Need help Asking user question in program

[pghTech]

The following opengl code has to source files and a few standard and gl based header files.

I would like to add to the program a question that promps the user if they would like to run the program in fullscreen then take that inputted answer (i.e. y or n) and set the fullscreen global variable defined in winmain.cpp to (true or false).

I am only familar with using cout/cin but I am not sure that would be the case in this program. Plus I am a little unsure where i would ask the question so that it is asked first before rendering the graphics.

I posted the code from both winmain.cpp and CGfxOpengl.cpp:

#define WIN32_LEAN_AND_MEAN
#define WIN32_EXTRA_LEAN

#include <windows.h>
#include <gl/gl.h>
#include <gl/glu.h>

#include "CGfxOpenGL.h"

bool exiting = false;
long windowWidth = 800;
long windowHeight = 600;
long windowBits = 32;
bool fullscreen = true;
HDC hDC;

CGfxOpenGL *g_glRender = NULL;

void SetupPixelFormat(HDC hDC)
{
    int pixelFormat;

    PIXELFORMATDESCRIPTOR pfd =
    {   
        sizeof(PIXELFORMATDESCRIPTOR),  // size
            1,                          // version
            PFD_SUPPORT_OPENGL |        // OpenGL window
            PFD_DRAW_TO_WINDOW |        // render to window
            PFD_DOUBLEBUFFER,           // support double-buffering
            PFD_TYPE_RGBA,              // color type
            32,                         // prefered color depth
            0, 0, 0, 0, 0, 0,           // color bits (ignored)
            0,                          // no alpha buffer
            0,                          // alpha bits (ignored)
            0,                          // no accumulation buffer
            0, 0, 0, 0,                 // accum bits (ignored)
            16,                         // depth buffer
            0,                          // no stencil buffer
            0,                          // no auxiliary buffers
            PFD_MAIN_PLANE,             // main layer
            0,                          // reserved
            0, 0, 0,                    // no layer, visible, damage masks
    };

    pixelFormat = ChoosePixelFormat(hDC, &pfd);
    SetPixelFormat(hDC, pixelFormat, &pfd);
}

LRESULT CALLBACK MainWindowProc(HWND hWnd, UINT uMsg, WPARAM wParam, LPARAM lParam)
{
    static HDC hDC;
    static HGLRC hRC;
    int height, width;

    // dispatch messages
    switch (uMsg)
    {   
    case WM_CREATE:         // window creation
        hDC = GetDC(hWnd);
        SetupPixelFormat(hDC);
        //SetupPalette();
        hRC = wglCreateContext(hDC);
        wglMakeCurrent(hDC, hRC);
        break;

    case WM_DESTROY:            // window destroy
    case WM_QUIT:
    case WM_CLOSE:                  // windows is closing

        // deselect rendering context and delete it
        wglMakeCurrent(hDC, NULL);
        wglDeleteContext(hRC);

        // send WM_QUIT to message queue
        PostQuitMessage(0);
        break;

    case WM_SIZE:
        height = HIWORD(lParam);        // retrieve width and height
        width = LOWORD(lParam);

        g_glRender->SetupProjection(width, height);

        break;

    case WM_ACTIVATEAPP:        // activate app
        break;

    case WM_PAINT:              // paint
        PAINTSTRUCT ps;
        BeginPaint(hWnd, &ps);
        EndPaint(hWnd, &ps);
        break;

    case WM_LBUTTONDOWN:        // left mouse button
        break;

    case WM_RBUTTONDOWN:        // right mouse button
        break;

    case WM_MOUSEMOVE:          // mouse movement
        break;

    case WM_LBUTTONUP:          // left button release
        break;

    case WM_RBUTTONUP:          // right button release
        break;

    case WM_KEYUP:
        break;

    case WM_KEYDOWN:
        int fwKeys;
        LPARAM keyData;
        fwKeys = (int)wParam;    // virtual-key code 
        keyData = lParam;          // key data 

        switch(fwKeys)
        {
        case VK_ESCAPE:
            PostQuitMessage(0);
            break;
        default:
            break;
        }

        break;

