OSG 多视图 实现导航拖拽器

本篇是实现一个拖拽器，通过控制右上角的立方体来选择我们的3D模型，通过选择立方体的某一个面，来直接设置模型的朝向， 同时拖拽器只能响应旋转。

我的实现方式主要通过多视图完成。首先我们重写osgGA::TrackballManipulator，只保留旋转事件。

MyTrackballManipulator.h部分实现：

#ifndef __MY_TRACKBALL_MANIPULATOR_H_
#define __MY_TRACKBALL_MANIPULATOR_H_

#include <osgGA/TrackballManipulator>
#include <osgGA/GUIActionAdapter>
#include <osgGA/GUIEventAdapter>

class MyTrackballManipulator : public osgGA::TrackballManipulator
{
public:
virtual bool handleMouseWheel(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& us);
virtual bool performMovementLeftMouseButton(const double eventTimeDelta, const double dx, const double dy);
virtual bool performMovementMiddleMouseButton(const double eventTimeDelta, const double dx, const double dy);
virtual bool performMovementRightMouseButton(const double eventTimeDelta, const double dx, const double dy);
virtual bool performMouseDeltaMovement(const float dx, const float dy);
virtual void applyAnimationStep(const double currentProgress, const double prevProgress);
};

#endif

// MyTrackballManipulator.cpp部分实现：

#include "MyTrackballManipulator.h"

bool MyTrackballManipulator::handleMouseWheel(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& us)
{
return true;
}

// 重写旋转事件
bool MyTrackballManipulator::performMovementLeftMouseButton(const double eventTimeDelta, const double dx, const double dy)
{
if (getVerticalAxisFixed())
rotateWithFixedVertical(dx, dy);
else
rotateTrackball(_ga_t0->getXnormalized(), _ga_t0->getYnormalized(),
_ga_t1->getXnormalized(), _ga_t1->getYnormalized(),
getThrowScale(eventTimeDelta));
return true;
}

bool MyTrackballManipulator::performMovementMiddleMouseButton(const double eventTimeDelta, const double dx, const double dy)
{
return true;
}

bool MyTrackballManipulator::performMovementRightMouseButton(const double eventTimeDelta, const double dx, const double dy)
{
return true;
}

bool MyTrackballManipulator::performMouseDeltaMovement(const float dx, const float dy)
{
return true;
}

void MyTrackballManipulator::applyAnimationStep(const double currentProgress, const double prevProgress)
{
}

以上就是我们重载漫游器的实现。

下面是View上点击事件的处理，包括点击检查，绘制立方体等。

//// CHUDPickHandler.h
#ifndef __CHUD_PICK_HANDLER_H_
#define __CHUD_PICK_HANDLER_H_

#include <iostream>
#include <osgViewer/View>
#include "MyTrackballManipulator.h"

// 用于标示点击的视图
static      bool        g_MasterViewClicked = true;
// 通过名字区分视图
static const std::string MASTER_VIEW_NAME   = "MASTERVIEW";
static const std::string SLAVE_VIEW_NAME    = "SLAVEVIEW";
// 全局漫游器的定义
static MyTrackballManipulator*myTrackballManipulator     = nullptr;
static osgGA::TrackballManipulator* trackballManipulator = nullptr;

class CHUDPickHandler : public osgGA::GUIEventHandler
{
public:
virtual bool handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa);
virtual void pick(osgViewer::View* view, const osgGA::GUIEventAdapter& ea);

void initVertexAndNormalData();
void callHudControllerModule();

osg::Group* createCustomCubeGeometry();

private:
osg::Vec3Array*     m_vec3VerCoords;
osg::Vec2Array*     m_vec2TexCoords;
osg::Vec3Array*     m_vec3Normalize;
osg::Vec4iArray*    m_vec4FaceVertexs;
};

#endif //__CHUD_PICK_HANDLER_H_

//// CHUDPickHandler.cpp 的实现

#include "CHUDEventHandler.h"

