cocos2d-x的A*寻路

如果你还不熟悉A*寻路，请先看下这篇文章《明明白白A*寻路，一定让你懂》http://blog.csdn.net/dssdss123/article/details/11494065

一、先介绍几个函数和结构：

1、virtual void draw()

这个函数跟与MFC上单文档里的OnDraw函数很像，这里只是少了dc，这个函数会一直被调用，无需刷新，也就是说，你无需像在MFC上一样调用Invalidate或者InvalidateRect

2、virtual void ccTouchBegan(CCTouch* pTouch, CCEvent* pEvent)

这个函数是下响应触摸的，当你点击屏幕时，就会进到这个函数。要使这个函数有效，你需要在init中调用
setTouchEnabled(true);    // 允许该层响应触摸
CCDirector::sharedDirector()->getTouchDispatcher()->addTargetedDelegate(this, 0, false);    // 注册单点触摸

在这个例子中，我们不需要多点触摸

3、ccColor4F结构

这个结构在ccDrawSolidRect函数中将会使用到，ccDrawSolidRect是画某种颜色的矩形，对应在MFC中，我们使用的是FillSolidRect。ccColor4F是RGBA的结构，RGB是三颜色，红绿蓝，最后一个alpha值，他表示这个颜色的透明度。为1是完全不透明，0时则完全透明。

二、实现

1、去掉coco自带的乱七八糟的显示

1）去掉帧频显示

在函数bool AppDelegate::applicationDidFinishLaunching()中

// turn on display FPS
//pDirector->setDisplayStats(true);

将pDirector->setDisplayStats(true)，注释掉

2）去掉menu，Hello World文字标签

在函数void HelloWorld::init()中

// Add the menu to HelloWorld layer as a child layer.
//this->addChild(pMenu, 1);

// Add the label to HelloWorld layer as a child layer.
//this->addChild(pLabel, 1);

将menu和label注释掉

3）替换背景图，并置于最底层

// 3. Add add a splash screen, show the cocos2d splash image.
CCSprite* pSprite = CCSprite::create("map.jpg");    // 将原先的HelloWorld.png，替换为自己的图片，这里我换成map.jpg
CC_BREAK_IF(! pSprite);

2、初始化地图

声明结构表示格子掩码等一些信息，我们的例子中，只需掩码，所以结构如下：

    struct ST_GRID    {        ST_GRID()  { gf = GRID_FLAG_DEFAULT; }        GRID_FLAG gf;    };    typedef vector<ST_GRID*> VEC_GRID;    VEC_GRID m_vecGrid;    // 保存地图产生的所有格子

初始化地图的格子掩码，如下：

void HelloWorld::InitMap(){    // 初始化格子掩码    srand((unsigned int)time(NULL));    for (int i = 0; i < GetRow() * GetCol(); i++)    {        int nRandFlag = ((int)(CCRANDOM_0_1() * 10)) % 4 == 0 ? GRID_FLAG_OBSTACLE : GRID_FLAG_DEFAULT;    // 十分之四的概率产生障碍        ST_GRID* pGrid = new ST_GRID;        if (!pGrid)        {            return ;        }        pGrid->gf = (GRID_FLAG)nRandFlag;        m_vecGrid.push_back(pGrid);    }}

3、寻路

定义一个结构，用于寻路过程中，记录每个格子的信息

    struct NODE    {        NODE()  {nIndex = 0; nG = 0; pParent = NULL;}        int nIndex;        int nG;        NODE* pParent;    };    vector<NODE*> m_vecPath;    // 寻路的路径

