Ogre渲染優化心得 -- 正確地合併靜態實體

 天龍的靜態實體合併方法是典型的反面教材.把所有物體都合併在成一個靜態實體了

正確的做法應該是按材質合併.不然效率可能會適得其反

具體原因,和前面講的地形是一樣的,

Ogre的一個靜態實體,是分region的,一個region類似於一個地形的tile

而裁剪都是以region爲單位,和前面提到的地形一模一樣,

如果分材質裁剪多個靜態實體,就沒問題了

附上我簡單更改過的天龍的代碼

 void System::bakeStaticGeometries(size_t maxMemoryUsage) { // 2011.2.24 LuoYinan 不要學天龍那樣把不同材質的物體合併成一個靜態實體, // 雖然這樣做簡單,而且StaticGeometry內部會自動按材質合併,但是包圍合卻只有一個(一個region一個) // 這樣攝像機的裁剪優化會大打折扣,可能你合併了還沒有不合並速度快... // 正確的做法應該是按材質(至少也要按mesh)合併靜態實體,這裏我們按mesh分類 clearStaticGeometries(); Ogre::StaticGeometry* sg = 0; int size = getTerrainData()->mTileSize * getTerrainData()->getScale().x; // 1.build mesh bucket typedef std::multimap<Ogre::ResourceHandle, WX::ObjectPtr> MeshBucketMap; MeshBucketMap meshBucket; WX::Scene::ObjectsByTypeRange objests = mSceneInfo->findObjectsByType(WX::StaticEntityObject::msType); for (WX::Scene::ObjectsByTypeIterator it = objests.first; it != objests.second; ++ it) { const ObjectPtr& object = *it; EntityList entities; object->queryBakableEntities(entities); if (!entities.empty()) { Ogre::ResourceHandle handle = entities.front()->getMesh()->getHandle(); meshBucket.insert( MeshBucketMap::value_type(handle, object) ); } } // 2.bake StaticGeometry Ogre::ResourceHandle last = 0; int i = 0; MeshBucketMap::iterator it = meshBucket.begin(); for (; it != meshBucket.end(); ++it) { if (it->first != last) // key changed { // build old if (sg) { sg->build(); //if (isEditable()) //{ //sg->dump(sg->getName() + ".txt"); //} } // create new sg = mSceneManager->createStaticGeometry("StaticGeometry" + Ogre::StringConverter::toString(i)); sg->setRegionDimensions(Ogre::Vector3(size, size, size)); mStaticGeometries.push_back(sg); ++ i; } // bake ObjectPtr& object = it->second; EntityList entities; object->queryBakableEntities(entities); object->bakeStaticGeometry(sg, entities); last = it->first; } // 最後一個,bulid if (sg) { sg->build(); //if (isEditable()) //{ //sg->dump(sg->getName() + ".txt"); //} } }