CGAL::intersection
#include <CGAL/intersections.h>
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Object
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intersection ( Type1<Kernel> obj1, Type2<Kernel> obj2)
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Two objects obj1 and obj2 intersect if there is a point
p that is part of both obj1 and obj2.
The
intersection
region of those two objects is defined as the set of all
points p that are part of both obj1 and obj2.
Note that for objects like triangles and polygons that enclose a
bounded region, this region is considered part of the object.
If a segment lies completely inside a triangle, then those two objects
intersect and the
intersection
region is the complete segment.
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The possible value for types Type1 and Type2 and the
possible return values wrapped in Object are the
following:
| type A |
type B |
return type |
| Line_2 |
Line_2 |
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| Segment_2 |
Line_2 |
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| Segment_2 |
Segment_2 |
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| Ray_2 |
Line_2 |
|
| Ray_2 |
Segment_2 |
|
| Ray_2 |
Ray_2 |
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| Triangle_2 |
Line_2 |
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| Triangle_2 |
Segment_2 |
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| Triangle_2 |
Ray_2 |
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| Triangle_2 |
Triangle_2 |
| Point_2 |
| Segment_2 |
| Triangle_2 |
| std::vector<Point_2> |
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| Iso_rectangle_2 |
Line_2 |
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| Iso_rectangle_2 |
Segment_2 |
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| Iso_rectangle_2 |
Ray_2 |
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| Iso_rectangle_2 |
Iso_rectangle_2 |
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| Plane_3 |
Line_3 |
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| Plane_3 |
Ray_3 |
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| Plane_3 |
Segment_3 |
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| Plane_3 |
Plane_3 |
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There is also an intersection function between 3 planes.
Example
The following example demonstrates the most common use of
intersection routines.
#include <CGAL/intersections.h>
void foo(CGAL::Segment_2<Kernel> seg, CGAL::Line_2<Kernel> line)
{
CGAL::Object result;
CGAL::Point_2<Kernel> ipoint;
CGAL::Segment_2<Kernel> iseg;
result = CGAL::intersection(seg, line);
if (CGAL::assign(ipoint, result)) {
// handle the point intersection case.
} else
if (CGAL::assign(iseg, result)) {
// handle the segment intersection case.
} else {
// handle the no intersection case.
}
}
See Also
CGAL::do_intersect
CGAL::Object