下面开始寻路

void HelloWorld::FindPath(){    vector<NODE*> vecClose;    // close表    vector<NODE*> vecOpen;     // open表    if (m_nStartIndex == -1 || m_nEndIndex == -1)    {        return ;    }    m_vecPath.clear();    // 这里，我们并没有delete，但却不会内存泄漏，因为cocos2d-x使用了跟java一样的技术 -- 内存回收机制，自动处理垃圾    // 先添加开始点    NODE* pNode = new NODE;    pNode->nIndex = m_nStartIndex;    vecClose.push_back(pNode);    int nStep = 0;    while(true)    {        if (nStep++ >= 200)    // 最多寻200格        {            break;        }        NODE* pNextNode = vecClose[vecClose.size() - 1];    // 取下一个路径        if (!pNextNode)        {            break;        }        if (pNextNode->nIndex == m_nEndIndex)    // 找到终点，就不再找了        {            break;        }        for (int i = 0; i < 8; i++)        {            int nIndex = GetIndexByDir(pNextNode->nIndex, i);    // 根据方向取索引            if (-1 == nIndex)            {                continue;            }            if (m_vecGrid[nIndex]->gf == GRID_FLAG_OBSTACLE)    // 障碍            {                continue;            }            if (InTable(nIndex, vecClose) != NULL)      // 在close表里            {                continue;            }            NODE* pNode = InTable(nIndex, vecOpen);     // 在open表里，比较G值，取G值更小的为新路径            if (pNode)            {                int nNewG = pNextNode->nG + GetGByIndex(pNextNode->nIndex, pNode->nIndex);                if (pNode->nG > nNewG)                {                    pNode->nG = nNewG;                    pNode->pParent = pNextNode;    // 改变节点的父节点                }                continue;            }            // 新搜索到的格子，添加到开放列表            pNode = new NODE;            pNode->nIndex = nIndex;            pNode->nG = pNextNode->nG + GetGByIndex(pNextNode->nIndex, pNode->nIndex);            pNode->pParent = pNextNode;            vecOpen.push_back(pNode);        }        // 找下一个路径，open表里F值最小的就是了        int nMinF = 0xFFFFFF;        pNextNode = NULL;        int nNextNodeIndex = 0;        for (int i = 0; i < (int)vecOpen.size(); i++)        {            NODE* pNode = vecOpen[i];            if (!pNode)            {                continue;            }            int nH = GetHByIndex(pNode->nIndex);    // 计算该点与终点的H值，即路径长度            int nF = nH + pNode->nG;    // F = H + G            if (nF < nMinF)            {                nMinF = nF;                pNextNode = pNode;                nNextNodeIndex = i;            }        }        // 找到F值最小的，放入close表，并从open表里删除        if (nNextNodeIndex >= 0 && nNextNodeIndex < (int)vecOpen.size())        {            vecClose.push_back(pNextNode);            vecOpen.erase(vecOpen.begin() + nNextNodeIndex);        }    }    // 寻路结束，找最优路径    pNode = vecClose[vecClose.size() - 1];    while (pNode)    {        m_vecPath.push_back(pNode);        pNode = pNode->pParent;    }}

4、展示到界面上

void HelloWorld::draw(){    // 画背景表格    CCSize size = CCDirector::sharedDirector()->getWinSize();    for (int i = 0; i < GetRow(); i++)    {        ccDrawLine(ccp(0, i * GRID_SIDELEN), ccp(size.width, i * GRID_SIDELEN));    }    for (int i = 0; i < GetCol(); i++)    {        ccDrawLine(ccp(i * GRID_SIDELEN, 0), ccp(i * GRID_SIDELEN, size.height));    }    // 画特殊格子颜色    // 寻路得到的路径    for (int i = 0; i < (int)m_vecPath.size(); i++)    {        CCPoint ptObstacleLT;        CCPoint ptObstacleRD;        GetRectPointByIndex(m_vecPath[i]->nIndex, ptObstacleLT, ptObstacleRD);        ccColor4F clrObstacle = {0, 1, 1, 0};        ccDrawSolidRect(ptObstacleLT, ptObstacleRD, clrObstacle);    }    // 开始点    CCPoint ptStartLT;    CCPoint ptStartRD;    GetRectPointByIndex(m_nStartIndex, ptStartLT, ptStartRD);    ccColor4F clrStart = {1, 0, 0, 1};    ccDrawSolidRect(ptStartLT, ptStartRD, clrStart);    // 结束点    CCPoint ptEndLT;    CCPoint ptEndRD;    GetRectPointByIndex(m_nEndIndex, ptEndLT, ptEndRD);    ccColor4F clrEnd = {0, 1, 0, 1};    ccDrawSolidRect(ptEndLT, ptEndRD, clrEnd);    // 障碍    for (int i = 0; i < (int)m_vecGrid.size(); i++)    {        if (m_vecGrid[i]->gf == GRID_FLAG_OBSTACLE)        {            CCPoint ptObstacleLT;            CCPoint ptObstacleRD;            GetRectPointByIndex(i, ptObstacleLT, ptObstacleRD);            ccColor4F clrObstacle = {0, 0, 1, 1};            ccDrawSolidRect(ptObstacleLT, ptObstacleRD, clrObstacle);        }    }}

