Help with WinApi ?

Even tough this is only a c++ forum, I hope some one can help me with my C WinApi problem. I have posted this question on CodeGuru Forums but no helpfull reply at all.
I have homework for school and we were instructed to write a game in plain c with conio2.h for graphical output. But I hvae decided to make it in WinApi.

Now here is my problem I have a function CheckStatus() which verifies if the game is over and if it is it asks the user play again or quit. If I put this function in WM_KEYDOWN it works ok, but if I move the function to the end of WM_PAINT, the window won't repaint on a new game unless you completley resize it or move arround the blank screen a few times. Does any 1 know what that could be?

Code:

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#include <stdio.h>
#include <stdlib.h>
#include <time.h>
#include <windows.h>
#include <commctrl.h>

#define WIDTH 1378
#define HEIGHT 820
#define WM_START 0x1337
#define IDM_FILE_NEW 1
#define IDM_FILE_REPLAY 2
#define IDM_FILE_DIFFICULTY 3
#define IDM_FILE_OPTIONS 4
#define IDM_FILE_QUIT 5

HINSTANCE Instance;
int GameOver = 0;
int GameDevelopment = 1;
int Misek;
int Resizing = 0;
int Tezavnost = 2;
int Vertical = 0;

struct Cat{
        int X, Y;
        int prevX, prevY;
}Cat;
struct Mice{
        char status;
        int X, Y;
}Mouse[50];
struct Dogs{
        int X, Y;
}Dog[200];

LRESULT CALLBACK WndProc(HWND, UINT, WPARAM, LPARAM);
void LoadAndBlitCat(HDC hWinDC);
void LoadAndBlitMice(HDC hWinDC);
void LoadAndBlitDogs(HDC hWinDC);
void InitializeAnimals(HWND hwnd);
void CheckStatus(HWND hwnd);
void AddMenus(HWND hwnd);

int WINAPI WinMain( HINSTANCE hInstance, HINSTANCE hPrevInstance,
                        LPSTR lpCmdLine, int nCmdShow )
{
  MSG  msg ;   
  WNDCLASS wc = {0};
  wc.lpszClassName = TEXT( "Windows" );
  wc.hInstance    = hInstance ;
  wc.hbrBackground = GetSysColorBrush(COLOR_3DFACE);
  wc.lpfnWndProc  = WndProc ;
  wc.hCursor      = LoadCursor(0,IDC_ARROW);
 
  RegisterClass(&wc);
  CreateWindow(wc.lpszClassName, TEXT("Windows"),
                WS_OVERLAPPED | WS_CAPTION | WS_SYSMENU | WS_THICKFRAME |
                    WS_MINIMIZEBOX | WS_MAXIMIZEBOX | WS_VISIBLE,
                GetSystemMetrics(SM_CXSCREEN)/9,
                                GetSystemMetrics(SM_CYSCREEN)/12,
                                WIDTH, HEIGHT, 0, 0, hInstance, 0); 

  while( GetMessage(&msg, NULL, 0, 0)) {
    TranslateMessage(&msg);
    DispatchMessage(&msg);
  }
  return (int) msg.wParam;
}

LRESULT CALLBACK WndProc( HWND hwnd, UINT msg, WPARAM wParam, LPARAM lParam ){
  HDC hdc;
  PAINTSTRUCT ps;
  switch(msg) 
  {
    case WM_START:{
                GameOver = 0;
                Misek = Tezavnost*5;
                GameDevelopment = 1;
                InitializeAnimals(hwnd);
            InvalidateRect(hwnd, NULL, TRUE);
                break;
        }
    case WM_CREATE:{
                AddMenus(hwnd);
                SendMessage(hwnd, WM_START, 0, 0);
            break;
    }
        case WM_KEYDOWN:{

                if(!Vertical){
                    Cat.prevX = Cat.X;
                    Cat.prevY = Cat.Y;
                }

        if(wParam == 0x57){
                    if(Cat.Y-34 <= 0)
                                Beep(500,500);
                    else
                            Cat.Y -= 34;
            }
                if(wParam == 0x41){
                    if(Cat.X-34 <= 0)
                                Beep(500,500);
                    else
                            Cat.X -= 34;
            }
                if(wParam == 0x53){
                    if(Cat.Y+34 >= HEIGHT-150)
                                Beep(500,500);
                    else
                            Cat.Y += 34;
            }
                if(wParam == 0x44){
                    if(Cat.X+34 >= WIDTH-34)
                                Beep(500,500);
                    else
                            Cat.X += 34;
            }
                CheckStatus(hwnd);
                Vertical = 1;
                InvalidateRect(hwnd, NULL, FALSE);
            break;
        }
        case WM_PAINT:{
               
