《精通DirectX 3D》第八章 深度测试与Alpha混合 02_AlphaBlend

《精通DirectX 3D》第八章 深度测试与Alpha混合 02_AlphaBlend

禁用Alpha混合



激活Alpha混合

// =============================================================================
//  Desc: Alpha混合测试
// =============================================================================

#include  < d3dx9.h >


// -----------------------------------------------------------------------------
//  Desc: 全局变量
// -----------------------------------------------------------------------------
LPDIRECT3D9             g_pD3D            =  NULL;  // Direct3D对象
LPDIRECT3DDEVICE9       g_pd3dDevice      =  NULL;  // Direct3D设备对象
LPD3DXMESH              g_pMesh           =  NULL;  // 网格模型对象
D3DMATERIAL9 *            g_pMeshMaterials  =  NULL;  // 网格模型材质
LPDIRECT3DTEXTURE9 *      g_pMeshTextures   =  NULL;  // 网格模型纹理
DWORD                   g_dwNumMaterials  =   0L ;    // 网格模型子块数量


// -----------------------------------------------------------------------------
//  Desc: 设置世界矩阵
// -----------------------------------------------------------------------------
VOID SetWorldMatrix()
{
     // 创建并设置世界矩阵
    D3DXMATRIXA16 matWorld;
    D3DXMatrixRotationY(  & matWorld, timeGetTime() / 1000.0f  );
    g_pd3dDevice -> SetTransform( D3DTS_WORLD,  & matWorld );
}

// -----------------------------------------------------------------------------
//  Desc: 设置观察矩阵和投影矩阵
// -----------------------------------------------------------------------------
VOID SetViewAndProjMatrix()
{
     // 创建并设置观察矩阵
    D3DXVECTOR3 vEyePt(  0.0f ,  15.0f ,  - 20.0f  );
    D3DXVECTOR3 vLookatPt(  0.0f ,  0.0f ,  0.0f  );
    D3DXVECTOR3 vUpVec(  0.0f ,  1.0f ,  0.0f  );
    D3DXMATRIXA16 matView;
    D3DXMatrixLookAtLH(  & matView,  & vEyePt,  & vLookatPt,  & vUpVec );
    g_pd3dDevice -> SetTransform( D3DTS_VIEW,  & matView );

     // 创建并设置投影矩阵
    D3DXMATRIXA16 matProj;
    D3DXMatrixPerspectiveFovLH(  & matProj, D3DX_PI / 4 ,  1.0f ,  1.0f ,  100.0f  );
    g_pd3dDevice -> SetTransform( D3DTS_PROJECTION,  & matProj );
}


// -----------------------------------------------------------------------------
//  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;
    d3dpp.EnableAutoDepthStencil  =  TRUE;
    d3dpp.AutoDepthStencilFormat  =  D3DFMT_D16;

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

     // Alpha混合设置, 设置混合系数
    g_pd3dDevice -> SetRenderState( D3DRS_ALPHABLENDENABLE,    true  );
    g_pd3dDevice -> SetRenderState( D3DRS_SRCBLEND,  D3DBLEND_SRCALPHA );
    g_pd3dDevice -> SetRenderState( D3DRS_DESTBLEND, D3DBLEND_INVSRCALPHA );

     // 深度测试相关设置
    g_pd3dDevice -> SetRenderState( D3DRS_ZENABLE,  true  );
    g_pd3dDevice -> SetRenderState( D3DRS_ZFUNC, D3DCMP_LESS );
    g_pd3dDevice -> SetRenderState( D3DRS_ZWRITEENABLE, TRUE );

     // 设置环境光
    g_pd3dDevice -> SetRenderState( D3DRS_AMBIENT,  0xffffffff  );

     // 设置观察矩阵和投影矩阵
    SetViewAndProjMatrix();

     return  S_OK;
}


// -----------------------------------------------------------------------------
//  Desc: 从绝对路径中提取纹理文件名
// -----------------------------------------------------------------------------
void  RemovePathFromFileName(LPSTR fullPath, LPWSTR fileName)
{
     // 先将fullPath的类型变换为LPWSTR
    WCHAR wszBuf[MAX_PATH];
    MultiByteToWideChar( CP_ACP,  0 , fullPath,  - 1 , wszBuf, MAX_PATH );
    wszBuf[MAX_PATH - 1 ]  =  L ' \0 ' ;

    WCHAR *  wszFullPath  =  wszBuf;

     // 从绝对路径中提取文件名
    LPWSTR pch = wcsrchr(wszFullPath, ' \\ ' );
     if  (pch)
        lstrcpy(fileName,  ++ pch);
     else
        lstrcpy(fileName, wszFullPath);
}


// -----------------------------------------------------------------------------
//  Desc: 创建场景图形
// -----------------------------------------------------------------------------
HRESULT InitGeometry()
{
    LPD3DXBUFFER pD3DXMtrlBuffer;

