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128 lines
5.1 KiB
128 lines
5.1 KiB
/* -*-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::Object |
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{ |
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public : |
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TransferFunction(); |
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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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/** Get the image that is used for passing the transfer function data to the GPU.*/ |
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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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const osg::Image* getImage() const { return _image.get(); } |
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protected: |
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virtual ~TransferFunction(); |
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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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/** 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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/** Get the minimum transfer function value.*/ |
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float getMinimum() const { return _colorMap.empty() ? 0.0f : _colorMap.begin()->first; } |
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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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/** 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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/** Clear the whole range to just represent a single color.*/ |
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void clear(const osg::Vec4& color = osg::Vec4(1.0f,1.0f,1.0f,1.0f)); |
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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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} |
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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 recomputation of 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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/** 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 transfer 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 transfer 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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protected: |
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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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}; |
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} |
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#endif
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