IDirect3DIndexBuffer9::Lock method (d3d9helper.h)

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

Syntax

HRESULT Lock(
  [in]  UINT  OffsetToLock,
  [in]  UINT  SizeToLock,
  [out] void  **ppbData,
  [in]  DWORD Flags
);

Parameters

[in] OffsetToLock

Type: UINT

Offset into the index data to lock, in bytes. Lock the entire index buffer by specifying 0 for both parameters, SizeToLock and OffsetToLock.

[in] SizeToLock

Type: UINT

Size of the index data to lock, in bytes. Lock the entire index buffer by specifying 0 for both parameters, SizeToLock and OffsetToLock.

[out] ppbData

Type: VOID**

VOID* pointer to a memory buffer containing the returned index data.

[in] Flags

Type: DWORD

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

Return value

Type: HRESULT

If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be D3DERR_INVALIDCALL.

Remarks

As a general rule, do not hold a lock across more than one frame. When working with index buffers, you are allowed to make multiple lock calls. However, you must ensure that the number of lock calls match the number of unlock calls. IDirect3DDevice9::DrawIndexedPrimitive calls will not succeed with any outstanding lock count on any currently set index buffer.

The D3DLOCK_DISCARD and D3DLOCK_NOOVERWRITE flags are valid only on buffers created with D3DUSAGE_DYNAMIC.

See Programming Tips (Direct3D 9) for information about using D3DLOCK_DISCARD or D3DLOCK_NOOVERWRITE.

Requirements

See also

IDirect3DIndexBuffer9

IDirect3DIndexBuffer9::Unlock

Index Buffers (Direct3D 9)