4(1.0f,1.0f,1.0f,1.0f);
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}
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2008-09-13 17:09:51 +08:00
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}
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2009-02-02 22:43:27 +08:00
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/** Get the number of image cells that are assigned to the represent the transfer function when download to the GPU.*/
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unsigned int getNumberImageCells() const { return _image.valid() ? _image->s() : 0; }
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/** Set the color for a specified transfer function value.
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* updateImage defaults to true, and tells the setColor function to update the associate osg::Image that
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* tracks the color map. Pass in false as the updateImage parameter if you are setting up many values
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* at once to avoid recomputating og the image data, then once all setColor calls are made explictly call
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* updateImage() to bring the osg::Image back into sync with the color map. */
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void setColor(float v, const osg::Vec4& color, bool updateImage=true);
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2009-02-02 22:43:27 +08:00
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/** Get the color for a specified transfer function value, interpolating the value if no exact match is found.*/
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osg::Vec4 getColor(float v) const;
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typedef std::map<float, osg::Vec4> ColorMap;
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/** Get the color map that stores the mapping between the the tranfser function value and the colour it maps to.*/
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ColorMap& getColorMap() { return _colorMap; }
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/** Get the const color map that stores the mapping between the the tranfser function value and the colour it maps to.*/
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const ColorMap& getColorMap() const { return _colorMap; }
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/** Assign a color map and automatically update the image to make sure they are in sync.*/
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void assign(const ColorMap& vcm);
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/** Manually update the associate osg::Image to represent the colors assigned in the color map.*/
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void updateImage();
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2008-09-13 17:09:51 +08:00
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2007-03-10 19:53:31 +08:00
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protected:
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2009-02-02 22:43:27 +08:00
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ColorMap _colorMap;
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void assignToImage(float lower_v, const osg::Vec4& lower_c, float upper_v, const osg::Vec4& upper_c);
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2007-03-10 19:53:31 +08:00
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};
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}
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#endif
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