游戏程序设计学习初窥简单DirectX代码实现

两天了，不知道一直在忙什么。不想浪费时间继续directX的学习。闲话少说。。。步入正题。。

前天把管道渲染基本流程过了一遍，现在一起看看，实际的代码是怎样实现的。

#include <d3dx9.h>
#define MAX_LOADSTRING 100

// 全局变量:
HINSTANCE hInst;				                // 当前实例
TCHAR szTitle[MAX_LOADSTRING];					// 标题栏文本
TCHAR szWindowClass[MAX_LOADSTRING];		        	// 主窗口类名
LPDIRECT3D9 g_pD3D = NULL;
LPDIRECT3DDEVICE9 g_pD3DDevice = NULL;
LPDIRECT3DVERTEXBUFFER9 g_pVertexBuffer = NULL; // Buffer to hold vertices

//定义顶点信息的结构体
struct CUSTOMVERTEX
{
    FLOAT x, y, z, rhw;		// The transformed position for the vertex.
    DWORD colour;			// The vertex colour.
};

//定义自由顶点格式
#define D3DFVF_CUSTOMVERTEX (D3DFVF_XYZRHW|D3DFVF_DIFFUSE)

//定义释放COM对象的宏
#define SafeRelease(pObject) if(pObject != NULL) {pObject->Release(); pObject=NULL;}

// 此代码模块中包含的函数的前向声明:
ATOM				MyRegisterClass(HINSTANCE hInstance);
BOOL				InitInstance(HINSTANCE, int);
LRESULT CALLBACK	WndProc(HWND, UINT, WPARAM, LPARAM);
LRESULT CALLBACK	About(HWND, UINT, WPARAM, LPARAM);

//初始化D3D设备
HRESULT InitialiseD3D(HWND hWnd)
{
    //First of all, create the main D3D object. If it is created successfully we 
    //should get a pointer to an IDirect3D8 interface.
	//取得D3D9的对象
    g_pD3D = Direct3DCreate9(D3D_SDK_VERSION);
    if(g_pD3D == NULL)
    {
        return E_FAIL;
    }

	//得到当前的显示模式
    //Get the current display mode
    D3DDISPLAYMODE d3ddm;
    if(FAILED(g_pD3D->GetAdapterDisplayMode(D3DADAPTER_DEFAULT, &d3ddm)))
    {
        return E_FAIL;
    }

	//创建一个D3D设备
    //Create a structure to hold the settings for our device
    D3DPRESENT_PARAMETERS d3dpp; 
    ZeroMemory(&d3dpp, sizeof(d3dpp));

    //Fill the structure. 
    //We want our program to be windowed, and set the back buffer to a format
    //that matches our current display mode
    d3dpp.Windowed = TRUE;//全屏模式还是窗口模式
    d3dpp.SwapEffect = D3DSWAPEFFECT_DISCARD;//后台缓冲区复制到前台时,清除后台缓冲区内容
    d3dpp.BackBufferFormat = d3ddm.Format;//屏幕的显示模式

	//创建一个Direct3D设备
    //Create a Direct3D device.
    if(FAILED(g_pD3D->CreateDevice(D3DADAPTER_DEFAULT, D3DDEVTYPE_HAL, hWnd, 
                                   D3DCREATE_SOFTWARE_VERTEXPROCESSING, &d3dpp, &g_pD3DDevice)))
    {
        return E_FAIL;
    }
    
    return S_OK;
}

HRESULT InitialiseVertexBuffer()
{
	VOID* pVertices;
	
	//顶点信息数组
	//Store each point of the triangle together with it's colour
	CUSTOMVERTEX cvVertices[] =
	{
		{250.0f, 100.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(255, 0, 0),},	//Vertex 1 - Red	(250, 100)
		{400.0f, 350.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 255, 0),},	//Vertex 2 - Green	(400, 350)
		{100.0f, 350.0f, 0.5f, 1.0f, D3DCOLOR_XRGB(0, 0, 255),},	//Vertex 3 - Blue	(100, 350)
	};

