贪吃蛇：越吃越长越要稳

fx-snake

local Snake = {}
local KEY = { DIRS = { { 1, 0 }, { -1, 0 }, { 0, 1 }, { 0, -1 } } }

function Snake.PickDir(snake, food)
    local head = snake[1]
    local best, bestScore = nil, -1e9
    for _, d in ipairs(KEY.DIRS) do
        -- 不许直接掉头
        if not (d[1] == -Snake.lastDir[1] and d[2] == -Snake.lastDir[2]) then
            local nx, ny = head.x + d[1], head.y + d[2]
            if Snake.InBounds(nx, ny) and not Snake.OnBody(nx, ny, snake) then
                -- 主分: 靠近豆子
                local score = -(math.abs(nx - food.x) + math.abs(ny - food.y)) * 10
                -- 辅分: 轻微随机防走位死循环
                score = score + math.random() * 3
                -- 附加: 周围空格数越多越安全
                score = score + Snake.FreeNeighbor(nx, ny, snake) * 2
                if score > bestScore then bestScore = score; best = d end
            end
        end
    end
    return best
end

function Snake.Step()
    local d = Snake.PickDir(SL:GetValue("snake"), SL:GetValue("food"))
    if not d then
        SL:PlayFxAt("snake_break")
        SL:SendEvent("snake_reset")
        return
    end
    Snake.lastDir = d
    SL:GrowHead(d[1], d[2])
    if SL:GetValue("headOnFood") then
        SL:SetValue("eaten", SL:GetValue("eaten") + 1)
        SL:PlayBurst(SL:GetValue("foodX"), SL:GetValue("foodY"), "food_glow", 6)
        SL:RespawnFood()
    else
        SL:PopTail()
    end
end

return Snake