前言
本示例主要演示osgEarth的事件处理的用法，内容比较多，这部分功能也很重要。
输入命令依然采用china-simple.earth的示例，加上了模型，但是模型并没有看到，可能是因为模型没有放大太小的原因。在代码中设置了不加载模型的话，会绘制两个半圆。
// 加载模型，但是看不到，估计是模型太小，需要放大
osgearth_manipd.exe earth_image/china-simple.earth --model axes.osgt
// 并没有加载模型
osgearth_manipd.exe earth_image/china-simple.earth --model modelToLoad
// 不加载模型，会默认创建一个半球，距离太远的话，半球也看不到
osgearth_manipd.exe earth_image/china-simple.earth执行效果
按下W键，开启坐标，也就是黄色的两条线，交点始终跟随 Thing 1 节点。
按键说明
| * | 左键 | 按住左键拖动地球 | * | u | 看不出来，没啥变化 |
| * | 中键 | 按住中键可以旋转地球 | * | o | 切换操作器，地球会有大小变化 |
| * | 右键 | 按住右键前后移动，缩放地球 | * | 8 | 视角绑定thing 1，也可以说跟踪 |
| * | 右键/左键 双击 | 越来越远/越来越近 | * | 9 | 视角绑定thing 2，也可以说跟踪 |
| * | 滚轮滚动 | 视角远近控制 | * | t | 地球三种转动状态的切换 |
| * | arrows | shift+上/下/左/右键， 好像没啥作用 | * | b | 解除绑定 '8' ‘9’，，或者说解除跟踪 |
| * | shift+左键 | 看不出来，没啥变化 | * | a | 看不出来，没啥变化 |
| * | q | 看不出来，没啥变化 | |||
| * | k | 看不出来，没啥变化 | |||
| * | L | 看不出来，没啥变化 | |||
| * | j | 定位到可以看见一组点的视点 | |||
| * | W | 绘制两条线，交点始终定位在thing 1上，屏幕坐标系 |
[注] 必须在英文下输入，如果没有注意，在中文状态下输入字符，地球会被卡住。此时只能退出重新运行程序。
thing1 thing 2,这两个文本是移动的。
代码分析
#include <string>
#include <osg/Notify>
#include <osg/Timer>
#include <osg/ShapeDrawable>
#include <osg/Depth>
#include <osg/PositionAttitudeTransform>
#include <osgGA/StateSetManipulator>
#include <osgGA/GUIEventHandler>
#include <osgViewer/Viewer>
#include <osgViewer/ViewerEventHandlers>
#include <osgEarth/GeoMath>
#include <osgEarth/GeoTransform>
#include <osgEarth/MapNode>
#include <osgEarth/TerrainEngineNode>
#include <osgEarth/Viewpoint>
#include <osgEarthUtil/EarthManipulator>
#include <osgEarthUtil/Controls>
#include <osgEarthUtil/ExampleResources>
#include <osgEarthUtil/LogarithmicDepthBuffer>
#include <osgEarthUtil/ViewFitter>
#include <osgEarthAnnotation/AnnotationUtils>
#include <osgEarthAnnotation/LabelNode>
#include <osgEarthSymbology/Style>
#include <osgEarth/ScreenSpaceLayout>
using namespace osgEarth::Util;
using namespace osgEarth::Util::Controls;
using namespace osgEarth::Annotation;
#define D2R (osg::PI/180.0)
#define R2D (180.0/osg::PI)
namespace
{
/**
* Tether callback test.是否绑定
*/
struct TetherCB : public EarthManipulator::TetherCallback
{
void operator()(osg::Node* node)
{
if ( node ) {
OE_WARN << "Tether on\n";
}
else {
OE_WARN << "Tether off\n";
}
}
};
/**
* Builds our help menu UI.创建左上角的说明文档
*/
Container* createHelp( osgViewer::View* view )
{
const char* text[] =
{
"left mouse :", "pan",
"middle mouse :", "rotate",
"right mouse :", "continuous zoom",
"double-click :", "zoom to point",
"scroll wheel :", "zoom in/out",
"arrows :", "pan",
//"1-6 :", "fly to preset viewpoints",
"shift-left-mouse :", "locked pan",
"u :", "toggle azimuth lock",
"o :", "toggle perspective/ortho",
"8 :", "Tether to thing 1",
"9 :", "Tether to thing 2",
"t :", "cycle tethermode",
"b :", "break tether",
"a :", "toggle viewpoint arcing",
"q :", "toggle throwing",
"k :", "toggle collision",
"L :", "toggle log depth buffer"