    default:
        break;
    }
    return DefWindowProc(hWnd, uMsg, wParam, lParam);
}

int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd)
{
    WNDCLASSEX windowClass;     // window class
    HWND       hwnd;            // window handle
    MSG        msg;             // message
    DWORD      dwExStyle;       // Window Extended Style
    DWORD      dwStyle;         // Window Style
    RECT       windowRect;

    g_glRender = new CGfxOpenGL;

    windowRect.left=(long)0;                        // Set Left Value To 0
    windowRect.right=(long)windowWidth; // Set Right Value To Requested Width
    windowRect.top=(long)0;                         // Set Top Value To 0
    windowRect.bottom=(long)windowHeight;   // Set Bottom Value To Requested Height

    // fill out the window class structure
    windowClass.cbSize          = sizeof(WNDCLASSEX);
    windowClass.style           = CS_HREDRAW | CS_VREDRAW;
    windowClass.lpfnWndProc     = MainWindowProc;
    windowClass.cbClsExtra      = 0;
    windowClass.cbWndExtra      = 0;
    windowClass.hInstance       = hInstance;
    windowClass.hIcon           = LoadIcon(NULL, IDI_APPLICATION);  // default icon
    windowClass.hCursor         = LoadCursor(NULL, IDC_ARROW);      // default arrow
    windowClass.hbrBackground   = NULL;                             // don't need background
    windowClass.lpszMenuName    = NULL;                             // no menu
    windowClass.lpszClassName   = "GLClass";
    windowClass.hIconSm         = LoadIcon(NULL, IDI_WINLOGO);      // windows logo small icon

    // register the windows class
    if (!RegisterClassEx(&windowClass))
        return 0;

    if (fullscreen)                             // fullscreen?
    {
        DEVMODE dmScreenSettings;                   // device mode
        memset(&dmScreenSettings,0,sizeof(dmScreenSettings));
        dmScreenSettings.dmSize = sizeof(dmScreenSettings); 
        dmScreenSettings.dmPelsWidth = windowWidth;         // screen width
        dmScreenSettings.dmPelsHeight = windowHeight;           // screen height
        dmScreenSettings.dmBitsPerPel = windowBits;             // bits per pixel
        dmScreenSettings.dmFields=DM_BITSPERPEL|DM_PELSWIDTH|DM_PELSHEIGHT;

        // 
        if (ChangeDisplaySettings(&dmScreenSettings, CDS_FULLSCREEN) != DISP_CHANGE_SUCCESSFUL)
        {
            // setting display mode failed, switch to windowed
            MessageBox(NULL, "Display mode failed", NULL, MB_OK);
            fullscreen = FALSE; 
        }
    }

    if (fullscreen)                             // Are We Still In Fullscreen Mode?
    {
        dwExStyle=WS_EX_APPWINDOW;                  // Window Extended Style
        dwStyle=WS_POPUP;                       // Windows Style
        ShowCursor(FALSE);                      // Hide Mouse Pointer
    }
    else
    {
        dwExStyle=WS_EX_APPWINDOW | WS_EX_WINDOWEDGE;   // Window Extended Style
        dwStyle=WS_OVERLAPPEDWINDOW;                    // Windows Style
    }

    AdjustWindowRectEx(&windowRect, dwStyle, FALSE, dwExStyle);     // Adjust Window To True Requested Size

    // class registered, so now create our window
    hwnd = CreateWindowEx(NULL,                                 // extended style
        "GLClass",                          // class name
        "BOGLGP - Chapter 2 - OpenGL Application",      // app name
        dwStyle | WS_CLIPCHILDREN |
        WS_CLIPSIBLINGS,
        0, 0,                               // x,y coordinate
        windowRect.right - windowRect.left,
        windowRect.bottom - windowRect.top, // width, height
        NULL,                               // handle to parent
        NULL,                               // handle to menu
        hInstance,                          // application instance
        NULL);                              // no extra params

    hDC = GetDC(hwnd);

    // check if window creation failed (hwnd would equal NULL)
    if (!hwnd)
        return 0;

