游戏引擎负责处理各种琐碎事务：组件游戏，确保它正确运行及关闭它。将游戏分解为事件：
下面这些事件只适用于任何游戏的部分核心事件：
● 初始化
● 启动
● 结束
● 激活
● 停用
● 绘制
● 循环
初始化事件在一开始运行游戏时发生，这时游戏执行重要的初始设置任务，包括创建游戏引擎本身。启动和结束事件对应于游戏的开始和结束，这时很适合执行与特定的游戏会话相关联的初始化和清理任务。在最小化游戏或者将其发送至后台，然后在恢复时，就将发生激活和停用事件。当游戏需要绘制自身时，将发送绘制事件，类似于WINDOWS WM_PAINT 消息。最后，循环事件使游戏执行一个单独的游戏周期，它非常重要。
游戏的计时机制：游戏在指定的时间内运行的周期越多，看起来就越平滑。事实上，大多数游戏设置都在15 － 16周期每秒的范围内，最快的速度可能达到30周期每秒，比电影还快。除了极少数的一些情况外，应该力求达到的最低速度设置为12周期每秒。
游戏引擎的类：
#ifndef _GAMEENGINE_H#define _GAMEENGINE_H#include <windows.h>//游戏事件BOOL GameInitialize(HINSTANCE hInstance); //初始化void GameStart(HWND hWnd); //启动void GameEnd(); //结束void GameActivate(HWND hWnd); //激活void GameDeactivate(HWND hWnd); //停用void GamePaint(HDC hdc); //绘制void GameCycle(); //循环//游戏引擎类class GameEngine
{
protected: static GameEngine * m_pGameEngine; //指向自身的静态指针 HINSTANCE m_hInstance; //实例句柄 HWND m_hWnd; //窗口句柄 TCHAR m_szWndClass[32]; //窗口类名 TCHAR m_szTitle[32]; //标题 WORD m_wIcon,m_wSmallIcon; //大小图标 int m_iWidth,m_iHeight; //游戏区的宽和高 int m_iFrameDelay; //帧的延迟时间(ms) BOOL m_bSleep; //休眠状态public: GameEngine(HINSTANCE hInstance,LPTSTR szWndClass,LPTSTR szTitle, WORD wIcon,WORD wSmallIcon,int iWidth=640,int iHeight=480); ~GameEngine();
static GameEngine * GetEngine() { return m_pGameEngine;};
BOOL Initialize(int iCmdShow); LRESULT HandlEvent(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam); HINSTANCE GetInstance() { return m_hInstance ;}; HWND GetWindow() { return m_hWnd;}; void SetWindow(HWND hWnd){ m_hWnd=hWnd ;}; LPSTR 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 SetFrameDelay(int iFrameRate){ m_iFrameDelay=1000/iFrameRate;}; BOOL GetSleep(){ return m_bSleep;}; void SetSleep(BOOL bSleep){ m_bSleep=bSleep;};
};LRESULT CALLBACK WndProc(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam);#endif其实现文件如下：
#include "GameEngine.h"//静态成员初始化GameEngine * GameEngine::m_pGameEngine=NULL;//构造成员函数GameEngine::GameEngine(HINSTANCE hInstance,LPSTR szWndClass,LPSTR szTitle, WORD wIcon,WORD wSmallIcon,int iWidth,int iHeight){ m_pGameEngine=this; m_hInstance=hInstance; m_hWnd=NULL; if(lstrlen(szWndClass)>0) lstrcpy(m_szWndClass,szWndClass); if(lstrlen(szTitle)>0) lstrcpy(m_szTitle,szTitle); m_wIcon=wIcon; m_wSmallIcon=wSmallIcon; m_iWidth=iWidth; m_iHeight=iHeight; m_iFrameDelay=50; //默认为20帧每妙 m_bSleep=TRUE;}//析构成员函数GameEngine::~GameEngine(){}//引擎初始化BOOL GameEngine::Initialize(int iCmdShow){ WNDCLASSEX wc; //创建主窗口的类 wc.cbSize=sizeof(WNDCLASSEX); wc.style=CS_HREDRAW|CS_VREDRAW; wc.lpfnWndProc=WndProc; wc.cbClsExtra=0; wc.cbWndExtra=0; wc.hbrBackground=(HBRUSH)(COLOR_WINDOW+1); wc.hCursor=LoadCursor(NULL,IDC_ARROW); wc.hIcon=LoadIcon(m_hInstance,MAKEINTRESOURCE(GetIcon())); wc.hIconSm=LoadIcon(m_hInstance,MAKEINTRESOURCE(GetSmallIcon())); wc.hInstance=m_hInstance; wc.lpszClassName=m_szWndClass; wc.lpszMenuName=NULL; //注册窗口类 if(!RegisterClassEx(&wc)) 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; int iWindowHeight=m_iHeight+GetSystemMetrics(SM_CYFIXEDFRAME)*2+GetSystemMetrics(SM_CYCAPTION); if(wc.lpszMenuName!