这里，我只介绍几个比较重要的函数，其他的就不赘述了，资源已上传到CSDN，请到这里免积分下载http://download.csdn.net/detail/dssdss123/6283613有疑问的童鞋留言哈

。。。。。。。。

啊，我还是直接上源码吧

#ifndef __HELLOWORLD_SCENE_H__#define __HELLOWORLD_SCENE_H__#include "cocos2d.h"#include "Box2D/Box2D.h"#include "SimpleAudioEngine.h"USING_NS_CC;enum STEP{    STEP_DEFAULT    = 0,    STEP_STARTPOINT = 1,    STEP_ENDPOINT   = 2,};enum GRID_FLAG{    GRID_FLAG_DEFAULT   = 0,        // 默认可通过    GRID_FLAG_OBSTACLE  = 1,        // 障碍};const int GRID_SIDELEN = 20;    // 不能为0//////////////////////////////////////////////////////////////////////////class HelloWorld : public cocos2d::CCLayer{public:    // Here's a difference. Method 'init' in cocos2d-x returns bool, instead of returning 'id' in cocos2d-iphone    virtual bool init();      // there's no 'id' in cpp, so we recommand to return the exactly class pointer    static cocos2d::CCScene* scene();        // a selector callback    void menuCloseCallback(CCObject* pSender);    // implement the "static node()" method manually    CREATE_FUNC(HelloWorld);public:    virtual void draw();    virtual bool ccTouchBegan(CCTouch* pTouch, CCEvent* pEvent);private:    void InitMap();private:    int GetRow();    int GetCol();    int GetIndexByPoint(CCPoint pt);    void GetRectPointByIndex(int nIndex, CCPoint &ptLT, CCPoint &ptRD);private:    int m_nStartIndex;    int m_nEndIndex;    struct ST_GRID    {        ST_GRID()  { gf = GRID_FLAG_DEFAULT; }        GRID_FLAG gf;    };    typedef vector<ST_GRID*> VEC_GRID;    VEC_GRID m_vecGrid;    struct NODE    {        NODE()  {nIndex = 0; nG = 0; pParent = NULL;}        int nIndex;        int nG;        NODE* pParent;    };    vector<NODE*> m_vecPath;    // 寻路的路径public:    void FindPath();private:    int GetIndexByDir(int nIndex, int nDir);    int GetGByIndex(int nStartIndex, int nEndIndex);    int GetHByIndex(int nIndex);    NODE *InTable(int nIndex, vector<NODE*> &vecTbl);private:    int m_nStep;};#endif  // __HELLOWORLD_SCENE_H__

