Re-enabled the disable of the transfer function

examples/osgtransferfunction/osgtransferfunction.cpp

@@ -18,6 +18,8 @@
 
 #include <osg/Geode>
 #include <osg/Geometry>
+#include <osg/ImageUtils>
+#include <osg/MatrixTransform>
 #include <osg/io_utils>
 
 #include <osgDB/ReadFile>
@@ -29,6 +31,308 @@
 #include <osgViewer/Viewer>
 
 
+class Histogram
+{
+public:
+    Histogram() {}
+
+    void analyse(const osg::Image* image, double interval=0.0);
+
+    void insertZeroBoundaryValues(float xMin=FLT_MAX, float xMax=-FLT_MAX);
+
+    osg::Node* createGraphicalRepresentation();
+
+    typedef std::map<float, float> ValueMap;
+
+    ValueMap& getValueMap() { return _valueMap; }
+
+protected:
+
+    ValueMap _valueMap;
+};
+
+struct PopulateHistogram
+{
+
+    PopulateHistogram(Histogram::ValueMap& valueMap):
+        _histogram(valueMap) {}
+
+    float cast(char v) { return v; }
+    float cast(unsigned char v) { return v; }
+    float cast(short v) { return v; }
+    float cast(unsigned short v) { return v; }
+    float cast(int v) { return v; }
+    float cast(unsigned int v) { return v; }
+    float cast(float v) { return v; }
+    float cast(double v) { return v; }
+
+    Histogram::ValueMap& _histogram;
+
+    void update(int v)
+    {
+        _histogram[v]+=1.0;
+    }
+
+    void normalize()
+    {
+        double maxValue = 0;
+        for(Histogram::ValueMap::iterator itr = _histogram.begin();
+            itr != _histogram.end();
+            ++itr)
+        {
+            if (itr->second>maxValue) maxValue = itr->second;
+        }
+
+        for(Histogram::ValueMap::iterator itr = _histogram.begin();
+            itr != _histogram.end();
+            ++itr)
+        {
+            itr->second /= maxValue;
+        }
+    }
+
+    void luminance(float l) { update(l); }
+    void alpha(float a) { update(a); }
+    void luminance_alpha(float l, float a) { update(l); }
+    void rgb(float r, float g, float b) { update(r); }
+    void rgba(float r, float g, float b, float a) { update(a); }
+};
+
+void Histogram::analyse(const osg::Image* image, double interval)
+{
+    PopulateHistogram populateHistogram(_valueMap);
+    readImage(image, populateHistogram);
+    populateHistogram.normalize();
+
+    for(Histogram::ValueMap::iterator itr = populateHistogram._histogram.begin();
+        itr != populateHistogram._histogram.end();
+        ++itr)
+    {
+        OSG_NOTICE<<"  "<<itr->first<<", "<<itr->second<<std::endl;
+    }
+}
+
+void Histogram::insertZeroBoundaryValues(float xMin, float xMax)
+{
+    if (_valueMap.empty())
+    {
+        if (xMin<xMax)
+        {
+            _valueMap[xMin] = 0.0;
+            _valueMap[xMax] = 0.0;
+        }
+        return;
+    }
+
+    float interval = 1.0f;
+    float min_gap_for_single_insertion = interval*1.5;
+    float min_gap_for_double_insertion = interval*2.5;
+
+    if (xMin<_valueMap.begin()->first)
+    {
+        _valueMap[xMin] = 0.0;
+    }
+
+    if (xMax>_valueMap.rbegin()->first)
+    {
+        _valueMap[xMax] = 0.0;
+    }
+
+    ValueMap::iterator itr = _valueMap.begin();
+    float previous_x = itr->first;
+    for(;
+        itr != _valueMap.end();
+        ++itr)
+    {
+        float current_x = itr->first;
+        float gap = current_x-previous_x;
+        if (gap>min_gap_for_double_insertion)
+        {
+            _valueMap[previous_x+interval] = 0.0f;
+            _valueMap[current_x-interval] = 0.0f;
+        }
+        else if  (gap>min_gap_for_single_insertion)
+        {
+            _valueMap[(previous_x+current_x)*0.5]=0.0f;
+        }
