lightmap.cpp

选自《3D游戏编程》第5章 实战例题：3D编程技术的实战例题

/**-----------------------------------------------------------------------------
 * \brief 光影贴图技巧的理解
 * 文件: LightMap.cpp
 *
 * 说明: 所谓光影贴图，是指在一些QUAKE类的游戏中，不使用实际光源而制作出光源效
 *       果的技巧.
 *       实际游戏中，壁面通过BSP树隔开，通过与光源间的运算，生成光影贴图，
 *       使用光影贴图，而非实际光源.
 *       
 *------------------------------------------------------------------------------
 */

#include <d3d9.h>
#include <d3dx9.h>



/**-----------------------------------------------------------------------------
 *  全局参数
 *------------------------------------------------------------------------------
 */
LPDIRECT3D9             g_pD3D       = NULL; /// 创建D3D设备的D3D对象参数
LPDIRECT3DDEVICE9       g_pd3dDevice = NULL; /// 渲染中使用的D3D设备
LPDIRECT3DVERTEXBUFFER9 g_pVB        = NULL; /// 储存顶点的顶点缓冲
LPDIRECT3DTEXTURE9		g_pTex0		 = NULL; /// Texture 0(壁面)
LPDIRECT3DTEXTURE9		g_pTex1		 = NULL; /// Texture 1(光影贴图)

D3DXMATRIXA16			g_matAni;

/// 定义用户顶点的结构体
struct CUSTOMVERTEX
{
    FLOAT x, y, z;	/// 顶点的变换坐标
    DWORD color;	/// 顶点的颜色
	FLOAT u,v;
};

/// 表现用户顶点结构体信息的FVF值
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZ|D3DFVF_DIFFUSE|D3DFVF_TEX1|D3DFVF_TEXCOORDSIZE2(0))


/**-----------------------------------------------------------------------------
 * Direct3D初始化
 *------------------------------------------------------------------------------
 */
HRESULT InitD3D( HWND hWnd )
{
    /// 创建一个用来创建设备的D3D对象
    if( NULL == ( g_pD3D = Direct3DCreate9( D3D_SDK_VERSION ) ) )
        return E_FAIL;

    /// 创建设备的结构体
    /// 绘制复杂对象时需要Z－缓冲.
    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;

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

    /// 起到卷起功能.
    g_pd3dDevice->SetRenderState( D3DRS_CULLMODE, D3DCULL_NONE );

    /// 起到Z－缓冲功能.
    g_pd3dDevice->SetRenderState( D3DRS_ZENABLE, TRUE );

    /// 顶点具有颜色值，起到光源功能.
    g_pd3dDevice->SetRenderState( D3DRS_LIGHTING, FALSE );

    return S_OK;
}




/**-----------------------------------------------------------------------------
 * 创建顶点缓冲，设置顶点值.
 *------------------------------------------------------------------------------
 */
HRESULT InitVB()
{
    /// 渲染一个正方体（cube）需要8个顶点声明
    CUSTOMVERTEX vertices[] =
    {
		{ -1,  1, 0 , 0xffffffff, 0, 0 },		/// v0
		{  1,  1, 0 , 0xffffffff, 1, 0 },		/// v1
		{ -1, -1, 0 , 0xffffffff, 0, 1 },		/// v2
		{  1, -1, 0 , 0xffffffff, 1, 1 },		/// v3
    };

    /// 创建顶点缓冲
    /// 设置储存8个用户顶点的存储器.
    /// 指定FVF，指定数据的储存格式.
    if( FAILED( g_pd3dDevice->CreateVertexBuffer( 4*sizeof(CUSTOMVERTEX),
                                                  0, D3DFVF_CUSTOMVERTEX,
                                                  D3DPOOL_DEFAULT, &g_pVB, NULL ) ) )
    {
        return E_FAIL;
    }

    /// 将顶点数据写入顶点缓冲. 
    /// 调用顶点的Lock()函数来定义指针.
    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;
}

HRESULT InitTexture()
{
    if( FAILED( D3DXCreateTextureFromFile( g_pd3dDevice, "env2.bmp", &g_pTex0 ) ) )
		return E_FAIL;

    if( FAILED( D3DXCreateTextureFromFile( g_pd3dDevice, "spotlite.bmp", &g_pTex1 ) ) )
		return E_FAIL;

	return S_OK;
}

/**-----------------------------------------------------------------------------
 * 几何信息初始化
 *------------------------------------------------------------------------------
 */
HRESULT InitGeometry()
{
	if( FAILED( InitVB() ) ) return E_FAIL;
	if( FAILED( InitTexture() ) ) return E_FAIL;

	return S_OK;
}


/**-----------------------------------------------------------------------------
 * 创建摄像机矩阵
 *------------------------------------------------------------------------------
 */
void SetupCamera()
{
	/// 创建世界矩阵
    D3DXMATRIXA16 matWorld;
	D3DXMatrixIdentity( &matWorld );
    g_pd3dDevice->SetTransform( D3DTS_WORLD, &matWorld );

    /// 创建视图矩阵
    D3DXVECTOR3 vEyePt( 0.0f, 0.0f,-3.0f );
    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 );

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

/**-----------------------------------------------------------------------------
 * 创建动画矩阵
 *------------------------------------------------------------------------------
 */
VOID Animate()
{
	D3DXMatrixIdentity( &g_matAni );
//	D3DXMatrixRotationZ( &g_matAni, GetTickCount()/500.0f ); 	/// 网格的Z轴旋转矩阵
}