                Vertical = 0;
                hdc = BeginPaint(hwnd, &ps);
               
                HBRUSH hFillBrush = GetSysColorBrush(COLOR_3DFACE);
                HBRUSH hBrushOld = (HBRUSH)SelectObject(hdc, hFillBrush);
                HPEN hLinePen = CreatePen(PS_NULL, 0, RGB(0, 0, 0));
            HPEN hPenOld = (HPEN)SelectObject(hdc, hLinePen);

                Rectangle(hdc, Cat.prevX, Cat.prevY, Cat.prevX+34, Cat.prevY+34);

        hLinePen = CreatePen(PS_SOLID, 2, RGB(0, 0, 0));
            hPenOld = (HPEN)SelectObject(hdc, hLinePen);

                if(GameDevelopment){
                        for(int i = 1;i<=WIDTH;i=i+34){
                            MoveToEx(hdc, i, 0, NULL);
                                LineTo(hdc, i, HEIGHT-139);
                        }
                        for(int i = 1;i<=HEIGHT-139;i=i+34){
                            MoveToEx(hdc, 0, i, NULL);
                                LineTo(hdc, WIDTH-17, i);
                        }

                        if(GameDevelopment == 1 || Resizing == 1){
                            LoadAndBlitMice(hdc);
                                Resizing = 0;
                    }
                        LoadAndBlitCat(hdc);
                        if(GameDevelopment == 1 || Resizing == 1){
                            LoadAndBlitDogs(hdc);
                                Resizing = 0;
                    }
                }

                SelectObject(hdc, hPenOld);
            DeleteObject(hLinePen);
                SelectObject(hdc, hBrushOld);
                DeleteObject(hFillBrush);
               
                EndPaint(hwnd, &ps);

        break;
        }
        case WM_SIZE:{
            Resizing = 1;
                break;
        }
    case WM_DESTROY:
    {
        PostQuitMessage(0);
        break;
    }
  }
  return DefWindowProc(hwnd, msg, wParam, lParam);
}

void AddMenus(HWND hwnd){
  HMENU hMenubar;
  HMENU hMenu;

  hMenubar = CreateMenu();
  hMenu = CreateMenu();

  AppendMenu(hMenu, MF_STRING, IDM_FILE_NEW, TEXT("&New"));
  AppendMenu(hMenu, MF_STRING, IDM_FILE_REPLAY, TEXT("&Replay"));
  AppendMenu(hMenu, MF_STRING, IDM_FILE_DIFFICULTY, TEXT("&Difficutly"));
  AppendMenu(hMenu, MF_STRING, IDM_FILE_OPTIONS, TEXT("&Options"));
  AppendMenu(hMenu, MF_SEPARATOR, 0, NULL);
  AppendMenu(hMenu, MF_STRING, IDM_FILE_QUIT, TEXT("&Quit"));

  AppendMenu(hMenubar, MF_POPUP, (UINT_PTR)hMenu, TEXT("&File"));
  SetMenu(hwnd, hMenubar);
}

void LoadAndBlitCat(HDC hWinDC){
        HBITMAP hBitmap;
    BITMAP qBitmap;
    HDC hLocalDC;

    hBitmap = (HBITMAP)LoadImage(NULL, TEXT("Cat.bmp"), IMAGE_BITMAP, 0, 0,
                LR_CREATEDIBSECTION | LR_DEFAULTSIZE | LR_LOADFROMFILE);
    hLocalDC = CreateCompatibleDC(hWinDC);

    GetObject((HGDIOBJ) hBitmap, sizeof(BITMAP), (LPVOID) &qBitmap);

    HBITMAP hOldBmp = (HBITMAP) SelectObject(hLocalDC, hBitmap);


