genesis-3d_engine/Engine/foundation/math/sphere_.h

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Copyright (c) 2004, Radon Labs GmbH
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#pragma once
#ifndef MATH_SPHERE_H
#define MATH_SPHERE_H
//------------------------------------------------------------------------------
/**
    @class Math::sphere

    A 3-dimensional sphere.

    (C) 2004 RadonLabs GmbH
*/
#include "math/vector.h"
#include "math/point.h"
#include "math/bbox.h"
#include "math/matrix44.h"
#include "math/rectangle.h"
#include "math/clipstatus.h"

//------------------------------------------------------------------------------
namespace Math
{
class sphere 
{
public:
    /// default constructor
    sphere();
    /// pos/radius constructor
    sphere(const point& _p, scalar _r);
    /// x,y,z,r constructor
    sphere(scalar _x, scalar _y, scalar _z, scalar _r);
    /// copy constructor
    sphere(const sphere& rhs);
    /// set position and radius
    void set(const point& _p, scalar _r);
    /// set x,y,z, radius
    void set(scalar _x, scalar _y, scalar _z, scalar _r);
    /// return true if box is completely inside sphere
	/// transform bounding box
	void transform(const matrix44& m);

    bool inside(const bbox& box) const;
    /// check if 2 spheres overlap
    bool intersects(const sphere& s) const;
    /// check if sphere intersects box
    bool intersects(const bbox& box) const;
    /// check if 2 moving sphere have contact
    bool intersect_sweep(const vector& va, const sphere& sb, const vector& vb, scalar& u0, scalar& u1) const;
    /// project sphere to screen rectangle (right handed coordinate system)
    rectangle<scalar> project_screen_rh(const matrix44& modelView, const matrix44& projection, scalar nearZ) const;
    /// get clip status of box against sphere
    ClipStatus::Type clipstatus(const bbox& box) const;
        
    point p;
    scalar r;
};

//------------------------------------------------------------------------------
/**
*/
inline
sphere::sphere() :
    r(1.0f)
{
    // empty
}

//------------------------------------------------------------------------------
/**
*/
inline
sphere::sphere(const point& _p, scalar _r) :
    p(_p),
    r(_r)
{
    // empty
}

//------------------------------------------------------------------------------
/**
*/
inline
sphere::sphere(scalar _x, scalar _y, scalar _z, scalar _r) :
    p(_x, _y, _z),
    r(_r)
{
    // empty
}

//------------------------------------------------------------------------------
/**
*/
inline
sphere::sphere(const sphere& rhs) :
    p(rhs.p),
    r(rhs.r)
{
    // empty
}

//------------------------------------------------------------------------------
/**
*/
inline void
sphere::set(const point& _p, scalar _r)
{
    this->p = _p;
    this->r = _r;
}

//------------------------------------------------------------------------------
/**
*/
inline void
sphere::set(scalar _x, scalar _y, scalar _z, scalar _r)
{
    this->p.set(_x, _y, _z);
    this->r = _r;
}

//------------------------------------------------------------------------------
/**
*/
inline bool 
sphere::intersects(const sphere& s) const 
{
    vector d(s.p - p);
    scalar rsum = s.r + r;
    return (d.lengthsq() <= (rsum * rsum));
}

//------------------------------------------------------------------------------
/**
    Return true if the bounding box is inside the sphere.
*/
inline bool
sphere::inside(const bbox& box) const
{
    vector v(this->r, this->r, this->r);
    point pmin(this->p - v);
    point pmax(this->p + v);
    bool lt = float4::less3_all(box.pmin, pmin);
    bool ge = float4::greaterequal3_all(box.pmax, pmax);
    return lt && ge;
}

//------------------------------------------------------------------------------
/**
    Get the clip status of a box against this sphere. Inside means: the
    box is completely inside the sphere.
*/
inline
ClipStatus::Type
sphere::clipstatus(const bbox& box) const
{
    if (this->inside(box)) return ClipStatus::Inside;
    else if (this->intersects(box)) return ClipStatus::Clipped;
    else return ClipStatus::Outside;
}

} // namespace Math
//------------------------------------------------------------------------------
#endif