//"W :", "坐标系", // 源代码并没有这两个提示
//"j :", "定位到指定点组的视点",
};
Grid* g = new Grid();// 创建网格
unsigned i, c, r;
std::cout << sizeof(text) << std::endl; // 存储所有指针占位多少
std::cout << sizeof(text[0]) << std::endl; // 每个指针占位多少
for( i=0; i<sizeof(text)/sizeof(text[0]); ++i )
{
c = i % 2;
r = i / 2;
g->setControl( c, r, new LabelControl(text[i]) );// 两列c，i行r,显示label控件
}
VBox* v = new VBox();
v->addControl( g );// 将网格控件放入VBox控件中
return v;
}
/**
* Some preset viewpoints to show off the setViewpoint function.
*/
static Viewpoint VPs[] = {
Viewpoint( "Africa", 0.0, 0.0, 0.0, 0.0, -90.0, 10e6 ),
Viewpoint( "California", -121.0, 34.0, 0.0, 0.0, -90.0, 6e6 ),
Viewpoint( "Europe", 0.0, 45.0, 0.0, 0.0, -90.0, 4e6 ),
Viewpoint( "Washington DC", -77.0, 38.0, 0.0, 0.0, -90.0, 1e6 ),
Viewpoint( "Australia", 135.0, -20.0, 0.0, 0.0, -90.0, 2e6 ),
Viewpoint( "Boston", -71.096936, 42.332771, 0, 0.0, -90, 1e5 )
};
/**
* Handler that demonstrates the "viewpoint" functionality in
* osgEarthUtil::EarthManipulator. Press a number key to fly to a viewpoint.
*/
struct FlyToViewpointHandler : public osgGA::GUIEventHandler
{
FlyToViewpointHandler( EarthManipulator* manip ) : _manip(manip) { }
bool handle( const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa )
{
if ( ea.getEventType() == ea.KEYDOWN && ea.getKey() >= '1' && ea.getKey() <= '6' )
{
_manip->setViewpoint( VPs[ea.getKey()-'1'], 4.0 );// 根据设置好的位置，123456定位不同的地点
aa.requestRedraw();
}
return false;
}
osg::observer_ptr<EarthManipulator> _manip;
};
/**
* Toggles the logarithmic depth buffer切换对数深度缓冲区
*/
struct ToggleLDB : public osgGA::GUIEventHandler
{
ToggleLDB(char key) : _key(key), _installed(false) { }// key=L
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
if ( !_installed )
{
_nfratio = aa.asView()->getCamera()->getNearFarRatio();// 获取到近/远率
_ldb.install(aa.asView()->getCamera());
aa.asView()->getCamera()->setNearFarRatio(0.00001);
}
else
{
_ldb.uninstall(aa.asView()->getCamera());
aa.asView()->getCamera()->setNearFarRatio(_nfratio);
}
_installed = !_installed;// 每次切换
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Toggle LDB"));
}
char _key;
float _nfratio;
bool _installed;
osgEarth::Util::LogarithmicDepthBuffer _ldb;
};
/**
* Toggles screen space layout on the sismulated objects 切换模拟对象的屏幕空间布局
*/
struct ToggleSSL : public osgGA::GUIEventHandler
{
ToggleSSL(osg::Group* g, char key) : _group(g), _key(key), _installed(false) { }// key=)
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
_installed = !_installed;
ScreenSpaceLayout::setDeclutteringEnabled(_installed);// 启动或禁用清理
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Toggle SSL"));
}
char _key;
osg::Group* _group;
bool _installed;
};
/**
* Handler to toggle "azimuth locking", which locks the camera's relative Azimuth
* while panning. For example, it can maintain "north-up" as you pan around. The
* caveat is that when azimuth is locked you cannot cross the poles.
