ogre实现加入物理效果terrain

//------------------------------------------------------------------------------------------------ void TriangleMeshData::addVertexData(const VertexData *vertex_data, const VertexData *blended_data, const Mesh::IndexMap *indexMap) { if (!vertex_data) return; const VertexData *data = (blended_data) ? blended_data: vertex_data; const unsigned int prev_size = _vertex_count; _vertex_count += (unsigned int)data->vertexCount; Ogre::Vector3* tmp_vert = new Ogre::Vector3[_vertex_count]; if (_vertices) { memcpy(tmp_vert,_vertices,sizeof(Vector3) * prev_size); delete[] _vertices; } _vertices = tmp_vert; // Get the positional buffer element { const Ogre::VertexElement* posElem = data->vertexDeclaration->findElementBySemantic(Ogre::VES_POSITION); Ogre::HardwareVertexBufferSharedPtr vbuf = data->vertexBufferBinding->getBuffer(posElem->getSource()); const unsigned int vSize = (unsigned int)vbuf->getVertexSize(); unsigned char* vertex = static_cast<unsigned char*>(vbuf->lock(Ogre::HardwareBuffer::HBL_READ_ONLY)); float* pReal; Ogre::Vector3 * curVertices = &_vertices[prev_size]; const unsigned int vertexCount = (unsigned int)data->vertexCount; for(unsigned int j = 0; j < vertexCount; ++j) { posElem->baseVertexPointerToElement(vertex, &pReal); vertex += vSize; curVertices->x = (*pReal++); curVertices->y = (*pReal++); curVertices->z = (*pReal++); // *curVertices = _transform * (*curVertices); curVertices++; } vbuf->unlock(); } // Get the bone index element if (_entity && _entity->hasSkeleton()) { Ogre::MeshPtr mesh = _entity->getMesh (); const Ogre::VertexElement* bneElem = vertex_data->vertexDeclaration->findElementBySemantic(Ogre::VES_BLEND_INDICES); assert (bneElem); { Ogre::HardwareVertexBufferSharedPtr vbuf = vertex_data->vertexBufferBinding->getBuffer(bneElem->getSource()); const unsigned int vSize = (unsigned int)vbuf->getVertexSize(); unsigned char* vertex = static_cast<unsigned char*>(vbuf->lock(Ogre::HardwareBuffer::HBL_READ_ONLY)); unsigned char* pBone; if (!_bone_mapping) _bone_mapping = new BoneMapping(); BoneMapping::iterator i; Ogre::Vector3 * curVertices = &_vertices[prev_size]; const unsigned int vertexCount = (unsigned int)vertex_data->vertexCount; for(unsigned int j = 0; j < vertexCount; ++j) { bneElem->baseVertexPointerToElement(vertex, &pBone); vertex += vSize; const unsigned char currBone = (indexMap) ? (*indexMap)[*pBone] : *pBone; i = _bone_mapping->find (currBone); Vector3Array* l = 0; if (i == _bone_mapping->end()) { l = new Vector3Array; _bone_mapping->insert(BoneMappingKey(currBone, l)); } else { l = i->second; } l->push_back(*curVertices); curVertices++; } vbuf->unlock(); } } }   从ogre中设置terrain的物理效果我认为可以分成两类：

