各位大侠。 小弟我想在xz平面画一个三角形。该怎么设置摄像机。和顶点坐标啊试了好多次都不出来。

#include <d3d9.h>

//-----------------------------------------
// Desc: 全局变量
//-----------------------------------------
LPDIRECT3D9             g_pD3D       = NULL;    //Direct3D对象
LPDIRECT3DDEVICE9       g_pd3dDevice = NULL;    //Direct3D设备对象
LPDIRECT3DVERTEXBUFFER9 g_pVB        = NULL;    //顶点缓冲区对象


//-----------------------------------------
// Desc: 顶点结构
//-----------------------------------------
struct CUSTOMVERTEX
{
    FLOAT x, y, z, rhw;
    DWORD color;
};
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW|D3DFVF_DIFFUSE)  //顶点格式


//-----------------------------------------
// Desc: 初始化Direct3D
//-----------------------------------------
HRESULT InitD3D( HWND hWnd )
{
    //创建Direct3D对象, 该对象用于创建Direct3D设备对象
    if( NULL == ( g_pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
        return E_FAIL;

    //设置D3DPRESENT_PARAMETERS结构, 准备创建Direct3D设备对象
    D3DPRESENT_PARAMETERS d3dpp;
    ZeroMemory( &d3dpp, sizeof(d3dpp) );
    d3dpp.Windowed = TRUE;
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;
    d3dpp.BackBufferFormat = D3DFMT_UNKNOWN;

    //创建Direct3D设备对象
    if( FAILED( g_pD3D->CreateDevice( D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd,
                                      D3DCREATE_SOFTWARE_VERTEXPROCESSING,
                                      &d3dpp, &g_pd3dDevice ) ) )
    {
        return E_FAIL;
    }

    return S_OK;
}


//-----------------------------------------
// Desc: 创建并填充顶点缓冲区
//-----------------------------------------
HRESULT InitVB()
{
    //顶点数据
    CUSTOMVERTEX vertices[] =
    {
    { 100.0f, 400.0f, 0.5f, 1.0f, 0xffff0000, },
        { 300.0f,  50.0f, 0.5f, 1.0f, 0xff00ff00, }, 
        { 500.0f, 400.0f, 0.5f, 1.0f, 0xff0000ff, },
    };

    //创建顶点缓冲区
    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 3*sizeof(CUSTOMVERTEX),
                                                  0, D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_DEFAULT, &g_pVB, NULL ) ) )
    {
        return E_FAIL;
    }

    //填充顶点缓冲区
    VOID* pVertices;
    if( FAILED( g_pVB->Lock( 0, sizeof(vertices), (void**)&pVertices, 0 ) ) )
        return E_FAIL;
    memcpy( pVertices, vertices, sizeof(vertices) );
    g_pVB->Unlock();

    return S_OK;
}


//-----------------------------------------
// Desc: 释放创建的对象
//-----------------------------------------
VOID Cleanup()
{
    //释放顶点缓冲区对象
    if( g_pVB != NULL )        
        g_pVB->Release();

    //释放Direct3D设备对象
    if( g_pd3dDevice != NULL ) 
        g_pd3dDevice->Release();

    //释放Direct3D对象
    if( g_pD3D != NULL )       
        g_pD3D->Release();
}


//-----------------------------------------
// Desc: 渲染图形 
//-----------------------------------------
VOID Render()
{
    //清空后台缓冲区
    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(45, 50, 170), 1.0f, 0 );

    //开始在后台缓冲区绘制图形
    if( SUCCEEDED( g_pd3dDevice->BeginScene() ) )
    {
        //在后台缓冲区绘制图形
        g_pd3dDevice->SetStreamSource( 0, g_pVB, 0, sizeof(CUSTOMVERTEX) );
        g_pd3dDevice->SetFVF( D3DFVF_CUSTOMVERTEX );
        g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLELIST, 0, 1 );

        //结束在后台缓冲区绘制图形
        g_pd3dDevice->EndScene();
    }

    //将在后台缓冲区绘制的图形提交到前台缓冲区显示
    g_pd3dDevice->Present( NULL, NULL, NULL, NULL );
}


//-----------------------------------------
// Desc: 消息处理
//-----------------------------------------
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 );
}


//-----------------------------------------
// Desc: 入口函数
//-----------------------------------------
INT WINAPI WinMain( HINSTANCE hInst, HINSTANCE, LPSTR, INT )
{
    //注册窗口类
    WNDCLASSEX wc = { sizeof(WNDCLASSEX), CS_CLASSDC, MsgProc, 0L, 0L,
                      GetModuleHandle(NULL), NULL, NULL, NULL, NULL,
                      "ClassName", NULL };
    RegisterClassEx( &wc );

    //创建窗口
    HWND hWnd = CreateWindow( "ClassName", "顶点缓冲区",
                              WS_OVERLAPPEDWINDOW, 200, 100, 600, 500,
                              GetDesktopWindow(), NULL, wc.hInstance, NULL );

    //初始化Direct3D
    if( SUCCEEDED( InitD3D( hWnd ) ) )
    {
        //创建并填充顶点缓冲区
        if( SUCCEEDED( InitVB() ) )
        {
            //显示窗口
            ShowWindow( hWnd, SW_SHOWDEFAULT );
            UpdateWindow( hWnd );

            //进入消息循环
            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();  //渲染图形
                }
            }
        }
    }

    UnregisterClass("ClassName", wc.hInstance);
    return 0;
}