Cocos2d-x game development-Finite State Machine (FSM) (4), cocos2d-xfsm

Cocos2d-x game development-Finite State Machine (FSM) (4), cocos2d-xfsm
Cocos2d-x game development-Finite State Machine (FSM) (4)

Although we understand FSM and can write our own FSM, there are better tools to help us complete this tedious task. SMC (http://smc.sourceforge.net/) is such a tool. :

Http://sourceforge.net/projects/smc/files/latest/download

Smc. jar under bin is a command line tool used to generate status classes. Run the following command:

$ java -jar Smc.jar Monkey.sm

1. FSM in the real world

First, define a state machine plain text file: Monkey. sm. The content is as follows:

// cheungmine// 2015-01-22// entity class%class Monkey// entity class header%header Monkey.h// inital state%start MonkeyMap::STOP// entity state map%map MonkeyMap%%STOPEntry {stop();}Exit {exit();}{walk WALK {}}WALKEntry {walk();}Exit {exit();}{stop STOP {}turn TURN {}}TURNEntry {turn();}Exit {exit();}{walk WALK {}}%%

Here, % class Monkey indicates the object class name: Monkey (Monkey. h and Monkey. cpp)

% Header specifies the header file: Monkey. h

% Map indicates the status chart class, which contains all States. Here is: MonkeyMap

% Start indicates the actual status. Here is STOP, and the corresponding class is MonkeyMap_STOP.

The section between %... % defines each status. The format is as follows:

STOP // status name Entry {// execute this function to enter this status stop ();} Exit {// execute this function to exit this status Exit exit ();} {// status switching logic walk {}}

When you run the following command, the system automatically generates the files Monkey_sm.h and Monkey_sm.cpp. Add the built-in statemap. h to the project.

java -jar Smc.jar Monkey.sm

2. entity class

We still need to implement the business logic by ourselves, that is, write Monkey. h and Monkey. cpp. However, this write of the Monkey class requires certain rules. The source code is as follows:

// Monkey.h//#ifndef MONKEY_H_#define MONKEY_H_#include "cocos2d.h"USING_NS_CC;#include "Monkey_sm.h"#define MAX_STOP_TIME  3#define MAX_WALK_TIME  10#define MAX_WALK_DIST  200class Monkey : public Node{public:    CREATE_FUNC(Monkey);    virtual bool init();    void stop();    void walk();    void turn();    void exit();private:    MonkeyContext * _fsm;    int    _step;    int    _curPos;    time_t _curTime;    // Sprite * _sprite;private:    void onIdleStop(float dt)    {        int d = (int) (time(0) - _curTime);        if (d > MAX_STOP_TIME) {            _fsm->walk();        }    }    void onIdleWalk(float dt)    {        if (_curPos > MAX_WALK_DIST || _curPos < -MAX_WALK_DIST) {            _fsm->turn();        }        int d = (int) (time(0) - _curTime);        if (d > MAX_WALK_TIME) {            _fsm->stop();        }        _curPos += _step;    }    void onIdleTurn(float dt)    {        _fsm->walk();    }};#endif // MONKEY_H_

OnIdle ???? It is the callback function that triggers the state. The business logic of the entity state change is implemented here.

// Monkey.cpp//#include "Monkey.h"#include <time.h>#include <assert.h>void Monkey::exit(){    this->unscheduleAllCallbacks();    cocos2d::log("exit()");}bool Monkey::init(){    _step = 1;    _curPos = 0;    _curTime = time(0);    // _sprite = Sprite::create("monkey.png");    // addChild(_sprite);    _fsm = new MonkeyContext(*this);    assert(_fsm);    _fsm->setDebugFlag(true);    _fsm->enterStartState();    return true;}void Monkey::stop(){    _curTime = time(0);    cocos2d::log("stop(): pos=%d", _curPos);    this->schedule(schedule_selector(Monkey::onIdleStop), 0.1f);}void Monkey::walk(){    _curTime = time(0);    cocos2d::log("walk(): pos=%d", _curPos);    this->schedule(schedule_selector(Monkey::onIdleWalk), 0.1f);}void Monkey::turn(){    _step *= -1;    cocos2d::log("turn(): step=%d", _step);    this->schedule(schedule_selector(Monkey::onIdleTurn), 0.1f);      }

3. State Machine

The frame code Smc has been generated for us: Monkey_sm.h and Monkey_sm.cpp:

