ogre分析之設(shè)計(jì)模式二mythma

:Apdater模式使得原本由于接口不兼容而不能一起工作的那些類可以一起工作。當(dāng)使用第工具包時(shí)候，這種模式經(jīng)常用到。OGRE使用了其他的幾個(gè)開源項(xiàng)目，如Cg數(shù)。為了處理壓縮文件和普通文件使用相同的接口，就需要Adapter。OGRE中處理文件使用Ogre::Archive，zzipZZIP_DIR來表示壓縮文件目OGRE使用的是對(duì)象適配器?？梢钥闯?，Adapter模式與Factory模式可以實(shí)現(xiàn)相同的效果——讓別的接口兼容（回顧一下用FactoryRenderSystem）,但是兩者的區(qū)別在于FactoryAdapter沒有創(chuàng)建別的對(duì)象的GoF把FactoryAdapter在結(jié)構(gòu)型模式中?？梢园l(fā)現(xiàn)，這兩種模式，OGRE的文件系統(tǒng)都使用了。Bridge的意圖是使得抽象部分與它的實(shí)現(xiàn)部分分離，這樣就使得兩部分都可以獨(dú)立變可以看到序列化Mesh文件的Serializer既有Ogre::MeshSerializer又有Ogre::MeshSerializerImpl。OGRE在讀寫Mesh文件的時(shí)候使用的是 以及它的子類，而Ogre::MeshSerializer Ogre::MeshSerializerImpl系列對(duì)外的“接口”，但二者是平輩關(guān)系。再看一下MeshSerializer的實(shí)現(xiàn)一切將會(huì) {//SetupmapnewMeshSerializerImpl_v1_1()));shSerializer_v1.20]",newMeshSerializerImpl_v1_2()));e(msCurrentVersion,newMeshSerializerImpl()));}{ torimpl=mImplementations.find(msCurrentVersion);if(impl==mImplementations.end()){}} 六、為其他對(duì)象提供一種以控制對(duì)該對(duì)象的。GoF提到四種常見的情況：Romote，Virtual、Protection以及SmartReference。在這里我只分析一下SmartReference。SmartPointer在STL中有std::auto_ptr，在BOOST中有boost::shared_ptr、 、boost::scoped_ptr boost::weak_ptroost::intrusive_ptr在Loki中則有Loki::SmartPtr各種SmartPointer都有不同的功能，適用的地方又各不相同。加上有的SmartPointer的行為又有點(diǎn)詭異，尤其是std::auto_ptr，所以實(shí)際應(yīng)用中一向?qū)χ硕鴧s步。ThisisastandardsharedpointerimplementationwhichusesareferencecountThisisastandardsharedpointerimplementationwhichusesareferencecounttoworkoutwhentodeletetheobject.OGREdoesnotusethisclassveryoften,becauseitisusuallymoreefficienttomakethedestructionofobjectsmoreintentional(inblocks,say).Howeverinsomecasesyoureallycannotlhowmanypeopleareusinganobject,andthisapproachisworthwhile(e.g.ControllerValue)附上Ogre::SharedPtr的實(shí)現(xiàn)： te<classT>classT*unsignedint*pUseCount;OGRE_AUTO_SHARED_MUTEX//publictoallowexternal/**Constructor,doesnotinitialisetheSharedPtr.<b>Dangerous!</b>Youhavetocallbind()beforeusingtheSharedPtr():pRep(0),pUseCount(0)explicitSharedPtr(T*rep):pRep(rep),pUseCount(newunsigned{}{//lock©othermutexpointerpRep=pUseCount=//HandlezeropointergracefullytomanageSTLcontainers{}}{if(pRep==r.pRep)return*this;//lock©othermutexpointerpRep=pUseCount=r.pUseCount;if(pUseCount){}return}{}inlineT&operator*()const{assert(pRep);return*pRep;}inlineT*operator->()const{assert(pRep);returnpRep;}inlineT*get()const{returnpRep;}/**BindsreptotheSharedPtr.AssumesthattheSharedPtrisvoidbind(T*{assert(!pRep&&!pUseCount);pUseCount=newunsignedint(1);pRep=rep;}inlineboolunique()const{assert(pUseCount);OGRE_LOCK_AUTO_SHARED_MUTEXreturn*pUseCount==1;}inlineunsignedintuseCount()const{assert(pUseCount);OGRE_LOCK_AUTO_SHARED_MUTEXreturn*pUseCount;}inlineunsignedint*useCountPointer()const{returnpUseCount;}inlineT*getPointer()const{returnpRep;}inlineboolisNull(void)const{returnpRep==0;inlinevoid{if{//can'tscopelockmutexbeforereleaseincasedeletedpRep=pUseCount=0;}}inlinevoid{booldestroyThis={//lockownmutexinlimitedscope(mustunlockbeforeif{if(--(*pUseCount)=={destroyThis=}}}}virtualvoid{//IFYOUGETACRASHHERE,YOUFORGOT UP//BEFORESHUTTINGOGRE//UsesetNull()beforeshutdownormakesureyourpointer//outofscopebeforeOGREshutsdowntoavoiddeletepRep;deletepRep;} te