/**-----------------------------------------------------------------------------
 * 删除初始化对象
 *------------------------------------------------------------------------------
 */
VOID Cleanup()
{
    if( g_pVB != NULL )        
        g_pVB->Release();

    if( g_pd3dDevice != NULL ) 
        g_pd3dDevice->Release();

    if( g_pD3D != NULL )       
        g_pD3D->Release();
}


/**-----------------------------------------------------------------------------
 * 绘制网格
 *------------------------------------------------------------------------------
 */
void DrawMesh( D3DXMATRIXA16* pMat )
{
    g_pd3dDevice->SetTransform( D3DTS_WORLD, pMat );
    g_pd3dDevice->SetStreamSource( 0, g_pVB, 0, sizeof(CUSTOMVERTEX) );
    g_pd3dDevice->SetFVF( D3DFVF_CUSTOMVERTEX );
	g_pd3dDevice->DrawPrimitive( D3DPT_TRIANGLESTRIP, 0, 2 );
}

/**-----------------------------------------------------------------------------
 * 绘图
 *------------------------------------------------------------------------------
 */
VOID Render()
{
	D3DXMATRIXA16	matWorld;

    /// 后置缓冲和Z－缓冲初始化
    g_pd3dDevice->Clear( 0, NULL, D3DCLEAR_TARGET|D3DCLEAR_ZBUFFER, D3DCOLOR_XRGB(0,0,255), 1.0f, 0 );

	/// 创建动画矩阵
	Animate();
    /// 开始渲染
    if( SUCCEEDED( g_pd3dDevice->BeginScene() ) )
    {
        g_pd3dDevice->SetTexture( 0, g_pTex0 );		/// 在0号纹理层固定纹理（壁面）
        g_pd3dDevice->SetTexture( 1, g_pTex1 );		/// 在1号纹理层固定纹理（光影贴图）

		g_pd3dDevice->SetTextureStageState( 0, D3DTSS_TEXCOORDINDEX, 0 );	/// 0号纹理：使用0号纹理索引
		g_pd3dDevice->SetTextureStageState( 1, D3DTSS_TEXCOORDINDEX, 0 );	/// 1号纹理：使用0号纹理索引
		g_pd3dDevice->SetSamplerState( 0, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR );	/// 0号纹理层的放大滤镜
		g_pd3dDevice->SetSamplerState( 1, D3DSAMP_MAGFILTER, D3DTEXF_LINEAR );	/// 1号纹理层的放大滤镜
		g_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLOROP,   D3DTOP_SELECTARG1 );
		g_pd3dDevice->SetTextureStageState( 0, D3DTSS_COLORARG1, D3DTA_TEXTURE );
		g_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAOP,   D3DTOP_SELECTARG1 );
		g_pd3dDevice->SetTextureStageState( 0, D3DTSS_ALPHAARG1, D3DTA_TEXTURE );

		g_pd3dDevice->SetTextureStageState( 1, D3DTSS_COLOROP,   D3DTOP_MODULATE );	/// 运用MODULATE运算进行颜色混合
		g_pd3dDevice->SetTextureStageState( 1, D3DTSS_COLORARG1, D3DTA_TEXTURE );
		g_pd3dDevice->SetTextureStageState( 1, D3DTSS_COLORARG2, D3DTA_CURRENT );
		g_pd3dDevice->SetTextureStageState( 1, D3DTSS_ALPHAOP,   D3DTOP_DISABLE );

		g_pd3dDevice->SetTextureStageState( 2, D3DTSS_COLOROP,   D3DTOP_DISABLE );
		g_pd3dDevice->SetTextureStageState( 2, D3DTSS_ALPHAOP,   D3DTOP_DISABLE );

		DrawMesh( &g_matAni );
        /// 结束渲染
        g_pd3dDevice->EndScene();
    }

    /// 显示后置缓冲的画面!
    g_pd3dDevice->Present( NULL, NULL, NULL, NULL );
}




/**-----------------------------------------------------------------------------
 * 窗口过程
 *------------------------------------------------------------------------------
 */
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 );
}




/**-----------------------------------------------------------------------------
 * 程序的起始地址
 *------------------------------------------------------------------------------
 */
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,
                      "BasicFrame", NULL };
    RegisterClassEx( &wc );

    /// 创建窗口
    HWND hWnd = CreateWindow( "BasicFrame", "LightMapping",
                              WS_OVERLAPPEDWINDOW, 100, 100, 500, 500,
                              GetDesktopWindow(), NULL, wc.hInstance, NULL );

    /// Direct3D初始化
    if( SUCCEEDED( InitD3D( hWnd ) ) )
    {
        if( SUCCEEDED( InitGeometry() ) )
        {
			/// 创建摄像机矩阵
			SetupCamera();

        	/// 显示窗口
			ShowWindow( hWnd, SW_SHOWDEFAULT );
			UpdateWindow( hWnd );

        	/// 消息循环
			MSG msg;
			ZeroMemory( &msg, sizeof(msg) );
			while( msg.message!=WM_QUIT )
			{
            	/// 消息队列中有消息时，调用相应的处理过程
				if( PeekMessage( &msg, NULL, 0U, 0U, PM_REMOVE ) )
				{
					TranslateMessage( &msg );
					DispatchMessage( &msg );
				}
				else
				/// 如果没有需要处理的消息，调用Render()函数
					Render();
			}
		}
    }

	/// 删除注册的类
    UnregisterClass( "D3D Tutorial", wc.hInstance );
    return 0;
}