一个简易的屏幕保护程序

// DEMO3_1.CPP - Demo of loading an icon and cursor resource

// INCLUDES ///////////////////////////////////////////////

#define WIN32_LEAN_AND_MEAN // just say no to MFC

#include <windows.h> // include all the windows headers

#include <windowsx.h> // include useful macros

#include <mmsystem.h>

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include<tchar.h>

//#include "DEMO3_1RES.H" // include the resource header

// DEFINES ////////////////////////////////////////////////

// defines for windows

#define WINDOW_CLASS_NAME "WINCLASS1"

#define WINDOW_WIDTH 480

#define WINDOW_HEIGHT 640

// GLOBALS ////////////////////////////////////////////////

HWND main_window_handle = NULL;

HINSTANCE main_instance = NULL;

#define KEYDOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0)

#define KEYUP(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1)

// FUNCTIONS //////////////////////////////////////////////

//LRESULT CALLBACK TimerProc(HWND)

LRESULT CALLBACK WindowProc(HWND hwnd,

UINT msg,

WPARAM wparam,

LPARAM lparam)

{

// this is the main message handler of the system

PAINTSTRUCT ps; // used in WM_PAINT

HDC hdc; // handle to a device context

//TCHAR buffer[80];

// what is the message

switch(msg)

{

case WM_CREATE:

{

// do initialization stuff here

// return success

return(0);

} break;

case WM_PAINT:

{

// simply validate the window

hdc = BeginPaint(hwnd,&ps);

// you would do all your painting here

EndPaint(hwnd,&ps);

// return success

return(0);

} break;

//////调用顺序：WM_CLOSE---->WM_DESTROY--->WM_QUIT

case WM_DESTROY:

{

// kill the application, this sends a WM_QUIT message

PostQuitMessage(0);

// return success

return(0);

} break;

default:break;

} // end switch

// process any messages that we didn't take care of

return (DefWindowProc(hwnd, msg, wparam, lparam));

} // end WinProc



///start game main

void Game_Main()

{

}

// WINMAIN ////////////////////////////////////////////////

int WINAPI WinMain( HINSTANCE hinstance,

HINSTANCE hprevinstance,

LPSTR lpcmdline,

int ncmdshow)

{

WNDCLASSEX winclass; // this will hold the class we create

HWND hwnd; // generic window handle

MSG msg; // generic message

HDC hdc;

HPEN pen;

int color_change_count = 100;///这里设置为0运行速度会很慢，估计是因为一开始就要调用函数创建画笔，消耗了时间

// first fill in the window class stucture

winclass.cbSize = sizeof(WNDCLASSEX);

winclass.style = CS_DBLCLKS | CS_OWNDC |

CS_HREDRAW | CS_VREDRAW;

winclass.lpfnWndProc = WindowProc;

winclass.cbClsExtra = 0;

winclass.cbWndExtra = 0;

winclass.hInstance = hinstance;

winclass.hIcon = LoadIcon(hinstance, IDI_APPLICATION);

winclass.hCursor = LoadCursor(hinstance, IDC_ARROW);

winclass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);

winclass.lpszMenuName = NULL;

winclass.lpszClassName = WINDOW_CLASS_NAME;

winclass.hIconSm = LoadIcon(hinstance, IDI_APPLICATION);

// register the window class

if (!RegisterClassEx(&winclass))

return(0);

// create the window

if (!(hwnd = CreateWindowEx(NULL, // extended style

WINDOW_CLASS_NAME, // class

"Demo of Custom Cursor and Icon", // title

WS_OVERLAPPEDWINDOW | WS_VISIBLE,

0,0, // initial x,y

400,400,

//GetSystemMetrics(SM_CXFULLSCREEN),

//GetSystemMetrics(SM_CYFULLSCREEN), // initial width, height

NULL, // handle to parent

NULL, // handle to menu

hinstance,// instance of this application

NULL))) // extra creation parms

return(0);

main_window_handle = hwnd;

main_instance = hinstance;

hdc = GetDC(hwnd);

//用法：它需要提供一个种子，这个种子会对应一个随机数，如果使用相同的种子后面的rand()函数会出现一样的随机数。

//如： srand(1); 直接使用1来初始化种子。不过为了防止随机数每次重复常常使用系统时间来初始化

srand(GetTickCount());

///endpoints of line

int x1 = rand()%WINDOW_WIDTH;

int y1 = rand()%WINDOW_HEIGHT;

int x2 = rand()%WINDOW_WIDTH;

int y2 = rand()%WINDOW_HEIGHT;

//intial velocity of each end

int x1v = -4 + rand()%8;

int y1v = -4 + rand()%8;

int x2v = -4 + rand()%8;

int y2v = -4 + rand()%8;

// enter main event loop, but this time we use PeekMessage()

// instead of GetMessage() to retrieve messages

while(TRUE)

{

DWORD start_time = GetTickCount();

// test if there is a message in queue, if so get it

if (PeekMessage(&msg,NULL,0,0,PM_REMOVE))

{

// test if this is a quit

if (msg.message == WM_QUIT)

break;



// translate any accelerator keys

TranslateMessage(&msg);

// send the message to the window proc

DispatchMessage(&msg);

} // end if

//is it time to change color?

if (++color_change_count >= 100)

{

color_change_count = 0;

//create a random color pen

if (pen)

DeleteObject(pen);

//create a new pen

pen = CreatePen(PS_SOLID,1,RGB(rand()%256,rand()%256,rand()%256));

SelectObject(hdc,pen);

}///end if

///move endpoints of line

x1 += x1v;

y1 += y1v;

x2 += x2v;

y2 += y2v;

/////test if either end hit window edge

////涉及碰撞理论的处理方法

if(x1 < 0 || x1 >= WINDOW_WIDTH)

{

///invert velocity

x1v = -x1v;

///bum endpoint back

x1 += x1v;

}///end if

if(y1 < 0 || y1 >= WINDOW_WIDTH)

{

///invert velocity

y1v = -y1v;

////bum endpoint back

y1 += y1v;

}///end if

if(x2 < 0 || x2 >= WINDOW_WIDTH)

{

///invert velocity

x2v = -x2v;

///bum endpoint back

x2 += x2v;

}///end if

if(y2 < 0 || y2 >= WINDOW_HEIGHT)

{

////invert velocity

y2v = -y2v;

y2 += y2v;

}

///move to end one of line

MoveToEx(hdc,x1,y1,NULL);

///draw to the other end

LineTo(hdc ,x2,y2);

////lock time to 30 fps which is aprox ,33 milliseconds

while((GetTickCount() - start_time) < 33) ////还是未理解在这里这样写的好处，望各位发表高见

;



// main game processing goes here

//Game_Main(); // or whatever your loop is called

if(KEYDOWN(VK_ESCAPE))

SendMessage(hwnd,WM_CLOSE,0,0);

} // end while

ReleaseDC(hwnd,hdc);

// return to Windows like this

return(msg.wParam);

} // end WinMain

///////////////////////////////////////////////////////////