Question

I’m writing an algorithm that iterates over a list of points, calculates the distance between them and inserts additional points if the distance is too great. However I seem to be lacking the proper familiarity with STL to come up with an elegant solution. I’m hoping that I can learn something, so I’ll just show you my code. You might have some hints for me.

for (std::list<PathPoint>::iterator it = ++points_.begin();
     it != points_.end(); it++)
{
    Vector curPos = it->getPosition();
    Vector prevPos = (--it)->getPosition();
    Vector vecFromPrev = curPos - prevPos;
    float distance = vecFromPrev.abs();
    it++;
    if (distance > MAX_DISTANCE_BETWEEN_POINTS)
    {               
        int pointsToInsert = (int)(distance / MAX_DISTANCE_BETWEEN_POINTS);             
        Vector curPos = prevPos;                
        for (int i = 0; i < pointsToInsert; i++)
        {
            curPos += vecFromPrev / pointsToInsert;
            it = points_.insert(it, PathPoint(curPos, false));
            it++;
        }
    }
}

Answer 1

Consider using adjacent_find to find an iterator position where the distance between consecutive elements is too large, then inserting pointsToInsert items.

http://www.sgi.com/tech/stl/adjacent_find.html

In addition, you could use generate with a functor to fill in the intermediate points.

http://www.sgi.com/tech/stl/generate.html

Not sure how deep you want to go into STL 🙂