为了方便加载.x文件中的框架和网格模型数据，Direct3D提供了一个ID3DXAllocateHierarchy接口，该接口中有4个纯虚函数：用来创建框架的CreateFrame()，创建网格容器的CreateMeshContainer()，销毁框架的DestroyFrame()，销毁网格容器的DestroyMeshContainer()。应用程序会在相应的时机自动调用这些对应的函数，以构建或者销毁对应的框架或网格模型。
This interface is implemented by the application to
allocate or free frame and mesh container objects. Methods on this are called
during loading and destroying frame hierarchies.
|
Method |
Description |
|
ID3DXAllocateHierarchy::CreateFrame |
Requests allocation of
a frame object. |
|
ID3DXAllocateHierarchy::CreateMeshContainer |
Requests allocation of
a mesh container object. |
|
ID3DXAllocateHierarchy::DestroyFrame |
Requests deallocation
of a frame object. |
|
ID3DXAllocateHierarchy::DestroyMeshContainer |
Requests deallocation
of a mesh container object. |
ID3DXAllocateHierarchy::CreateFrame
Requests allocation of a frame object.
HRESULT CreateFrame(
LPCSTR Name,
LPD3DXFRAME * ppNewFrame
);
Parameters
- Name
- [in] Name of the frame to be created.
- ppNewFrame
- [out, retval] Returns the created frame object.
Return Values
The return values of this method are implemented by an
application programmer. In general, if no error occurs, program the method to
return D3D_OK. Otherwise, program the method to return an appropriate error
message from D3DERR or D3DXERR, as this will cause D3DXLoadMeshHierarchyFromX to
fail also, and return the error.
ID3DXAllocateHierarchy::CreateMeshContainer
Requests allocation of a mesh container object.
HRESULT CreateMeshContainer(
LPCSTR Name,
CONST D3DXMESHDATA * pMeshData,
CONST D3DXMATERIAL * pMaterials,
CONST D3DXEFFECTINSTANCE * pEffectInstances,
DWORD NumMaterials,
CONST DWORD * pAdjacency,
LPD3DXSKININFO pSkinInfo,
LPD3DXMESHCONTAINER * ppNewMeshContainer
);
Parameters
- Name
- [in] Name of the mesh.
- pMeshData
- [in] Pointer to the mesh data structure.
- pMaterials
- [in] Array of materials used in the mesh.
- pEffectInstances
- [in] Array of effect instances used in the mesh.
- NumMaterials
- [in] Number of materials in the materials array.
- pAdjacency
- [in] Adjacency array for the mesh.
- pSkinInfo
- [in] Pointer to the skin mesh object if skin data
is found.
- ppNewMeshContainer
- [out, retval] Returns the created mesh container.
Return Values
The return values of this method are implemented by an
application programmer. In general, if no error occurs, program the method to
return D3D_OK. Otherwise, program the method to return an appropriate error
message from D3DERR or D3DXERR, as this will cause D3DXLoadMeshHierarchyFromX to
fail also, and return the error.
ID3DXAllocateHierarchy::DestroyFrame
Requests deallocation of a frame object.
HRESULT DestroyFrame(
LPD3DXFRAME pFrameToFree
);
Parameters
- pFrameToFree
- [in] Pointer to the frame to be deallocated.
Return Values
The return values of this method are implemented by an
application programmer. In general, if no error occurs, program the method to
return D3D_OK. Otherwise, program the method to return an appropriate error
message from D3DERR or D3DXERR, as this will cause D3DXLoadMeshHierarchyFromX to
fail also, and return the error.
ID3DXAllocateHierarchy::DestroyMeshContainer
Requests deallocation of a mesh container object.
HRESULT DestroyMeshContainer(
LPD3DXMESHCONTAINER pMeshContainerToFree
);
Parameters
- pMeshContainerToFree
- [in] Pointer to the mesh container object to be
deallocated.
