Direct3D Execute-Buffer Objects

Execute buffers contain a vertex list followed by an instruction stream. The instruction stream consists of operation codes, or opcodes, and the data that modifies those opcodes. For a description of execute buffers, see Execute Buffers.

You can create a Direct3D execute-buffer object by calling the IDirect3DDevice::CreateExecuteBuffer method.

lpD3DDevice->CreateExecuteBuffer(

lpDesc, // Address of a DIRECT3DEXECUTEBUFFERDESC structure

lplpDirect3DExecuteBuffer, // Address to contain a pointer to the

// Direct3DExecuteBuffer object

pUnkOuter); // NULL

Execute-buffer objects reside on a device list. You can use the IDirect3DDevice::CreateExecuteBuffer method to allocate space for the actual buffer, which may be on the hardware device.

The buffer is filled with two contiguous arrays of vertices and opcodes by using the following calls to the IDirect3DExecuteBuffer::Lock, IDirect3DExecuteBuffer::Unlock, and IDirect3DExecuteBuffer::SetExecuteData methods:

lpD3DExBuf->Lock(

lpDesc);. // Address of a DIRECT3DEXECUTEBUFFERDESC structure

// .

// . Store contents through the supplied address

// .

lpD3DExBuf->Unlock();

lpD3DExBuf->SetExecuteData(

lpData); // Address of a D3DEXECUTEDATA structure

The last call in the preceding example is to the IDirect3DExecuteBuffer::SetExecuteData method. This method notifies Direct3D where the two parts of the buffer reside relative to the address that was returned by the call to the IDirect3DExecuteBuffer::Lock method.

You can use the IDirect3DExecuteBuffer interface to get and set execute data, and to lock, unlock, optimize, and validate the execute buffer.