IDirect3DVertexBuffer9::Lock

Locks a range of vertex data and obtains a pointer to the vertex buffer memory.

HRESULT Lock( UINT OffsetToLock,  UINT SizeToLock,  VOID ** ppbData,  DWORD Flags  ); 

 ： OffsetToLock SizeToLock 0 ，  

Parameters

OffsetToLock
[in] Offset into the vertex data to lock, in bytes. To lock the entire vertex buffer, specify 0 for both parameters, SizeToLock and OffsetToLock.
SizeToLock
[in] Size of the vertex data to lock, in bytes. To lock the entire vertex buffer, specify 0 for both parameters, SizeToLock and OffsetToLock.
ppbData
[out] VOID* pointer to a memory buffer containing the returned vertex data.
Flags
[in] Combination of zero or more locking flags that describe the type of lock to perform. For this method, the valid flags are:

D3DLOCK_DISCARD

D3DLOCK_NO_DIRTY_UPDATE

D3DLOCK_NOSYSLOCK

D3DLOCK_READONLY

D3DLOCK_NOOVERWRITE

For a description of the flags, see
D3DLOCK .
 
 

IDirect3DIndexBuffer9::Lock

Locks a range of index data and obtains a pointer to the index buffer memory.

HRESULT Lock( UINT OffsetToLock, UINT SizeToLock, VOID ** ppbData, DWORD Flags ); 

Parameters

OffsetToLock
[in] Offset into the index data to lock, in bytes. Lock the entire index buffer by specifying 0 for both parameters, SizeToLock and OffsetToLock.
SizeToLock
[in] Size of the index data to lock, in bytes. Lock the entire index buffer by specifying 0 for both parameters, SizeToLock and OffsetToLock.
ppbData
[out] VOID* pointer to a memory buffer containing the returned index data.
Flags
[in] Combination of zero or more locking flags that describe the type of lock to perform. For this method, the valid flags are:

D3DLOCK_DISCARD

D3DLOCK_NO_DIRTY_UPDATE

D3DLOCK_NOSYSLOCK

D3DLOCK_READONLY

D3DLOCK_NOOVERWRITE

For a description of the flags, see
D3DLOCK .