+        previous_x = current_x;
+    }
+}
+
+osg::Node* Histogram::createGraphicalRepresentation()
+{
+    if (_valueMap.empty()) return 0;
+
+    osg::ref_ptr<osg::MatrixTransform> transform = new osg::MatrixTransform;
+
+    float xMin = _valueMap.begin()->first;
+    float xMax = _valueMap.rbegin()->first;
+
+    float depth = 0.0f;
+    float yMax = 0.0f;
+
+    // find yMax
+    for(ValueMap::iterator itr = _valueMap.begin();
+        itr != _valueMap.end();
+        ++itr)
+    {
+        float y = itr->second;
+        if (y>yMax) yMax = y;
+    }
+
+    float xScale = 1.0f/(xMax-xMin);
+    float yScale = 1.0f/yMax;
+
+    {
+        osg::ref_ptr<osg::Geode> geode = new osg::Geode;
+        transform->addChild(geode.get());
+
+        osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry;
+        geode->addDrawable(geometry.get());
+        geode->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
+        geode->getOrCreateStateSet()->setMode(GL_BLEND, osg::StateAttribute::ON);
+
+        osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
+        geometry->setVertexArray(vertices.get());
+
+        osg::ref_ptr<osg::Vec4Array> colours = new osg::Vec4Array;
+        geometry->setColorArray(colours.get(), osg::Array::BIND_PER_PRIMITIVE_SET);
+        colours->push_back(osg::Vec4(1.0,1.0,1.0,1.0));
+        colours->push_back(osg::Vec4(1.0,1.0,1.0,1.0));
+        colours->push_back(osg::Vec4(1.0,1.0,1.0,0.1));
+
+
+        unsigned numColumnsRequired = _valueMap.size();
+        vertices->reserve(numColumnsRequired*3);
+        for(ValueMap::iterator itr = _valueMap.begin();
+            itr != _valueMap.end();
+            ++itr)
+        {
+            float x = itr->first;
+            float y = itr->second;
+
+            vertices->push_back(osg::Vec3(x*xScale, 0.0f, depth));
+            vertices->push_back(osg::Vec3(x*xScale, y*yScale, depth));
+            vertices->push_back(osg::Vec3(x*xScale, yMax*yScale, depth));
+        }
+
+        osg::ref_ptr<osg::DrawElementsUShort> background_primitives = new osg::DrawElementsUShort(GL_TRIANGLE_STRIP);
+        osg::ref_ptr<osg::DrawElementsUShort> historgram_primitives = new osg::DrawElementsUShort(GL_TRIANGLE_STRIP);
+        osg::ref_ptr<osg::DrawElementsUShort> outline_primitives = new osg::DrawElementsUShort(GL_LINE_STRIP);
+        for(unsigned int i=0; i<numColumnsRequired; ++i)
+        {
+            int iv = i*3;
+
+            background_primitives->push_back(iv+2);
+            background_primitives->push_back(iv+1);
+
+            historgram_primitives->push_back(iv+1);
+            historgram_primitives->push_back(iv+0);
+
+            outline_primitives->push_back(iv+1);
+
+        }
+
+        geometry->addPrimitiveSet(outline_primitives.get());
+        geometry->addPrimitiveSet(historgram_primitives.get());
+        geometry->addPrimitiveSet(background_primitives.get());
+    }
+
+    //transform->setMatrix(osg::Matrix::scale(xScale/(maxX-minY), yScale/(yMax), 1.0f));
+
+    transform->setMatrix(osg::Matrix::scale(2.0,1.0,1.0)*osg::Matrix::rotate(osg::DegreesToRadians(90.0), osg::Vec3d(1.0,0.0,0.0)));
+
+    return transform.release();
+}
+
+osg::Node* createGraphicalRepresentation(osg::TransferFunction1D* tf, unsigned int channel)
+{
+    typedef osg::TransferFunction1D::ColorMap ColorMap;
+    ColorMap& colorMap = tf->getColorMap();
+    if (colorMap.empty()) return 0;
+
+    osg::ref_ptr<osg::MatrixTransform> transform = new osg::MatrixTransform;
+
+    float xMin = colorMap.begin()->first;
+    float xMax = colorMap.rbegin()->first;