#include <osg/Texture2D>
#include <osgDB/ReadFile>
#include <osgViewer/CompositeViewer>
#include <osgUtil/Optimizer>

bool CHUDPickHandler::handle(const osgGA::GUIEventAdapter& ea, osgGA::GUIActionAdapter& aa)
{
osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);
if (view == nullptr)
{
return false;
}

switch (ea.getEventType())
{
case (osgGA::GUIEventAdapter::DOUBLECLICK) :
{
pick(view, ea);
return false;
}
case(osgGA::GUIEventAdapter::PUSH) :
{
// 用于标示点击的视图，便于对用的漫游器操作
osgViewer::View* view = dynamic_cast<osgViewer::View*>(&aa);
if (view)
{
if (view->getName() == MASTER_VIEW_NAME)
{
g_MasterViewClicked = true;
}
else
{
g_MasterViewClicked = false;
}
}
return false;
}
case(osgGA::GUIEventAdapter::FRAME) :
{
if (g_MasterViewClicked)
{
myTrackballManipulator->setRotation(trackballManipulator->getRotation());
}
else
{
trackballManipulator->setRotation(myTrackballManipulator->getRotation());
}

return false;
}
default:
return false;
}
}

// 我们只对导航立方体进行操作
void CHUDPickHandler::pick(osgViewer::View* view, const osgGA::GUIEventAdapter& evt)
{
if (view->getName() == MASTER_VIEW_NAME)
{
return;
}

osg::Group* group = nullptr;
osg::Geometry* geom = nullptr;

osgUtil::LineSegmentIntersector::Intersections intersections;
if (view->computeIntersections(evt, intersections))
{
osgUtil::LineSegmentIntersector::Intersection intersection = *intersections.begin();
const osg::NodePath& nodePath = intersection.nodePath;
int len = (int)nodePath.size();

geom = (len >= 1) ? dynamic_cast<osg::Geometry*>(nodePath[len - 1]) : nullptr;
group = (len >= 2) ? dynamic_cast<osg::Group*>(nodePath[len - 2]) : nullptr;
}

if (geom && group)
{
const std::string facename = geom->getName();
std::cout << " face name is " << facename << std::endl;

int index = ::atoi(facename.c_str());
double degree = 0.0f;
double zerodegree = 0.0f;
osg::Vec3f v3;
switch (index)
{
case 0:
{
myTrackballManipulator->setRotation(osg::Quat(
osg::inDegrees(90.0f), osg::Vec3(1.0f, zerodegree, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, 1.0f, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, zerodegree, 1.0f)
));
}
break;
case 5:
{
myTrackballManipulator->setRotation(osg::Quat(
osg::inDegrees(90.0f), osg::Vec3(1.0f, zerodegree, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, 1.0f, zerodegree),
osg::inDegrees(90.0f), osg::Vec3(zerodegree, zerodegree, 1.0f)
));
}
break;
case 1:
{
myTrackballManipulator->setRotation(osg::Quat(
osg::inDegrees(90.0), osg::Vec3(1.0f, zerodegree, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, 1.0f, zerodegree),
osg::inDegrees(180.0f), osg::Vec3(zerodegree, zerodegree, 1.0f)
));
}
break;
case 4:
{
myTrackballManipulator->setRotation(osg::Quat(
osg::inDegrees(90.0), osg::Vec3(1.0f, zerodegree, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, 1.0f, zerodegree),
osg::inDegrees(270.0f), osg::Vec3(zerodegree, zerodegree, 1.0f)
));
}
break;
case 2:
{
myTrackballManipulator->setRotation(osg::Quat(
osg::inDegrees(zerodegree), osg::Vec3(1.0f, zerodegree, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, 1.0f, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, zerodegree, 1.0f)
));
}
break;
case 3:
{
myTrackballManipulator->setRotation(osg::Quat(
osg::inDegrees(180.0), osg::Vec3(1.0f, zerodegree, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, 1.0f, zerodegree),
osg::inDegrees(zerodegree), osg::Vec3(zerodegree, zerodegree, 1.0f)
));
}
break;
default:
break;
}
}
}