*/
struct LockAzimuthHandler : public osgGA::GUIEventHandler // 锁定/解锁 方位角
{
LockAzimuthHandler(char key, EarthManipulator* manip) // 传入key = u
: _key(key), _manip(manip) { }
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
bool lockAzimuth = _manip->getSettings()->getLockAzimuthWhilePanning();
std::cout << "按下 u" << std::endl;// 确实收到消息，但是在操作上并没有看到所定方位角
_manip->getSettings()->setLockAzimuthWhilePanning(!lockAzimuth);// 设置为当前状态相反的状态
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Toggle azimuth locking"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Handler to toggle "viewpoint transition arcing", which causes the camera to "arc"
* as it travels from one viewpoint to another.
*/
struct ToggleArcViewpointTransitionsHandler : public osgGA::GUIEventHandler
{
ToggleArcViewpointTransitionsHandler(char key, EarthManipulator* manip)
: _key(key), _manip(manip) { }// key=a
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
bool arc = _manip->getSettings()->getArcViewpointTransitions();
std::cout << "按下 a" << std::endl;// 确实收到消息，但是没看出什么变化
_manip->getSettings()->setArcViewpointTransitions(!arc);
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Arc viewpoint transitions"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Toggles the throwing feature.切换投掷功能。
*/
struct ToggleThrowingHandler : public osgGA::GUIEventHandler
{
ToggleThrowingHandler(char key, EarthManipulator* manip)
: _key(key), _manip(manip)// key=q
{
}
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
bool throwing = _manip->getSettings()->getThrowingEnabled();
std::cout << "按下 q" << std::endl;// 确实收到消息，但是没看出什么变化
_manip->getSettings()->setThrowingEnabled( !throwing );
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Toggle throwing"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Toggles the collision feature.切换碰撞功能。
*/
struct ToggleCollisionHandler : public osgGA::GUIEventHandler
{
ToggleCollisionHandler(char key, EarthManipulator* manip)
: _key(key), _manip(manip)// key=k
{
}
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
bool value = _manip->getSettings()->getTerrainAvoidanceEnabled();
std::cout << "按下 k" << std::endl;// 确实收到消息，但是没看出什么变化
_manip->getSettings()->setTerrainAvoidanceEnabled( !value );
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Toggle terrain avoidance"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Breaks a tether.三种状态的切换
*/
struct CycleTetherMode : public osgGA::GUIEventHandler
{
CycleTetherMode(char key, EarthManipulator* manip)
: _key(key), _manip(manip) { }// key=t
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
EarthManipulator::TetherMode mode = _manip->getSettings()->getTetherMode();
if ( mode == _manip->TETHER_CENTER ) {
_manip->getSettings()->setTetherMode( _manip->TETHER_CENTER_AND_HEADING );// 相机将跟随节点，仅跟随方向旋转
OE_NOTICE << "Tether mode = TETHER_CENTER_AND_HEADING\n";
}
else if ( mode == _manip->TETHER_CENTER_AND_HEADING ) {
_manip->getSettings()->setTetherMode( _manip->TETHER_CENTER_AND_ROTATION ); // 摄影机将跟随节点和节点所做的所有旋转
OE_NOTICE << "Tether mode = TETHER_CENTER_AND_ROTATION\n";
}
else {
_manip->getSettings()->setTetherMode( _manip->TETHER_CENTER );// 摄影机将跟随节点的中心。
OE_NOTICE << "Tether mode = CENTER\n";
}
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Cycle Tether Mode"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Breaks a tether.解绑
*/
struct BreakTetherHandler : public osgGA::GUIEventHandler
