【如何用C++编程制作一个简单的游戏引擎】

1. 写一个游戏引擎类的头文件（.h）；
2. 写一个游戏引擎类的实现文件（.cpp）；
3. 在编程中如何调用游戏引擎。

一 、在VS2015中新建一个 Visual C++ 常规空项目，添加一个游戏引擎头文件实现文件。详细步骤如下：

 二 、游戏引擎头文件 GameEngine.h 源代码：

#pragma once
#include 


int WINAPI        WinMain(HINSTANCE hInstance,
	HINSTANCE hPrevInstance,
	PSTR szCmdLine,
	int iCmdShow);

LRESULT CALLBACK  WndProc(HWND hWnd,
	UINT msg,
	WPARAM wParam,
	LPARAM lParam);

BOOL GameInitialize(HINSTANCE hInstance);
void GameStart(HWND hWindow);
void GameEnd();
void GameActivate(HWND hWindow);
void GameDeactivate(HWND hWindow);
void GamePaint(HDC hDC);
void GameCycle();

class GameEngine
{
protected:
	//成员变量
	static GameEngine*  m_pGameEngine;
	HINSTANCE           m_hInstance;
	HWND                m_hWindow;
	TCHAR               m_szWindowClass[32];
	TCHAR               m_szTitle[32];
	WORD                m_wIcon, m_wSmallIcon;
	int                 m_iWidth, m_iHeight;
	int                 m_iFrameDelay;
	BOOL                m_bSleep;

public:
	//构造函数/析构函数
	GameEngine(HINSTANCE hInstance, LPTSTR szWindowClass, LPTSTR szTitle,
		WORD wIcon, WORD wSmallIcon, int iWidth = 640, int iHeight = 480);
	virtual ~GameEngine();

	
	static GameEngine*  GetEngine() { return m_pGameEngine; };
	BOOL                Initialize(int iCmdShow);
	LRESULT             HandleEvent(HWND hWindow, UINT msg, WPARAM wParam,
		LPARAM lParam);

	
	HINSTANCE GetInstance() { return m_hInstance; };
	HWND      GetWindow() { return m_hWindow; };
	void      SetWindow(HWND hWindow) { m_hWindow = hWindow; };
	LPTSTR    GetTitle() { return m_szTitle; };
	WORD      GetIcon() { return m_wIcon; };
	WORD      GetSmallIcon() { return m_wSmallIcon; };
	int       GetWidth() { return m_iWidth; };
	int       GetHeight() { return m_iHeight; };
	int       GetFrameDelay() { return m_iFrameDelay; };
	void      SetFrameRate(int iFrameRate) {
		m_iFrameDelay = 1000 / iFrameRate;
	};
	BOOL      GetSleep() { return m_bSleep; };
	void      SetSleep(BOOL bSleep) { m_bSleep = bSleep; };
};

三 、游戏引擎实现文件 GameEngine.cpp 源代码：

#include "GameEngine.h"

GameEngine *GameEngine::m_pGameEngine = NULL;

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance,PSTR szCmdLine, int iCmdShow)
{
	MSG         msg;
	static int  iTickTrigger = 0;
	int         iTickCount;

	if (GameInitialize(hInstance))
	{
		// 初始化游戏引擎
		if (!GameEngine::GetEngine()->Initialize(iCmdShow))
			return FALSE;

		// 进入主消息循环
		while (TRUE)
		{
			if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE))
			{
				// 处理消息
				if (msg.message == WM_QUIT)
					break;
				TranslateMessage(&msg);
				DispatchMessage(&msg);
			}
			else
			{
				//确保游戏引擎没有处在休眠状态
				if (!GameEngine::GetEngine()->GetSleep())
				{
					// Check the tick count to see if a game cycle has elapsed
					iTickCount = GetTickCount();
					if (iTickCount > iTickTrigger)
					{
						iTickTrigger = iTickCount +
							GameEngine::GetEngine()->GetFrameDelay();
						GameCycle();
					}
				}
			}
		}
		return (int)msg.wParam;
	}

	// 结束游戏
	GameEnd();

	return TRUE;
}

LRESULT CALLBACK WndProc(HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam)
{
	// 将所有Windows消息路由到游戏引擎
	return GameEngine::GetEngine()->HandleEvent(hWindow, msg, wParam, lParam);
}

//-----------------------------------------------------------------
// 游戏引擎的构造函数/析构函数
//-----------------------------------------------------------------
GameEngine::GameEngine(HINSTANCE hInstance, LPTSTR szWindowClass,
	LPTSTR szTitle, WORD wIcon, WORD wSmallIcon, int iWidth, int iHeight)
{
	// 设置游戏引擎的成员变量
	m_pGameEngine = this;
	m_hInstance = hInstance;
	m_hWindow = NULL;
	if (lstrlen(szWindowClass) > 0)
		lstrcpy(m_szWindowClass, szWindowClass);
	if (lstrlen(szTitle) > 0)
		lstrcpy(m_szTitle, szTitle);
	m_wIcon = wIcon;
	m_wSmallIcon = wSmallIcon;
	m_iWidth = iWidth;
	m_iHeight = iHeight;
	m_iFrameDelay = 50;   // 游戏周期,一般设为20帧/秒
	m_bSleep = TRUE;
}

GameEngine::~GameEngine()
{
}


BOOL GameEngine::Initialize(int iCmdShow)
{
	WNDCLASSEX    wndclass;

