#pragma once

#include <osg/Geode>
#include <osg/Geometry>

class SphereSegment : public osg::Geode {
public:
    SphereSegment(void);

    SphereSegment(float radius,
        unsigned int longitudeSteps,
        unsigned int lattitudeSteps,
        float longStart,
        float longEnd,
        float latStart,
        float latEnd);

    SphereSegment(const SphereSegment& copy, const osg::CopyOp& copyop = osg::CopyOp::SHALLOW_COPY);

protected:
    ~SphereSegment(void);

public:
    // 0 >= longStart/longEnd <= 180
    // 0 >= latStart/latEnd <= 360
    void Compute(float radius,
        unsigned int longitudeSteps,
        unsigned int lattitudeSteps,
        float longStart,
        float longEnd,
        float latStart,
        float latEnd);
private:
    osg::Vec2 SphereMap(osg::Vec3& vertex, float radius);

    inline unsigned int Idx(unsigned int r, unsigned int c, unsigned int row_len) {
        return c + r * row_len;
    }
};