#include "HelloWorldScene.h"using namespace cocos2d;CCScene* HelloWorld::scene(){    CCScene * scene = NULL;    do     {        // 'scene' is an autorelease object        scene = CCScene::create();        CC_BREAK_IF(! scene);        // 'layer' is an autorelease object        HelloWorld *layer = HelloWorld::create();        CC_BREAK_IF(! layer);        // add layer as a child to scene        scene->addChild(layer);    } while (0);    // return the scene    return scene;}// on "init" you need to initialize your instancebool HelloWorld::init(){    bool bRet = false;    do     {        //////////////////////////////////////////////////////////////////////////        // super init first        //////////////////////////////////////////////////////////////////////////        CC_BREAK_IF(! CCLayer::init());        //////////////////////////////////////////////////////////////////////////        // add your codes below...        //////////////////////////////////////////////////////////////////////////        // 1. Add a menu item with "X" image, which is clicked to quit the program.        // Create a "close" menu item with close icon, it's an auto release object.        CCMenuItemImage *pCloseItem = CCMenuItemImage::create(            "CloseNormal.png",            "CloseSelected.png",            this,            menu_selector(HelloWorld::menuCloseCallback));        CC_BREAK_IF(! pCloseItem);        // Place the menu item bottom-right conner.        pCloseItem->setPosition(ccp(CCDirector::sharedDirector()->getWinSize().width - 20, 20));        // Create a menu with the "close" menu item, it's an auto release object.        CCMenu* pMenu = CCMenu::create(pCloseItem, NULL);        pMenu->setPosition(CCPointZero);        CC_BREAK_IF(! pMenu);        // Add the menu to HelloWorld layer as a child layer.        //this->addChild(pMenu, 1);        // 2. Add a label shows "Hello World".        // Create a label and initialize with string "Hello World".        CCLabelTTF* pLabel = CCLabelTTF::create("Hello World", "Arial", 24);        CC_BREAK_IF(! pLabel);        // Get window size and place the label upper.         CCSize size = CCDirector::sharedDirector()->getWinSize();        pLabel->setPosition(ccp(size.width / 2, size.height - 50));        // Add the label to HelloWorld layer as a child layer.        //this->addChild(pLabel, 1);        // 3. Add add a splash screen, show the cocos2d splash image.        CCSprite* pSprite = CCSprite::create("map.jpg");        CC_BREAK_IF(! pSprite);        // Place the sprite on the center of the screen        pSprite->setPosition(ccp(size.width/2, size.height/2));        // Add the sprite to HelloWorld layer as a child layer.        this->addChild(pSprite, -1);        setTouchEnabled(true);        CCDirector::sharedDirector()->getTouchDispatcher()->addTargetedDelegate(this,0,false);        m_nStep = STEP_STARTPOINT;        m_nStartIndex = -1;        m_nEndIndex = -1;        InitMap();        bRet = true;    } while (0);    return bRet;}void HelloWorld::menuCloseCallback(CCObject* pSender){    // "close" menu item clicked    CCDirector::sharedDirector()->end();}//////////////////////////////////////////////////////////////////////////void HelloWorld::InitMap(){    srand((unsigned int)time(NULL));    for (int i = 0; i < GetRow() * GetCol(); i++)    {        int nRandFlag = ((int)(CCRANDOM_0_1() * 10)) % 4 == 0 ? GRID_FLAG_OBSTACLE : GRID_FLAG_DEFAULT;        ST_GRID* pGrid = new ST_GRID;        if (!pGrid)        {            return ;        }        pGrid->gf = (GRID_FLAG)nRandFlag;        m_vecGrid.push_back(pGrid);    }}//////////////////////////////////////////////////////////////////////////void HelloWorld::FindPath(){    vector<NODE*> vecClose;    vector<NODE*> vecOpen;    if (m_nStartIndex == -1 || m_nEndIndex == -1)    {        return ;    }    m_vecPath.clear();    // 先添加开始点    NODE* pNode = new NODE;    pNode->nIndex = m_nStartIndex;    vecClose.push_back(pNode);    int nStep = 0;    while(true)    {        if (nStep++ >= 200)        {            break;        }        NODE* pNextNode = vecClose[vecClose.size() - 1];        if (!pNextNode)        {            break;        }        if (pNextNode->nIndex == m_nEndIndex)        {            break;        }        for (int i = 0; i < 8; i++)        {            int nIndex = GetIndexByDir(pNextNode->nIndex, i);            if (-1 == nIndex)            {                continue;            }            if (m_vecGrid[nIndex]->gf == GRID_FLAG_OBSTACLE)    // 障碍            {                continue;            }            if (InTable(nIndex, vecClose) != NULL)      // 在close表里            {                continue;            }            NODE* pNode = InTable(nIndex, vecOpen);     // 在open表里            if (pNode)            {                int nNewG = pNextNode->nG + GetGByIndex(pNextNode->nIndex, pNode->nIndex);                if (pNode->nG > nNewG)                {                    pNode->nG = nNewG;                    pNode->pParent = pNextNode;                }                continue;            }            // 新搜索到的格子            pNode = new NODE;            pNode->nIndex = nIndex;            pNode->nG = pNextNode->nG + GetGByIndex(pNextNode->nIndex, pNode->nIndex);            pNode->pParent = pNextNode;            vecOpen.push_back(pNode);        }        int nMinF = 0xFFFFFF;        pNextNode = NULL;        int nNextNodeIndex = 0;        for (int i = 0; i < (int)vecOpen.size(); i++)        {            NODE* pNode = vecOpen[i];            if (!pNode)            {                continue;            }            int nH = GetHByIndex(pNode->nIndex);            int nF = nH + pNode->nG;            if (nF < nMinF)            {                nMinF = nF;                pNextNode = pNode;                nNextNodeIndex = i;            }        }        if (nNextNodeIndex >= 0 && nNextNodeIndex < (int)vecOpen.size())        {            vecClose.push_back(pNextNode);            vecOpen.erase(vecOpen.begin() + nNextNodeIndex);        }    }    // 寻路结束，找最优路径    pNode = vecClose[vecClose.size() - 1];    while (pNode)    {        m_vecPath.push_back(pNode);        pNode = pNode->pParent;    }}//////////////////////////////////////////////////////////////////////////int HelloWorld::GetIndexByDir(int nIndex, int nDir){    if (nIndex < 0 || nIndex >= (int)m_vecGrid.size())    {        return -1;    }    int nRow = nIndex / GetCol();    int nCol = nIndex % GetCol();    switch(nDir)    {    case 0:     // 上        nRow += 1;        break;    case 1:     // 右上        nRow += 1;        nCol +=1;        break;    case 2:     // 右        nCol += 1;        break;    case 3:     // 右下        nRow -= 1;        nCol += 1;        break;    case 4:     // 下        nRow -= 1;        break;    case 5:     // 左下        nRow -= 1;        nCol -= 1;        break;    case 6:     // 左        nCol -= 1;        break;    case 7:     // 左上        nRow += 1;        nCol -= 1;        break;    default:        break;    }    if (nRow < 0 || nRow >= GetRow()        || nCol < 0 || nCol >= GetCol())    {        return -1;    }    return nRow * GetCol() + nCol;}//////////////////////////////////////////////////////////////////////////int HelloWorld::GetGByIndex(int nStartIndex, int nEndIndex){    int nStartRow = nStartIndex / GetCol();    int nStartCol = nStartIndex % GetCol();    int nEndRow = nEndIndex / GetCol();    int nEndCol = nEndIndex % GetCol();    if (nStartRow == nEndRow || nStartCol == nEndCol)    {        return 10;    }    return 14;}//////////////////////////////////////////////////////////////////////////int