Game Loop

[L E G I O N]

/**
        GameLoop project

**/

#include <windows.h>
#include <iostream>
#include <time.h>
using namespace std;

const string APPTITLE = "Game Loop";
HWND window;
HDC device;
bool gameover = false;


/**
 ** Loads and draws a bitmap from a file and then frees the memory
 **/
void DrawBitmap(char *filename, int x, int y)
{
    //load the bitmap image
    HBITMAP image = (HBITMAP)LoadImage(0,"wu.bmp",IMAGE_BITMAP,0,0,LR_LOADFROMFILE);
	 
    //read the bitmap's properties
    BITMAP bm;
    GetObject(image, sizeof(BITMAP), &bm);

    //create a device context for the bitmap
    HDC hdcImage = CreateCompatibleDC(device);
    SelectObject(hdcImage, image);

    //draw the bitmap to the window (bit block transfer)
    BitBlt( 
        device,                  //destination device context
        x, y,                    //x,y location on destination
        bm.bmWidth, bm.bmHeight, //width,height of source bitmap
        hdcImage,                  //source bitmap device context
        0, 0,                    //start x,y on source bitmap
        SRCCOPY);                //blit method

    //delete the device context and bitmap
    DeleteDC(hdcImage);
    DeleteObject((HBITMAP)image);
}

/**
 ** Startup and loading code goes here
 **/
bool Game_Init()
{
    //start up the random number generator
    srand(time(NULL));

    return 1;
}

/**
 ** Update function called from inside game loop
 **/
void Game_Run()
{
    if (gameover == true) return;

    //get the drawing surface
    RECT rect;
    GetClientRect(window, &rect);

    //draw bitmap at random location
		int x = 1;
		int y = 2;
		DrawBitmap("wu.bmp", x, y);
	
}

/**
 ** Shutdown code
 **/
void Game_End()
{
    //free the device
    ReleaseDC(window, device);
}

/**
 ** Window callback function
 **/
LRESULT CALLBACK WinProc(HWND hWnd, UINT message, WPARAM wParam, LPARAM lParam)
{
    switch (message) 
    {
        case WM_DESTROY:
            gameover = true;
            PostQuitMessage(0);
            break;
    }
    return DefWindowProc(hWnd, message, wParam, lParam);
}

/**
 ** MyRegiserClass function sets program window properties
 **/
ATOM MyRegisterClass(HINSTANCE hInstance)
{
    //create the window class structure
    WNDCLASSEX wc;
    wc.cbSize = sizeof(WNDCLASSEX); 

    //fill the struct with info
    wc.style         = CS_HREDRAW | CS_VREDRAW;
    wc.lpfnWndProc   = (WNDPROC)WinProc;
    wc.cbClsExtra     = 0;
    wc.cbWndExtra     = 0;
    wc.hInstance     = hInstance;
    wc.hIcon         = NULL;
    wc.hCursor       = LoadCursor(NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH);
    wc.lpszMenuName  = NULL;
    wc.lpszClassName = APPTITLE.c_str();
    wc.hIconSm       = NULL;

    //set up the window with the class info
    return RegisterClassEx(&wc);
}

/**
 ** Helper function to create the window and refresh it
 **/
BOOL InitInstance(HINSTANCE hInstance, int nCmdShow)
{
    //create a new window
    window = CreateWindow(
       APPTITLE.c_str(),              //window class
       APPTITLE.c_str(),              //title bar
       WS_OVERLAPPEDWINDOW,   //window style
       CW_USEDEFAULT,         //x position of window
       CW_USEDEFAULT,         //y position of window
       640,                   //width of the window
       480,                   //height of the window
       NULL,                  //parent window
       NULL,                  //menu
       hInstance,             //application instance
       NULL);                 //window parameters

    //was there an error creating the window?
    if (window == 0) return 0;

    //display the window
    ShowWindow(window, nCmdShow);
    UpdateWindow(window);

    //get device context for drawing
    device = GetDC(window);

    return 1;
}

/**
 ** Entry point function
 **/
int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nCmdShow)
{
    MSG msg;

    //create window
    MyRegisterClass(hInstance);
    if (!InitInstance (hInstance, nCmdShow)) return 0;

    //initialize the game
    if (!Game_Init()) return 0;

    // main message loop
    while (!gameover)
    {
        //process Windows events
        if (PeekMessage(&msg, NULL, 0, 0, PM_REMOVE)) 
        {
            TranslateMessage(&msg);
            DispatchMessage(&msg);
        }
        
        //process game loop
        Game_Run();
    }

    //free game resources
    Game_End();

    return msg.wParam;
}

hey guys im working on this project and i need to make the image move randomly actually 2 images and im having trouble because i can get the 1 image on screen but it doesent move..... :s if someone could help me with this id appreciate it
thanks!

[L E G I O N]

im working out of a book and one of the excercises is instead of having a bunch of random images on the screen

its just one that moves around and does not fly off the screen and i've REALLy tried everything i possibly could but am getting nowhere so hopefully someone on here can give me a hand with this

[L E G I O N]

i got it working
but does anyone know how to change the screen to RED
its set on BLACK_BRUSH right now...

[Disch]

What kind of crap book is encouraging WinGDI for game development?

If I were you I would toss that book and pick up a game development lib and just follow the free online tutorials. I recommend SFML (http://www.sfml-dev.org)

Game libs are simpler and faster. Save yourself a headache.

[L E G I O N]

yeah i agree man... but im taking VGDD in school right now... and for 2d programming this is what we have to "learn"
and its BS because the teacher does the code himself and puts hacks in to make the program work and then he tries to explain it but its ALLOVER the place and i'm paying $40,000 for the course and i havent learned hardly anything excpet unity3d and how to right click on a mac lol

[Vexer]

What kind of crap book is encouraging WinGDI for game development?

I have a book called Beginning Game Programming by Jonathan Harbour. Looking at the code you provided, this is the exact same as found in one of the first chapters. He is NOT encouraging the use of the WinGDI, he is just using to "get something on the screen" while he demonstrates how to create a proper game loop. A few chapters later, he gets into DirectX.