/* === S Y N F I G ========================================================= */
/*! \file curve_helper.h
** \brief Curve Helper Header
**
** $Id$
**
** \legal
** Copyright (c) 2002-2005 Robert B. Quattlebaum Jr., Adrian Bentley
**
** This package is free software; you can redistribute it and/or
** modify it under the terms of the GNU General Public License as
** published by the Free Software Foundation; either version 2 of
** the License, or (at your option) any later version.
**
** This package 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 GNU
** General Public License for more details.
** \endlegal
*/
/* ========================================================================= */
/* === S T A R T =========================================================== */
#ifndef __SYNFIG_CURVE_HELPER_H
#define __SYNFIG_CURVE_HELPER_H
/* === H E A D E R S ======================================================= */
#include <ETL/bezier>
#include "rect.h"
#include "real.h"
#include "vector.h"
#include <vector>
/* === M A C R O S ========================================================= */
/* === T Y P E D E F S ===================================================== */
/* === C L A S S E S & S T R U C T S ======================================= */
namespace synfig {
//line helper functions
inline Real line_point_distsq(const Point &p1, const Point &p2,
const Point &p, float &t)
{
Vector v,vt;
v = p2 - p1;
vt = p - p1;
t = v.mag_squared() > 1e-12 ? (vt*v)/v.mag_squared() : 0; //get the projected time value for the current line
//get distance to line segment with the time value clamped 0-1
if(t >= 1) //use p+v
{
vt += v; //makes it pp - (p+v)
t = 1;
}else if(t > 0) //use vt-proj
{
vt -= v * t; // vt - proj_v(vt) //must normalize the projection vector to work
}else
{
t = 0;
}
//else use p
return vt.mag_squared();
}
//----- RAY CLASS AND FUNCTIONS --------------
struct Ray
{
Point p;
Vector v;
Ray() {}
Ray(const Point &pin, const Vector &vin):p(pin), v(vin) {}
};
/* This algorithm calculates the INTERSECTION of 2 line segments
(not the closest point or anything like that, just intersection)
//parameter values returned are [0,1]
*/
int intersect(const Point &p1, const Vector &v1, float &t1,
const Point &p2, const Vector &v2, float &t2);
inline bool intersect_line_segments(const Point &a, const Point &b, float &tout,
const Point &c, const Point &d, float &sout)
{
Vector v1(b-a), v2(d-c);
//ok so treat both lines as parametric (so we can find the time values simultaneously)
float t,s;
if( intersect(a,v1,t, b,v2,s) && t >= 0 && t <= 1 && s >= 0 && s <= 1 )
{
tout = t;
sout = s;
return true;
}
return false;
}
//Find the closest point on the curve to a point (and return its distance, and time value)
Real find_closest(const etl::bezier<Point> &curve, const Point &point, float step, Real *closest, float *t);
//----------- Rectangle helper functions ---------------
template < typename T >
inline void Bound(etl::rect<T> &r, const etl::bezier<Point> &b)
{
r.set_point(b[0][0],b[0][1]);
r.expand(b[1][0],b[1][1]);
r.expand(b[2][0],b[2][1]);
r.expand(b[3][0],b[3][1]);
}
/*template < typename T >
inline bool intersect(const etl::rect<T> &r1, const etl::rect<T> &r2)
{
return (r1.minx < r2.maxx) &
(r2.minx < r1.maxx) &
(r1.miny < r2.maxy) &
(r2.miny < r1.maxy);
}*/
//----- Convex Hull of a Bezier Curve --------------
struct BezHull
{
Point p[4];
int size;
void Bound(const etl::bezier<Point> &b);
};
//Line Intersection
int intersect(const Rect &r1, const Point &p, const Vector &v);
int intersect(const Rect &r1, const Point &p); //inside or to the right
int intersect(const BezHull &bh, const Point &p, const Vector &v);
//int intersect(const etl::bezier<Point> &b, const Point &p, const Vector &v);
int intersect(const etl::bezier<Point> &b, const Point &p); //for use in containment tests for regions
//Curve intersection object
class CIntersect
{
public:
struct SCurve;
private:
void recurse_intersect(const SCurve &left, const SCurve &right, int depth = 0);
public:
//size should be equal
typedef std::vector< std::pair<float,float > > intersect_set;
intersect_set times;
int max_depth;
CIntersect();
bool operator()(const etl::bezier<Point> &b1, const etl::bezier<Point> &b2);
};
}; // END of namespace synfig
/* === E N D =============================================================== */
#endif