Lua - FSM
lua实现的 FSM(finite-state machine)
代码实现
为方便阅读，只粘了核心代码。完整版可移步Github：Lua_FSM - SouthBegonia
状态基类 BaseFSMState.lua
---@class BaseFSMState FSM状态基类
---@field public stateName string @状态名
---@field private entryCondition function @进入此状态的条件
BaseFSMState = {}
BaseFSMState.__index = BaseFSMState;
---实例化状态
---@public
---@param stateName string
function BaseFSMState.New(stateName)
---@type BaseFSMState
local fsmState = setmetatable({}, BaseFSMState);
fsmState.stateName = stateName;
fsmState.entryCondition = nil;
return fsmState;
end
---设置 进入此状态的条件
---@public
---@param condition function
function BaseFSMState:SetEntryCondition(condition)
self.entryCondition = condition;
end
---判断 是否满足进入此状态的条件
---@public
---@return boolean
function BaseFSMState:CheckEntryCondition()
if (self.entryCondition ~= nil) then
return self.entryCondition();
end
return true;
end
---进入状态
---@public
function BaseFSMState:OnEnter()
end
---更新状态
---@public
function BaseFSMState:OnUpdate()
end
---离开状态
---@public
function BaseFSMState:OnLeave()
end
状态机基类 BaseFSM.lua
---@class BaseFSM FSM基类
---@field private states table<string, BaseFSMState> @持有的状态 的表（key=BaseFSM.stateName value=BaseFSMState）
---@field private previousState BaseFSMState @先前状态
---@field private currentState BaseFSMState @当前状态
BaseFSM = {};
BaseFSM.__index = BaseFSM;
---构造 状态机实例
---@public
---@return BaseFSM
function BaseFSM.New()
---@type BaseFSM
local fsm = setmetatable({}, BaseFSM);
fsm.states = {};
fsm.previousState = nil;
fsm.currentState = nil;
return fsm;
end
---添加 状态
---@param fsmState BaseFSMState
---@return boolean @是否 成功添加状态
function BaseFSM:AddState(fsmState)
if (fsmState == nil) then
--Error
return false;
end
if (self.states[fsmState.stateName] ~= nil) then
--Error
return false;
end
self.states[fsmState.stateName] = fsmState;
return true;
end
---设置 初始状态
---@param fsmStateName string
function BaseFSM:SetStartState(fsmStateName)
local startFSMState = self.states[fsmStateName];
if (startFSMState == nil) then
--Error
return false;
end
self.previousState = nil;
self.currentState = startFSMState;
self.currentState:OnEnter();
return true;
end
---获取 当前状态
---@public
---@return BaseFSMState
function BaseFSM:GetCurrentState()
return self.currentState;
end
---切换到 目标状态
---@public
---@param fsmStateName string
---@return boolean
function BaseFSM:ChangeState(fsmStateName)
---@type BaseFSMState
local targetFSMState = self.states[fsmStateName];
if (targetFSMState == nil) then
--Error
return false;
end
if (self.currentState == targetFSMState) then
--Error
return false;
end
if (not targetFSMState:CheckEntryCondition()) then
--Log
return false;
end
self.currentState:OnLeave();
self.previousState = self.currentState;
self.currentState = targetFSMState;
self.currentState:OnEnter();
return true;
end
---@public
function BaseFSM:Update()
if (self.currentState ~= nil) then
self.currentState:OnUpdate();
end
end
测试：
---------- 添加 场景状态枚举 ----------
local SceneFSMStateDefine = {
Login = "Login",
Home = "Home",
Battle = "Battle",
}
---------- 实例化 各场景状态 ----------
---@type BaseFSMState
local sceneLoginFSMState = BaseFSMState.New(SceneFSMStateDefine.Login);
sceneLoginFSMState.OnEnter = function()
print("进入 Login状态");
end
sceneLoginFSMState.OnLeave = function()
print("退出 Login状态");
end
---@type BaseFSMState
local sceneHomeFSMState = BaseFSMState.New(SceneFSMStateDefine.Home);
sceneHomeFSMState.OnEnter = function()
print("进入 Home状态");
end
sceneHomeFSMState.OnLeave = function()
print("退出 Home状态");
end
---@type BaseFSMState
local sceneBattleFSMState = BaseFSMState.New(SceneFSMStateDefine.Battle);
sceneBattleFSMState.OnEnter = function()
print("进入 Battle状态");
end
sceneBattleFSMState.OnLeave = function()
print("退出 Battle状态");
end
---------- 实例化 场景状态机 ----------
print("---------- 构造 FSM ----------");
local sceneFSM = BaseFSM.New();
sceneFSM:AddState(sceneLoginFSMState);
sceneFSM:AddState(sceneHomeFSMState);
sceneBattleFSMState:SetEntryCondition(function()
--设置Battle状态的切换条件:仅当在Home状态时才可切换至Battle
return sceneFSM:GetCurrentState() == sceneHomeFSMState;
end)
sceneFSM:AddState(sceneBattleFSMState);
print("---------- 设定 FSM初始状态为 Login ----------");
sceneFSM:SetStartState(SceneFSMStateDefine.Login);
print("---------- 切换 FSM状态为 Battle ----------");
sceneFSM:ChangeState(SceneFSMStateDefine.Battle);
print("---------- 切换 FSM状态为 Home ----------");
sceneFSM:ChangeState(SceneFSMStateDefine.Home);
print("---------- 切换 FSM状态为 Battle ----------");
sceneFSM:ChangeState(SceneFSMStateDefine.Battle);
--[[
OUTPUT:
---------- 构造 FSM ----------
---------- 设定 FSM初始状态为 Login ----------
进入 Login状态
---------- 切换 FSM状态为 Battle ----------
---------- 切换 FSM状态为 Home ----------
退出 Login状态
进入 Home状态
---------- 切换 FSM状态为 Battle ----------
退出 Home状态
进入 Battle状态
--]]
