#include <osg/BezierCurves>头文件源码

以下是 `osg/BezierCurves` 头文件的源码：

#ifndef OSG_BEZIERCURVES
#define OSG_BEZIERCURVES 1

#include <osg/Array>
#include <osg/Vec3>

namespace osg {

/** A class for representing Bezier curves. */
class BezierCurve
{
    public:

        BezierCurve() {}

        BezierCurve(const BezierCurve& copy, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
            _controlPoints(copy._controlPoints),
            _tessellation(copy._tessellation),
            _tessellationCache(copy._tessellationCache),
            _dirty(true) {}

        BezierCurve(const osg::Vec3Array* controlPoints):
            _controlPoints(controlPoints),
            _tessellation(10),
            _dirty(true) {}

        BezierCurve(const osg::Vec3Array* controlPoints, unsigned int tessellation):
            _controlPoints(controlPoints),
            _tessellation(tessellation),
            _dirty(true) {}

        inline void setControlPoints(const osg::Vec3Array* controlPoints) { _controlPoints = controlPoints; _dirty=true; }
        inline const osg::Vec3Array* getControlPoints() const { return _controlPoints.get(); }

        inline void setTessellation(unsigned int tessellation) { _tessellation = tessellation; _dirty=true; }
        inline unsigned int getTessellation() const { return _tessellation; }

        inline const osg::Vec3Array* getTessellationCache() const { if (_dirty) const_cast<BezierCurve*>(this)->buildCache(); return _tessellationCache.get(); }

        inline osg::Vec3 evaluate(float t) const
        {
            if (_dirty) const_cast<BezierCurve*>(this)->buildCache();
            return _tessellationCache->at(unsigned int(t*float(_tessellation)));
        }

        inline void evaluate(float t, osg::Vec3& P, osg::Vec3& T) const
        {
            if (_dirty) const_cast<BezierCurve*>(this)->buildCache();

            unsigned int index = unsigned int(t*float(_tessellation));
            const osg::Vec3& p0 = _tessellationCache->at(index);
            const osg::Vec3& p1 = _tessellationCache->at(index+1);

            P = p0;
            T = p1-p0;
        }

    private:

        void buildCache() const;

        osg::ref_ptr<const osg::Vec3Array> _controlPoints;
        unsigned int _tessellation;
        mutable osg::ref_ptr<osg::Vec3Array> _tessellationCache;
        mutable bool _dirty;
};


/** A class for representing a set of Bezier curves */
class BezierCurveArray : public osg::Array<BezierCurve>
{
    public:

        BezierCurveArray(){}

        BezierCurveArray(const BezierCurveArray& copy, const osg::CopyOp& copyop=osg::CopyOp::SHALLOW_COPY):
            osg::Array<BezierCurve>(copy,copyop) {}

        META_Array(osg, BezierCurveArray, 0x160);

};

}

#endif

该头文件定义了 `BezierCurve` 和 `BezierCurveArray` 两个类，用于表示贝塞尔曲线。其中， `BezierCurve` 类用于表示一条贝塞尔曲线，包括控制点、分割数量等属性；`BezierCurveArray` 类则是一个贝塞尔曲线数组。