Prepares a device for drawing lines.
This method has no parameters.
If the method succeeds, the return value is D3D_OK. If the method fails, the return value can be one of the following: D3DERR_INVALIDCALL, D3DXERR_INVALIDDATA.
Calling ID3DXLine::Begin is optional. If called outside of a ID3DXLine::Begin/ID3DXLine::End sequence, the draw functions will internally call ID3DXLine::Begin and ID3DXLine::End. To avoid extra overhead, this method should be used if more than one draw function will be called successively.