c++ - 在 Ogre3d 中创建手动网格？

Question

我对为什么我手动创建的网格没有正确显示感到有点困惑。我已经创建了顶点和索引缓冲区，它们似乎(虽然我不是 100% 确定)包含正确的值。

基本上，我正在创建一个 mapSize * mapSize 顶点网格，高度为 0，然后从中创建三角形。

void TerrainGeneration::createTerrainMesh() {
  /// Create the mesh via the MeshManager
      Ogre::MeshPtr msh = Ogre::MeshManager::getSingleton().createManual("TerrainTest", "General");
  Ogre::SubMesh* sub = msh->createSubMesh();

  const size_t nVertices = mapSize*mapSize;
  const size_t vbufCount = 3*2*nVertices;

  float vertices[vbufCount];

  size_t vBufCounter = 0;
  for(int z = 0; z < mapSize; z++) {
          for(int x = 0; x < mapSize; x++) {
          //Position
      vertices[vBufCounter] = x;
      vertices[vBufCounter+1] = 0;
      vertices[vBufCounter+2] = z;
      //Normal
      vertices[vBufCounter+3] = 0;
      vertices[vBufCounter+4] = 1;
      vertices[vBufCounter+5] = 0;

      vBufCounter += 6;
      }
  }

  Ogre::RenderSystem* rs = Ogre::Root::getSingleton().getRenderSystem();
      Ogre::RGBA colours[nVertices];
      Ogre::RGBA *pColour = colours;

  //Create triangles
  const size_t ibufCount = 6*(mapSize - 1)*(mapSize - 1);
  unsigned int faces[ibufCount];

  size_t iBufCounter = 0;
  for(int x=0; x <= mapSize -2; x++) {
    for(int y=0; y <= mapSize -2; y++) {
        faces[iBufCounter] = vertices[(y*mapSize) + x];
        faces[iBufCounter+1] = vertices[((y+1)*mapSize) + x];
        faces[iBufCounter+2] = vertices[((y+1)*mapSize) + (x+1)];

        faces[iBufCounter+3] = vertices[(y*mapSize) + x];
        faces[iBufCounter+4] = vertices[((y+1)*mapSize) + (x+1)];
        faces[iBufCounter+5] = vertices[(y*mapSize) + (x+1)];

        iBufCounter += 6;
    }
}









/// Create vertex data structure for n*n vertices shared between submeshes
    msh->sharedVertexData = new Ogre::VertexData();
    msh->sharedVertexData->vertexCount = nVertices;

/// Create declaration (memory format) of vertex data
    Ogre::VertexDeclaration* decl = msh->sharedVertexData->vertexDeclaration;
    size_t offset = 0;
    // 1st buffer
    decl->addElement(0, offset, Ogre::VET_FLOAT3, Ogre::VES_POSITION);
    offset += Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT3);
    decl->addElement(0, offset, Ogre::VET_FLOAT3, Ogre::VES_NORMAL);
    offset += Ogre::VertexElement::getTypeSize(Ogre::VET_FLOAT3);
    /// Allocate vertex buffer of the requested number of vertices (vertexCount) 
    /// and bytes per vertex (offset)
    Ogre::HardwareVertexBufferSharedPtr vbuf = 
    Ogre::HardwareBufferManager::getSingleton().createVertexBuffer(
    offset, msh->sharedVertexData->vertexCount, Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);
    /// Upload the vertex data to the card
    vbuf->writeData(0, vbuf->getSizeInBytes(), vertices, true);

    /// Set vertex buffer binding so buffer 0 is bound to our vertex buffer
    Ogre::VertexBufferBinding* bind = msh->sharedVertexData->vertexBufferBinding; 
    bind->setBinding(0, vbuf);

    /// Allocate index buffer of the requested number of vertices (ibufCount) 
    Ogre::HardwareIndexBufferSharedPtr ibuf = Ogre::HardwareBufferManager::getSingleton().
    createIndexBuffer(
    Ogre::HardwareIndexBuffer::IT_16BIT, 
    ibufCount, 
    Ogre::HardwareBuffer::HBU_STATIC_WRITE_ONLY);

    /// Upload the index data to the card
    ibuf->writeData(0, ibuf->getSizeInBytes(), faces, true);

    /// Set parameters of the submesh
    sub->useSharedVertices = true;
    sub->indexData->indexBuffer = ibuf;
    sub->indexData->indexCount = ibufCount;
    sub->indexData->indexStart = 0;

    /// Set bounding information (for culling)
    msh->_setBounds(Ogre::AxisAlignedBox(-5000,-5000,-5000,5000,5000,5000));
    //msh->_setBoundingSphereRadius(Ogre::Math::Sqrt(3*100*100));

    /// Notify -Mesh object that it has been loaded
    msh->load();

}

我初始化网格并按如下方式加载它

Ogre::Entity* thisEntity = mSceneMgr->createEntity("cc", "TerrainTest", "General");
thisEntity->setMaterialName("Examples/Rockwall");
Ogre::SceneNode* thisSceneNode = mSceneMgr->getRootSceneNode()->createChildSceneNode();
thisSceneNode->setPosition(0, 0, 0);
thisSceneNode->attachObject(thisEntity);

如有任何见解，我们将不胜感激。

Answer 1

好的，我从 Ogre3d 论坛上得到了一个非常有帮助的人 bstone 的回答。

事实证明，在创建索引列表以创建面时，我错误地传递了顶点列表中的坐标，而不是顶点的索引。

 faces[iBufCounter] = vertices[(y*mapSize) + x];
 faces[iBufCounter+1] = vertices[((y+1)*mapSize) + x];
 faces[iBufCounter+2] = vertices[((y+1)*mapSize) + (x+1)];

 faces[iBufCounter+3] = vertices[(y*mapSize) + x];
 faces[iBufCounter+4] = vertices[((y+1)*mapSize) + (x+1)];
 faces[iBufCounter+5] = vertices[(y*mapSize) + (x+1)];

应该是

 faces[iBufCounter] = (y*mapSize) + x;
 faces[iBufCounter+1] = ((y+1)*mapSize) + x;
 faces[iBufCounter+2] = ((y+1)*mapSize) + (x+1);

 faces[iBufCounter+3] = (y*mapSize) + x;
 faces[iBufCounter+4] = ((y+1)*mapSize) + (x+1);
 faces[iBufCounter+5] = (y*mapSize) + (x+1);

但是我的代码中某处仍然存在问题，尽管根据其他人的说法，它可能不在我发布的这段代码中。

另一位用户还建议我以更简单的方式创建地形并发布了以下代码

int mapSize = 16;
Ogre::ManualObject *man = m_sceneManager->createManualObject("TerrainTest");
man->begin("Examples/Rockwall",Ogre::RenderOperation::OT_TRIANGLE_LIST);
for(int z = 0; z < mapSize; ++z)
{
   for(int x = 0; x < mapSize; ++x)
   {
      man->position(x,0,z);
      man->normal(0,1,0);
      man->textureCoord(x,z);
   }
}
for(int z = 0; z < mapSize-1; ++z)
{
   for(int x = 0; x < mapSize-1; ++x)
   {
      man->quad((x) + (z) * mapSize, (x) + (z + 1) * mapSize, (x + 1) + (z + 1) * mapSize, (x + 1) + (z) * mapSize);
   }
}
man->end();
m_sceneManager->getRootSceneNode()->attachObject(man);