HelloWorld::GetHByIndex(int nIndex){    int nRow = nIndex / GetCol();    int nCol = nIndex % GetCol();    int nEndRow = m_nEndIndex / GetCol();    int nEndCol = m_nEndIndex % GetCol();    return (abs(nEndRow - nRow) + abs(nEndCol - nCol))*10;}//////////////////////////////////////////////////////////////////////////HelloWorld::NODE *HelloWorld::InTable(int nIndex, vector<NODE*> &vecTbl){    for (int i = 0; i < (int)vecTbl.size(); i++)    {        if (nIndex == vecTbl[i]->nIndex)        {            return vecTbl[i];        }    }    return NULL;}//////////////////////////////////////////////////////////////////////////int HelloWorld::GetRow(){    CCSize size = CCDirector::sharedDirector()->getWinSize();    return size.height / GRID_SIDELEN;}//////////////////////////////////////////////////////////////////////////int HelloWorld::GetCol(){    CCSize size = CCDirector::sharedDirector()->getWinSize();    return size.width / GRID_SIDELEN;}//////////////////////////////////////////////////////////////////////////int HelloWorld::GetIndexByPoint(CCPoint pt){    pt.x = pt.x > (int)pt.x ? pt.x + 1 : pt.x;    pt.y = pt.y > (int)pt.y ? pt.y + 1 : pt.y;    return (int)pt.y / GRID_SIDELEN * GetCol() + (int)pt.x / GRID_SIDELEN;}//////////////////////////////////////////////////////////////////////////void HelloWorld::draw(){    // 画背景表格    CCSize size = CCDirector::sharedDirector()->getWinSize();    for (int i = 0; i < GetRow(); i++)    {        ccDrawLine(ccp(0, i * GRID_SIDELEN), ccp(size.width, i * GRID_SIDELEN));    }    for (int i = 0; i < GetCol(); i++)    {        ccDrawLine(ccp(i * GRID_SIDELEN, 0), ccp(i * GRID_SIDELEN, size.height));    }    // 画特殊格子颜色    // 寻路得到的路径    for (int i = 0; i < (int)m_vecPath.size(); i++)    {        CCPoint ptObstacleLT;        CCPoint ptObstacleRD;        GetRectPointByIndex(m_vecPath[i]->nIndex, ptObstacleLT, ptObstacleRD);        ccColor4F clrObstacle = {0, 1, 1, 1};        ccDrawSolidRect(ptObstacleLT, ptObstacleRD, clrObstacle);    }    // 开始点    CCPoint ptStartLT;    CCPoint ptStartRD;    GetRectPointByIndex(m_nStartIndex, ptStartLT, ptStartRD);    ccColor4F clrStart = {1, 0, 0, 1};    ccDrawSolidRect(ptStartLT, ptStartRD, clrStart);    // 结束点    CCPoint ptEndLT;    CCPoint ptEndRD;    GetRectPointByIndex(m_nEndIndex, ptEndLT, ptEndRD);    ccColor4F clrEnd = {0, 1, 0, 1};    ccDrawSolidRect(ptEndLT, ptEndRD, clrEnd);    // 障碍    for (int i = 0; i < (int)m_vecGrid.size(); i++)    {        if (m_vecGrid[i]->gf == GRID_FLAG_OBSTACLE)        {            CCPoint ptObstacleLT;            CCPoint ptObstacleRD;            GetRectPointByIndex(i, ptObstacleLT, ptObstacleRD);            ccColor4F clrObstacle = {0, 0, 1, 1};            ccDrawSolidRect(ptObstacleLT, ptObstacleRD, clrObstacle);        }    }}//////////////////////////////////////////////////////////////////////////void HelloWorld::GetRectPointByIndex(int nIndex, CCPoint &ptLT, CCPoint &ptRD){    ptLT.x = nIndex % GetCol() * GRID_SIDELEN;    ptLT.y = nIndex / GetCol() * GRID_SIDELEN;    ptRD.x = ptLT.x + GRID_SIDELEN;    ptRD.y = ptLT.y + GRID_SIDELEN;}//////////////////////////////////////////////////////////////////////////bool HelloWorld::ccTouchBegan(CCTouch *pTouch, CCEvent *pEvent){    if (!pTouch)    {        return false;    }    int nIndex = GetIndexByPoint(pTouch->getLocation());    if (m_vecGrid[nIndex]->gf == GRID_FLAG_OBSTACLE)    {        return false;    }    if (STEP_STARTPOINT == m_nStep)    {        m_nStartIndex = nIndex;        m_nStep = STEP_ENDPOINT;    }    else if (STEP_ENDPOINT == m_nStep)    {        m_nEndIndex = nIndex;        m_nStep = STEP_STARTPOINT;        FindPath();    }    return true;}

哎，想来想去，还是直接上源码比较直截了当。。。。。寻路效果如下，红色是起点，绿色是终点，蓝色是障碍物，浅蓝色是最终寻路路径：

资源已上传到CSDN，请到这里免积分下载http://download.csdn.net/detail/dssdss123/6283613