//// ex: set ro:// DO NOT EDIT.// generated by smc (http://smc.sourceforge.net/)// from file : Monkey.sm//#ifndef MONKEY_SM_H#define MONKEY_SM_H#define SMC_USES_IOSTREAMS#include "statemap.h"// Forward declarations.class MonkeyMap;class MonkeyMap_STOP;class MonkeyMap_WALK;class MonkeyMap_TURN;class MonkeyMap_Default;class MonkeyState;class MonkeyContext;class Monkey;class MonkeyState :    public statemap::State{public:    MonkeyState(const char * const name, const int stateId)    : statemap::State(name, stateId)    {};    virtual void Entry(MonkeyContext&) {};    virtual void Exit(MonkeyContext&) {};    virtual void stop(MonkeyContext& context);    virtual void turn(MonkeyContext& context);    virtual void walk(MonkeyContext& context);protected:    virtual void Default(MonkeyContext& context);};class MonkeyMap{public:    static MonkeyMap_STOP STOP;    static MonkeyMap_WALK WALK;    static MonkeyMap_TURN TURN;};class MonkeyMap_Default :    public MonkeyState{public:    MonkeyMap_Default(const char * const name, const int stateId)    : MonkeyState(name, stateId)    {};};class MonkeyMap_STOP :    public MonkeyMap_Default{public:    MonkeyMap_STOP(const char * const name, const int stateId)    : MonkeyMap_Default(name, stateId)    {};    virtual void Entry(MonkeyContext&);    virtual void Exit(MonkeyContext&);    virtual void walk(MonkeyContext& context);};class MonkeyMap_WALK :    public MonkeyMap_Default{public:    MonkeyMap_WALK(const char * const name, const int stateId)    : MonkeyMap_Default(name, stateId)    {};    virtual void Entry(MonkeyContext&);    virtual void Exit(MonkeyContext&);    virtual void stop(MonkeyContext& context);    virtual void turn(MonkeyContext& context);};class MonkeyMap_TURN :    public MonkeyMap_Default{public:    MonkeyMap_TURN(const char * const name, const int stateId)    : MonkeyMap_Default(name, stateId)    {};    virtual void Entry(MonkeyContext&);    virtual void Exit(MonkeyContext&);    virtual void walk(MonkeyContext& context);};class MonkeyContext :    public statemap::FSMContext{public:    explicit MonkeyContext(Monkey& owner)    : FSMContext(MonkeyMap::STOP),      _owner(&owner)    {};    MonkeyContext(Monkey& owner, const statemap::State& state)    : FSMContext(state),      _owner(&owner)    {};    virtual void enterStartState()    {        getState().Entry(*this);    }    inline Monkey& getOwner()    {        return *_owner;    };    inline MonkeyState& getState()    {        if (_state == NULL)        {            throw statemap::StateUndefinedException();        }        return dynamic_cast<MonkeyState&>(*_state);    };    inline void stop()    {        getState().stop(*this);    };    inline void turn()    {        getState().turn(*this);    };    inline void walk()    {        getState().walk(*this);    };private:    Monkey* _owner;};#endif // MONKEY_SM_H//// Local variables://  buffer-read-only: t// End://

//// ex: set ro:// DO NOT EDIT.// generated by smc (http://smc.sourceforge.net/)// from file : Monkey.sm//#include "Monkey.h"#include "Monkey_sm.h"using namespace statemap;// Static class declarations.MonkeyMap_STOP MonkeyMap::STOP("MonkeyMap::STOP", 0);MonkeyMap_WALK MonkeyMap::WALK("MonkeyMap::WALK", 1);MonkeyMap_TURN MonkeyMap::TURN("MonkeyMap::TURN", 2);void MonkeyState::stop(MonkeyContext& context){    Default(context);}void MonkeyState::turn(MonkeyContext& context){    Default(context);}void MonkeyState::walk(MonkeyContext& context){    Default(context);}void MonkeyState::Default(MonkeyContext& context){    throw (        TransitionUndefinedException(            context.getState().getName(),            context.getTransition()));}void MonkeyMap_STOP::Entry(MonkeyContext& context){    Monkey& ctxt = context.getOwner();    ctxt.stop();}void MonkeyMap_STOP::Exit(MonkeyContext& context){    Monkey& ctxt = context.getOwner();    ctxt.exit();}void MonkeyMap_STOP::walk(MonkeyContext& context){    context.getState().Exit(context);    context.setState(MonkeyMap::WALK);    context.getState().Entry(context);}void MonkeyMap_WALK::Entry(MonkeyContext& context){    Monkey& ctxt = context.getOwner();    ctxt.walk();}void MonkeyMap_WALK::Exit(MonkeyContext& context){    Monkey& ctxt = context.getOwner();    ctxt.exit();}void MonkeyMap_WALK::stop(MonkeyContext& context){    context.getState().Exit(context);    context.setState(MonkeyMap::STOP);    context.getState().Entry(context);}void MonkeyMap_WALK::turn(MonkeyContext& context){    context.getState().Exit(context);    context.setState(MonkeyMap::TURN);    context.getState().Entry(context);}void MonkeyMap_TURN::Entry(MonkeyContext& context){    Monkey& ctxt = context.getOwner();    ctxt.turn();}void MonkeyMap_TURN::Exit(MonkeyContext& context){    Monkey& ctxt = context.getOwner();    ctxt.exit();}void MonkeyMap_TURN::walk(MonkeyContext& context){    context.getState().Exit(context);    context.setState(MonkeyMap::WALK);    context.getState().Entry(context);}//// Local variables://  buffer-read-only: t// End://

4. Summary

FSM is a fixed paradigm, so using tools to help us reduce the chances of making mistakes. The input file is entity. sm. We focus on the business logic, so status-related code smc has been generated for us. Compare the manually created classes and automatically generated classes by the smc Framework tool:

Using in cocos2d-x is simple:

bool HelloWorld::init(){    //////////////////////////////    // 1. super init first    if ( !Layer::init() )    {        return false;    }        auto rootNode = CSLoader::createNode("MainScene.csb");    addChild(rootNode);    auto closeItem = static_cast<ui::Button*>(rootNode->getChildByName("Button_1"));    closeItem->addTouchEventListener(CC_CALLBACK_1(HelloWorld::menuCloseCallback, this));    /////////////////// test ///////////////////////    Monkey * mk = Monkey::create();    addChild(mk);    return true;}

That's it! Read the following carefully:

Cocos2d-x game development tour (Zhong Dilong)