// 这里主要是初始化立方体的顶点信息，纹理坐标信息，还有需要的顶点生成面
void CHUDPickHandler::initVertexAndNormalData()
{
m_vec3VerCoords = new osg::Vec3Array(8);
(*m_vec3VerCoords)[0] = osg::Vec3(10.0f, 10.0f, 10.0f);
(*m_vec3VerCoords)[1] = osg::Vec3(-10.0f, 10.0f, 10.0f);
(*m_vec3VerCoords)[2] = osg::Vec3(10.0f, -10.0f, 10.0f);
(*m_vec3VerCoords)[3] = osg::Vec3(-10.0f, -10.0f, 10.0f);
(*m_vec3VerCoords)[4] = osg::Vec3(10.0f, 10.0f, -10.0f);
(*m_vec3VerCoords)[5] = osg::Vec3(-10.0f, 10.0f, -10.0f);
(*m_vec3VerCoords)[6] = osg::Vec3(10.0f, -10.0f, -10.0f);
(*m_vec3VerCoords)[7] = osg::Vec3(-10.0f, -10.0f, -10.0f);

m_vec2TexCoords = new osg::Vec2Array(4);
(*m_vec2TexCoords)[0] = osg::Vec2(0.0f, 0.0f);
(*m_vec2TexCoords)[1] = osg::Vec2(1.0f, 0.0f);
(*m_vec2TexCoords)[2] = osg::Vec2(1.0f, 1.0f);
(*m_vec2TexCoords)[3] = osg::Vec2(0.0f, 1.0f);

m_vec3Normalize = new osg::Vec3Array(6);

m_vec4FaceVertexs = new osg::Vec4iArray(6);
(*m_vec4FaceVertexs)[0] = osg::Vec4i(7, 6, 2, 3);
(*m_vec4FaceVertexs)[1] = osg::Vec4i(4, 5, 1, 0);
(*m_vec4FaceVertexs)[2] = osg::Vec4i(3, 2, 0, 1);
(*m_vec4FaceVertexs)[3] = osg::Vec4i(5, 4, 6, 7);
(*m_vec4FaceVertexs)[4] = osg::Vec4i(5, 7, 3, 1);
(*m_vec4FaceVertexs)[5] = osg::Vec4i(6, 4, 0, 2);
}

osg::Group* CHUDPickHandler::createCustomCubeGeometry()
{
// 初始化立方体信息
initVertexAndNormalData();

//
osg::Group* root = new osg::Group;
root->setName("root");

char imagePath[64];
char faceName[16];
for (int i = 0; i < 6; i++)
{
sprintf(imagePath, "D:\\softwares\\side%d.png", i + 1);
sprintf(faceName, "%d", i);
osg::Image* image = osgDB::readImageFile(imagePath);
osg::Geometry* geom = new osg::Geometry;
//   一个面的四个顶点
osg::Vec3Array* coords = new osg::Vec3Array(4);
osg::Vec4i v4 = (*m_vec4FaceVertexs)[i];
(*coords)[0] = (*m_vec3VerCoords)[v4.x()];
(*coords)[1] = (*m_vec3VerCoords)[v4.y()];
(*coords)[2] = (*m_vec3VerCoords)[v4.z()];
(*coords)[3] = (*m_vec3VerCoords)[v4.w()];
geom->setVertexArray(coords);
// 面法线
osg::Vec3Array* norm = new osg::Vec3Array(1);
(*norm)[0] = ((*coords)[0] - (*coords)[1]) ^ ((*coords)[1] - (*coords)[2]);
(*norm)[0].normalize();
(*m_vec3Normalize)[i] = (*norm)[0];
geom->setNormalArray(norm, osg::Array::BIND_OVERALL);
// 纹理坐标
osg::Vec2Array* tcoords = new osg::Vec2Array(4);
(*tcoords)[0] = osg::Vec2(0.0f, 0.0f);
(*tcoords)[1] = osg::Vec2(1.0f, 0.0f);
(*tcoords)[2] = osg::Vec2(1.0f, 1.0f);
(*tcoords)[3] = osg::Vec2(0.0f, 1.0f);
geom->setTexCoordArray(0, tcoords);
geom->addPrimitiveSet(new osg::DrawArrays(osg::PrimitiveSet::QUADS, 0, coords->size()));
geom->setName(faceName);

