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

225 lines
5.5 KiB
C
Raw Normal View History

/****************************************************************************
Copyright (c) 2004,RadonLabs GmbH
Copyright (c) 2011-2013,WebJet Business Division,CYOU
http://www.genesis-3d.com.cn
Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:
The above copyright notice and this permission notice shall be included in
all copies or substantial portions of the Software.
THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
THE SOFTWARE.
****************************************************************************/
#pragma once
#ifndef MATH_LINE_H
#define MATH_LINE_H
//------------------------------------------------------------------------------
/**
@class Math::line
A line in 3d space.
(C) 2004 RadonLabs GmbH
*/
#include "math/point.h"
#include "math/vector.h"
#include "math/scalar.h"
//------------------------------------------------------------------------------
namespace Math
{
class line
{
public:
/// default constructor
line();
/// component constructor
line(const point& startPoint, const point& endPoint);
/// copy constructor
line(const line& rhs);
/// set start and end point
void set(const point& startPoint, const point& endPoint);
/// get start point
const point& start() const;
/// get end point
point end() const;
/// get vector
const vector& vec() const;
/// get length
scalar length() const;
/// get squared length
scalar lengthsq() const;
/// minimal distance of point to line
scalar distance(const point& p) const;
/// intersect with line
bool intersect(const line& l, point& pa, point& pb) const;
/// return t of the closest point on the line
scalar closestpoint(const point& p) const;
/// return p = b + m*t
point pointat(scalar t) const;
point b;
vector m;
};
//------------------------------------------------------------------------------
/**
*/
inline
line::line()
{
// empty
}
//------------------------------------------------------------------------------
/**
*/
inline
line::line(const point& startPoint, const point& endPoint) :
b(startPoint),
m(endPoint - startPoint)
{
// empty
}
//------------------------------------------------------------------------------
/**
*/
inline
line::line(const line& rhs) :
b(rhs.b),
m(rhs.m)
{
// empty
}
//------------------------------------------------------------------------------
/**
*/
inline void
line::set(const point& startPoint, const point& endPoint)
{
this->b = startPoint;
this->m = endPoint - startPoint;
}
//------------------------------------------------------------------------------
/**
*/
inline const point&
line::start() const
{
return this->b;
}
//------------------------------------------------------------------------------
/**
*/
inline point
line::end() const
{
return this->b + this->m;
}
//------------------------------------------------------------------------------
/**
*/
inline const vector&
line::vec() const
{
return this->m;
}
//------------------------------------------------------------------------------
/**
*/
inline scalar
line::length() const
{
return this->m.length();
}
//------------------------------------------------------------------------------
/**
*/
inline scalar
line::lengthsq() const
{
return this->m.lengthsq();
}
//------------------------------------------------------------------------------
/**
Returns a point on the line which is closest to a another point in space.
This just returns the parameter t on where the point is located. If t is
between 0 and 1, the point is on the line, otherwise not. To get the
actual 3d point p:
p = m + b*t
*/
inline scalar
line::closestpoint(const point& p) const
{
vector diff(p - this->b);
scalar l = float4::dot3(this->m, this->m);
if (l > 0.0f)
{
scalar t = float4::dot3(this->m, diff) / l;
return t;
}
else
{
return 0.0f;
}
}
//------------------------------------------------------------------------------
/**
*/
inline scalar
line::distance(const point& p) const
{
vector diff(p - this->b);
scalar l = float4::dot3(this->m, this->m);
if (l > 0.0f)
{
scalar t = float4::dot3(this->m, diff) / l;
diff = diff - this->m * t;
return diff.length();
}
else
{
// line is really a point...
vector v(p - this->b);
return v.length();
}
}
//------------------------------------------------------------------------------
/**
Returns p = b + m * t, given t. Note that the point is not on the line
if 0.0 > t > 1.0
*/
inline point
line::pointat(scalar t) const
{
return this->b + this->m * t;
}
} // namespace Math
//------------------------------------------------------------------------------
#endif