ELS square movement

1、 The main function （els.main.c）

#include<Windows.h>
#include"resource.h"
#include"els_h.h"
LRESULT CALLBACK PELouSi(HWND hWnd, UINT oMsg, WPARAM wParam, LPARAM lParam);
int WINAPI WinMain(HINSTANCE hInstance,HINSTANCE hPreInstance,LPSTR ipCmdLine,int nCmdShow)
{
    // Initialize window class .
    WNDCLASSEX  db;
    HWND hWnd;
    MSG msg;// Structural variable .

    db.cbClsExtra = 0;
    db.cbSize = sizeof(WNDCLASSEX);
    db.cbWndExtra = 0;

    db.hbrBackground = (HBRUSH)COLOR_BACKGROUND;// The background color .
    
    // Return value ： Handle of mouse .
    // Parameters 1： If the system cursor is loaded ,NULL、 If you load a custom cursor , Fill in the real column handle ,hInstance; Parameters 2： System cursor , Fill in the defined macro directly 、 If you load a custom cursor , Just use MAKEINTRESOURCE(240) Load the corresponding resources ID.
    //db.hCursor = LoadCursor(NULL,IDC_HAND);// Load the system defined cursor .
    db.hCursor = LoadCursor(hInstance,MAKEINTRESOURCE (IDC_NODROP));// Customized cursor . Resource file -> add to -> resources ->Cursor->IDC_NODROP-> newly build .
    
    // Return value ： Handle to icon .
    // Parameters 1： If the system cursor is loaded ,NULL、 If you load a custom cursor , Fill in the real column handle ,hInstance; Parameters 2： System cursor , Fill in the defined macro directly 、 If you load a custom cursor , Just use MAKEINTRESOURCE(240) Load the corresponding resources ID.
    //db.hIcon = LoadIcon(NULL,IDI_ASTERISK);// Load the system defined cursor .
    db.hIcon = LoadIcon(hInstance,MAKEINTRESOURCE(IDI_ICON1));// Status bar icons .
    
    //db.hIconSm = NULL;// The icon in the upper left corner is defined for this . If it is blank, it defaults to the status bar icon .
    db.hIconSm = LoadIcon(NULL,IDI_HAND);
    db.hInstance = hInstance;
    db.lpfnWndProc = PELouSi;// Callback function name .
    db.lpszClassName = "els";
    db.lpszMenuName = NULL;
    db.style = CS_HREDRAW | CS_VREDRAW;

    if(0==RegisterClassEx(&db))
    {
        int a = GetLastError();
        return 0;
    }

    // create a window .hWnd Window handle Failure to return NULL. 
    // Window style ： Parameters 4.
    hWnd=CreateWindowEx(WS_EX_TOPMOST,"els","els square ",WS_OVERLAPPEDWINDOW,100,100,500,600,NULL,NULL,hInstance,NULL);

    if (NULL == hWnd)// Window handle . Unique identification of the window .
    {

        return 0;
    }

    // Display window
    ShowWindow(hWnd, nCmdShow);
    
    // Message loop . queue .
    while(GetMessage(&msg, NULL, 0, 0))
    {
        TranslateMessage(&msg);
        DispatchMessage(&msg);
    }
    return 0;
}
    // Callback function
    // Return value ：LRESULT,CALLBACK Calling convention .
    // Parameters 1： Window handle ; Parameters 2： news ID.
LRESULT CALLBACK PELouSi(HWND hWnd, UINT nMsg, WPARAM wParam, LPARAM lParam)// LRESULT:long type ;UINT： Unsigned integer , News ID.
{
    PAINTSTRUCT pt;// Defining structure .
    HDC hDc;
    // Close window message
    switch (nMsg)
    {
    case WM_CREATE:// The first message received by the window information handler , It is also the first message processed by the callback function ( by WM_CREATE). This message is generated only once , It is generally used to initialize some data .
        //GetLastError();// Optimize .
        Oncreate();// Game data initialization .
        break;
    case WM_TIMER:
        OnTimer(hWnd);
        break;
    // Is the second message processed by the callback function ( by WM_PAINT).
    // When a part of the display area of the window changes to （ Invalid ）, So much so that （ Update the screen ） when , The program will be notified by this message .
    // The last member of the window structure CS_HREDRAW|CS_VREDRAW, The purpose is when the window size changes , produce WM_PAINT news .
    // When windows overlap , When the overlap gradually appears .
    case WM_PAINT:
        //GetLastError();// Optimize .
        hDc=BeginPaint(hWnd,&pt);//getDC, Identification of window operable area .
        // Draw the contents of the window in between .
        // Draw squares .
        OnPaint(hDc);// Increase code readability .
        