+
+    float depth = 0.0f;
+    float yMax = 0.0f;
+
+    // find yMax
+    for(ColorMap::iterator itr = colorMap.begin();
+        itr != colorMap.end();
+        ++itr)
+    {
+        float y = itr->second[channel];
+        if (y>yMax) yMax = y;
+    }
+
+    float xScale = 1.0f/(xMax-xMin);
+    float yScale = 1.0f/yMax;
+
+    {
+        osg::ref_ptr<osg::Geode> geode = new osg::Geode;
+        transform->addChild(geode.get());
+
+        osg::ref_ptr<osg::Geometry> geometry = new osg::Geometry;
+        geode->addDrawable(geometry.get());
+        geode->getOrCreateStateSet()->setMode(GL_LIGHTING, osg::StateAttribute::OFF);
+        geode->getOrCreateStateSet()->setMode(GL_BLEND, osg::StateAttribute::ON);
+
+        osg::ref_ptr<osg::Vec3Array> vertices = new osg::Vec3Array;
+        geometry->setVertexArray(vertices.get());
+
+        osg::ref_ptr<osg::Vec4Array> colours = new osg::Vec4Array;
+        geometry->setColorArray(colours.get(), osg::Array::BIND_PER_PRIMITIVE_SET);
+        colours->push_back(osg::Vec4(1.0,1.0,1.0,1.0));
+        colours->push_back(osg::Vec4(1.0,1.0,1.0,1.0));
+        colours->push_back(osg::Vec4(1.0,1.0,1.0,0.1));
+
+
+        unsigned numColumnsRequired = colorMap.size();
+        vertices->reserve(numColumnsRequired*3);
+        for(ColorMap::iterator itr = colorMap.begin();
+            itr != colorMap.end();
+            ++itr)
+        {
+            float x = itr->first;
+            float y = itr->second[channel];
+
+            vertices->push_back(osg::Vec3(x*xScale, 0.0f, depth));
+            vertices->push_back(osg::Vec3(x*xScale, y*yScale, depth));
+            vertices->push_back(osg::Vec3(x*xScale, yMax*yScale, depth));
+        }
+
+        osg::ref_ptr<osg::DrawElementsUShort> background_primitives = new osg::DrawElementsUShort(GL_TRIANGLE_STRIP);
+        osg::ref_ptr<osg::DrawElementsUShort> historgram_primitives = new osg::DrawElementsUShort(GL_TRIANGLE_STRIP);
+        osg::ref_ptr<osg::DrawElementsUShort> outline_primitives = new osg::DrawElementsUShort(GL_LINE_STRIP);
+        for(unsigned int i=0; i<numColumnsRequired; ++i)
+        {
+            int iv = i*3;
+
+            background_primitives->push_back(iv+2);
+            background_primitives->push_back(iv+1);
+
+            historgram_primitives->push_back(iv+1);
+            historgram_primitives->push_back(iv+0);
+
+            outline_primitives->push_back(iv+1);
+
+        }
+
+        geometry->addPrimitiveSet(outline_primitives.get());
+        geometry->addPrimitiveSet(historgram_primitives.get());
+        geometry->addPrimitiveSet(background_primitives.get());
+    }
+
+    //transform->setMatrix(osg::Matrix::scale(xScale/(maxX-minY), yScale/(yMax), 1.0f));
+
+    transform->setMatrix(osg::Matrix::scale(2.0,1.0,1.0)*osg::Matrix::rotate(osg::DegreesToRadians(90.0), osg::Vec3d(1.0,0.0,0.0)));
+
+    return transform.release();
+}
+
 
 osg::TransferFunction1D* readTransferFunctionFile(const std::string& filename, float colorScale=1.0f)
 {
@@ -108,8 +412,16 @@ int main(int argc, char ** argv)
         OSG_NOTICE<<"No image found."<<std::endl;
     }
 
+    Histogram histogram;
+    histogram.analyse(image.get());
 
-    viewer.setSceneData( model.get() );
+    osg::ref_ptr<osg::Group> group = new osg::Group;
+    group->addChild(histogram.createGraphicalRepresentation());
+    //if (tf.valid()) group->addChild(createGraphicalRepresentation(tf.get(),1));
+
+    viewer.setSceneData(group.get());
+
+    osgDB::writeNodeFile(*viewer.getSceneData(),"graph.osgt");
 
     return viewer.run();
 }