    BitBlt(hWinDC, Cat.X, Cat.Y, qBitmap.bmWidth, qBitmap.bmHeight, hLocalDC, 0, 0, SRCCOPY);
    SelectObject(hLocalDC, hOldBmp);

        DeleteDC(hLocalDC);
        DeleteObject(hBitmap);
}
void LoadAndBlitMice(HDC hWinDC){
        HBITMAP hBitmap;
    BITMAP qBitmap;
    HDC hLocalDC;
   
    hBitmap = (HBITMAP)LoadImage(NULL, TEXT("Mouse.bmp"), IMAGE_BITMAP, 0, 0,
                LR_CREATEDIBSECTION | LR_DEFAULTSIZE | LR_LOADFROMFILE);
    hLocalDC = CreateCompatibleDC(hWinDC);

    GetObject((HGDIOBJ) hBitmap, sizeof(BITMAP), (LPVOID) &qBitmap);

    HBITMAP hOldBmp = (HBITMAP) SelectObject(hLocalDC, hBitmap);

    for(int i=0;i<Tezavnost*5;i++)
                if(Mouse[i].status != 'D')
            BitBlt(hWinDC, Mouse[i].X, Mouse[i].Y, qBitmap.bmWidth, qBitmap.bmHeight, hLocalDC, 0, 0, SRCCOPY);
               

    SelectObject(hLocalDC, hOldBmp);

        DeleteDC(hLocalDC);
        DeleteObject(hBitmap);
}
void LoadAndBlitDogs(HDC hWinDC){
        HBITMAP hBitmap;
    BITMAP qBitmap;
    HDC hLocalDC;
   
    hBitmap = (HBITMAP)LoadImage(NULL, TEXT("Batman.bmp"), IMAGE_BITMAP, 0, 0,
                LR_CREATEDIBSECTION | LR_DEFAULTSIZE | LR_LOADFROMFILE);
    hLocalDC = CreateCompatibleDC(hWinDC);

    GetObject((HGDIOBJ) hBitmap, sizeof(BITMAP), (LPVOID) &qBitmap);

    HBITMAP hOldBmp = (HBITMAP) SelectObject(hLocalDC, hBitmap);

    for(int i=0;i<Tezavnost*50;i++)
        BitBlt(hWinDC, Dog[i].X, Dog[i].Y, qBitmap.bmWidth, qBitmap.bmHeight, hLocalDC, 0, 0, SRCCOPY);
       
    SelectObject(hLocalDC, hOldBmp);

        DeleteDC(hLocalDC);
        DeleteObject(hBitmap);
}

void InitializeAnimals(HWND hwnd){
        int i, j, si;
        Cat.X =2;
        Cat.Y=2;

        srand(time(NULL));

        for(i=0;i<Tezavnost*5;i++)
                Mouse[i].status = 'A';

        for(i=0;i<Tezavnost*5;i++){//Misi XY
            do{
                    si=0;
                    Mouse[i].X = (rand()%40*34)+2;
                    Mouse[i].Y = (rand()%20*34)+2;
                for(j=0;i>j;j++)
                            if((Mouse[i].Y == Mouse[j].Y && Mouse[i].X == Mouse[i].X) ||
                                (Mouse[i].Y == Cat.Y && Mouse[i].X == Cat.X))
                                    si=1;
                }while(si);
        }

        for(i=0;i<Tezavnost*50;i++){//Psi XY
            do{
                    si=0;
                    Dog[i].X = (rand()%40*34)+2;
                    Dog[i].Y = (rand()%20*34)+2;
                        for(j=0;i>j;j++)
                            if((Dog[i].X == Cat.X && Dog[i].Y == Cat.Y) || (
                                Dog[i].X == Dog[j].X && Dog[i].Y == Dog[j].Y) ||
                                (Dog[i].X == Mouse[j].X && Dog[i].Y == Mouse[j].Y))
                                    si=1;
                        if(Dog[i].X == Mouse[j].X && Dog[i].Y == Mouse[j].Y)
                                si=1;
                }while(si);
        }
}