        EndPaint(hWnd, &pt);// end .
        break;
    case WM_KEYDOWN:
        switch (wParam)
        {
        case VK_RETURN:
            OnReturn(hWnd);
            break;
        case VK_LEFT:
                break;
        case VK_RIGHT:
                break;
        case VK_UP:
                break;
        case VK_DOWN:
                break;
        }
        break;
    case WM_DESTROY:
        KillTimer(hWnd, DEF_TIMER1);
            PostQuitMessage(0);// call PostQuitMessage(0) This function emits WM_QUIT news .// The point and fork system generates WM_CLOSE,WM_DESTROY,WM_QUIT.
            break;
        
    }// Manually handle the cross off message .

    return DefWindowProc(hWnd, nMsg, wParam, lParam);
    //LRESULT a=DefWindowProc(hWnd, oMsg, wParam, lParam);// function
    //return a;
}

2、 Head function （els.h）

#ifndef N_d
#define N_d

#include<Windows.h>
#include<time.h>
#define DEF_TIMER1 1234
void OnPaint(HDC hDc);
// Display box .
void PaintSqare(HDC hMemDC);
// Generate random blocks .
int CreateRandomSqare();
// Random blocks close to the background .
void  CopySqareToBack();

void Oncreate();

// Enter key .
void OnReturn(HWND hWnd);
// The fall of the square .
void SqareDwon();
// Timer response function .
void OnTimer(HWND hWnd);

#endif

3、 Function implementation (els.c)

#include"els_h.h"
// Background array
char g_arrBackGroud[20][10] = {0};
char g_arrSqare[2][4] = {0};

void OnPaint(HDC hDc)
{
    // Create compatibility DC.
    HDC hMemDC = CreateCompatibleDC(hDc);// Memory id by ：HMemDc, window id hDc.

    // Create compatibility bitmap .
    HBITMAP hBitmapBack= CreateCompatibleBitmap(hDc, 500, 600);

    // Connect .
    SelectObject(hMemDC, hBitmapBack);

    PaintSqare(hMemDC);
    
    // Pass on ：
    // Return value ： Failure to return 0, Successfully returned non-zero .
    // Parameters 1： The goal is DC, window DC
    // Parameters 2,3： The starting position of the target , Attention is based on our window .
    // Parameters 4,5： The size of the area .
    // Parameters 6： Source DC, That is, our memory DC.
    // Parameters 7,8： The starting position of the memory picture .
    // Parameters 9： delivery .
    //
    BitBlt(hDc, 0, 0, 300, 600, hMemDC, 0, 0, SRCCOPY);

    // Release DC
    DeleteObject(hBitmapBack);
    DeleteDC(hMemDC);
    
    
}
void Oncreate()
{
    srand((unsigned int)time(NULL));// Only once .
    CreateRandomSqare();
    CopySqareToBack();
}
void PaintSqare(HDC hMemDC)
{
    int i = 0,
        j = 0;

    // Draw a big square .
    Rectangle(hMemDC, 0, 0, 300, 600);// The coordinates of the starting position and the ending position of the rectangular box from the running window .
    
    // Specify a square .
    /*g_arrBackGroud[2][4] = 1;
    g_arrBackGroud[3][3] = 1;
    g_arrBackGroud[3][4] = 1;
    g_arrBackGroud[3][5] = 1;*/

    // Traverse
    for (i=0 ; i < 20; i++)
    {
        for (j=0 ; j < 10; j++)
        {
            if (1 == g_arrBackGroud[i][j])
            {
                // Draw squares .
                Rectangle(hMemDC, j*30, i*30, j*30 + 30, i*30 + 30);// The coordinates of the starting position and the ending position of the rectangular box from the running window .

