osglight解析

来源：互联网发布：我国关于网络诈骗法律编辑：程序博客网时间：2024/05/16 14:10

osglight解析如下:

// callback to make the loaded model oscilate up and down.

class ModelTransformCallback : public osg::NodeCallback

{

public:

ModelTransformCallback(const osg::BoundingSphere& bs)

{

_firstTime = 0.0;

_period = 4.0f;

_range = bs.radius()*0.5f;

}

virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)

{

osg::PositionAttitudeTransform* pat = dynamic_cast<osg::PositionAttitudeTransform*>(node);

const osg::FrameStamp* frameStamp = nv->getFrameStamp();

if (pat && frameStamp)

{

if (_firstTime==0.0)

{

_firstTime = frameStamp->getSimulationTime();

}

double phase = (frameStamp->getSimulationTime()-_firstTime)/_period;

phase -= floor(phase);

phase *= (2.0 * osg::PI);

osg::Quat rotation;

rotation.makeRotate(phase,1.0f,1.0f,1.0f);

pat->setAttitude(rotation);//PositionAttitudeTransform位置变换节点->旋转

pat->setPosition(osg::Vec3(0.0f,0.0f,sin(phase))*_range);//PositionAttitudeTransform位置变换节点->平移

}

// must traverse the Node's subgraph

traverse(node,nv);

}

double _firstTime;

double _period;

double _range;

};

osg::Node* createLights(osg::BoundingBox& bb,osg::StateSet* rootStateSet)

{

osg::Group* lightGroup = new osg::Group;

float modelSize = bb.radius();

// create a spot light.

osg::Light* myLight1 = new osg::Light;

myLight1->setLightNum(0);

myLight1->setPosition(osg::Vec4(bb.corner(4),1.0f));

myLight1->setAmbient(osg::Vec4(1.0f,0.0f,0.0f,1.0f));

myLight1->setDiffuse(osg::Vec4(1.0f,0.0f,0.0f,1.0f));

myLight1->setSpotCutoff(20.0f);

myLight1->setSpotExponent(50.0f);

myLight1->setDirection(osg::Vec3(1.0f,1.0f,-1.0f));

osg::LightSource* lightS1 = new osg::LightSource;

lightS1->setLight(myLight1);

lightS1->setLocalStateSetModes(osg::StateAttribute::ON);

lightS1->setStateSetModes(*rootStateSet,osg::StateAttribute::ON);

lightGroup->addChild(lightS1);

// create a local light.

osg::Light* myLight2 = new osg::Light;

myLight2->setLightNum(1);

myLight2->setPosition(osg::Vec4(0.0,0.0,0.0,1.0f));

myLight2->setAmbient(osg::Vec4(0.0f,1.0f,1.0f,1.0f));

myLight2->setDiffuse(osg::Vec4(0.0f,1.0f,1.0f,1.0f));

myLight2->setConstantAttenuation(1.0f);

myLight2->setLinearAttenuation(2.0f/modelSize);

myLight2->setQuadraticAttenuation(2.0f/osg::square(modelSize));

osg::LightSource* lightS2 = new osg::LightSource;

lightS2->setLight(myLight2);

lightS2->setLocalStateSetModes(osg::StateAttribute::ON);

lightS2->setStateSetModes(*rootStateSet,osg::StateAttribute::ON);

//MatrixTransform设置路径动画

osg::MatrixTransform* mt = new osg::MatrixTransform();

{

// set up the animation path

osg::AnimationPath* animationPath = new osg::AnimationPath;

animationPath->insert(0.0,osg::AnimationPath::ControlPoint(bb.corner(0)));

animationPath->insert(1.0,osg::AnimationPath::ControlPoint(bb.corner(1)));

animationPath->insert(2.0,osg::AnimationPath::ControlPoint(bb.corner(2)));

animationPath->insert(3.0,osg::AnimationPath::ControlPoint(bb.corner(3)));

animationPath->insert(4.0,osg::AnimationPath::ControlPoint(bb.corner(4)));

animationPath->insert(5.0,osg::AnimationPath::ControlPoint(bb.corner(5)));

animationPath->insert(6.0,osg::AnimationPath::ControlPoint(bb.corner(6)));

animationPath->insert(7.0,osg::AnimationPath::ControlPoint(bb.corner(7)));

animationPath->insert(8.0,osg::AnimationPath::ControlPoint(bb.corner(0)));

animationPath->setLoopMode(osg::AnimationPath::SWING);

mt->setUpdateCallback(new osg::AnimationPathCallback(animationPath));//矩阵变换节点设置移动