void CheckStatus(HWND hwnd){
        int i;
    for(i=0;i<Tezavnost*5;i++){
            if(Mouse[i].Y == Cat.Y && Mouse[i].X == Cat.X){
                    Mouse[i].status = 'D';
                            if(--Misek == 0){
                                    if(MessageBox(hwnd, TEXT("YOU WIN"), TEXT("MessageBox"), MB_YESNO) == IDYES)
                                            SendMessage(hwnd, WM_START, 0, 0);
                                        else
                                            SendMessage(hwnd, WM_CLOSE, 0, 0);
                                }
                                i=1000;
                }
        }
        for(i=0;i<Tezavnost*50;i++){
            if(Dog[i].Y == Cat.Y && Dog[i].X == Cat.X){
                        if(MessageBox(hwnd, TEXT("YOU LOST"), TEXT("MessageBox"), MB_YESNO) == IDYES)
                            SendMessage(hwnd, WM_START, 0, 0);
                    else
                                SendMessage(hwnd, WM_CLOSE, 0, 0);
                        i=1000;
                        }
        }
}

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This is the code the works but if I would put CheckStatus at the end of WM_PAINT it doesn't restart properly.

Moved to windows forum.

I'm pretty sure paint is NOT where you want to check for status changes / actions from the user. Why do you want it to be in the paint code?

Because i you press W+A it sends 2 WM_KEYDOWN messages so first it goes up and the coordinates change by -34 then it goes left and it changes by -34 and if you hit something with the upward movment you loose. But if i were to check this in paint the coordinates are already - - so if nothing is there you don't loose. But for now I just disabled moving vertically.

Quote:

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Originally Posted by Sevko

Because i you press W+A it sends 2 WM_KEYDOWN messages so first it goes up and the coordinates change by -34 then it goes left and it changes by -34 and if you hit something with the upward movment you loose. But if i were to check this in paint the coordinates are already - - so if nothing is there you don't loose. But for now I just disabled moving vertically.

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I don't really follow what you're saying here. All paint should do is draw what you want to draw. No checking for win/loss, no actual moving things, just drawing things.

If what you're saying is "if they press W+A fast enough I want them to move northwest without worrying if they ran into something", then the answer is to make a different key for northwest.

Quote:

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Originally Posted by Sevko

I have homework for school and we were instructed to write a game in plain c with conio2.h for graphical output. But I hvae decided to make it in WinApi.

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I would think your instructor gave you the assignment for a reason... like maybe he wants you to have a given programming experience...

The game is not going to work proplerly with your status check in WM_PAINT because that's not what the WM_PAINT message is about... it is sent when a portion of a window is changed or occluded and needs to be re-drawn. You need to devise another way to know when your game is over... like sending a "Game Over" message and processing it in your windproc.

As has been said Paint or OnPaint() is the wrong place to change the status of the game. If you follow a simple model-view-controller paradigm you will have a much better chance of success.

The view or the painting in your case should never change the status of the application. If you are looking to make a game loop in Win32 the best way I know how is to use the WM_IDLE message in your WndProc and then do your updating and rendering/drawing in the block of code that intercepts the message. The view only renders the data it has been given access to. If the view changes you get a different view of the same data. If the data changes you get the same view but with different data.

A few observations.....

Your paint will be very slow, with over 100 BitBlt() calls + LoadImage() + CreateDC() each time the screen is redrawn.
I would consider double buffering (I have posted plenty of examples) as only the 'cat' moves, the 'mice' and 'dogs' could be drawn once to a mem DC when a game starts and this whole mem DC blitted once as a backgraound (instead of the 110 possible blits) each time the 'cat' moves [2 blits total; background and then cat].

Your paint should ONLY call one BitBlt() using the PAINTSTRUCT's HDC and RECT. WM_PAINT is often generated outside your app and so should be as quick as possible (and never modify the 'state' as pointed out).

To call for a quicker paint, use InvalidateRect() followed by an UpdateWindow().
This bypasses the OS msg queue and posts the paint directly to the callback. [WM_PAINT msgs are also generated outside your app and are the lowest priority in the OS msg queue. Multiple WM_PAINT msgs are concatinated in the msg queue, which may cause issues ie jerky updates, shearing, flicker etc).

You have a GDI leak in your paint.
The hLinePen is allocated memory and selected into the DC (the default is in hPenOld).
A new GDI object is allocated over hLinePen and selected into the DC (probably the original hLinePen is now in hPenOld and the original / default pen is lost).