// 设置纹理状态
if (image)
{
osg::StateSet* stateset = new osg::StateSet;
osg::Texture2D* texture = new osg::Texture2D;
texture->setImage(image);
stateset->setTextureAttributeAndModes(0, texture, osg::StateAttribute::ON);
geom->setStateSet(stateset);
}

root->addChild(geom);
}

return root;
}

void CHUDPickHandler::callHudControllerModule()
{
// 通过视图管理器管理视图
osg::ref_ptr<osgViewer::CompositeViewer> viewer = new osgViewer::CompositeViewer;

//
osg::ref_ptr<osg::Node> cow = osgDB::readNodeFile("cow.osg");

//
osgUtil::Optimizer op;
op.optimize(cow);

// 窗口信息
osg::ref_ptr<osg::GraphicsContext::Traits> traits = new osg::GraphicsContext::Traits();
traits->x = 100;
traits->y = 100;
traits->width = 1200;
traits->height = 900;
traits->windowDecoration = true;
traits->doubleBuffer = true;
traits->sharedContext = 0;

//
osg::ref_ptr<osg::GraphicsContext> gc = osg::GraphicsContext::createGraphicsContext(traits);
gc->setClearColor(osg::Vec4(0.2, 0.2, 0.2, 0.3f));
gc->setClearMask(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);

//
{
osg::ref_ptr<osgViewer::View> view = new osgViewer::View;
view->setName(MASTER_VIEW_NAME);
viewer->addView(view);

view->setSceneData(cow);
view->getCamera()->setViewport(new osg::Viewport(0, 0, traits->width, traits->height));
view->getCamera()->setGraphicsContext(gc);

trackballManipulator = new osgGA::TrackballManipulator;
view->setCameraManipulator(trackballManipulator);

// 以下貌似么有用，不确定
//osg::ref_ptr<CHUDPickHandler> chudPicker = new CHUDPickHandler();
//view->addEventHandler(chudPicker);
}

{
osg::ref_ptr<osgViewer::View> view = new osgViewer::View;
view->setName(SLAVE_VIEW_NAME);
viewer->addView(view);

myTrackballManipulator = new MyTrackballManipulator;
view->setCameraManipulator(myTrackballManipulator);
osg::ref_ptr<CHUDPickHandler> chudPicker = new CHUDPickHandler();
view->addEventHandler(chudPicker);

// 生成自定义几何体
osg::Group* group = chudPicker->createCustomCubeGeometry();
view->setSceneData(group);
view->getCamera()->setViewport(new osg::Viewport(traits->width * 0.8f, traits->height * 0.8f,
traits->width * 0.2f, traits->height * 0.2f));
view->getCamera()->setGraphicsContext(gc);
view->getCamera()->setRenderOrder(osg::Camera::RenderOrder::POST_RENDER);
}

viewer->realize();
viewer->run();
}

这样我们就完成了场景的创建。以及对应的点击处理。我们只需要在main 里调用即可。

#include "CHUDEventHandler.h"

int main(int argc, char** argv)
{
CHUDPickHandler c;
c.callHudControllerModule();

return 0;
}

OK，基于多视图的导航器，就这样实现了。但是单视图HUD技术没有实现，也没有找到解决思路。希望知道的我们可以一起讨论下。