{
BreakTetherHandler(char key, EarthManipulator* manip)
: _key(key), _manip(manip) { }//key=b
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
_manip->clearViewpoint();// 解除所有操作器绑定，恢复自由状态。thing1和 thing2 的状态改变明显
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Break a tether"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Adjusts the position offset.调整位置偏移。
*/
struct SetPositionOffset : public osgGA::GUIEventHandler
{
SetPositionOffset(EarthManipulator* manip)
: _manip(manip) { }
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && (ea.getModKeyMask() & ea.MODKEY_SHIFT) )
{
Viewpoint oldvp = _manip->getViewpoint();
double seconds = 0.5; // 时间秒。每次切换都需要0.5秒
if ( ea.getKey() == ea.KEY_Left )// 左键
{
Viewpoint vp;
vp.positionOffset() = oldvp.positionOffset().get() + osg::Vec3f(-1000,0,0);
_manip->setViewpoint( vp, seconds );
}
else if ( ea.getKey() == ea.KEY_Right )// 右键
{
Viewpoint vp;
vp.positionOffset() = oldvp.positionOffset().get() + osg::Vec3f(1000,0,0);
_manip->setViewpoint( vp, seconds );
}
else if ( ea.getKey() == ea.KEY_Up )// 上键
{
Viewpoint vp;
vp.positionOffset() = oldvp.positionOffset().get() + osg::Vec3f(0,0,1000);
_manip->setViewpoint( vp, seconds );
}
else if ( ea.getKey() == ea.KEY_Down )// 下键
{
Viewpoint vp;
vp.positionOffset() = oldvp.positionOffset().get() + osg::Vec3f(0,0,-1000);
_manip->setViewpoint( vp, seconds );
}
aa.requestRedraw();
return true;
}
return false;
}
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* Toggles perspective/ortho projection matrix. 切换投影矩阵，透视投影矩阵和正射投影矩阵
*/
struct ToggleProjMatrix : public osgGA::GUIEventHandler
{
ToggleProjMatrix(char key, EarthManipulator* manip)
: _key(key), _manip(manip)// ley=o
{
}
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
osg::Matrix proj = aa.asView()->getCamera()->getProjectionMatrix();
if ( proj(3,3) == 0 )
{
OE_NOTICE << "Switching to orthographc.\n";
proj.getPerspective(_vfov, _ar, _zn, _zf); // 获取值
aa.asView()->getCamera()->setProjectionMatrixAsOrtho(-1, 1, -1, 1, _zn, _zf);// 正射投影矩阵
}
else
{
OE_NOTICE << "Switching to perspective.\n";
aa.asView()->getCamera()->setProjectionMatrixAsPerspective(_vfov, _ar, _zn, _zf);// 透视矩阵
}
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Toggle projection matrix type"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
double _vfov, _ar, _zn, _zf;
};
// 定位到某组点的视点，一组点都可以看到
struct FitViewToPoints : public osgGA::GUIEventHandler
{
std::vector<GeoPoint> _points;
const SpatialReference* _mapSRS;
FitViewToPoints(char key, EarthManipulator* manip, const SpatialReference* mapSRS)
: _key(key), _manip(manip), _mapSRS(mapSRS)// key=j
{
// Set up a list of control points
const SpatialReference* srs = SpatialReference::get("wgs84");
_points.push_back(GeoPoint(srs, -120, 30, 0));
_points.push_back(GeoPoint(srs, -100, 45, 0));
}
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
// fitter 创建适合摄影机视图平截头体的视点，以尽可能紧密地包围一组地理空间点。
ViewFitter fitter(_mapSRS, aa.asView()->getCamera());
fitter.setBuffer( 100000.0 );
Viewpoint vp;
if (fitter.createViewpoint(_points, vp))// 根据_points重新生成一个vp视点
{
_manip->setViewpoint(vp);// 定位到vp视点
aa.requestRedraw();
}
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("FitViewToPoints"));
}
char _key;
osg::ref_ptr<EarthManipulator> _manip;
};
/**
* A simple simulator that moves an object around the Earth. We use this to
* demonstrate/test tethering.
