138 lines
5.6 KiB
C++
138 lines
5.6 KiB
C++
/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield
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*
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* This library is open source and may be redistributed and/or modified under
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* the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or
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* (at your option) any later version. The full license is in LICENSE file
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* included with this distribution, and on the openscenegraph.org website.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* OpenSceneGraph Public License for more details.
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*/
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#ifndef OSG_LOD
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#define OSG_LOD 1
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#include <osg/Group>
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namespace osg {
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/** LOD - Level Of Detail group node which allows switching between children
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depending on distance from eye point.
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Typical uses are for load balancing - objects further away from
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the eye point are rendered at a lower level of detail, and at times
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of high stress on the graphics pipeline lower levels of detail can
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also be chosen by adjusting the viewers's Camera/CullSettings LODScale value.
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Each child has a corresponding valid range consisting of a minimum
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and maximum distance. Given a distance to the viewer (d), LOD displays
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a child if min <= d < max. LOD may display multiple children simultaneously
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if their corresponding ranges overlap. Children can be in any order,
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and don't need to be sorted by range or amount of detail. If the number of
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ranges (m) is less than the number of children (n), then children m+1 through
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n are ignored.
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*/
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class OSG_EXPORT LOD : public Group
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{
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public :
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LOD();
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/** Copy constructor using CopyOp to manage deep vs shallow copy.*/
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LOD(const LOD&,const CopyOp& copyop=CopyOp::SHALLOW_COPY);
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META_Node(osg, LOD);
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virtual void traverse(NodeVisitor& nv);
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virtual bool addChild(Node *child);
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virtual bool addChild(Node *child, float min, float max);
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virtual bool removeChildren(unsigned int pos,unsigned int numChildrenToRemove=1);
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typedef std::pair<float,float> MinMaxPair;
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typedef std::vector<MinMaxPair> RangeList;
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/** Modes which control how the center of object should be determined when computing which child is active.*/
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enum CenterMode
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{
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USE_BOUNDING_SPHERE_CENTER,
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USER_DEFINED_CENTER
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};
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/** Set how the center of object should be determined when computing which child is active.*/
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void setCenterMode(CenterMode mode) { _centerMode=mode; }
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/** Get how the center of object should be determined when computing which child is active.*/
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CenterMode getCenterMode() const { return _centerMode; }
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/** Sets the object-space point which defines the center of the osg::LOD.
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center is affected by any transforms in the hierarchy above the osg::LOD.*/
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inline void setCenter(const Vec3& center) { _centerMode=USER_DEFINED_CENTER; _userDefinedCenter = center; }
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/** return the LOD center point. */
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inline const Vec3& getCenter() const { if (_centerMode==USER_DEFINED_CENTER) return _userDefinedCenter; else return getBound().center(); }
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/** Set the object-space reference radius of the volume enclosed by the LOD.
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* Used to detmine the bounding sphere of the LOD in the absense of any children.*/
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inline void setRadius(float radius) { _radius = radius; }
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/** Get the object-space radius of the volume enclosed by the LOD.*/
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inline float getRadius() const { return _radius; }
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/** Modes that control how the range values should be intepreted when computing which child is active.*/
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enum RangeMode
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{
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DISTANCE_FROM_EYE_POINT,
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PIXEL_SIZE_ON_SCREEN
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};
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/** Set how the range values should be intepreted when computing which child is active.*/
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void setRangeMode(RangeMode mode) { _rangeMode = mode; }
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/** Get how the range values should be intepreted when computing which child is active.*/
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RangeMode getRangeMode() const { return _rangeMode; }
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/** Sets the min and max visible ranges of range of specifiec child.
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Values are floating point distance specified in local objects coordinates.*/
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void setRange(unsigned int childNo, float min,float max);
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/** returns the min visible range for specified child.*/
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inline float getMinRange(unsigned int childNo) const { return _rangeList[childNo].first; }
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/** returns the max visible range for specified child.*/
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inline float getMaxRange(unsigned int childNo) const { return _rangeList[childNo].second; }
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/** returns the number of ranges currently set.
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* An LOD which has been fully set up will have getNumChildren()==getNumRanges(). */
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inline unsigned int getNumRanges() const { return _rangeList.size(); }
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/** set the list of MinMax ranges for each child.*/
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inline void setRangeList(const RangeList& rangeList) { _rangeList=rangeList; }
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/** return the list of MinMax ranges for each child.*/
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inline const RangeList& getRangeList() const { return _rangeList; }
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virtual BoundingSphere computeBound() const;
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protected :
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virtual ~LOD() {}
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CenterMode _centerMode;
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Vec3 _userDefinedCenter;
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float _radius;
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RangeMode _rangeMode;
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RangeList _rangeList;
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};
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}
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#endif
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