【Lua实战】寻路缓存：重复路径的计算复用

-- 寻路缓存：整路缓存
local pathCache = {}
local function findPathCached(sx, sy, ex, ey)
    local key = sx .. "_" .. sy .. "_" .. ex .. "_" .. ey
    local entry = pathCache[key]
    if entry and os.time() - entry.ts < 600 then
        entry.ts = os.time()
        return entry.path, true
    end
    local path = findPath(sx, sy, ex, ey)
    if path then
        pathCache[key] = {path = path, ts = os.time()}
    end
    return path, false
end

-- 分段复用：段落回收
local player = class(actor)
local segCache = {}
local function salvageSegments(oldPath)
    local runStart = 1
    for i = 2, #oldPath do
        local blocked = isBlocked(oldPath[i].x, oldPath[i].y)
        if blocked or i == #oldPath then
            if not blocked then
                segCache[oldPath[runStart].x .. "_" .. oldPath[runStart].y ..
                    "_" .. oldPath[i].x .. "_" .. oldPath[i].y] =
                    {from = runStart, to = i}
            end
            runStart = i + 1
        end
    end
end