*/
// 一个简单的模拟器，可以使物体绕地球运动。用来演示跟踪thing
struct Simulator : public osgGA::GUIEventHandler
{
Simulator( osg::Group* root, EarthManipulator* manip, MapNode* mapnode, osg::Node* model, const char* name, char key)
: _manip(manip), _mapnode(mapnode), _model(model), _name(name), _key(key) // key=8 或 9
{
if ( !model )
{
// 模型不存在，则创建一个半球，半径和颜色
_model = AnnotationUtils::createHemisphere(250.0, osg::Vec4(1,.7,.4,1));
std::cout << "no model" << std::endl;
}
_geo = new GeoPositionNode();
_geo->getPositionAttitudeTransform()->addChild(_model);
Style style;
TextSymbol* text = style.getOrCreate<TextSymbol>();
text->size() = 32.0f;
text->declutter() = false;
text->pixelOffset()->set(50, 50);// 文本偏移像素点
_label = new LabelNode(_name, style);// _name 即要显示的名称
_label->setDynamic( true );// 因为文本移动，所以此处设置为true
_label->setHorizonCulling(false);// 不需要裁剪
_geo->getPositionAttitudeTransform()->addChild(_label);
mapnode->addChild(_geo.get());
}
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if ( ea.getEventType() == ea.FRAME )// 此语段为标签添加了动画
{
double t0 = osg::Timer::instance()->time_s();// 儒略日时间
double t = fmod( t0, 6000.0 ) / 6000.0;// t0%6000/6000, 将数字控制在[0,1)范围内
GeoPoint p = _start.interpolate(_end, t);// 差值，在_end和t之间
// GeoMath::bearing 以弧度计算从一个点到下一个点的初始方位
double bearing = GeoMath::bearing(_start.y(), _start.x(), p.y(), p.x());
float a = sin(t0*0.2);// a值没有被用
float pitch = 0.0;
_geo->setPosition(p);
_geo->setLocalRotation(
osg::Quat(pitch, osg::Vec3d(1, 0, 0)) *
osg::Quat(bearing, osg::Vec3d(0, 0, -1)));
}
else if ( ea.getEventType() == ea.KEYDOWN )
{
if ( ea.getKey() == _key )// 8 或 9
{
Viewpoint vp = _manip->getViewpoint();
//vp.setNode( _pat.get() );
vp.setNode(_model);
vp.range() = 25000.0;
vp.pitch() = -45.0;
_manip->setViewpoint(vp, 2.0);// 2秒内飞到指定位置
}
return true;
}
return false;
}
std::string _name;
char _key;
MapNode* _mapnode;
EarthManipulator* _manip;
GeoPoint _start, _end;
LabelNode* _label;
osg::Node* _model;
float _heading;
float _pitch;
osg::ref_ptr<GeoPositionNode> _geo;
};
/**
* Place an X at the sim entity position, in screen space.
