osgSim::SphereSegment分析

osgSphereSegment分析

/* -*-c++-*- OpenSceneGraph - Copyright (C) 1998-2006 Robert Osfield * * This library is open source and may be redistributed and/or modified under * the terms of the OpenSceneGraph Public License (OSGPL) version 0.0 or * (at your option) any later version.  The full license is in LICENSE file * included with this distribution, and on the openscenegraph.org website. * * This library is distributed in the hope that it will be useful, * but WITHOUT ANY WARRANTY; without even the implied warranty of * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the * OpenSceneGraph Public License for more details.*/#ifndef OSGSIM_SPHERESEGMENT#define OSGSIM_SPHERESEGMENT 1#include <osgSim/Export>#include <osg/Vec3>#include <osg/Vec4>#include <osg/Geode>#include <osg/Matrixd>#include <osg/BlendFunc>namespace osgSim{/**A SphereSegment是Geode节点 来展示球体一部分（ 也可能是全部). 球面是对齐的，这样穿过两级的直线与z轴平行。球面段通过不同组件开关进行渲染或关闭。    - 球面指定区域.

<p class="ordinary-output target-output" style="margin-top: 0px; margin-bottom: 5px; padding-top: 0px; padding-bottom: 0px; line-height: 22px; font-size: 14px; color: rgb(51, 51, 51); font-family: arial;"><span left-pos="33|21,20|3" right-pos="33|21,20|3" space="" class="high-light-bg" style="border-top-left-radius: 5px; border-top-right-radius: 5px; border-bottom-right-radius: 5px; border-bottom-left-radius: 5px; cursor: pointer; background: yellow;">--球体表面指定区域的</span><span left-pos="24|8,13|6" right-pos="24|8,13|6" space="">边界周围</span><span left-pos="0|12" right-pos="0|12" space="1|">的边缘线</span></p>    -四个辐条r <i>spokes</i>, 辐条是一条线，这条线从球面中心到渲染区域的一角.    - 四个平面区域 planar,平面区域由辐条之间的空间构成.警告:    -, and specifying areas where the centre of      the rendered area <i>is</i> the Z axis may lead to unexpected      geometry.<p class="ordinary-output target-output" style="margin-top: 0px; margin-bottom: 5px; padding-top: 0px; padding-bottom: 0px; line-height: 22px; font-size: 14px; color: rgb(51, 51, 51); font-family: arial;"><span left-pos="0|22" right-pos="0|22" space="">      -值得注意的是，</span><span left-pos="23|20" right-pos="23|20" space="">通过</span><span left-pos="44|6" right-pos="44|6" space="">球</span><span left-pos="50|11" right-pos="50|11" space="1|">的两个极点的线</span><span left-pos="62|30" right-pos="0|30" space="">平行于z轴。</span><span left-pos="92|21" right-pos="30|21" space="">这意味着</span><span left-pos="114|19" right-pos="52|19" space="1|">当指定</span><span left-pos="145|14" right-pos="11|14" space="">要渲染的区域</span><span left-pos="159|1" right-pos="25|1" space="">，指定区域的渲染区域的中心是Z轴将导致</span>导致不可知的<span left-pos="276|8" right-pos="6|8" space="">几何体geometry</span><span left-pos="284|1" right-pos="14|1" space="1|">。</span></p>    - 也可以渲染整个球。通过指定 elevation      and azimuth ranges round the full 360 degrees. When doing      so 考虑转换平面、辐条线、边沿设为off关闭状态, to avoid rendering artefacts, e.g. the upper and lower      planes will be coincident.*/class OSGSIM_EXPORT SphereSegment: public osg::Geode{public:    /**    DrawMask represents a bit field, the values of which may be OR'ed together    指定哪一部分绘制. E.g.    \code    sphereSegment->setDrawMask(SphereSegment::DrawMask(SphereSegment::SURFACE|SphereSegment::SPOKES));    \endcode    */    enum DrawMask{        SURFACE =   0x00000001, ///< Draw the specified area on the sphere's surface        SPOKES =    0x00000002, ///< Draw the spokes from the sphere's centre to the surface's corners        EDGELINE =  0x00000008, ///< Draw the line round the edge of the area on the sphere's surface        SIDES =     0x00000010, ///< Draw the planes from the sphere's centre to the edge of the sphere's surface        ALL =       0x7fffffff  ///< Draw every part of the sphere segment    };    /** 构造函数. */    SphereSegment():osg::Geode(),                    _centre(0.0f,0.0f,0.0f), _radius(1.0f),                    _azMin(0.0f), _azMax(osg::PI/2.0f),                    _elevMin(0.0f), _elevMax(osg::PI/2.0f),                    _density(10),                    _drawMask(DrawMask(ALL))    {        init();    }    /**    Construct by angle ranges. Note that the azimuth 'zero' is the Y axis; specifying    an azimuth range from azMin -osg::PI/2.0f to azMax osg::PI/2.0f will cover the    'top half' of the circle in the XY plane. The elev angles are 'out' of the 'zero'    XY plane with +ve angles above the plane, and -ve angles below.    @param centre       sphere centre    @param radius       radius of sphere    @param azMin        azimuth minimum    @param azMax        azimuth maximum    @param elevMin      elevation minimum    @param elevMax      elevation maximum    @param density      number of units to divide the azimuth and elevation ranges into    */    SphereSegment(const osg::Vec3& centre, float radius, float azMin, float azMax,                    float elevMin, float elevMax, int density):        osg::Geode(),        _centre(centre), _radius(radius),        _azMin(azMin), _azMax(azMax),        _elevMin(elevMin), _elevMax(elevMax),        _density(density),        _drawMask(DrawMask(ALL))    {        init();    }//方位角又称地平经度(Azimuth (angle)缩写Az)，是在平面上量度物体之间的角度差的方法之一。是从某点的指北方向线起，依顺时针方向到目标方向线之间的水平夹角。//elev 高处，高地，高度，海拔，（枪炮的）仰角，射角;升级，上进，向上;//density n.<span style="white-space:pre"></span>密度;稠密，浓厚;[物]浓度，比重;愚钝    /**    Construct by vector.    @param centre      球中心    @param radius       球半径    @param vec          vector 指向从球心到绘制区域球表面的中心    @param azRange      azimuth range in radians (中心沿 along vec)    @param elevRange    elevation range in radians (中心沿 along vec)    @param density      number of units to divide the azimuth and elevation ranges into    */    SphereSegment(const osg::Vec3& centre, float radius, const osg::Vec3& vec, float azRange,                    float elevRange, int density);    /** Copy constructor */    SphereSegment(const SphereSegment& rhs, const osg::CopyOp& co):        osg::Geode(rhs,co),        _centre(rhs._centre), _radius(rhs._radius),        _azMin(rhs._azMin), _azMax(rhs._azMax),        _elevMin(rhs._elevMin), _elevMax(rhs._elevMax),        _density(rhs._density),        _drawMask(rhs._drawMask)    {        init();    }    /** Set the centre point of the SphereSegment */    void setCentre(const osg::Vec3& c);    /** Get the centre point of the SphereSegment */    const osg::Vec3& getCentre() const;    /** Set the radius of the SphereSegment */    void setRadius(float r);    /** Get the radius of the SphereSegment */    float getRadius() const;    /** Set the area of the sphere segment    @param vec          vector pointing from sphere centre to centre point                        of rendered area on sphere surface    @param azRange      azimuth range in radians (with centre along vec)    @param elevRange    elevation range in radians (with centre along vec)    */    void setArea(const osg::Vec3& vec, float azRange, float elevRange);    /** Get the area of the sphere segment    @param vec          vector pointing from sphere centre to centre point                        of rendered area on sphere surface (normalized)    @param azRange     方位角范围 range in radians (with centre along vec)    @param elevRange   仰角范围（与XY平面夹角，弧度0-2pi） (with centre along vec)    */    void getArea(osg::Vec3& vec, float& azRange, float& elevRange) const;    /** Set the area of the sphere segment    @param azMin        azimuth minimum    @param azMax        azimuth maximum    @param elevMin      elevation minimum    @param elevMax      elevation maximum    */    void setArea(float azMin, float azMax, float elevMin, float elevMax);    /** Get the area of the sphere segment    @param azMin        azimuth minimum    @param azMax        azimuth maximum    @param elevMin      elevation minimum    @param elevMax      elevation maximum    */    void getArea(float &azMin, float &azMax, float &elevMin, float &elevMax) const;    /** Set the density of the sphere segment */    void setDensity(int d);    /** Get the density of the sphere segment */    int getDensity() const;    /**    Specify the DrawMask.    @param dm   Bitmask specifying which parts of the sphere segment should be drawn.    @see DrawMask    */    void setDrawMask(int dm);    /** Get the DrawMask */    int getDrawMask() const { return _drawMask; }    /** Set the color of the surface. */    void setSurfaceColor(const osg::Vec4& c);    /** Get the color of the surface. */    const osg::Vec4& getSurfaceColor() const { return _surfaceColor; }    /** Set the color of the spokes. */    void setSpokeColor(const osg::Vec4& c);    /** Get the color of the spokes. */    const osg::Vec4& getSpokeColor() const { return _spokeColor; }    /** Set the color of the edge line. */    void setEdgeLineColor(const osg::Vec4& c);    /** Get the color of the edge line. */    const osg::Vec4& getEdgeLineColor() const { return _edgeLineColor; }    /** Set the color of the planes. */    void setSideColor(const osg::Vec4& c);    /** Get the color of the planes. */    const osg::Vec4& getSideColor() const { return _planeColor; }    /** Set color of all components. */    void setAllColors(const osg::Vec4& c);    META_Node(osgSim, SphereSegment);    /** A list of vertex arrays representing a list of lines.