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void Geom::pair_intersect ( Curve const &  A,
double  Al,
double  Ah,
Curve const &  B,
double  Bl,
double  Bh,
Crossings &  ret,
unsigned  depth = 0 
)

This uses the local bounds functions of curves to generically intersect two. It passes in the curves, time intervals, and keeps track of depth, while returning the results through the Crossings parameter.

Definition at line 318 of file path-intersection.cpp.

References intersect_polish_root(), and linear_intersect().

                                                         {
   // std::cout << depth << "(" << Al << ", " << Ah << ")\n";
    OptRect Ar = A.boundsLocal(Interval(Al, Ah));
    if (!Ar) return;

    OptRect Br = B.boundsLocal(Interval(Bl, Bh));
    if (!Br) return;
    
    if(! Ar->intersects(*Br)) return;
    
    //Checks the general linearity of the function
    if((depth > 12)) { // || (A.boundsLocal(Interval(Al, Ah), 1).maxExtent() < 0.1 
                    //&&  B.boundsLocal(Interval(Bl, Bh), 1).maxExtent() < 0.1)) {
        double tA, tB, c;
        if(linear_intersect(A.pointAt(Al), A.pointAt(Ah), 
                            B.pointAt(Bl), B.pointAt(Bh), 
                            tA, tB, c)) {
            tA = tA * (Ah - Al) + Al;
            tB = tB * (Bh - Bl) + Bl;
            intersect_polish_root(A, tA,
                                  B, tB);
            if(depth % 2)
                ret.push_back(Crossing(tB, tA, c < 0));
            else
                ret.push_back(Crossing(tA, tB, c > 0));
            return;
        }
    }
    if(depth > 12) return;
    double mid = (Bl + Bh)/2;
    pair_intersect(B, Bl, mid,
                    A, Al, Ah,
                    ret, depth+1);
    pair_intersect(B, mid, Bh,
                    A, Al, Ah,
                    ret, depth+1);
}


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