99 lines
3.7 KiB
Plaintext
99 lines
3.7 KiB
Plaintext
//C++ header - Open Scene Graph - Copyright (C) 1998-2002 Robert Osfield
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//Distributed under the terms of the GNU Library General Public License (LGPL)
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//as published by the Free Software Foundation.
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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.
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The children are ordered from most detailed (for close up views) to the least
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(see from a distance), and a set of ranges are used to decide which LOD is used
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at different view distances, the criteria used is child 'i' is used when
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range[i]<dist<range[i+1] is true. This requires there to be n+1 range values where the number of
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children is n, since no maximum distance of infinity is assumed. If the number of range values (m)
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is insufficient then the children m through to n will be ignored, only 0..m-1 will be used
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during rendering.
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*/
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class SG_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 removeChild(Node *child);
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typedef std::pair<float,float> MinMaxPair;
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typedef std::vector<MinMaxPair> RangeList;
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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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void setCenterMode(CenterMode mode) { _centerMode=mode; }
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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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/** 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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/** return the list of MinMax ranges for each child.*/
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inline RangeList& getRangeList() { return _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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protected :
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virtual ~LOD() {}
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CenterMode _centerMode;
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Vec3 _userDefinedCenter;
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RangeList _rangeList;
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};
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}
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#endif
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