世嘉MD游戏开发进阶篇【二】：C语言实现有限状态机

有限状态机应用是非常广泛的，比如关卡的切换、角色动画状态的切换等等，我自己写了个有限状态机，开发世嘉MD游戏的朋友可以用得到，对于解耦还是有点帮助的，不必挤在一个文件里。

没有学过MD游戏开发基础的可以翻看我写的基础篇教程。

C语言开发世嘉MD游戏-基础篇

https://blog.csdn.net/qq272508839/category_9528531.html

//=================================================

FSM.c文件代码如下：

#include <genesis.h>
#include "FSM.h"

void initStateMgr(StateMgr *_stateMgr, u8 _stateCount)
{
    _stateMgr->preState = NULL;
    _stateMgr->curState = NULL;
    _stateMgr->stateList = MEM_alloc(sizeof(State) * _stateCount);
    for (u8 i = 0; i < _stateCount; i++)
    {
        _stateMgr->stateList[i].ID = i;
        _stateMgr->stateList[i].enter = NULL;
        _stateMgr->stateList[i].stay = NULL;
        _stateMgr->stateList[i].exit = NULL;
    }
    _stateMgr->stateCount = _stateCount;
}

void regStateEvent(StateMgr *_stateMgr, u8 _stateIndex, void (*_enter)(), void (*_stay)(), void (*_exit)())
{
    _stateMgr->stateList[_stateIndex].enter = _enter;
    _stateMgr->stateList[_stateIndex].stay = _stay;
    _stateMgr->stateList[_stateIndex].exit = _exit;
}

void changeState(StateMgr *_stateMgr, u8 _stateIndex)
{
    if (_stateIndex < 0 || _stateIndex > _stateMgr->stateCount - 1)
        return;
    if (_stateMgr->stateList == NULL)
        return;
    if (_stateMgr->stateList[_stateIndex].enter == NULL)
        return;

    _stateMgr->preState = _stateMgr->curState;

    if (_stateMgr->preState != NULL && _stateMgr->preState->exit != NULL)
        _stateMgr->preState->exit();

    _stateMgr->curState = &(_stateMgr->stateList[_stateIndex]);

    if (_stateMgr->curState != NULL)
        _stateMgr->curState->enter();
}

void updateState(StateMgr *_stateMgr)
{
    if (_stateMgr->curState != NULL)
        _stateMgr->curState->stay();
}

FSM.h头文件代码如下：

#ifndef _FSM_H_
#define _FSM_H_

#include <genesis.h>

typedef struct state
{
    u8 ID;
    void (*enter)(void);
    void (*stay)(void);
    void (*exit)(void);
} State;

typedef struct statemgr
{
    u8 stateCount;
    State *preState;
    State *curState;
    State *stateList;
} StateMgr;

//初始化状态管理，给_stateMgr分配内存
void initStateMgr(StateMgr *_stateMgr, u8 _stateCount);
//注册状态事件：enter，stay，exit
//_stateIndex是状态索引值
void regStateEvent(StateMgr *_stateMgr, u8 _stateIndex, void (*_enter)(), void (*_stay)(), void (*_exit)());
//改变状态
void changeState(StateMgr *_stateMgr, u8 _stateIndex);
//状态update
void updateState(StateMgr *_stateMgr);

#endif