Method set_parent

plugins/3dveins.cpp:320–328

    float density() { return float(num_tiles) / num_unmined; }

    void set_parent(Ptr pp) {
        if (parent)
            parent->add_tiles(-num_tiles);
        parent = pp;
        if (parent)
            parent->add_tiles(num_tiles);

        parent_depth = (pp ? pp->parent_depth+1 : 0);
    }

    int parent_mat() {
        return parent ? parent->vein.first : SMC_LAYER;