}

// create marker for point light.显示点光源

osg::Geometry* marker = new osg::Geometry;

osg::Vec3Array* vertices = new osg::Vec3Array;

vertices->push_back(osg::Vec3(0.0,0.0,0.0));

marker->setVertexArray(vertices);

marker->addPrimitiveSet(new osg::DrawArrays(GL_POINTS,0,1));

osg::StateSet* stateset = new osg::StateSet;

osg::Point* point = new osg::Point;

point->setSize(4.0f);

stateset->setAttribute(point);

marker->setStateSet(stateset);

osg::Geode* markerGeode = new osg::Geode;

markerGeode->addDrawable(marker);

//光源和光源的显示点都加入到矩阵变换节点,即都产生路径动画

mt->addChild(lightS2);

mt->addChild(markerGeode);

lightGroup->addChild(mt);

return lightGroup;

}

osg::Geometry* createWall(const osg::Vec3& v1,const osg::Vec3& v2,const osg::Vec3& v3,osg::StateSet* stateset)

{

//其实是以v1,v2,v3画了一个矩形,但进行了细分.

//也可以直接根据矩形的个点直接画,但由于插值,效果不好,颜色不纯.把noXSteps=noYSteps=100改成

//noXSteps=noYSteps=2则与直接画矩形的效果类似

// create a drawable for occluder.

osg::Geometry* geom = new osg::Geometry;

geom->setStateSet(stateset);

unsigned int noXSteps = 100;

unsigned int noYSteps = 100;

osg::Vec3Array* coords = new osg::Vec3Array;

coords->reserve(noXSteps*noYSteps);

osg::Vec3 dx = (v2-v1)/((float)noXSteps-1.0f);

osg::Vec3 dy = (v3-v1)/((float)noYSteps-1.0f);

unsigned int row;

osg::Vec3 vRowStart = v1;

for(row=0;row<noYSteps;++row)

{

osg::Vec3 v = vRowStart;

for(unsigned int col=0;col<noXSteps;++col)

{

coords->push_back(v);

v += dx;

}

vRowStart+=dy;

}

geom->setVertexArray(coords);

osg::Vec4Array* colors = new osg::Vec4Array(1);

(*colors)[0].set(1.0f,1.0f,1.0f,1.0f);

geom->setColorArray(colors);

geom->setColorBinding(osg::Geometry::BIND_OVERALL);

for(row=0;row<noYSteps-1;++row)

{

osg::DrawElementsUShort* quadstrip = new osg::DrawElementsUShort(osg::PrimitiveSet::QUAD_STRIP);

quadstrip->reserve(noXSteps*2);

for(unsigned int col=0;col<noXSteps;++col)

{

quadstrip->push_back((row+1)*noXSteps+col);

quadstrip->push_back(row*noXSteps+col);

}

geom->addPrimitiveSet(quadstrip);

}

// create the normals.

osgUtil::SmoothingVisitor::smooth(*geom);

return geom;

}

osg::Node* createRoom(osg::Node* loadedModel)

{

// default scale for this model.

osg::BoundingSphere bs(osg::Vec3(0.0f,0.0f,0.0f),1.0f);

osg::Group* root = new osg::Group;

if (loadedModel)

{

const osg::BoundingSphere& loaded_bs = loadedModel->getBound();//获取球体包围盒

osg::PositionAttitudeTransform* pat = new osg::PositionAttitudeTransform();

pat->setPivotPoint(loaded_bs.center());

pat->setUpdateCallback(new ModelTransformCallback(loaded_bs));

pat->addChild(loadedModel);

bs = pat->getBound();

root->addChild(pat);

