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/*
* KSeg
* Copyright (C) 1999-2006 Ilya Baran
*
* This program 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 program 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.
*
* You should have received a copy of the GNU General Public License
* along with this program; if not, write to the Free Software
* Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
*
* Send comments and/or bug reports to:
* ibaran@mit.edu
*/
#include "G_ray.H"
#include "G_segment.H"
#include "G_line.H"
#include "G_drawstyle.H"
#include "KSegView.H"
//drawing:
void G_ray::draw(QPainter &p, const G_drawstyle &d, bool selected)
{
QRect r = p.window();
if(!inRect(r)) return;
G_segment(p1, p1 + dir * 200000000).draw(p, d, selected);
return;
}
//the mapping is via the tangent function. So when p = 0, the location is -inf and when p = 1 it's inf.
G_point G_ray::getPointOnCurve(double p) const
{
double c;
c = pow(p, 1./81.) * M_PI / (2 + SMALL);
return p1 + tan(c) * dir;
}
double G_ray::getParamFromPoint(const G_point &p) const
{
double c;
c = atan((p - p1).length());
return CUBE(CUBE(CUBE(CUBE(c / M_PI * (2 + SMALL)))));
}
G_point G_ray::getNearestPoint(const G_point &p) const
{
double x = (p - p1) * dir / (dir * dir);
if(x <= 0 || !myFinite(x)) return p1;
return p1 + dir * x;
}
bool G_ray::inRect(const QRect &r) const
{
if(r.contains(p1.toQPoint())) return true;
if(p1.getX() < r.left() && dir.getX() < 0) return false;
if(p1.getX() > r.right() && dir.getX() > 0) return false;
if(p1.getY() < r.top() && dir.getY() < 0) return false;
if(p1.getY() > r.bottom() && dir.getY() > 0) return false;
//the following could be optimized
G_segment tmp;
tmp = G_segment(r.topLeft(), r.bottomLeft());
if(getIntersection(&tmp).isValid()) return true;
tmp = G_segment(r.topRight(), r.bottomRight());
if(getIntersection(&tmp).isValid()) return true;
tmp = G_segment(r.bottomLeft(), r.bottomRight());
if(getIntersection(&tmp).isValid()) return true;
tmp = G_segment(r.topRight(), r.topLeft());
if(getIntersection(&tmp).isValid()) return true;
return false;
}
G_point G_ray::getIntersection(const G_curve *c, int which) const
{
if(c->getType() == G_RAY) {
G_ray *r = (G_ray *)c;
double s, t, tmp;
tmp = dir % r->dir;
if(fabs(tmp) < SMALL) return G_point::inValid();
s = r->dir % (p1 - r->p1) / tmp;
t = dir % (p1 - r->p1) / tmp;
if( s < -SMALL || t < -SMALL)
return G_point::inValid();
if(s < 0) s = 0;
return p1 + s * dir;
}
if(c->getType() == G_SEGMENT) {
G_segment *s = (G_segment *)c;
double r, t, tmp;
tmp = dir % (s->getP2() - s->getP1());
if(fabs(tmp) < SMALL) return G_point::inValid();
r = (s->getP2() - s->getP1()) % (p1 - s->getP1()) / tmp;
t = dir % (p1 - s->getP1()) / tmp;
if( r < -SMALL || t < -SMALL || t > 1 + SMALL)
return G_point::inValid();
if(r < 0) r = 0;
return p1 + r * dir;
}
if(c->getType() == G_LINE) {
G_line *l = (G_line *)c;
double r, tmp;
tmp = dir % l->getDirection();
if(fabs(tmp) < SMALL) return G_point::inValid();
r = ((p1.getY() - l->getP1().getY()) * (l->getDirection().getX()) -
(p1.getX() - l->getP1().getX()) * (l->getDirection().getY())) / tmp;
if(r < -SMALL) return G_point::inValid();
if(r < 0) r = 0;
return p1 + r * dir;
}
return c->getIntersection(this, which);
}
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