	//通过设备创建顶点缓冲
	//Create the vertex buffer from our device
	if(FAILED(g_pD3DDevice->CreateVertexBuffer(3 * sizeof(CUSTOMVERTEX),
                                               0, D3DFVF_CUSTOMVERTEX,
                                               D3DPOOL_DEFAULT, &g_pVertexBuffer,NULL)))
	{
		return E_FAIL;
	}

	//锁定顶点缓冲，并得到一个存放顶点信息的缓冲区的指针
	//Get a pointer to the vertex buffer vertices and lock the vertex buffer
	if(FAILED(g_pVertexBuffer->Lock(0, sizeof(cvVertices), (void**)&pVertices, 0)))
	{
		return E_FAIL;
	}

	//复制顶点信息
	//Copy our stored vertices values into the vertex buffer
	memcpy(pVertices, cvVertices, sizeof(cvVertices));

	//解锁顶点缓冲区
	//Unlock the vertex buffer
	g_pVertexBuffer->Unlock();

    return S_OK;
}

void Render()
{
    if(g_pD3DDevice == NULL)
    {
        return;
    }

    //Clear the backbuffer to black
	//清空后备缓冲区为黑色
    g_pD3DDevice->Clear(0, NULL, D3DCLEAR_TARGET, D3DCOLOR_XRGB(0, 0, 0), 1.0f, 0);
    
    //Begin the scene
	//开始绘制场景
    g_pD3DDevice->BeginScene();
    

    //Rendering our triangle
	//渲染三角形
	g_pD3DDevice->SetStreamSource(0, g_pVertexBuffer, 0, sizeof(CUSTOMVERTEX));
	g_pD3DDevice->SetFVF(D3DFVF_CUSTOMVERTEX);
	g_pD3DDevice->DrawPrimitive(D3DPT_TRIANGLELIST, 0, 1);


    //End the scene
	//结束绘制场景
    g_pD3DDevice->EndScene();
    
    //Filp the back and front buffers so that whatever has been rendered on the back buffer
    //will now be visible on screen (front buffer).
	//翻页显示
    g_pD3DDevice->Present(NULL, NULL, NULL, NULL);
}

//释放所使用到的所有COM对象
void CleanUp()
{
	SafeRelease(g_pVertexBuffer);
	SafeRelease(g_pD3DDevice);
	SafeRelease(g_pD3D);
}

//游戏循环
void GameLoop()
{
    //进入游戏循环
    MSG msg; 
    BOOL fMessage;

    PeekMessage(&msg, NULL, 0U, 0U, PM_NOREMOVE);
    
    while(msg.message != WM_QUIT)
    {
        fMessage = PeekMessage(&msg, NULL, 0U, 0U, PM_REMOVE);

        if(fMessage)
        {
            //处理消息
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        else
        {
            //No message to process, so render the current scene
			//如果没有消息，则渲染当前的场景
            Render();
        }

    }
}

int APIENTRY _tWinMain(HINSTANCE hInstance,
                     HINSTANCE hPrevInstance,
                     LPTSTR    lpCmdLine,
                     int       nCmdShow)
{
    //Register the window class
	//注册Windows的窗口类
    WNDCLASSEX wc = {sizeof(WNDCLASSEX), CS_CLASSDC, WndProc, 0L, 0L, 
                     GetModuleHandle(NULL), NULL, NULL, NULL, NULL,
                     "D3DDrawGraphics", NULL};
    RegisterClassEx(&wc);

    //Create the application's window
	//创建一个窗口
    HWND hWnd = CreateWindow("D3DDrawGraphics", "D3D绘制简单图形", 
                              WS_OVERLAPPEDWINDOW, 50, 50, 500, 500,
                              GetDesktopWindow(), NULL, wc.hInstance, NULL);

    //Initialize Direct3D
	//初始化Direct3D
    if(SUCCEEDED(InitialiseD3D(hWnd)))
    { 
        //Show our window
		//显示窗口
        ShowWindow(hWnd, SW_SHOWDEFAULT);
        UpdateWindow(hWnd);

