Lua坐标旋转：二维旋转变换的公式实现

local function rotate(x, y, a)
    return x * math.cos(a) + y * math.sin(a),
        x * math.sin(a) - y * math.cos(a)   -- 符号写反，镜像旋转
end

local function rotate(cx, cy, x, y, a)
    local dx, dy = x - cx, y - cy
    local c, s = math.cos(a), math.sin(a)
    return cx + dx * c - dy * s,
        cy + dx * s + dy * c     -- 绕中心旋转
end
local nx, ny = rotate(200, 200, 230, 200, 1.57)
sendmsg(actor, 1, "旋转后坐标 " .. nx .. "," .. ny)