第一类很简单是从高度图直接读出然后建立定点索引序列，自己动手创建地形；

第二类是从实体创建，很简单的说就是从mesh模型来创建，这样的好处就是不用自己渲染了。。。

现在只实现了第二类的方法，其实本质就是从mesh里提取顶点信息和索引信息然后填充到

    NxTriangleMeshDesc* triangleMeshDesc; 剩下的无非是生成对应的模型而已；

 NxActor* PhysxTool::CreateTriangleMesh(TriangleMeshData* data,NxPhysicsSDK *gPhysicsSDK,NxScene*gScene) { NxTriangleMeshDesc* triangleMeshDesc; // Create descriptor for triangle mesh triangleMeshDesc= new NxTriangleMeshDesc(); triangleMeshDesc->numVertices = data->getVertexCount(); triangleMeshDesc->pointStrideBytes = sizeof(NxVec3); triangleMeshDesc->points = (void*)data->getVertices(); triangleMeshDesc->numTriangles = data->getIndexCount()/3; triangleMeshDesc->flags = 0; triangleMeshDesc->triangles = (void*)data->getIndices(); triangleMeshDesc->triangleStrideBytes = 3 * sizeof(NxU32); triangleMeshDesc->heightFieldVerticalAxis= NX_Y; triangleMeshDesc->heightFieldVerticalExtent= -1000.0f; // The actor has one shape, a triangle mesh NxInitCooking(); MemoryWriteBuffer buf; bool status = NxCookTriangleMesh(*triangleMeshDesc, buf); NxTriangleMesh* pMesh; if (status) { pMesh = gPhysicsSDK->createTriangleMesh(MemoryReadBuffer(buf.data)); } else { assert(false); pMesh = NULL; } NxCloseCooking(); // Create TriangleMesh above code segment. NxTriangleMeshShapeDesc tmsd; tmsd.meshData = pMesh; tmsd.userData = triangleMeshDesc; tmsd.localPose.t = NxVec3(0, 0, 0); tmsd.meshPagingMode = NX_MESH_PAGING_AUTO; tmsd.shapeFlags = NX_SF_FEATURE_INDICES; NxActorDesc actorDesc; assert(tmsd.isValid()); actorDesc.shapes.pushBack(&tmsd); if (pMesh) return gScene->createActor(actorDesc); else return NULL; }

 

返回的actor就可以直接使用了，因为没有设置body，所以默认为static，当有物体落到表面是自动进行碰撞检测；

这个实现的关键还在于对mesh的数据的提取，这是从ogreode中“剽窃”的一段代码，演示如何提取顶点数据和索引数据；

//const bool isHWanimated = isSkeletonAnimated && entity->isHardwareAnimationEnabled(); if (isSkeletonAnimated) { _entity->addSoftwareAnimationRequest(false); _entity->_updateAnimation(); } if (_entity->getMesh()->sharedVertexData) { if (!isSkeletonAnimated) addVertexData (_entity->getMesh()->sharedVertexData); else addVertexData (_entity->getMesh()->sharedVertexData, _entity->_getSkelAnimVertexData(), &_entity->getMesh()->sharedBlendIndexToBoneIndexMap); } for(unsigned int i = 0;i < _entity->getNumSubEntities();++i) { SubMesh *sub_mesh = _entity->getSubEntity(i)->getSubMesh(); if (!sub_mesh->useSharedVertices) { addIndexData(sub_mesh->indexData,_vertex_count); if (!isSkeletonAnimated) addVertexData (sub_mesh->vertexData); else addVertexData (sub_mesh->vertexData, _entity->getSubEntity(i)->_getSkelAnimVertexData(), &sub_mesh->blendIndexToBoneIndexMap); } else { addIndexData (sub_mesh->indexData); } }

 

addindex和addvertex分别向该类中写入数据：

void TriangleMeshData::addIndexData(IndexData *data, const unsigned int offset) { const unsigned int prev_size = _index_count; _index_count += (unsigned int)data->indexCount; TriangleIndex* tmp_ind = new TriangleIndex[_index_count]; if (_indices) { memcpy (tmp_ind, _indices, sizeof(unsigned int) * prev_size); delete[] _indices; } _indices = tmp_ind; const unsigned int numTris = (unsigned int) data->indexCount / 3; HardwareIndexBufferSharedPtr ibuf = data->indexBuffer; const bool use32bitindexes = (ibuf->getType() == HardwareIndexBuffer::IT_32BIT); unsigned int index_offset = prev_size; if (use32bitindexes) { const unsigned int* pInt = static_cast<unsigned int*>(ibuf->lock(HardwareBuffer::HBL_READ_ONLY)); for(unsigned int k = 0; k < numTris; ++k) { _indices[index_offset ++] = offset + *pInt++; _indices[index_offset ++] = offset + *pInt++; _indices[index_offset ++] = offset + *pInt++; } ibuf->unlock(); } else { const unsigned short* pShort = static_cast<unsigned short*>(ibuf->lock(HardwareBuffer::HBL_READ_ONLY)); for(unsigned int k = 0; k < numTris; ++k) { _indices[index_offset ++] = offset + static_cast<unsigned int> (*pShort++); _indices[index_offset ++] = offset + static_cast<unsigned int> (*pShort++); _indices[index_offset ++] = offset + static_cast<unsigned int> (*pShort++); } ibuf->unlock(); } }