            }
        }
    }

}
// Create random block .
int CreateRandomSqare()
{
    int nIndex=rand()%7;
    switch (nIndex)
    {
    case 0:
        g_arrBackGroud[0][0] = 1, g_arrBackGroud[0][1] = 1, g_arrBackGroud[0][2] = 0, g_arrBackGroud[0][3] = 0;
        g_arrBackGroud[1][0] = 0, g_arrBackGroud[1][1] = 1, g_arrBackGroud[1][2] = 1, g_arrBackGroud[1][3] = 0;
        break;
    case 1:
        g_arrBackGroud[0][0] = 0, g_arrBackGroud[0][1] = 1, g_arrBackGroud[0][2] = 1, g_arrBackGroud[0][3] = 0;
        g_arrBackGroud[1][0] = 1, g_arrBackGroud[1][1] = 1, g_arrBackGroud[1][2] = 0, g_arrBackGroud[1][3] = 0;

        break;
    case 2:
        g_arrBackGroud[0][0] = 1, g_arrBackGroud[0][1] = 0, g_arrBackGroud[0][2] = 0, g_arrBackGroud[0][3] = 0;
        g_arrBackGroud[1][0] = 1, g_arrBackGroud[1][1] = 1, g_arrBackGroud[1][2] = 1, g_arrBackGroud[1][3] = 0;

        break;
    case 3:
        g_arrBackGroud[0][0] = 0, g_arrBackGroud[0][1] =0 , g_arrBackGroud[0][2] = 1, g_arrBackGroud[0][3] = 0;
        g_arrBackGroud[1][0] = 1, g_arrBackGroud[1][1] = 1, g_arrBackGroud[1][2] = 1, g_arrBackGroud[1][3] = 0;

        break;
    case 4:
        g_arrBackGroud[0][0] = 0, g_arrBackGroud[0][1] = 1, g_arrBackGroud[0][2] = 0, g_arrBackGroud[0][3] = 0;
        g_arrBackGroud[1][0] = 1, g_arrBackGroud[1][1] = 1, g_arrBackGroud[1][2] = 1, g_arrBackGroud[1][3] = 0;

        break;
    case 5:
        g_arrBackGroud[0][0] = 0, g_arrBackGroud[0][1] = 1, g_arrBackGroud[0][2] = 1, g_arrBackGroud[0][3] = 0;
        g_arrBackGroud[1][0] = 0, g_arrBackGroud[1][1] = 1, g_arrBackGroud[1][2] = 1, g_arrBackGroud[1][3] = 0;

        break;
    case 6:
        g_arrBackGroud[0][0] = 1, g_arrBackGroud[0][1] = 1, g_arrBackGroud[0][2] = 1, g_arrBackGroud[0][3] = 1;
        g_arrBackGroud[1][0] = 0, g_arrBackGroud[1][1] = 0, g_arrBackGroud[1][2] = 0, g_arrBackGroud[1][3] = 0;

        break;
    
    }
    return nIndex;
}
void  CopySqareToBack()
{
    int i = 0,
        j = 0;
    for (i = 0; i < 2; i++)
    {
        for (j = 0; j < 4; j++)
        {
            g_arrBackGroud[i][j + 3] = g_arrSqare[i][j];
        }
    }
}
void OnReturn(HWND hWnd)
{
    // Start timer
// Return value ： Successfully returned non-zero .
// Parameters 1： Window handle hWnd,NUL
// Parameters 2： Timer ID   Ignore
// Parameters 3： Time interval between , millisecond 1000ms=1s.
// Parameters 4： Set to NULL Address of processing function .
    SetTimer(hWnd, DEF_TIMER1, 500, NULL);

}

void SqareDwon()
{
    int i = 0,
        j = 0;
    for (i = 19; i >=0; i--)
    {
        for (j = 0; j < 10; j++)
        {
            if (1==g_arrBackGroud[i][j])
            {
                g_arrBackGroud[i + 1][j] = g_arrBackGroud[i][j];
                g_arrBackGroud[i][j]=0;
            }
        }
    }
}

void OnTimer(HWND hWnd)
{
    HDC hDc=GetDC(hWnd);// Kernel object .
    SqareDwon();
    // Display box ：
    //PaintSqare(hDc);
    OnPaint(hDc);
    ReleaseDC(hWnd, hDc);
}