Ogre中mesh的顶点数据与索引数据

【转】Ogre的mesh的顶点数据与索引数据

转载自：http://blog.csdn.net/zhuxiaoyang2000/article/details/6565962

//读取的数据用于物理引擎的计算/** * 获取Ogre的Mesh信息* @param mesh: Ogre的Mesh指针* @return void*/void ActorNode::GetMeshInformation(const Ogre::Mesh* const mesh,                     size_t &vertex_count,Ogre::Vector3* &vertices,                      size_t &index_count,unsigned long* &indices,                       const Ogre::Vector3 &position /* = Ogre::Vector3::ZERO */,                      const Ogre::Quaternion &orient /* = Ogre::Quaternion::IDENTITY */,                      const Ogre::Vector3 &scale /* = Ogre::Vector3::UNIT_SCALE */){bool added_shared = false;size_t current_offset = 0;size_t shared_offset = 0;size_t next_offset = 0;size_t index_offset = 0;vertex_count = index_count = 0;// 计算顶点数据与索引数据的大小for ( unsigned short i = 0; i < mesh->getNumSubMeshes(); ++i){   Ogre::SubMesh* submesh = mesh->getSubMesh(i);   // 只需要添加the shared vertices一次   if(submesh->useSharedVertices)   {    if( !added_shared )    {     vertex_count += mesh->sharedVertexData->vertexCount;     added_shared = true;    }   }   else   {    vertex_count += submesh->vertexData->vertexCount;   }   // Add the indices 索引   index_count += submesh->indexData->indexCount;}// Allocate space for the vertices and indices// 分配内存vertices = new Ogre::Vector3[vertex_count];indices = new unsigned long[index_count];added_shared = false;// 添加具体的数据for (unsigned short i = 0; i < mesh->getNumSubMeshes(); ++i){   Ogre::SubMesh* submesh = mesh->getSubMesh(i);   Ogre::VertexData* vertex_data = submesh->useSharedVertices ? mesh->sharedVertexData : submesh->vertexData;   if ((!submesh->useSharedVertices) || (submesh->useSharedVertices && !added_shared))   {    if(submesh->useSharedVertices)    {     added_shared = true;     shared_offset = current_offset;    }    // 位置索引    const Ogre::VertexElement* posElem =     vertex_data->vertexDeclaration->findElementBySemantic(Ogre::VES_POSITION);    // 位置数据    Ogre::HardwareVertexBufferSharedPtr vbuf =     vertex_data->vertexBufferBinding->getBuffer(posElem->getSource());    unsigned char* vertex =     static_cast<unsigned char*>(vbuf->lock(Ogre::HardwareBuffer::HBL_READ_ONLY));    // There is _no_ baseVertexPointerToElement() which takes an Ogre::Real or a double    // as second argument. So make it float, to avoid trouble when Ogre::Real will    // be comiled/typedefed as double:    //Ogre::Real* pReal;    float* pReal;    for( size_t j = 0; j < vertex_data->vertexCount; ++j, vertex += vbuf->getVertexSize())    {     // 添加顶点数据     posElem->baseVertexPointerToElement(vertex, &pReal);     Ogre::Vector3 pt(pReal[0], pReal[1], pReal[2]);     vertices[current_offset + j] = (orient * (pt * scale)) + position;    }    vbuf->unlock();    next_offset += vertex_data->vertexCount;   }   Ogre::IndexData* index_data = submesh->indexData;   size_t numTris = index_data->indexCount / 3;   Ogre::HardwareIndexBufferSharedPtr ibuf = index_data->indexBuffer;   bool use32bitindexes = (ibuf->getType() == Ogre::HardwareIndexBuffer::IT_32BIT);   unsigned long* pLong = static_cast<unsigned long*>(ibuf->lock(Ogre::HardwareBuffer::HBL_READ_ONLY));   unsigned short* pShort = reinterpret_cast<unsigned short*>(pLong);   size_t offset = (submesh->useSharedVertices)? shared_offset : current_offset;   if ( use32bitindexes )   {    for ( size_t k = 0; k < numTris*3; ++k)    {     // 添加索引数据     indices[index_offset++] = pLong[k] + static_cast<unsigned long>(offset);    }   }   else   {    for ( size_t k = 0; k < numTris*3; ++k)    {     indices[index_offset++] = static_cast<unsigned long>(pShort[k]) +      static_cast<unsigned long>(offset);    }   }   ibuf->unlock();   current_offset = next_offset;  }}