Return Values
The return values of this method are implemented by an
application programmer. In general, if no error occurs, program the method to
return D3D_OK. Otherwise, program the method to return an appropriate error
message from D3DERR or D3DXERR, as this will cause D3DXLoadMeshHierarchyFromX to
fail also, and return the error.
cAllocateHierarchy类继承自ID3DXAllocateHierarchy接口，在cAllocateHierarchy类需要重载这4个纯虚函数以实现动画网格模型数据的加载和释放。
该类的定义如下：
class cAllocateHierarchy : public ID3DXAllocateHierarchy
{
private:
HRESULT AllocateName(LPCSTR name, LPSTR* ret_name);
public:
STDMETHOD(CreateFrame)(LPCSTR name, LPD3DXFRAME* ret_frame);
STDMETHOD(CreateMeshContainer)(LPCSTR name,
CONST D3DXMESHDATA* mesh_data,
CONST D3DXMATERIAL* xmaterials,
CONST D3DXEFFECTINSTANCE* effect_instances,
DWORD num_materials,
CONST DWORD* adjacency,
LPD3DXSKININFO skin_info,
LPD3DXMESHCONTAINER* ret_mesh_container);
STDMETHOD(DestroyFrame)(THIS_ LPD3DXFRAME frame_to_free);
STDMETHOD(DestroyMeshContainer)(THIS_ LPD3DXMESHCONTAINER base_mesh_container);
};
函数AllocateFrame()用来为框架生成一个名称：
HRESULT cAllocateHierarchy::AllocateName(LPCSTR name, LPSTR* ret_name)
{
if(name != NULL)
{
UINT length = (UINT)strlen(name) + 1;
*ret_name = new CHAR[length];
if(*ret_name == NULL)
return E_OUTOFMEMORY;
memcpy(*ret_name, name, length * sizeof(CHAR));
}
else
{
*ret_name = NULL;
}
return S_OK;
}
函数CreateFrame()的作用在于生成一个新的扩展框架，并按照指定的参数为该框架命名：
HRESULT cAllocateHierarchy::CreateFrame(LPCSTR name, LPD3DXFRAME* ret_frame)
{
*ret_frame = NULL;
D3DXFRAME_DERIVED* new_frame = new D3DXFRAME_DERIVED;
if(new_frame == NULL)
return E_OUTOFMEMORY;
HRESULT hr = AllocateName(name, &new_frame->Name);
if(FAILED(hr))
{
delete new_frame;
return hr;
}
D3DXMatrixIdentity(&new_frame->TransformationMatrix);
D3DXMatrixIdentity(&new_frame->CombinedTransformMatrix);
new_frame->pMeshContainer = NULL;
new_frame->pFrameSibling = NULL;
new_frame->pFrameFirstChild = NULL;
*ret_frame = new_frame;
return S_OK;
}
在一个框架创建好后，需要创建该框架的网格容器，这通过函数CreateMeshContainer()来实现：
HRESULT cAllocateHierarchy::CreateMeshContainer(LPCSTR name,
CONST D3DXMESHDATA* mesh_data,
CONST D3DXMATERIAL* xmaterials,
CONST D3DXEFFECTINSTANCE* effect_instances,
DWORD num_materials,
CONST DWORD* adjacency,
LPD3DXSKININFO skin_info,
LPD3DXMESHCONTAINER* ret_mesh_container)
{
*ret_mesh_container = NULL;
if(mesh_data->Type != D3DXMESHTYPE_MESH)
return E_FAIL;
ID3DXMesh* mesh_ptr = mesh_data->pMesh;
DWORD fvf = mesh_ptr->GetFVF();
if(fvf == 0)
return E_FAIL;
// create a mesh container and zero it
D3DXMESHCONTAINER_DERIVED* new_mesh_container = new D3DXMESHCONTAINER_DERIVED;
if(new_mesh_container == NULL)
return E_OUTOFMEMORY;
memset(new_mesh_container, 0, sizeof(D3DXMESHCONTAINER_DERIVED));
// copy mesh name
HRESULT hr = AllocateName(name, &new_mesh_container->Name);
if(FAILED(hr))
{
DestroyMeshContainer(new_mesh_container);
return hr;
}
IDirect3DDevice9* device;
mesh_ptr->GetDevice(&device);
new_mesh_container->MeshData.Type = D3DXMESHTYPE_MESH;
// be sure mesh contain normal
if(!(fvf & D3DFVF_NORMAL))
{
hr = mesh_ptr->CloneMeshFVF(mesh_ptr->GetOptions(), fvf | D3DFVF_NORMAL, device,
&new_mesh_container->MeshData.pMesh);
if(FAILED(hr))
{
release_com(device);
DestroyMeshContainer(new_mesh_container);
return hr;
}
mesh_ptr = new_mesh_container->MeshData.pMesh;
D3DXComputeNormals(mesh_ptr, NULL);
}
else
{
new_mesh_container->MeshData.pMesh = mesh_ptr;
mesh_ptr->AddRef(); // !! important, so DestroyMeshContainer() will not crash.
