使用向量使用递归函数减速

Question

我每帧运行此功能大约30次并且经历了大幅减速。这个功能是它的原因，任何想法为什么？

bool Pathfinding::takeStep(
    std::vector<std::vector<int>>* vec, int px, int py, int sx, int sy, int r)
{
    if (px == sx && py == sy) return true;  // destination reached
    bool clear = true;
    // step up
    if ((*vec)[px][py - 1] == -1)  // location not tested yet
    {
        for (int i = 0; i < r * 2; ++i)
        {
            int tx = px - r + i;
            int ty = py - r - 1;
            // Make sure test coordinates are on the grid
            if (tx > 0 && ty > 0 && tx < width && ty < height)
            {
                // already stuck
                if (grid[tx][ty] == 1) clear = false;
            }
            else
                clear = false;  // not on grid
        }
        if (clear)
        {
            // keep moving
            (*vec)[px][py - 1] = (*vec)[px][py] + 1;
            // add one to step count and confirm this way is clear
            if (takeStep(vec, px, py - 1, sx, sy, r)) return true;
        }
        else
        {
            (*vec)[px][py - 1] = -2;  // mark as already tried
        }
    }
    return false;
}