}

bs.radius()*=1.5f;

//把球体包围盒扩展成立体包围盒

// create a bounding box, which we'll use to size the room.

osg::BoundingBox bb;

bb.expandBy(bs);

// create statesets.

osg::StateSet* rootStateSet = new osg::StateSet;

root->setStateSet(rootStateSet);

//能够背面剔除,相当于可以看穿墙,看到屋内的东西

osg::StateSet* wall = new osg::StateSet;

wall->setMode(GL_CULL_FACE,osg::StateAttribute::ON);

osg::StateSet* floor = new osg::StateSet;

floor->setMode(GL_CULL_FACE,osg::StateAttribute::ON);

osg::StateSet* roof = new osg::StateSet;

roof->setMode(GL_CULL_FACE,osg::StateAttribute::ON);

osg::Geode* geode = new osg::Geode;

// create front side.

geode->addDrawable(createWall(bb.corner(0),

bb.corner(4),

bb.corner(1),

wall));

// right side

geode->addDrawable(createWall(bb.corner(1),

bb.corner(5),

bb.corner(3),

wall));

// left side

geode->addDrawable(createWall(bb.corner(2),

bb.corner(6),

bb.corner(0),

wall));

// back side

geode->addDrawable(createWall(bb.corner(3),

bb.corner(7),

bb.corner(2),

wall));

// floor

geode->addDrawable(createWall(bb.corner(0),

bb.corner(1),

bb.corner(2),

floor));

// roof

geode->addDrawable(createWall(bb.corner(6),

bb.corner(7),

bb.corner(4),

roof));

root->addChild(geode);

root->addChild(createLights(bb,rootStateSet));

return root;

}

int main( int argc, char **argv )

{

......

if (!loadedModel) loadedModel = osgDB::readNodeFile("glider.osg");

// create a room made of foor walls, a floor, a roof, and swinging light fitting.

osg::Node* rootnode = createRoom(loadedModel);

viewer.setSceneData( rootnode );

.....

viewer.getCamera()->setCullingMode( viewer.getCamera()->getCullingMode() & ~osg::CullStack::SMALL_FEATURE_CULLING);

return viewer.run();

}

立体包围盒的8个点的索引号如图(如顶是(4576),前是0154):

Osglight完整源代码如下:

#include <osgViewer/Viewer>

#include <osg/Group>

#include <osg/Node>

#include <osg/Light>

#include <osg/LightSource>

#include <osg/StateAttribute>

#include <osg/Geometry>

#include <osg/Point>

#include <osg/MatrixTransform>

#include <osg/PositionAttitudeTransform>

#include <osgDB/Registry>

#include <osgDB/ReadFile>

#include <osgUtil/Optimizer>

#include <osgUtil/SmoothingVisitor>

#include "stdio.h"

// callback to make the loaded model oscilate up and down.

class ModelTransformCallback : public osg::NodeCallback

{

public:

ModelTransformCallback(const osg::BoundingSphere& bs)

{

_firstTime = 0.0;

_period = 4.0f;

_range = bs.radius()*0.5f;

}

virtual void operator()(osg::Node* node, osg::NodeVisitor* nv)

{

osg::PositionAttitudeTransform* pat = dynamic_cast<osg::PositionAttitudeTransform*>(node);

const osg::FrameStamp* frameStamp = nv->getFrameStamp();

if (pat && frameStamp)

{

if (_firstTime==0.0)

{

_firstTime = frameStamp->getSimulationTime();

}

double phase = (frameStamp->getSimulationTime()-_firstTime)/_period;

phase -= floor(phase);

phase *= (2.0 * osg::PI);

osg::Quat rotation;

rotation.makeRotate(phase,1.0f,1.0f,1.0f);

pat->setAttitude(rotation);

pat->setPosition(osg::Vec3(0.0f,0.0f,sin(phase))*_range);