=NULL) iWindowHeight+=GetSystemMetrics(SM_CYMENU); int iXWindowPos=(GetSystemMetrics(SM_CXSCREEN)-iWindowWidth)/2; int iYWindowPos=(GetSystemMetrics(SM_CYSCREEN)-iWindowHeight)/2; //创建窗口 m_hWnd=CreateWindow(m_szWndClass,m_szTitle,WS_POPUPWINDOW|WS_CAPTION|WS_MINIMIZEBOX,iXWindowPos,iYWindowPos, iWindowWidth,iWindowHeight,NULL,NULL,m_hInstance,NULL); if(!m_hWnd) return FALSE; //显示和更新窗口 ShowWindow(m_hWnd,iCmdShow); UpdateWindow(m_hWnd); return TRUE;}//游戏消息处理函数LRESULT GameEngine::HandlEvent(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam){ switch(msg) { case WM_CREATE: //设置游戏窗口并开始游戏 SetWindow(hWnd); GameStart(hWnd); return 0; case WM_SETFOCUS: //激活游戏并更新休眠状态 GameActivate(hWnd); SetSleep(FALSE); return 0; case WM_KILLFOCUS: //停用游戏并更新休眠状态 GameDeactivate(hWnd); SetSleep(TRUE); return 0; case WM_PAINT: HDC hDc; PAINTSTRUCT ps; hDc=BeginPaint(hWnd,&ps); //绘制游戏 GamePaint(hDc); EndPaint(hWnd,&ps); return 0; case WM_DESTROY: //结束游戏 GameEnd(); PostQuitMessage(0); return 0;
} return DefWindowProc(hWnd,msg,wParam,lParam);}LRESULT CALLBACK WndProc(HWND hWnd,UINT msg,WPARAM wParam,LPARAM lParam){ return GameEngine::GetEngine()->HandlEvent(hWnd,msg,wParam,lParam);}//主函数入口int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPreInstance,PSTR szCommandLine,int iCmdShow ){ MSG msg; static int iTickTriger=0; int iTickCount; if(GameInitialize(hInstance)) { if(!GameEngine::GetEngine()->Initialize(iCmdShow)) return FALSE; while(TRUE) { if(PeekMessage(&msg,NULL,0,0,PM_REMOVE)) { if(msg.message==WM_QUIT) break; TranslateMessage(&msg); DispatchMessage(&msg); } else { //确保游戏引擎没有休眠 if(!GameEngine::GetEngine()->GetSleep()) { //检查滴答计数,查看是否经历了一个周期 iTickCount=GetTickCount(); if(iTickCount>iTickTriger) { iTickTriger=iTickCount+GameEngine::GetEngine()->GetFrameDelay(); //游戏循环 GameCycle(); } } } } } //游戏结束 GameEnd(); return TRUE;}其使用方法：
xxx.h文件要先声明一个全局游戏引擎指针。
#include "resource.h"#include "GameEngine.h"GameEngine * g_pGame; //全局游戏引擎指针然后xxx.cpp文件包含该xxx.h文件，在实现相应的游戏事件：
#include "Blizzard.h"BOOL GameInitialize(HINSTANCE hInstance){ g_pGame=new GameEngine(hInstance,TEXT("PRIZE"),TEXT("PRIZE"),IDI_PRIZE,IDI_PRIZE); if(g_pGame==NULL) return FALSE; g_pGame->SetFrameDelay(15); return TRUE;}void GameStart(HWND hWnd){ srand(GetTickCount());}void GameEnd(){}void GameActivate(HWND hWnd){ HDC hDc; RECT rect; GetClientRect(hWnd,&rect); hDc=GetDC(hWnd); DrawText(hDc,"Here comes ....",-1,&rect,DT_SINGLELINE|DT_CENTER|DT_VCENTER); ReleaseDC(hWnd,hDc);}void GameDeactivate(HWND hWnd){}void GamePaint(HDC hdc){}void GameCycle(){ HDC hDc; HWND hWnd=g_pGame->GetWindow(); hDc=GetDC(hWnd); DrawIcon(hDc,rand()%g_pGame->GetWidth(),rand()%g_pGame->GetHeight(),(HICON)(WORD)GetClassLong(hWnd,GCL_HICON)); ReleaseDC(hWnd,hDc);}