bool Polygon2d::intersects(const Point2& origin, const Vector2& direction, RayIntersectionType it) const
{
Point2 endpoint = origin + direction;
if( Polygon2d::encompasses(origin) || Polygon2d::encompasses(endpoint) )
{
return true;
}
// We need to test each minor line segment to see if it intersects.
// NOTE: There are more efficient algorithms for doing this, which
// involve sorting a list of points. This was easy to write.
blocxx::Array<Point2>::const_iterator first = m_points.begin();
blocxx::Array<Point2>::const_iterator previous = first;
blocxx::Array<Point2>::const_iterator current = previous + 1;
NumberType unused1, unused2;
while( current != m_points.end() )
{
if( segmentsIntersect(origin, direction, *previous, *current - *previous, unused1, unused2) )
{
return true;
}
previous = current;
++current;
}
// CHECKME! I think this test is redundant for any enclosed polygon.
if( segmentsIntersect(origin, direction, *previous, *first - *previous, unused1, unused2) )
{
return true;
}
return false;
}
// As above, but returns info about where along segment p1-p2 collision occurs. Returns 0 if segment is entirely contained in rect.
bool Rect::intersects(const Point &p1, const Point &p2, member_type &collisionTime) const
{
collisionTime = 0;
return (
segmentsIntersect(p1, p2, Point(min.x, min.y), Point(min.x, max.y), collisionTime) ||
segmentsIntersect(p1, p2, Point(min.x, max.y), Point(max.x, max.y), collisionTime) ||
segmentsIntersect(p1, p2, Point(max.x, max.y), Point(max.x, min.y), collisionTime) ||
segmentsIntersect(p1, p2, Point(max.x, min.y), Point(min.x, min.y), collisionTime) ||
contains(p1) || contains(p2)
);
}
vector<coord> algs::visibleVertices(const vector<pair<coord, coord> > &edges, vector<coord> visible, const coord &vertex)
{
//cout << "visible vertices size: " << visible.size() << endl;
//cout << "edges size: " << edges.size() << endl;
for(vector<pair<coord, coord> >::size_type k = 0; k < edges.size(); ++k){
vector<coord>::iterator iter = visible.begin();
while(iter != visible.end()){
//if edge intersects with anything, remove from visible coords
if(segmentsIntersect(vertex, *iter, edges[k].first, edges[k].second))
visible.erase(iter);
else
++iter;
}
}
return visible;
}