* The point of this is to test the EarthManipulator::UpdateCameraCallback
* which provides a frame-synched camera matrix (post-update traversal)
*/
// 创建一个十字坐标
struct CalculateWindowCoords : public osgGA::GUIEventHandler
{
CalculateWindowCoords(char key, EarthManipulator* manip, Simulator* sim)
: _key(key), _active(false), _sim(sim), _xform(0L)
{
//nop
}
void onUpdateCamera(const osg::Camera* cam)
{
if (_active)
{
if (!_xform)
{
osg::Geometry* geom = new osg::Geometry();
osg::Vec3Array* verts = new osg::Vec3Array();
verts->push_back(osg::Vec3(-10000, 0, 0));
verts->push_back(osg::Vec3( 10000, 0, 0));
verts->push_back(osg::Vec3( 0, -10000, 0));
verts->push_back(osg::Vec3( 0, 10000, 0));
verts->push_back(osg::Vec3( 0, 0, -10000));
verts->push_back(osg::Vec3( 0, 0, 10000));
geom->setVertexArray(verts);
osg::Vec4Array* colors = new osg::Vec4Array();
colors->push_back(osg::Vec4(1, 1, 0, 1));// 黄色线
colors->setBinding(colors->BIND_OVERALL);
geom->setColorArray(colors);
geom->addPrimitiveSet(new osg::DrawArrays(GL_LINES, 0, 6));// 6个点，绘制3条线，但屏幕上仅能看出2条线，水平和垂直
geom->setCullingActive(false);// 不裁剪
geom->getOrCreateStateSet()->setAttributeAndModes(new osg::Depth(osg::Depth::ALWAYS, 0, 1, true), 1);//深度设置
_xform = new osg::MatrixTransform();
_xform->addChild(geom);
osg::View* view = const_cast<osg::View*>(cam->getView());
ControlCanvas::getOrCreate(view)->addChild(_xform);
}
/// 坐标变换 V_clip=M_projection⋅M_view⋅M_model⋅V_local 裁剪坐标=透视矩阵*观察矩阵*模型矩阵*本地坐标——来自OpenGL
GeoPoint p = _sim->_geo->getPosition();// 获取thing1的坐标点
osg::Vec3d world;
p.toWorld(world);// 转化为世界坐标
osg::Matrix worldToWindow =
cam->getViewMatrix() *
cam->getProjectionMatrix() *
cam->getViewport()->computeWindowMatrix();// 世界坐标转到窗口坐标
osg::Vec3d win = world * worldToWindow;// 得到窗口坐标
_xform->setMatrix(osg::Matrix::translate(win));
}
}
bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
if (ea.getEventType() == ea.KEYDOWN && ea.getKey() == _key)
{
_active = !_active;
aa.requestRedraw();
return true;
}
return false;
}
void getUsage(osg::ApplicationUsage& usage) const
{
using namespace std;
usage.addKeyboardMouseBinding(string(1, _key), string("Show Window Coords"));
}
osg::MatrixTransform* _xform;
Simulator* _sim;
bool _active;
char _key;
};
// 更新相机回调
struct CameraUpdater : public EarthManipulator::UpdateCameraCallback
{
CalculateWindowCoords* _calc;
CameraUpdater(CalculateWindowCoords* calc) : _calc(calc) { }
void onUpdateCamera(const osg::Camera* cam)
{
_calc->onUpdateCamera(cam);// 当物体运动时，需要让十字线跟随物体运动
}
};
}
int main(int argc, char** argv)
{
osg::ArgumentParser arguments(&argc,argv);
if (arguments.read("--help") || argc==1)
{
OE_WARN << "Usage: " << argv[0] << " [earthFile] [--model modelToLoad]"
<< std::endl;
return 0;
}
osgViewer::Viewer viewer(arguments);
// install the programmable manipulator.安装操作器
EarthManipulator* manip = new EarthManipulator();
viewer.setCameraManipulator( manip );
// UI: 创建帮助说明控件，在左上角的位置。当鼠标移动到控件上之后，是无法点击到地球上的，没有鼠标穿透功能。
Container* help = createHelp(&viewer);
// MapNodeHelper 显示帮助
// load() 加载earth映射文件并处理所有内置示例命令行参数和XML外部变量(help)。
osg::Node* earthNode = MapNodeHelper().load( arguments, &viewer, help );
if (!earthNode)
{
OE_WARN << "Unable to load earth model." << std::endl;
return -1;
}
osg::Group* root = new osg::Group();
root->addChild( earthNode );
// 获取mapNode
osgEarth::MapNode* mapNode = osgEarth::MapNode::findMapNode( earthNode );
// user model?
