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Added support for using pixel size control of LOD levels.

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This commit is contained in:
Robert Osfield 2004-06-30 19:07:05 +00:00
parent b22de2eba0
commit a8ee967f14
3 changed files with 156 additions and 3 deletions
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111
examples/osgsimulation/osgsimulation.cpp
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@ -5,9 +5,12 @@
#include <osg/ShapeDrawable>
#include <osg/Texture2D>
#include <osg/PositionAttitudeTransform>
#include <osg/MatrixTransform>
#include <osgDB/ReadFile>
#include <osgText/Text>
#include <osgSim/SphereSegment>
#include <osgParticle/ExplosionEffect>
@ -18,6 +21,108 @@
// for the grid data..
#include "../osghangglide/terrain_coords.h"
osg::AnimationPath* createAnimationPath(const osg::Vec3& center,float radius,double looptime)
{
// set up the animation path
osg::AnimationPath* animationPath = new osg::AnimationPath;
animationPath->setLoopMode(osg::AnimationPath::LOOP);
int numSamples = 40;
float yaw = 0.0f;
float yaw_delta = 2.0f*osg::PI/((float)numSamples-1.0f);
float roll = osg::inDegrees(30.0f);
double time=0.0f;
double time_delta = looptime/(double)numSamples;
for(int i=0;i<numSamples;++i)
{
osg::Vec3 position(center+osg::Vec3(sinf(yaw)*radius,cosf(yaw)*radius,0.0f));
osg::Quat rotation(osg::Quat(roll,osg::Vec3(0.0,1.0,0.0))*osg::Quat(-(yaw+osg::inDegrees(90.0f)),osg::Vec3(0.0,0.0,1.0)));
animationPath->insert(time,osg::AnimationPath::ControlPoint(position,rotation));
yaw += yaw_delta;
time += time_delta;
}
return animationPath;
}
osg::Node* createMovingModel(const osg::Vec3& center, float radius)
{
float animationLength = 10.0f;
osg::AnimationPath* animationPath = createAnimationPath(center,radius,animationLength);
osg::Group* model = new osg::Group;
osg::Node* glider = osgDB::readNodeFile("glider.osg");
if (glider)
{
const osg::BoundingSphere& bs = glider->getBound();
float size = radius/bs.radius()*0.3f;
osg::MatrixTransform* positioned = new osg::MatrixTransform;
positioned->setDataVariance(osg::Object::STATIC);
positioned->setMatrix(osg::Matrix::translate(-bs.center())*
osg::Matrix::scale(size,size,size)*
osg::Matrix::rotate(osg::inDegrees(-90.0f),0.0f,0.0f,1.0f));
positioned->addChild(glider);
osg::PositionAttitudeTransform* xform = new osg::PositionAttitudeTransform;
xform->getOrCreateStateSet()->setMode(GL_NORMALIZE, osg::StateAttribute::ON);
xform->setUpdateCallback(new osg::AnimationPathCallback(animationPath,0.0,1.0));
xform->addChild(positioned);
model->addChild(xform);
}
osg::Node* cessna = osgDB::readNodeFile("cessna.osg");
if (cessna)
{
const osg::BoundingSphere& bs = cessna->getBound();
osgText::Text* text = new osgText::Text;
float size = radius/bs.radius()*0.3f;
text->setPosition(bs.center());
text->setText("Cessna");
text->setAlignment(osgText::Text::CENTER_CENTER);
text->setAxisAlignment(osgText::Text::SCREEN);
text->setCharacterSize(40.0f);
text->setCharacterSizeMode(osgText::Text::SCREEN_COORDS);
osg::Geode* geode = new osg::Geode;
geode->addDrawable(text);
osg::LOD* lod = new osg::LOD;
lod->setRangeMode(osg::LOD::PIXEL_SIZE_ON_SCREEN);
lod->addChild(geode,0.0f,100.0f);
lod->addChild(cessna,100.0f,10000.0f);
osg::MatrixTransform* positioned = new osg::MatrixTransform;
positioned->getOrCreateStateSet()->setMode(GL_NORMALIZE, osg::StateAttribute::ON);
positioned->setDataVariance(osg::Object::STATIC);
positioned->setMatrix(osg::Matrix::translate(-bs.center())*
osg::Matrix::scale(size,size,size)*
osg::Matrix::rotate(osg::inDegrees(180.0f),0.0f,0.0f,1.0f));
//positioned->addChild(cessna);
positioned->addChild(lod);
osg::MatrixTransform* xform = new osg::MatrixTransform;
xform->setUpdateCallback(new osg::AnimationPathCallback(animationPath,0.0f,2.0));
xform->addChild(positioned);
model->addChild(xform);
}
return model;
}
osg::Vec3 computeTerrainIntersection(osg::Node* subgraph,float x,float y)
{
osgUtil::IntersectVisitor iv;
@ -132,6 +237,12 @@ void build_world(osg::Group *root)
// add the updater node to the scene graph
root->addChild(psu);
}
// create the moving models.
{
root->addChild(createMovingModel(osg::Vec3(500.0f,500.0f,500.0f),100.0f));
}
}

