OSGEarth绘制Geometry：绘多边形（三）

功能描述如下：

1. 鼠标多次点击的区域绘制多边形，为黄色；

2. 最近一次点击的点以及第一次点击的点和鼠标move到的点之间连线，为两条红色的虚线，表示下次即将绘制的区域块。

代码如下：drawpolygon.h

class DrawPolygon : public HandleAdapter
{
public:
DrawPolygon(GraphicsView* view);
~DrawPolygon();

protected:
virtual void slotPicked(osg::Vec3d pos);
virtual void slotMoveing(osg::Vec3d pos);
virtual void slotRightHandle();

private:
std::vector<osg::Vec3d> m_vecPoints;

// 多边形绘制
osgEarth::Symbology::Style m_polygonStyle;
osgEarth::Annotation::FeatureNode* m_pFeatureNode;
osgEarth::Annotation::FeatureEditor* m_pPolygonEdit;

// 虚线
osgEarth::Symbology::Style m_stippleLineStyle;
osgEarth::Annotation::FeatureNode* m_pStippleFeatureNode;
};

功能实现如下：drawpolygon.cpp

DrawPolygon::DrawPolygon(GraphicsView* view)
: HandleAdapter(view)
{
m_vecPoints.clear();
m_pFeatureNode = NULL;
m_pStippleFeatureNode = NULL;
m_pPolygonEdit = NULL;

// 多边形的style
m_polygonStyle.getOrCreate<osgEarth::Symbology::PolygonSymbol>()
->fill()->color() = osgEarth::Symbology::Color::Yellow;
m_polygonStyle.getOrCreate<osgEarth::Symbology::AltitudeSymbol>()
->clamping() = osgEarth::Symbology::AltitudeSymbol::CLAMP_TO_TERRAIN;
m_polygonStyle.getOrCreate<osgEarth::Symbology::AltitudeSymbol>()
->technique() = osgEarth::Symbology::AltitudeSymbol::TECHNIQUE_DRAPE;
m_polygonStyle.getOrCreate<osgEarth::Symbology::AltitudeSymbol>()
->verticalOffset() = 0.1;

// 线的style
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::LineSymbol>()
->stroke()->color() = osgEarth::Symbology::Color::Red;
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::LineSymbol>()
->stroke()->width() = 2.0;
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::LineSymbol>()
->tessellation() = 20.0;
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::AltitudeSymbol>()
->clamping() = osgEarth::Symbology::AltitudeSymbol::CLAMP_TO_TERRAIN;
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::AltitudeSymbol>()
->technique() = osgEarth::Symbology::AltitudeSymbol::TECHNIQUE_DRAPE;
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::AltitudeSymbol>()
->verticalOffset() = 0.1;
m_stippleLineStyle.getOrCreate<osgEarth::Symbology::LineSymbol>()
->stroke()->stipple() = 255;
}

DrawPolygon::~DrawPolygon()
{

}

void DrawPolygon::slotPicked(osg::Vec3d pos)
{
m_vecPoints.push_back(pos);
if (m_vecPoints.size() <= 2)
{
return;
}

if (m_pPolygonEdit != NULL)
{
m_pPolygonEdit->removeChildren(0, m_pPolygonEdit->getNumChildren());
m_pPolygonEdit = NULL;
}
if (m_pFeatureNode == NULL)
{
osgEarth::Features::Feature* pFeature = new osgEarth::Features::Feature(
new osgEarth::Symbology::Polygon,
m_pMap3D->getSRS(), m_polygonStyle);

m_pFeatureNode = new osgEarth::Annotation::FeatureNode(
m_pMap3D->getMapNode(), pFeature);

m_pLayerGroup->addChild(m_pFeatureNode);
}

osgEarth::Symbology::Geometry* pGeometry = m_pFeatureNode->getFeature()->getGeometry();
pGeometry->clear();
m_pFeatureNode->setStyle(m_polygonStyle);
for (int i = 0; i < m_vecPoints.size(); ++i)
{
pGeometry->push_back(m_vecPoints[i]);
}

m_pFeatureNode->init();
if (m_pStippleFeatureNode != NULL)
{
m_pStippleFeatureNode->getFeature()->getGeometry()->clear();
}
if (m_pPolygonEdit == NULL)
{
m_pPolygonEdit = new osgEarth::Annotation::FeatureEditor(m_pFeatureNode);
m_pLayerGroup->addChild(m_pPolygonEdit);
}
}

void DrawPolygon::slotMoveing(osg::Vec3d pos)
{
if (m_vecPoints.size() < 2)
{
return;
}
if (m_pStippleFeatureNode == NULL)
{
osgEarth::Features::Feature* pFeature = new osgEarth::Features::Feature(
new osgEarth::Annotation::LineString,
m_pMap3D->getSRS(), m_stippleLineStyle);
m_pStippleFeatureNode = new osgEarth::Annotation::FeatureNode(
m_pMap3D->getMapNode(), pFeature);

m_pLayerGroup->addChild(m_pStippleFeatureNode);
}

osgEarth::Symbology::Geometry* pGeometry = m_pStippleFeatureNode->getFeature()->getGeometry();
pGeometry->clear();
m_pStippleFeatureNode->setStyle(m_stippleLineStyle);
pGeometry->push_back(m_vecPoints[0]);
pGeometry->push_back(pos);
pGeometry->push_back(m_vecPoints[m_vecPoints.size() - 1]);

m_pStippleFeatureNode->init();
}

void DrawPolygon::slotRightHandle()
{
m_vecPoints.clear();
if (m_pStippleFeatureNode != NULL)
{
m_pStippleFeatureNode->getFeature()->getGeometry()->clear();
}
// 确保下次绘制的多边形和这个没任何关系
m_pFeatureNode = nullptr;
}