	// 为主窗口创建窗口类
	wndclass.cbSize = sizeof(wndclass);
	wndclass.style = CS_HREDRAW | CS_VREDRAW;
	wndclass.lpfnWndProc = WndProc;
	wndclass.cbClsExtra = 0;
	wndclass.cbWndExtra = 0;
	wndclass.hInstance = m_hInstance;
	wndclass.hIcon = LoadIcon(m_hInstance,
		MAKEINTRESOURCE(GetIcon()));
	wndclass.hIconSm = LoadIcon(m_hInstance,
		MAKEINTRESOURCE(GetSmallIcon()));
	wndclass.hCursor = LoadCursor(NULL, IDC_ARROW);
	wndclass.hbrBackground = (HBRUSH)(COLOR_WINDOW + 1);
	wndclass.lpszMenuName = NULL;
	wndclass.lpszClassName = m_szWindowClass;

	// 注册窗口类
	if (!RegisterClassEx(&wndclass))
		return FALSE;

	// 根据游戏大小计算窗口大小和位置
	int iWindowWidth = m_iWidth + GetSystemMetrics(SM_CXFIXEDFRAME) * 2,
		iWindowHeight = m_iHeight + GetSystemMetrics(SM_CYFIXEDFRAME) * 2 +
		GetSystemMetrics(SM_CYCAPTION);
	if (wndclass.lpszMenuName != NULL)
		iWindowHeight += GetSystemMetrics(SM_CYMENU);
	int iXWindowPos = (GetSystemMetrics(SM_CXSCREEN) - iWindowWidth) / 2,
		iYWindowPos = (GetSystemMetrics(SM_CYSCREEN) - iWindowHeight) / 2;

	// 创建窗口
	m_hWindow = CreateWindow(m_szWindowClass, m_szTitle, WS_POPUPWINDOW |
		WS_CAPTION | WS_MINIMIZEBOX, iXWindowPos, iYWindowPos, iWindowWidth,
		iWindowHeight, NULL, NULL, m_hInstance, NULL);
	if (!m_hWindow)
		return FALSE;

	// 显示并更新窗口
	ShowWindow(m_hWindow, iCmdShow);
	UpdateWindow(m_hWindow);

	return TRUE;
}

LRESULT GameEngine::HandleEvent(HWND hWindow, UINT msg, WPARAM wParam, LPARAM lParam)
{
	// 将Windows消息路由到游戏引擎成员函数
	switch (msg)
	{
	case WM_CREATE:
		// 设置游戏窗口并开始游戏
		SetWindow(hWindow);
		GameStart(hWindow);
		return 0;

	case WM_SETFOCUS:
		//激活游戏并更新睡眠状态
		GameActivate(hWindow);
		SetSleep(FALSE);
		return 0;

	case WM_KILLFOCUS:
		// 停用游戏并更新睡眠状态
		GameDeactivate(hWindow);
		SetSleep(TRUE);
		return 0;

	case WM_PAINT:
		HDC         hDC;
		PAINTSTRUCT ps;
		hDC = BeginPaint(hWindow, &ps);

		// 绘制游戏
		GamePaint(hDC);

		EndPaint(hWindow, &ps);
		return 0;

	case WM_DESTROY:
		// 结束游戏并退出应用程序
		GameEnd();
		PostQuitMessage(0);
		return 0;
	}
	return DefWindowProc(hWindow, msg, wParam, lParam);
}

四 、调用游戏引擎，添加一个要做的游戏应用文件 FIRSTGAME.cpp 源码如下：

#pragma once

#include 
#include "Resource.h"
#include "GameEngine.h"

GameEngine* g_pGame;

BOOL GameInitialize(HINSTANCE hInstance)
{
	// 创建游戏引擎
	g_pGame = new GameEngine(hInstance, TEXT("第一个游戏"),
		TEXT("第一个游戏"), IDI_ICON1, IDI_ICON2);
                           //IDI_ICON1, IDI_ICON2 这是建立游戏资源.ico后缀图片的ID
	if (g_pGame == NULL)
		return FALSE;

	// 设定游戏速度为15帧/秒
	g_pGame->SetFrameRate(15);

	return TRUE;
}

void GameStart(HWND hWindow)
{
	
}

void GameEnd()
{
	// 清理游戏引擎
	delete g_pGame;
}

void GameActivate(HWND hWindow)
{
	HDC   hDC;
	RECT  rect;

	// 在游戏屏幕上绘制激活文本
	GetClientRect(hWindow, &rect);
	hDC = GetDC(hWindow);
	DrawText(hDC, TEXT("第一个游戏开始!"), -1, &rect,
		DT_SINGLELINE | DT_CENTER | DT_VCENTER);
	ReleaseDC(hWindow, hDC);
}

void GameDeactivate(HWND hWindow)
{
	HDC   hDC;
	RECT  rect;

	// 在游戏屏幕上绘制激停文本
	GetClientRect(hWindow, &rect);
	hDC = GetDC(hWindow);
	DrawText(hDC, TEXT("第一个游戏结束!"), -1, &rect,
		DT_SINGLELINE | DT_CENTER | DT_VCENTER);
	ReleaseDC(hWindow, hDC);
}

void GamePaint(HDC hDC)
{
}

void GameCycle()
{
	HDC   hDC;
	HWND  hWindow = g_pGame->GetWindow();

	// 在游戏屏幕上的任意位置绘制游戏图标
	hDC = GetDC(hWindow);
	DrawIcon(hDC,200,200,(HICON)(WORD)GetClassLong(hWindow, GCL_HICON));
	ReleaseDC(hWindow, hDC);
}

五 、编译后运行画面：

六 、源代码出自如下书籍资料：

1.游戏编程精粹     作者：(美) Michael Dickheiser著

2.游戏编程入门    作者：(美) Michael Morrison著