19
include/osg/LOD
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@ -55,14 +55,17 @@ class SG_EXPORT LOD : public Group
typedef std::pair<float,float> MinMaxPair;
typedef std::vector<MinMaxPair> RangeList;
/** Modes which control how the center of object should be determined when computed which child is active.*/
enum CenterMode
{
USE_BOUNDING_SPHERE_CENTER,
USER_DEFINED_CENTER
};
/** Set how the center of object should be determined when computed which child is active.*/
void setCenterMode(CenterMode mode) { _centerMode=mode; }
/** Get how the center of object should be determined when computed which child is active.*/
CenterMode getCenterMode() const { return _centerMode; }
/** Sets the object-space point which defines the center of the osg::LOD.
@ -72,6 +75,21 @@ class SG_EXPORT LOD : public Group
/** return the LOD center point. */
inline const Vec3& getCenter() const { if (_centerMode==USER_DEFINED_CENTER) return _userDefinedCenter; else return getBound().center(); }
/** Modes that control how the range values should be intepreted when computing which child is active.*/
enum RangeMode
{
DISTANCE_FROM_EYE_POINT,
PIXEL_SIZE_ON_SCREEN
};
/** Set how the range values should be intepreted when computing which child is active.*/
void setRangeMode(RangeMode mode) { _rangeMode = mode; }
/** Get how the range values should be intepreted when computing which child is active.*/
RangeMode getRangeMode() const { return _rangeMode; }
/** Sets the min and max visible ranges of range of specifiec child.
Values are floating point distance specified in local objects coordinates.*/
void setRange(unsigned int childNo, float min,float max);
@ -101,6 +119,7 @@ class SG_EXPORT LOD : public Group
CenterMode _centerMode;
Vec3 _userDefinedCenter;
RangeMode _rangeMode;
RangeList _rangeList;
};

29
src/osg/LOD.cpp
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@ -11,6 +11,7 @@
* OpenSceneGraph Public License for more details.
*/
#include <osg/LOD>
#include <osg/CullStack>
#include <algorithm>
@ -39,13 +40,35 @@ void LOD::traverse(NodeVisitor& nv)
break;
case(NodeVisitor::TRAVERSE_ACTIVE_CHILDREN):
{
float distance = nv.getDistanceToEyePoint(getCenter(),true);
float required_range = 0;
if (_rangeMode==DISTANCE_FROM_EYE_POINT)
{
required_range = nv.getDistanceToEyePoint(getCenter(),true);
}
else
{
osg::CullStack* cullStack = dynamic_cast<osg::CullStack*>(&nv);
if (cullStack)
{
required_range = cullStack->pixelSize(getBound());
}
else
{
// fallback to selecting the highest res tile by
// finding out the max range
for(unsigned int i=0;i<_rangeList.size();++i)
{
required_range = osg::minimum(required_range,_rangeList[i].first);
}
}
}
unsigned int numChildren = _children.size();
if (_rangeList.size()<numChildren) numChildren=_rangeList.size();
for(unsigned int i=0;i<numChildren;++i)
{
if (_rangeList[i].first<=distance && distance<_rangeList[i].second)
if (_rangeList[i].first<=required_range && required_range<_rangeList[i].second)
{
_children[i]->accept(nv);
}