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added line-line and line-segment intersection

This commit is contained in:
Nico Pietroni 2007-01-03 15:49:00 +00:00
parent 07fb3ae2df
commit 56086c51ae
1 changed files with 63 additions and 2 deletions
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65
vcg/space/intersection2.h
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@ -21,7 +21,7 @@
* *
****************************************************************************/
/****************************************************************************
History
****************************************************************************/
@ -29,9 +29,11 @@
#ifndef __VCGLIB_INTERSECTION_2
#define __VCGLIB_INTERSECTION_2
#include <vcg/space/line2.h>
#include <vcg/space/segment2.h>
#include <vcg/space/point2.h>
#include <vcg/space/triangle2.h>
#include <vcg/space/box2.h>
@ -50,6 +52,65 @@ template<class SCALAR_TYPE>
return (((p0-p1)^(p2-p1))<=0);
}
///return if exist the intersection point
///between 2 lines in a 2d plane
template<class SCALAR_TYPE>
inline bool LineLineIntersection(const vcg::Line2<SCALAR_TYPE> & l0,
const vcg::Line2<SCALAR_TYPE> & l1,
Point2<SCALAR_TYPE> &p)
{
const SCALAR_TYPE EPSILON= SCALAR_TYPE(1e-8);
///first line
SCALAR_TYPE x1=l0.Origin().X();
SCALAR_TYPE y1=l0.Origin().Y();
SCALAR_TYPE x2=x1+l0.Direction().X();
SCALAR_TYPE y2=y1+l0.Direction().Y();
///second line
SCALAR_TYPE x3=l1.Origin().X();
SCALAR_TYPE y3=l1.Origin().Y();
SCALAR_TYPE x4=x3+l1.Direction().X();
SCALAR_TYPE y4=y3+l1.Direction().Y();
///then find intersection
///denominator
SCALAR_TYPE den=((x1-x2)*(y3-y4))-((y1-y2)*(x3-x4));
if (fabs(den)<EPSILON)
return false;
SCALAR_TYPE d0=(x1*y2)-(y1*x2);
SCALAR_TYPE d1=(x3*y4)-(y3*x4);
SCALAR_TYPE numx=(d0*(x3-x4))-(d1*(x1-x2));
SCALAR_TYPE numy=(d0*(y3-y4))-(d1*(y1-y2));
p.X()=numx/den;
p.Y()=numy/den;
return true;
}
/// interseciton between point and triangle
template<class SCALAR_TYPE>
inline bool LineSegmentIntersection(const vcg::Line2<SCALAR_TYPE> & line,
const vcg::Segment2<SCALAR_TYPE> &seg,
Point2<SCALAR_TYPE> &p_inters)
{
///first compute intersection between lines
vcg::Line2<SCALAR_TYPE> line2;
line2.SetOrigin(seg.P0());
vcg::Point2<SCALAR_TYPE> dir=seg.P1()-seg.P0();
dir.Normalize();
line2.SetDirection(dir);
if(!LineLineIntersection(line,line2,p_inters))
return false;
///then test if intersection point is nearest
///to both extremes then lenght of the segment
SCALAR_TYPE d0=(seg.P1()-p_inters).Norm();
SCALAR_TYPE d1=(seg.P0()-p_inters).Norm();
SCALAR_TYPE lenght=(seg.P0()-seg.P1()).Norm();
return ((d0<lenght)&&(d1<lenght));
}
/// interseciton between point and triangle
template<class SCALAR_TYPE>
inline bool Intersection( const Triangle2<SCALAR_TYPE> & t,const Point2<SCALAR_TYPE> & p)