cocos通过载入tiled 生成的tmx文件来生成游戏地图，本文主要分析cocos载入地图模块的源码。
如图所示，地图载入模块由以上几个类组成。
对外的入口是类CCTMXTiledMap，在使用该类时，程序员不需要知道其底层的其他类便可解析tmx文件生成地图。
那么，我们首先分析类CCTMXTiledMap是如何调用其他类进行解析，该类的声明如下：
class CC_DLL CCTMXTiledMap :public CCNode{/** the map's size property measured intiles */CC_SYNTHESIZE_PASS_BY_REF(CCSize,m_tMapSize, MapSize);/** the tiles's size property measured inpixels */CC_SYNTHESIZE_PASS_BY_REF(CCSize,m_tTileSize, TileSize);/** map orientation */CC_SYNTHESIZE(int, m_nMapOrientation,MapOrientation);/** object groups */CC_PROPERTY(CCArray*, m_pObjectGroups,ObjectGroups);/** properties */CC_PROPERTY(CCDictionary*, m_pProperties,Properties);public:/*** @js ctor*/CCTMXTiledMap();/*** @js NA* @lua NA*/virtual ~CCTMXTiledMap();/** creates a TMX Tiled Map with a TMXfile.*/static CCTMXTiledMap* create(const char*tmxFile);/** initializes a TMX Tiled Map with a TMXformatted XML string and a path to TMX resources */static CCTMXTiledMap* createWithXML(constchar* tmxString, const char* resourcePath);/** initializes a TMX Tiled Map with a TMXfile */bool initWithTMXFile(const char *tmxFile);/** initializes a TMX Tiled Map with a TMXformatted XML string and a path to TMX resources */bool initWithXML(const char* tmxString,const char* resourcePath);/** return the TMXLayer for the specificlayer* @js getLayer*/CCTMXLayer* layerNamed(const char*layerName);/** return the TMXObjectGroup for thespecific group* @js getObjectGroup*/CCTMXObjectGroup* objectGroupNamed(constchar *groupName);/** return the value for the specificproperty name* @js getProperty*/CCString *propertyNamed(const char*propertyName);/** return properties dictionary for tileGID */CCDictionary* propertiesForGID(int GID); private: CCTMXLayer *parseLayer(CCTMXLayerInfo *layerInfo, CCTMXMapInfo *mapInfo);CCTMXTilesetInfo *tilesetForLayer(CCTMXLayerInfo *layerInfo, CCTMXMapInfo *mapInfo);void buildWithMapInfo(CCTMXMapInfo*mapInfo);protected://! tile propertiesCCDictionary* m_pTileProperties; };
通过查看函数实现，，我们发现函数
/** creates a TMX Tiled Map with a TMX file.*/static CCTMXTiledMap* create(const char*tmxFile);
通过调用函数
/** initializes a TMX Tiled Mapwith a TMX file */bool initWithTMXFile(const char *tmxFile);
来实现文件的解析，并创建一个CCTMXTiledMap对象返回给使用者。
boolCCTMXTiledMap::initWithTMXFile(const char *tmxFile){CCAssert(tmxFile != NULL &&strlen(tmxFile)>0, "TMXTiledMap: tmx file should not bi NULL");setContentSize(CCSizeZero);CCTMXMapInfo *mapInfo =CCTMXMapInfo::formatWithTMXFile(tmxFile);if (! mapInfo){return false;}CCAssert(mapInfo->getTilesets()->count() != 0, "TMXTiledMap: Map not found.Please check the filename.");buildWithMapInfo(mapInfo);return true;}
通过看源码，我们发现有2个重要的函数CCTMXMapInfo::formatWithTMXFile(tmxFile)和buildWithMapInfo(mapInfo)，看名字应该能知道formatWithTMXFile是解析XML文件将其结构化，buildWithMapInfo是将结构化的数据变成CCNode从而显示在游戏界面上。
接下来，我们查看CCTMXMapInfo是如何组织数据以及如何解析XML文件的，首先我们还是查看CCTMXMapInfo的声明
class CC_DLL CCTMXMapInfo :public CCObject, public CCSAXDelegator{ public:/// map orientationCC_SYNTHESIZE(int, m_nOrientation, Orientation);/// map width & heightCC_SYNTHESIZE_PASS_BY_REF(CCSize,m_tMapSize, MapSize);/// tiles width & heightCC_SYNTHESIZE_PASS_BY_REF(CCSize,m_tTileSize, TileSize);/// LayersCC_PROPERTY(CCArray*, m_pLayers, Layers);/// tilesetsCC_PROPERTY(CCArray*, m_pTilesets,Tilesets);/// ObjectGroupsCC_PROPERTY(CCArray*, m_pObjectGroups,ObjectGroups);/// parent elementCC_SYNTHESIZE(int, m_nParentElement,ParentElement);/// parent GIDCC_SYNTHESIZE(unsigned int, m_uParentGID,ParentGID);/// layer attribsCC_SYNTHESIZE(int, m_nLayerAttribs,LayerAttribs);/// is storing characters?CC_SYNTHESIZE(bool, m_bStoringCharacters,StoringCharacters);/// propertiesCC_PROPERTY(CCDictionary*, m_pProperties,Properties);public:/*** @js ctor* @lua NA*/CCTMXMapInfo();/*** @js NA* @lua NA*/virtual ~CCTMXMapInfo();/** creates a TMX Format with a tmx file */static CCTMXMapInfo *formatWithTMXFile(const char *tmxFile);/** creates a TMX Format with an XML stringand a TMX resource path */static CCTMXMapInfo * formatWithXML(constchar* tmxString, const char* resourcePath);/** initializes a TMX format with a tmx file* @lua NA*/bool initWithTMXFile(const char *tmxFile);/** initializes a TMX format with an XMLstring and a TMX resource path* @lua NA*/bool initWithXML(const char* tmxString,const char* resourcePath);/** initializes parsing of an XML file,either a tmx (Map) file or tsx (Tileset) file */bool parseXMLFile(const char *xmlFilename);/* initializes parsing of an XML string,either a tmx (Map) string or tsx (Tileset) string */bool parseXMLString(const char *xmlString);CCDictionary* getTileProperties();void setTileProperties(CCDictionary*tileProperties);/** implement pure virtual methods ofCCSAXDelegator* @js NA*/void startElement(void *ctx, const char*name, const char **atts);/*** @js NA*/void endElement(void *ctx, const char*name);/*** @js NA*/void textHandler(void *ctx, const char *ch,int len);inline const char* getCurrentString(){return m_sCurrentString.c_str(); }inline void setCurrentString(const char*currentString){ m_sCurrentString = currentString; }inline const char* getTMXFileName(){ returnm_sTMXFileName.c_str(); }inline void setTMXFileName(const char*fileName){ m_sTMXFileName = fileName; }private:void internalInit(const char* tmxFileName,const char* resourcePath);protected://! tmx filenamestd::string m_sTMXFileName;// tmx resource pathstd::string m_sResources;//! current stringstd::string m_sCurrentString;//! tile propertiesCCDictionary* m_pTileProperties;unsigned int m_uCurrentFirstGID;};
通过查看声明 我们发现CCTMXMapInfo主要包括以下几个数据：
走马观花之外，这才是深入体验，探索自我的最佳时间，