*/    typedef std::vector< osg::ref_ptr<osg::Vec3Array> > LineList;    /** Compute the interesection lines between subgraph and this sphere segment.      * The matrix is the transform that takes the subgraph into the same coordiante frame as the sphere segment.      * The resulting intersections are in the coordinate frame of the sphere segment. */    LineList computeIntersection(const osg::Matrixd& matrix, osg::Node* subgraph);    /** Compute the interesection lines between specified drawable and this sphere segment.      * The matrix is the transform that takes the subgraph into the same coordiante frame as the sphere segment.      * The resulting intersections are in the coordinate frame of the sphere segment. */    LineList computeIntersection(const osg::Matrixd& matrix, osg::Drawable* drawable);    /** Compute the interesection lines between subgraph and this sphere segment.      * The matrix is the transform that takes the subgraph into the same coordiante frame as the sphere segment.      * The resulting intersections are in the coordinate frame of the sphere segment. */    osg::Node* computeIntersectionSubgraph(const osg::Matrixd& matrix, osg::Node* subgraph);    /** Compute the interesection lines between specified drawable and this sphere segment.      * The matrix is the transform that takes the subgraph into the same coordiante frame as the sphere segment.      * The resulting intersections are in the coordinate frame of the sphere segment. */    osg::Node* computeIntersectionSubgraph(const osg::Matrixd& matrix, osg::Drawable* drawable);private:    void init();    // Shared constructor code, generates the drawables    void dirtyAllDrawableDisplayLists();    // Force re-calling of gl functions    void dirtyAllDrawableBounds();          // Force recalculation of bound geometry    // SphereSegment is actually made up of a number of Drawable classes,    // all of which are nested private classes, as declared below. These    // classes are defined in the .cpp for minimum visibility and physical    // coupling. (Reduces time spent compiling! :-)    //    // Each of the nested classes holds a pointer to the SphereSegment    // 'parent', which stores the geometry details, and performs any    // work required. The nested classes are lightweight objects which    // just pass the work on.    //    // Why are things done with these sub-Drawables? Alpha-blended    // Drawables need to be drawn last, depth sorted, and the various    // components of a SphereSegment also need to be depth sorted    // against one another (they may all be drawn with alpha blending).    // Making these Drawables allows us to get the OSG to depth sort    // for us.    class Surface;    friend class Surface;    bool Surface_computeBound(osg::BoundingBox&) const;    void Surface_drawImplementation(osg::State&) const;    class EdgeLine;    friend class EdgeLine;    bool EdgeLine_computeBound(osg::BoundingBox&) const;    void EdgeLine_drawImplementation(osg::State&) const;    enum BoundaryAngle{MIN,MAX};        // Why here and not in Side class? Because we can't forward    enum SideOrientation{AZIM,ELEV};   // declare enums, Side is in the .cpp, and this is tidier...    class Side;    friend class Side;    bool Side_computeBound(osg::BoundingBox&, SideOrientation, BoundaryAngle) const;    void Side_drawImplementation(osg::State&, SideOrientation, BoundaryAngle) const;    class Spoke;    friend class Spoke;    bool Spoke_computeBound(osg::BoundingBox&, BoundaryAngle, BoundaryAngle) const;    void Spoke_drawImplementation(osg::State&, BoundaryAngle, BoundaryAngle) const;    // Sphere segment geometry details    osg::Vec3 _centre;    float _radius;    float _azMin, _azMax, _elevMin, _elevMax;    int _density;    // Draw details    int         _drawMask;    osg::Vec4   _surfaceColor;    osg::Vec4   _spokeColor;    osg::Vec4   _edgeLineColor;    osg::Vec4   _planeColor;};}#endif