}
// load materials and textures
UINT num_faces = mesh_ptr->GetNumFaces();
new_mesh_container->NumMaterials = max(1, num_materials);
new_mesh_container->pMaterials = new D3DXMATERIAL[new_mesh_container->NumMaterials];
new_mesh_container->ppTextures = new LPDIRECT3DTEXTURE9[new_mesh_container->NumMaterials];
new_mesh_container->pAdjacency = new DWORD[num_faces * 3];
if((new_mesh_container->pAdjacency == NULL) || (new_mesh_container->pMaterials == NULL) ||
(new_mesh_container->ppTextures == NULL))
{
release_com(device);
DestroyMeshContainer(new_mesh_container);
return E_OUTOFMEMORY;
}
memcpy(new_mesh_container->pAdjacency, adjacency, sizeof(DWORD) * num_faces * 3);
memset(new_mesh_container->ppTextures, 0, sizeof(LPDIRECT3DTEXTURE9) * new_mesh_container->NumMaterials);
D3DXMATERIAL* xmaterials_ptr = new_mesh_container->pMaterials;
if(num_materials > 0)
{
memcpy(xmaterials_ptr, xmaterials, sizeof(D3DXMATERIAL) * num_materials);
xmaterials_ptr->MatD3D.Ambient = xmaterials_ptr->MatD3D.Diffuse;
for(UINT i = 0; i < num_materials; i++)
{
if(xmaterials_ptr[i].pTextureFilename != NULL)
{
WCHAR w_texture_path[MAX_PATH];
WCHAR w_filename[MAX_PATH];
RemovePathFromFileName(xmaterials_ptr[i].pTextureFilename, w_filename);
DXUTFindDXSDKMediaFileCch(w_texture_path, MAX_PATH, w_filename);
if(FAILED( D3DXCreateTextureFromFileW(device, w_texture_path, &new_mesh_container->ppTextures[i]) ))
new_mesh_container->ppTextures[i] = NULL;
}
}
}
else
{
xmaterials_ptr[0].pTextureFilename = NULL;
memset(&xmaterials_ptr[0].MatD3D, 0, sizeof(D3DMATERIAL9));
xmaterials_ptr[0].MatD3D.Diffuse.r = 0.5f;
xmaterials_ptr[0].MatD3D.Diffuse.r = 0.5f;
xmaterials_ptr[0].MatD3D.Diffuse.b = 0.5f;
xmaterials_ptr[0].MatD3D.Specular = xmaterials_ptr[0].MatD3D.Diffuse;
xmaterials_ptr[0].MatD3D.Ambient = xmaterials_ptr[0].MatD3D.Diffuse;
}
release_com(device);
*ret_mesh_container = new_mesh_container;
return S_OK;
}
在此实现的骨骼动画网格模型中没有涉及到蒙皮信息，所以在CreateMeshContainer()函数中没有处理参数skin_info指向的蒙皮信息。
函数DestroyFrame()只有一个参数指向准备释放的框架对象：
HRESULT cAllocateHierarchy::DestroyFrame(LPD3DXFRAME frame_to_free)
{
SAFE_DELETE_ARRAY(frame_to_free->Name);
SAFE_DELETE(frame_to_free);
return S_OK;
}
函数DestroyMeshContainer()也只有一个参数指向将要释放的网格容器对象：
HRESULT cAllocateHierarchy::DestroyMeshContainer(LPD3DXMESHCONTAINER base_mesh_container)
{
if(base_mesh_container == NULL)
return S_OK;
D3DXMESHCONTAINER_DERIVED* mesh_container = (D3DXMESHCONTAINER_DERIVED*) base_mesh_container;
SAFE_DELETE_ARRAY(mesh_container->Name);
SAFE_DELETE_ARRAY(mesh_container->pAdjacency);
SAFE_DELETE_ARRAY(mesh_container->pMaterials);
if(mesh_container->ppTextures != NULL)
{
for(UINT i = 0; i < mesh_container->NumMaterials; i++)
release_com(mesh_container->ppTextures[i]);
}
SAFE_DELETE_ARRAY(mesh_container->ppTextures);
SAFE_RELEASE(mesh_container->MeshData.pMesh);
SAFE_RELEASE(mesh_container->pSkinInfo);
SAFE_DELETE(mesh_container);
return S_OK;
}