// 加载模型,这里传入osg osgt格式的模型，并没有显示
osg::ref_ptr<osg::Node> model;
std::string modelFile;
if (arguments.read("--model", modelFile))
model = osgDB::readRefNodeFile(modelFile + ".osgearth_shadergen");
osg::Group* sims = new osg::Group();
root->addChild( sims );
const SpatialReference* wgs84 = SpatialReference::get("wgs84");// 坐标系
// Simulator for tethering: 系留模拟器
// thing 1 和 thing 2 会随着时间移动
Simulator* sim1 = new Simulator(sims, manip, mapNode, model.get(), "Thing 1", '8');// 8：绑住第一个物体
sim1->_name = "Thing 1";
sim1->_start = GeoPoint(wgs84, 45.0, 55.0, 10000);// 开始坐标点
sim1->_end = GeoPoint(wgs84, -45, -55.0, 10000); // 结束坐标点
viewer.addEventHandler(sim1); // 加入到操作器
Simulator* sim2 = new Simulator(sims, manip, mapNode, model.get(), "Thing 2", '9');// 9：绑住第二个物体
sim2->_name = "Thing 2";
sim2->_start = GeoPoint(wgs84, 45.0, 54.0, 10000);
sim2->_end = GeoPoint(wgs84, -44.0, -54.0, 10000);
viewer.addEventHandler(sim2);
manip->getSettings()->getBreakTetherActions().push_back( EarthManipulator::ACTION_GOTO ); // 操作器动作，直接过去
// Set the minimum distance to something larger than the default
// 距离物体小于最小距离时，物体会变大
manip->getSettings()->setMinMaxDistance(10.0, manip->getSettings()->getMaxDistance());
// Sets the maximum focal point offsets (usually for tethering)
manip->getSettings()->setMaxOffset(5000.0, 5000.0);
// Pitch limits. 俯仰角范围
manip->getSettings()->setMinMaxPitch(-90, 90);
viewer.setSceneData( root );
//为 鼠标左键按下、修改键、拖动鼠标的动作指定行为。
manip->getSettings()->bindMouse(
EarthManipulator::ACTION_EARTH_DRAG,
osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON,
osgGA::GUIEventAdapter::MODKEY_SHIFT );
manip->getSettings()->bindMouseClick(
EarthManipulator::ACTION_GOTO,
osgGA::GUIEventAdapter::LEFT_MOUSE_BUTTON,
osgGA::GUIEventAdapter::MODKEY_SHIFT);
manip->getSettings()->setArcViewpointTransitions( true );
// 设置tether连接和断裂时的动作回调
manip->setTetherCallback( new TetherCB() );
//viewer.addEventHandler(new FlyToViewpointHandler( manip ));
// 添加 自定义的各个事件处理
viewer.addEventHandler(new LockAzimuthHandler('u', manip));
viewer.addEventHandler(new ToggleArcViewpointTransitionsHandler('a', manip));
viewer.addEventHandler(new ToggleThrowingHandler('q', manip));
viewer.addEventHandler(new ToggleCollisionHandler('k', manip));
viewer.addEventHandler(new ToggleProjMatrix('o', manip));
viewer.addEventHandler(new BreakTetherHandler('b', manip));
viewer.addEventHandler(new CycleTetherMode('t', manip));
viewer.addEventHandler(new SetPositionOffset(manip));// 设置偏移
viewer.addEventHandler(new ToggleLDB('L'));
viewer.addEventHandler(new ToggleSSL(sims, ')'));
viewer.addEventHandler(new FitViewToPoints('j', manip, mapNode->getMapSRS()));
// 根据 thing 1 的位置，更新相机
CalculateWindowCoords* calc = new CalculateWindowCoords('W', manip, sim1);// 根据thing 1计算窗口坐标
viewer.addEventHandler(calc);
manip->setUpdateCameraCallback(new CameraUpdater(calc));// 相机回调
viewer.getCamera()->setSmallFeatureCullingPixelSize(-1.0f);
while(!viewer.done())
{
viewer.frame();
// simulate slow frame rate
//OpenThreads::Thread::microSleep(1000*1000);
}
return 0;
}
