Direct3d 的一个数据类型

请问D3DXMATRIX这是个什么类型啊？
我的例子代码调试通不过
说这个类型没有定义
在引入的头文件里面的确没有这个类型的定义
可是后面却用到了
谁能帮忙看一下错在哪里呢？
谢谢
代码如下：#include <d3d8.h>
#include <mmsystem.h>
LPDIRECT3D8             g_pD3D       = NULL; // Used to create the D3DDevice
LPDIRECT3DDEVICE8       g_pd3dDevice = NULL; // Our rendering device
LPDIRECT3DVERTEXBUFFER8 g_pVB        = NULL; // Buffer to hold vertices
UINT g_uQueryCancelAutoPlay = 0;
struct CUSTOMVERTEX
{
    FLOAT x, y, z;      
    DWORD color;        
};// Our custom FVF, which describes our custom vertex structure
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE)//-----------------------------------------------------------------------------
// Name: InitD3D()
// Desc: Initializes Direct3D
//-----------------------------------------------------------------------------
HRESULT InitD3D( HWND hWnd )
{    if( NULL == ( g_pD3D = Direct3DCreate8( D3D_SDK_VERSION ) ) )
        return E_FAIL;
    D3DDISPLAYMODE d3ddm;
    if( FAILED( g_pD3D->GetAdapterDisplayMode( D3DADAPTER_DEFAULT, &d3ddm ) ) )
        return E_FAIL;
    D3DPRESENT_PARAMETERS d3dpp;
    ZeroMemory( &d3dpp, sizeof(d3dpp) );
    d3dpp.Windowed = TRUE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.BackBufferFormat = d3ddm.Format;
    if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
                                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                                      &d3dpp, &g_pd3dDevice ) ) )
    {
        return E_FAIL;
    }
    g_pd3dDevice->SetRenderState( D3DRS_CULLMODE, D3DCULL_NONE );
    g_pd3dDevice->SetRenderState( D3DRS_LIGHTING, FALSE );    return S_OK;
}
//-----------------------------------------------------------------------------
// Name: InitGeometry()
// Desc: Creates the scene geometry
//-----------------------------------------------------------------------------
HRESULT InitGeometry()
{    CUSTOMVERTEX g_Vertices[] =
    {
        { -1.0f,-1.0f, 0.0f, 0xffff0000, },
        {  1.0f,-1.0f, 0.0f, 0xff0000ff, },
        {  0.0f, 1.0f, 0.0f, 0xffffffff, },
    };
    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 3*sizeof(CUSTOMVERTEX),
                                                  0, D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_DEFAULT, &g_pVB ) ) )
    {
        return E_FAIL;
    }    VOID* pVertices;    if( FAILED( g_pVB->Lock( 0, sizeof(g_Vertices), (BYTE**)&pVertices, 0 ) ) )
        return E_FAIL;    memcpy( pVertices, g_Vertices, sizeof(g_Vertices) );
    g_pVB->Unlock();    return S_OK;
}
//-----------------------------------------------------------------------------
// Name: Cleanup()
// Desc: Releases all previously initialized objects
//-----------------------------------------------------------------------------
VOID Cleanup()
{
    if( g_pVB != NULL )
        g_pVB->Release();    if( g_pd3dDevice != NULL )
        g_pd3dDevice->Release();    if( g_pD3D != NULL )
        g_pD3D->Release();
}//-----------------------------------------------------------------------------
// Name: SetupMatrices()
// Desc: Sets up the world, view, and projection transform matrices.
//-----------------------------------------------------------------------------
void SetupMatrices()
{  D3DXMATRIX matWorld;    D3DXMatrixRotationY( &matWorld, timeGetTime()/150.0f );
    g_pd3dDevice->SetTransform( D3DTS_WORLD, &matWorld );
    D3DXMATRIX matView;
    D3DXMatrixLookAtLH( &matView, &D3DXVECTOR3( 0.0f, 3.0f,-5.0f ),
                                  &D3DXVECTOR3( 0.0f, 0.0f, 0.0f ),
                                  &D3DXVECTOR3( 0.0f, 1.0f, 0.0f ) );
    g_pd3dDevice->SetTransform( D3DTS_VIEW, &matView );
D3DXMATRIX matProj;
    D3DXMatrixPerspectiveFovLH( &matProj, D3DX_PI/4, 1.0f, 1.0f, 100.0f );
    g_pd3dDevice->SetTransform( D3DTS_PROJECTION, &matProj );
}//-----------------------------------------------------------------------------
// Name: Render()
// Desc: Draws the scene
//-----------------------------------------------------------------------------
VOID Render()
{    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0,0,0), 1.0f, 0 );
    g_pd3dDevice->BeginScene();
    SetupMatrices();
    g_pd3dDevice->SetStreamSource( 0, g_pVB, sizeof(CUSTOMVERTEX) );    g_pd3dDevice->SetVertexShader( D3DFVF_CUSTOMVERTEX );
    g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLESTRIP, 0, 1 );
    g_pd3dDevice->EndScene();
    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:
            PostQuitMessage( 0 );
            return 0; case WM_SYSCOMMAND:
{
switch (wParam)
{
case SC_SCREENSAVE:
case SC_MONITORPOWER:
return 0;
break;
}
break;
}

default: 
{
if (!g_uQueryCancelAutoPlay)
{ 
g_uQueryCancelAutoPlay = RegisterWindowMessage(TEXT("QueryCancelAutoPlay"));
} 
if (msg && msg == g_uQueryCancelAutoPlay)
{ 
return TRUE;    
}
}
}    return DefWindowProc( hWnd, msg, wParam, lParam );
}
//-----------------------------------------------------------------------------
// Name: WinMain()
// Desc: The application's entry point
//-----------------------------------------------------------------------------
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR, INT )
{    WNDCLASSEX wc = { sizeof(WNDCLASSEX), 
CS_CLASSDC, 
MsgProc, 0L, 0L,
GetModuleHandle(NULL), 
NULL, NULL, NULL, NULL,
"D3D Tutorial", NULL };
    RegisterClassEx( &wc );
    HWND hWnd = CreateWindow( "D3D Tutorial", "D3D 教学",
                              WS_OVERLAPPEDWINDOW, 100, 100, 256, 256,
                              GetDesktopWindow(), NULL, wc.hInstance, NULL );
    if( SUCCEEDED( InitD3D( hWnd ) ) )
    {        if( SUCCEEDED( InitGeometry() ) )
        {            ShowWindow( hWnd, SW_SHOWDEFAULT );
            UpdateWindow( hWnd );
            MSG msg;
            ZeroMemory( &msg, sizeof(msg) );
            while( msg.message!=WM_QUIT )
            {
                if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
                {
                    TranslateMessage( &msg );
                    DispatchMessage( &msg );
                }
                else
                    Render();
            }
        }
    }
    Cleanup();
    UnregisterClass( "D3D Tutorial", wc.hInstance );
    return 0;
}