【入门夯实】随机游走：带边界的醉汉步生成

-- 每秒全盘随机四方向
dir = ({ 0, 90, 180, 270 })[math.random(1, 4)]

local dirs = { { 1, 0 }, { 0, 1 }, { -1, 0 }, { 0, -1 } }
local cur = 1
local function wanderStep(x, y)
    if math.random(1, 100) <= 30 then
        cur = math.random(1, 4)
    end
    local d = dirs[cur]
    local nx, ny = x + d[1], y + d[2]
    if nx < 10 or nx > 20 or ny < 10 or ny > 20 then
        cur = (cur + 2) % 4 + 1
        d = dirs[cur]
        nx, ny = x + d[1], y + d[2]
    end
    return nx, ny
end

local turnRate = alert and 60 or 30
if math.random(1, 100) <= turnRate then
    cur = math.random(1, 4)
end