hey I have a question, I am in ch.4 of tricks where you draw programs..I am trying to just draw a circle but I can''t seem to do that...I would like if someone could show me how to create it, the book really doesn''t show how to just make a regular circle that doesn''t move that just stays one place on the screen..Also, the program 4.4cpp I am trying to add a second circle to that, program..Can anyone show me how to go about doing that, thanks a lot...Here is the code to the program with only one moving ball.. ////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////////// // DEMO4_4.CPP - Ellipse Animation Demo // INCLUDES /////////////////////////////////////////////// #define WIN32_LEAN_AND_MEAN // just say no to MFC #include // include all the windows headers #include // include useful macros #include // very important and include WINMM.LIB too! #include #include #include // DEFINES //////////////////////////////////////////////// // defines for windows #define WINDOW_CLASS_NAME "WINCLASS1" #define WINDOW_WIDTH 400 #define WINDOW_HEIGHT 300 // MACROS ///////////////////////////////////////////////// #define KEYDOWN(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 1 : 0) #define KEYUP(vk_code) ((GetAsyncKeyState(vk_code) & 0x8000) ? 0 : 1) // GLOBALS //////////////////////////////////////////////// HWND main_window_handle = NULL; // globally track main window HINSTANCE hinstance_app = NULL; // globally track hinstance char buffer[80]; // general printing buffer // FUNCTIONS ////////////////////////////////////////////// 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 // 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); // end painting EndPaint(hwnd,&ps); // return success return(0); } break; 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 // 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; // graphics device context // 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(NULL, IDI_APPLICATION); winclass.hCursor = LoadCursor(NULL, IDC_ARROW); winclass.hbrBackground = (HBRUSH)GetStockObject(BLACK_BRUSH); winclass.lpszMenuName = NULL; winclass.lpszClassName = WINDOW_CLASS_NAME; winclass.hIconSm = LoadIcon(NULL, IDI_APPLICATION); // save hinstance in global hinstance_app = hinstance; // register the window class if (!RegisterClassEx(&winclass)) return(0); // create the window if (!(hwnd = CreateWindowEx(NULL, // extended style WINDOW_CLASS_NAME, // class "Ellipse Animation Demo", // title WS_OVERLAPPEDWINDOW | WS_VISIBLE, 0,0, // initial x,y WINDOW_WIDTH, // initial width WINDOW_HEIGHT,// initial height NULL, // handle to parent NULL, // handle to menu hinstance,// instance of this application NULL))) // extra creation parms return(0); // save main window handle main_window_handle = hwnd; // get the graphics device context once this time and keep it // this is possible due to the CS_OWNDC flag hdc = GetDC(hwnd); // seed random number generator srand(GetTickCount()); // create the pens and brushes HPEN white_pen = CreatePen(PS_SOLID, 1, RGB(255,255,255)); HPEN black_pen = CreatePen(PS_SOLID, 1, RGB(0,0,0)); HBRUSH green_brush = CreateSolidBrush(RGB(0,255,0)); HBRUSH black_brush = CreateSolidBrush(RGB(0,0,0)); // starting position of ball int ball_x = WINDOW_WIDTH/2; int ball_y = WINDOW_HEIGHT/2; // initial velocity of ball int xv = -4+rand()%20; int yv = -4+rand()%10; // enter main event loop, but this time we use PeekMessage() // instead of GetMessage() to retrieve messages while(TRUE) { // 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 ////////////////////////////////////////////////////////// // ERASE the last position of the ball // first select the black pen and brush into context SelectObject(hdc, black_pen); SelectObject(hdc, black_brush); // draw the ball Ellipse(hdc, ball_x, ball_y, ball_x + 32, ball_y + 32); // MOVE the ball ball_x+=xv; ball_y+=yv; // test for collisions, first x-axis if (ball_x < 0 || ball_x > WINDOW_WIDTH - 32) { // invert x-velocity of ball xv=-xv; // push ball back ball_x+=xv; } // end if else // test for y-axis collisions if (ball_y < 0 || ball_y > WINDOW_HEIGHT - 32) { // invert y-velocity of ball yv=-yv; // push ball back ball_y+=yv; } // end if // now select the green and white colors for brush and pen SelectObject(hdc, white_pen); SelectObject(hdc, green_brush); // DRAW the ball Ellipse(hdc, ball_x, ball_y, ball_x + 32, ball_y + 32); // main game processing goes here if (KEYDOWN(VK_ESCAPE)) SendMessage(hwnd, WM_CLOSE, 0,0); // slow system down a little Sleep(10); } // end while // delete all the objects DeleteObject(white_pen); DeleteObject(black_pen); DeleteObject(green_brush); DeleteObject(black_brush); // release the device context ReleaseDC(hwnd,hdc); // return to Windows like this return(msg.wParam); } // end WinMain /////////////////////////////////////////////////////////////

GDI right??? just use the Ellipse like this :

The Ellipse function draws an ellipse. The center of the ellipse is the center of the specified bounding rectangle. The ellipse is outlined by using the current pen and is filled by using the current brush.

BOOL Ellipse(
HDC hdc, // handle to device context
int nLeftRect, // x-coord of bounding rectangle''s upper-left corner
int nTopRect, // y-coord of bounding rectangle''s upper-left corner
int nRightRect, // x-coord of bounding rectangle''s lower-right corner
int nBottomRect // y-coord of bounding rectangle''s lower-right corner
);



"You won''t get wise with the sleep still in your eyes." - Neil Peart