     // 加载文件模型
     if ( FAILED( D3DXLoadMeshFromX( L " Heli.x " , D3DXMESH_SYSTEMMEM, 
                                   g_pd3dDevice, NULL, 
                                    & pD3DXMtrlBuffer, NULL,  & g_dwNumMaterials, 
                                    & g_pMesh ) ) )
    {
         return  E_FAIL;
    }

     // 提取材质和纹理数据
    D3DXMATERIAL *  d3dxMaterials  =  (D3DXMATERIAL * )pD3DXMtrlBuffer -> GetBufferPointer();
    g_pMeshMaterials  =   new  D3DMATERIAL9[g_dwNumMaterials];
    g_pMeshTextures   =   new  LPDIRECT3DTEXTURE9[g_dwNumMaterials];

     for ( DWORD i = 0 ; i < g_dwNumMaterials; i ++  )
    {
        g_pMeshMaterials[i]  =  d3dxMaterials[i].MatD3D;
        g_pMeshMaterials[i].Ambient  =  g_pMeshMaterials[i].Diffuse;

        g_pMeshTextures[i]  =  NULL;
         if ( d3dxMaterials[i].pTextureFilename  !=  NULL  &&  
            strlen(d3dxMaterials[i].pTextureFilename)  >   0  )
        {
             // 获取纹理文件名
            WCHAR filename[ 256 ];
            RemovePathFromFileName(d3dxMaterials[i].pTextureFilename, filename);

             // 创建纹理对象
             if ( FAILED( D3DXCreateTextureFromFile( g_pd3dDevice, filename, 
                                                    & g_pMeshTextures[i] ) ) )
            {
                 return  E_FAIL;
            }
        }
    }

     // 释放保存模型材质和纹理数据的数据对象
    pD3DXMtrlBuffer -> Release();

     return  S_OK;
}


// -----------------------------------------------------------------------------
//  Desc: 释放创建的对象
// -----------------------------------------------------------------------------
VOID Cleanup()
{
     // 释放网格模型材质
     if ( g_pMeshMaterials  !=  NULL ) 
        delete[] g_pMeshMaterials;

     // 释放网格模型纹理
     if ( g_pMeshTextures )
    {
         for ( DWORD i  =   0 ; i  <  g_dwNumMaterials; i ++  )
        {
             if ( g_pMeshTextures[i] )
                g_pMeshTextures[i] -> Release();
        }
        delete[] g_pMeshTextures;
    }

     // 释放网格模型对象
     if ( g_pMesh  !=  NULL )
        g_pMesh -> 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()
{
     // 清除后缓冲区和深度缓冲区
    g_pd3dDevice -> Clear(  0 , NULL, D3DCLEAR_TARGET | D3DCLEAR_ZBUFFER, 
                         D3DCOLOR_XRGB( 0 , 0 , 255 ),  1.0f ,  0  );
    
     // 开始在后台缓冲区绘制图形
     if ( SUCCEEDED( g_pd3dDevice -> BeginScene() ) )
    {
        SetWorldMatrix();    // 设置世界矩阵

         // 绘制不透明部分, 必须先绘制不透明的物体
         for ( DWORD i = 0 ; i < g_dwNumMaterials; i ++  )
        {
             if (g_pMeshMaterials[i].Diffuse.a == 1.0f )
            {
                g_pd3dDevice -> SetMaterial(  & g_pMeshMaterials[i] );
                g_pd3dDevice -> SetTexture(  0 , g_pMeshTextures[i] );
                g_pMesh -> DrawSubset( i );
            }
        }

         // 绘制透明部分
         for ( DWORD i = 0 ; i < g_dwNumMaterials; i ++  )
        {
             if (g_pMeshMaterials[i].Diffuse.a != 1 .f)
            {
                g_pd3dDevice -> SetMaterial(  & g_pMeshMaterials[i] );
                g_pd3dDevice -> SetTexture(  0 , g_pMeshTextures[i] );
                g_pMesh -> DrawSubset( i );
            }
        }

         // 结束在后台缓冲区渲染图形
        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 ;

     case  WM_KEYDOWN:
         switch (wParam)
        {
         case   48 :   // "0"键, 禁用Alpha混合
            g_pd3dDevice -> SetRenderState(D3DRS_ALPHABLENDENABLE,  false );
             break ;

         case   49 :  // "1"键, 激活Alpha混合
            g_pd3dDevice -> SetRenderState(D3DRS_ALPHABLENDENABLE,  true );
             break ;
        }
         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,
                      L " ClassName " , NULL };
    RegisterClassEx(  & wc );

     // 创建窗口
    HWND hWnd  =  CreateWindow(  L " ClassName " , L " Alpha混合 " , 
                              WS_OVERLAPPEDWINDOW,  200 ,  100 ,  500 ,  500 ,
                              GetDesktopWindow(), NULL, wc.hInstance, NULL );

     // 初始化Direct3D
     if ( SUCCEEDED( InitD3D( hWnd ) ) )
    {
         // 创建场景图形
         if ( SUCCEEDED( InitGeometry() ) )
        {
             // 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();
            }
        }
    }

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