directx 9 - getsurfacelevel() and lockrect() run-time error - c++

Question

In the code below i wanted to display an image or some pixels by using surface and backbuffer.
It compiles correctly but gives a run-time error when reach to GetSurfaceLevel or LockRect.
The code:
#include <d3d9.h>
#include <windows.h>
//-----------------------------------------------------------------------------
// Global variables
//-----------------------------------------------------------------------------
LPDIRECT3D9 g_pD3D = NULL; // Used to create the D3DDevice
LPDIRECT3DDEVICE9 g_pd3dDevice = NULL; // Our rendering device
LPDIRECT3DSURFACE9 surf,back;
D3DLOCKED_RECT lock ;
IDirect3DTexture9* texture = NULL;
HRESULT InitD3D( HWND );
HRESULT InitVB();
VOID Cleanup();
VOID Render();
LRESULT WINAPI MsgProc( HWND , UINT , WPARAM , LPARAM );
//-----------------------------------------------------------------------------
// Name: wWinMain()
// Desc: The application's entry point
//-----------------------------------------------------------------------------
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR, INT )
{
UNREFERENCED_PARAMETER( hInst );
// Register the window class
WNDCLASSEX wc =
{
sizeof( WNDCLASSEX ), CS_CLASSDC, MsgProc, 0L, 0L,
GetModuleHandle( NULL ), NULL, NULL, NULL, NULL,
"D3D Tutorial", NULL
};
RegisterClassEx( &wc );
// Create the application's window
HWND hWnd = CreateWindow( "D3D Tutorial", "D3D Tutorial 02: Vertices",
WS_OVERLAPPEDWINDOW, 100, 100, 320, 240,
NULL, NULL, wc.hInstance, NULL );
// Initialize Direct3D
if( SUCCEEDED( InitD3D( hWnd ) ) ){
// Create the vertex buffer
if( SUCCEEDED( InitVB() ) )
{
// Show the window
ShowWindow( hWnd, SW_SHOWDEFAULT );
UpdateWindow( hWnd );
printf("4");
Render();
printf("5");
// Enter the message loop
MSG msg;
ZeroMemory( &msg, sizeof( msg ) );
while( msg.message != WM_QUIT )
{
if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
{
TranslateMessage( &msg );
DispatchMessage( &msg );
}
}
}
}
UnregisterClass( "D3D Tutorial", wc.hInstance );
return 0;
}
//-----------------------------------------------------------------------------
// Name: InitD3D()
// Desc: Initializes Direct3D
//-----------------------------------------------------------------------------
HRESULT InitD3D( HWND hWnd )
{
// Create the D3D object.
if( NULL == ( g_pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
return E_FAIL;
// Set up the structure used to create the D3DDevice
D3DPRESENT_PARAMETERS d3dpp;
ZeroMemory( &d3dpp, sizeof( d3dpp ) );
d3dpp.Flags = D3DPRESENTFLAG_LOCKABLE_BACKBUFFER;
d3dpp.Windowed = TRUE; // program windowed, not fullscreen
d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD; // discard old frames
d3dpp.hDeviceWindow = hWnd;
// Create the D3DDevice
if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
D3DCREATE_SOFTWARE_VERTEXPROCESSING,
&d3dpp, &g_pd3dDevice ) ) )
{
return E_FAIL;
}
// Device state would normally be set here
return S_OK;
}
//-----------------------------------------------------------------------------
// Name: InitVB()
// Desc: Creates a vertex buffer and fills it with our vertices. The vertex
// buffer is basically just a chuck of memory that holds vertices. After
// creating it, we must Lock()/Unlock() it to fill it. For indices, D3D
// also uses index buffers. The special thing about vertex and index
// buffers is that they can be created in device memory, allowing some
// cards to process them in hardware, resulting in a dramatic
// performance gain.
//-----------------------------------------------------------------------------
HRESULT InitVB()
{
typedef struct {char r,g,b;}st;
g_pd3dDevice->CreateTexture(320,240,0,0,D3DFMT_R8G8B8,
D3DPOOL_MANAGED,&texture,NULL);
g_pd3dDevice->CreateOffscreenPlainSurface(4,4,D3DFMT_R8G8B8
,D3DPOOL_MANAGED,&surf,NULL);
texture->GetSurfaceLevel(0,&surf);
surf->LockRect(&lock,NULL,0);
st st3[]={{0,0,255,},{0,255,0,},{255,0,0,},{127,127,127,},
{255,0,0,},{0,0,255,},{127,127,127,},{0,255,0,},
{0,255,0,},{127,127,127,},{255,0,0,},{0,0,255},
{127,127,127,},{255,0,0,},{0,255,0,},{255,0,0,},
};
void *b,*c;
b=(void *)st3;
c=(void *)lock.pBits;
memcpy(c, b, sizeof(st3));
surf->UnlockRect();
return S_OK;
}
//-----------------------------------------------------------------------------
// Name: Cleanup()
// Desc: Releases all previously initialized objects
//-----------------------------------------------------------------------------
VOID Cleanup()
{
if( g_pd3dDevice != NULL )
g_pd3dDevice->Release();
if( g_pD3D != NULL )
g_pD3D->Release();
}
//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Draws the scene
//-----------------------------------------------------------------------------
VOID Render()
{
// Clear the backbuffer to a blue color
g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB( 10, 10, 10 ), 1.0f, 0 );
if( SUCCEEDED( g_pd3dDevice->BeginScene() ) )
{
g_pd3dDevice->GetBackBuffer(0,0,D3DBACKBUFFER_TYPE_MONO,&back);
g_pd3dDevice->UpdateSurface(surf, NULL, back, NULL);
// End the scene
g_pd3dDevice->EndScene();
}
// Present the backbuffer contents to the display
g_pd3dDevice->Present( NULL, NULL, NULL, NULL );
}
//-----------------------------------------------------------------------------
// Name: MsgProc()
// Desc: The window's message handler
//-----------------------------------------------------------------------------
LRESULT WINAPI MsgProc( HWND hWnd, UINT msg, WPARAM wParam, LPARAM lParam )
{
switch( msg )
{
case WM_DESTROY:
Cleanup();
PostQuitMessage( 0 );
return 0;
}
return DefWindowProc( hWnd, msg, wParam, lParam );
}