Hi I am compiling Win32 C++ code using Bloodshed DevC++.
My program draws circles on the screen, and updates to new positions every second on a timer.
I verified that the timer works and WM_PAINT is getting called, but the Window only updates when I minimize and restore the window. Why won't it redraw on it's own every second?

Here's the code:

Code:
#include <windows.h>
#include <math.h>

/*  Declare Windows procedure  */
LRESULT CALLBACK WindowProcedure (HWND, UINT, WPARAM, LPARAM);

RECT rect = {0,800,0,600};

/*  Make the class name into a global variable  */
char szClassName[ ] = "Perimeter";

bool flag = true;

int WINAPI WinMain (HINSTANCE hThisInstance,
                    HINSTANCE hPrevInstance,
                    LPSTR lpszArgument,
                    int nFunsterStil)

{
    HWND hwnd;               /* This is the handle for our window */
    MSG messages;            /* Here messages to the application are saved */
    WNDCLASSEX wincl;        /* Data structure for the windowclass */

    /* The Window structure */
    wincl.hInstance = hThisInstance;
    wincl.lpszClassName = szClassName;
    wincl.lpfnWndProc = WindowProcedure;      /* This function is called by windows */
    wincl.style = CS_HREDRAW | CS_VREDRAW;                 /* Catch double-clicks */
    wincl.cbSize = sizeof (WNDCLASSEX);

    /* Use default icon and mouse-pointer */
    wincl.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hIconSm = LoadIcon (NULL, IDI_APPLICATION);
    wincl.hCursor = LoadCursor (NULL, IDC_ARROW);
    wincl.lpszMenuName = NULL;                 /* No menu */
    wincl.cbClsExtra = 0;                      /* No extra bytes after the window class */
    wincl.cbWndExtra = 0;                      /* structure or the window instance */
    /* Use Windows's default color as the background of the window */
    wincl.hbrBackground = (HBRUSH) CreateSolidBrush(RGB(255,255,255));

    /* Register the window class, and if it fails quit the program */
    if (!RegisterClassEx (&wincl))
        return 0;

    /* The class is registered, let's create the program*/
    hwnd = CreateWindowEx (
           0,                   /* Extended possibilites for variation */
           szClassName,         /* Classname */
           "Perimeter",       /* Title Text */
           WS_OVERLAPPEDWINDOW, /* default window */
           CW_USEDEFAULT,       /* Windows decides the position */
           CW_USEDEFAULT,       /* where the window ends up on the screen */
           800,                 /* The programs width */
           600,                 /* and height in pixels */
           HWND_DESKTOP,        /* The window is a child-window to desktop */
           NULL,                /* No menu */
           hThisInstance,       /* Program Instance handler */
           NULL                 /* No Window Creation data */
           );

    /* Make the window visible on the screen */
    ShowWindow (hwnd, nFunsterStil);

    /* Run the message loop. It will run until GetMessage() returns 0 */
    while (GetMessage (&messages, NULL, 0, 0))
    {
        /* Translate virtual-key messages into character messages */
        TranslateMessage(&messages);
        /* Send message to WindowProcedure */
        DispatchMessage(&messages);
    }

    /* The program return-value is 0 - The value that PostQuitMessage() gave */
    return messages.wParam;
}

/*  This function is called by the Windows function DispatchMessage()  */

struct COORDINATE
{
     int x, y;       
};
COORDINATE ships[20];

void DrawCircle(HDC hdc, int radius, int xCenter, int yCenter, COLORREF color)
{
     HRGN hrgn;
     HBRUSH hbrush;
     int xLeft = xCenter - radius, xRight = xCenter + radius, yTop = yCenter - radius, yBottom = yCenter + radius;
     hrgn = CreateEllipticRgn(xLeft,yTop,xRight,yBottom);
     hbrush = CreateSolidBrush(color);
     FillRgn(hdc,hrgn,hbrush);
     DeleteObject(hrgn);
     DeleteObject(hbrush);
}

void DrawWindow(HDC hdc)
{
     for(int i = 0; i < 5; i++)
     {
          DrawCircle(hdc, 20, ships[i].x, ships[i].y, RGB(255,0,0));
     }
}



void Init()
{
     for(int i = 0; i < 20; i++) {ships[i].x=0; ships[i].y=0;}
     ships[0].x = 350;
     ships[0].y = 200;
     ships[1].x = 400;
     ships[1].y = 200;
     ships[2].x = 400;
     ships[2].y = 250;     
     ships[3].x = 450;
     ships[3].y = 250;
     ships[4].x = 450;
     ships[4].y = 300;
}

LRESULT CALLBACK WindowProcedure (HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam)
{
     HDC hdc;
     PAINTSTRUCT ps;
     switch (message)
     {
        case WM_PAINT:
             hdc = BeginPaint(hwnd,&ps);
             DrawWindow(hdc);             
             EndPaint(hwnd,&ps);
             break;
        case WM_TIMER:
             for(int i = 0; i < 5; i++) {ships[i].x+=10; ships[i].y+=10;}
             UpdateWindow(hwnd);
             break;
        case WM_CREATE:
             Init();
             SetTimer(hwnd, 1000,1000,NULL);
             UpdateWindow(hwnd);
             break;
        case WM_DESTROY:
             PostQuitMessage (0);
             break;
        default:
             return DefWindowProc (hwnd, message, wParam, lParam);
     }
     return 0;
}