osgEarth教程（二）——VS配置osgEarth及第一个小例子

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本文主要介绍通过VS配置编译好的osgEarth，并完成第一个小例子。

一、VS配置osgEarth

打开VS，新建win32控制台项目，选择空项目。

（1）配置包含目录

在工程上右键->属性->VC++目录

包含目录：E:\osg+osgearth_64\include

（2）配置库文件

在工程上右键->属性->VC++目录

库目录：E:\osg+osgearth_64\lib

右键->属性->链接器->输入->附加依赖项，输入如下文件：

（下列为debug模式的依赖库，若选择release模式，则去除库名称后的d即可，如osgd.lib->osg.lib）
osgd.lib
osgUtild.lib
osgDBd.lib
osgGAd.lib
osgViewerd.lib
osgEarthd.lib
osgEarthUtild.lib
osgEarthFeaturesd.lib
osgEarthSymbologyd.lib
OpenThreadsd.lib

二、小例子

新建cpp文件test.cpp，并输入如下代码：

#include <osgGA/GUIEventHandler>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgEarth/MapNode>
#include <osgEarth/Registry>
#include <osgEarth/ObjectIndex>
#include <osgEarthUtil/EarthManipulator>
#include <osgEarthUtil/ExampleResources>
#include <osgEarthUtil/Controls>
#include <osgEarthUtil/RTTPicker>
#include <osgEarthFeatures/Feature>
#include <osgEarthFeatures/FeatureIndex>

#define LC "[feature_query] "

using namespace osgEarth::Util;
using namespace osgEarth::Util::Controls;
using namespace osgEarth::Features;

//-----------------------------------------------------------------------

/**
* Creates a simple user interface for the demo.
*/
Container* createUI()
{
	VBox* vbox = new VBox();
	vbox->setVertAlign(Control::ALIGN_TOP);
	vbox->setHorizAlign(Control::ALIGN_RIGHT);
	vbox->addControl(new LabelControl("Feature Query Demo", Color::Yellow));
	vbox->addControl(new LabelControl("Click on a feature to see its attributes."));
	return vbox;
}

//-----------------------------------------------------------------------

/**
* Query Callback that displays the targeted feature's attributes in a
* user interface grid control.
*/

class ReadoutCallback : public RTTPicker::Callback
{
public:
	ReadoutCallback(ControlCanvas* container) : _lastFID(~0)
	{
		_grid = new Grid();
		_grid->setBackColor(osg::Vec4(0, 0, 0, 0.7f));
		container->addControl(_grid);
	}

	void onHit(ObjectID id)
	{
		FeatureIndex* index = Registry::objectIndex()->get<FeatureIndex>(id).get();
		Feature* feature = index ? index->getFeature(id) : 0L;
		if (feature && feature->getFID() != _lastFID)
		{
			_grid->clearControls();
			unsigned r = 0;

			_grid->setControl(0, r, new LabelControl("FID", Color::Red));
			_grid->setControl(1, r, new LabelControl(Stringify() << feature->getFID(), Color::White));
			++r;

			const AttributeTable& attrs = feature->getAttrs();
			for (AttributeTable::const_iterator i = attrs.begin(); i != attrs.end(); ++i, ++r)
			{
				_grid->setControl(0, r, new LabelControl(i->first, 14.0f, Color::Yellow));
				_grid->setControl(1, r, new LabelControl(i->second.getString(), 14.0f, Color::White));
			}
			if (!_grid->visible())
				_grid->setVisible(true);

			_lastFID = feature->getFID();
		}
	}

	void onMiss()
	{
		_grid->setVisible(false);
		_lastFID = 0u;
	}

	bool accept(const osgGA::GUIEventAdapter& ea, const osgGA::GUIActionAdapter& aa)
	{
		return ea.getEventType() == ea.RELEASE; // click
	}

	Grid*     _grid;
	FeatureID _lastFID;
};

//------------------------------------------------------------------------

int main(int argc, char** argv)
{
	osg::ArgumentParser arguments(&argc, argv);

	// a basic OSG viewer
	osgViewer::Viewer viewer(arguments);

	// install our default manipulator (do this before using MapNodeHelper)
	viewer.setCameraManipulator(new EarthManipulator());

	// load an earth file, and support all or our example command-line options
	// and earth file <external> tags
	osg::Group* root = MapNodeHelper().load(arguments, &viewer, createUI());
	if (root)
	{
		viewer.setSceneData(root);

		MapNode* mapNode = MapNode::findMapNode(root);
		if (mapNode)
		{
			// Install the query tool.
			RTTPicker* picker = new RTTPicker();
			viewer.addEventHandler(picker);
			picker->addChild(mapNode);

			// Install a readout for feature metadata.
			ControlCanvas* canvas = ControlCanvas::getOrCreate(&viewer);
			picker->setDefaultCallback(new ReadoutCallback(canvas));
		}

		return viewer.run();
	}
	else
	{
		OE_NOTICE
			<< "\nUsage: " << argv[0] << " file.earth" << std::endl
			<< MapNodeHelper().usage() << std::endl;
	}
}

复制下列文件至项目根目录：

cloud_combined_2048.jpg

clouds.clr

clouds.earth

设置命令行参数：

右键->属性->调试->命令参数->clouds.earth

运行，即可看到下列结果：