		//Initialize Vertex Buffer
		//初始化顶点缓冲
		if(SUCCEEDED(InitialiseVertexBuffer()))
		{
			//Start game running: Enter the game loop
			//开始游戏: 进入游戏循环
			GameLoop();
		}
    }
    
    CleanUp();

	//撤销窗口类的注册
    UnregisterClass("D3DDrawGraphics", wc.hInstance);
    
    return 0;
}



//
//  函数: MyRegisterClass()
//
//  目的: 注册窗口类。
//
//  注释: 
//
//    仅当希望在已添加到 Windows 95 的
//    “RegisterClassEx”函数之前此代码与 Win32 系统兼容时，
//    才需要此函数及其用法。调用此函数
//    十分重要，这样应用程序就可以获得关联的
//   “格式正确的”小图标。
//
ATOM MyRegisterClass(HINSTANCE hInstance)
{
	WNDCLASSEX wcex;

	wcex.cbSize = sizeof(WNDCLASSEX); 

	wcex.style			= CS_HREDRAW | CS_VREDRAW;
	wcex.lpfnWndProc	= (WNDPROC)WndProc;
	wcex.cbClsExtra		= 0;
	wcex.cbWndExtra		= 0;
	wcex.hInstance		= hInstance;
	wcex.hIcon			= LoadIcon(hInstance, (LPCTSTR)IDI_MY);
	wcex.hCursor		= LoadCursor(NULL, IDC_ARROW);
	wcex.hbrBackground	= (HBRUSH)(COLOR_WINDOW+1);
	wcex.lpszMenuName	= (LPCTSTR)IDC_MY;
	wcex.lpszClassName	= szWindowClass;
	wcex.hIconSm		= LoadIcon(wcex.hInstance, (LPCTSTR)IDI_SMALL);

	return RegisterClassEx(&wcex);
}

//
//   函数: InitInstance(HANDLE, int)
//
//   目的: 保存实例句柄并创建主窗口
//
//   注释: 
//
//        在此函数中，我们在全局变量中保存实例句柄并
//        创建和显示主程序窗口。
//
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
   HWND hWnd;

   hInst = hInstance; // 将实例句柄存储在全局变量中

   hWnd = CreateWindow(szWindowClass, szTitle, WS_OVERLAPPEDWINDOW,
      CW_USEDEFAULT, 0, CW_USEDEFAULT, 0, NULL, NULL, hInstance, NULL);

   if (!hWnd)
   {
      return FALSE;
   }

   ShowWindow(hWnd, nCmdShow);
   UpdateWindow(hWnd);

   return TRUE;
}

//
//  函数: WndProc(HWND, unsigned, WORD, LONG)
//
//  目的: 处理主窗口的消息。
//
//  WM_COMMAND	- 处理应用程序菜单
//  WM_PAINT	- 绘制主窗口
//  WM_DESTROY	- 发送退出消息并返回
//
//
LRESULT CALLBACK WndProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch(message)
    {
        case WM_DESTROY:
            PostQuitMessage(0);
            return 0;
        break;
        case WM_KEYUP: 
            switch (wParam)
            { 
                case VK_ESCAPE:
                    //User has pressed the escape key, so quit
                    DestroyWindow(hWnd);
                    return 0;
                break;
            } 
        break;

    }

    return DefWindowProc(hWnd, message, wParam, lParam);
}

// “关于”框的消息处理程序。
LRESULT CALLBACK About(HWND hDlg, UINT message, WPARAM wParam, LPARAM lParam)
{
	switch (message)
	{
	case WM_INITDIALOG:
		return TRUE;

	case WM_COMMAND:
		if (LOWORD(wParam) == IDOK || LOWORD(wParam) == IDCANCEL) 
		{
			EndDialog(hDlg, LOWORD(wParam));
			return TRUE;
		}
		break;
	}
	return FALSE;
}