    ShowWindow(hwnd, SW_SHOW);          // display the window
    UpdateWindow(hwnd);                 // update the window

    g_glRender->Init();

    while (!exiting)
    {
        g_glRender->Prepare(0.0f);
        g_glRender->Render();
        SwapBuffers(hDC);

        while (PeekMessage (&msg, NULL, 0, 0, PM_NOREMOVE))
        {
            if (!GetMessage (&msg, NULL, 0, 0))
            {
                exiting = true;
                break;
            }

            TranslateMessage (&msg);
            DispatchMessage (&msg);
        }
    }

    delete g_glRender;

    if (fullscreen)
    {
        ChangeDisplaySettings(NULL,0);          // If So Switch Back To The Desktop
        ShowCursor(TRUE);                       // Show Mouse Pointer
    }

    return (int)msg.wParam;
}

CGfxOpenGl

#ifdef _WINDOWS
#include <windows.h>
#endif


#include <gl/gl.h>
#include <gl/glu.h>
#include <math.h>
#include "CGfxOpenGL.h"


// disable implicit float-double casting
#pragma warning(disable:4305)

CGfxOpenGL::CGfxOpenGL()
{
	
}

CGfxOpenGL::~CGfxOpenGL()
{
}

bool CGfxOpenGL::Init()
{   
    // clear to black background
    glClearColor(0.0, 0.0, 0.0, 0.0);

    m_angle = 0.0f;

    return true;
}

bool CGfxOpenGL::Shutdown()
{
    return true;
}

void CGfxOpenGL::SetupProjection(int width, int height)
{
    if (height == 0)                    // don't want a divide by zero
    {
        height = 1;                 
    }

    glViewport(0, 0, width, height);        // reset the viewport to new dimensions
    glMatrixMode(GL_PROJECTION);            // set projection matrix current matrix
    glLoadIdentity();                       // reset projection matrix

    // calculate aspect ratio of window
    gluPerspective(52.0f,(GLfloat)width/(GLfloat)height,1.0f,1000.0f);

    glMatrixMode(GL_MODELVIEW);             // set modelview matrix
    glLoadIdentity();                       // reset modelview matrix

    m_windowWidth = width;
    m_windowHeight = height;
}

void CGfxOpenGL::Prepare(float dt)
{
    m_angle += 0.1f;
}

void CGfxOpenGL::Render()
{
    // clear screen and depth buffer
    glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);     
    glLoadIdentity();

    // move back 5 units and rotate about all 3 axes
    glTranslatef(0.0, 0.0, -5.0f);
    glRotatef(m_angle, 1.0f, 0.0f, 0.0f);
    glRotatef(m_angle, 0.0f, 1.0f, 0.0f);
    glRotatef(m_angle, 0.0f, 0.0f, 1.0f);

    // lime greenish color
    glColor3f(0.7f, 1.0f, 0.3f);

    // draw the triangle such that the rotation point is in the center
    glBegin(GL_TRIANGLES);
        glVertex3f(1.0f, -1.0f, 0.0f);
        glVertex3f(-1.0f, -1.0f, 0.0f);
        glVertex3f(0.0f, 1.0f, 0.0f);
    glEnd();
}

 

[cpjust]

You can use AfxMessageBox(), or if you prefer MFC you can use CWnd::MessageBox()...

 

[Miros]

Or if you're a dinosaur who writes naked C, you can use MessageBox!

 

[pghTech]

Since currently winmain.cpp seems to just setup the window for the application could I:

1)move the fullscreen variable to my CGfxOpenGL.h file as a private

2)create two new functions in CGfxOpenGL.h one to take the return selected button (yes / no) to define member variable CGfxOpenGl.fullscreen = <return of AfxMessagebox>
The other function just to retrieve CGfxOpenGl.fullscreen?

Then where it currently states in winmain.cpp

if(fullscreen)

do something like

if (CGfxOpenGl.fullscreen)

and it would retrieve what the users input was?

Or am I going about this wrong?

 

[Miros]

Not sure about the AFX version, but the MFC and naked C versions return ID_YES and ID_NO as the return values. So you'd just need a simple if statement or conditional expression to check the value and set it to something meaningful to you.

Something like:

fullscreen = ID_YES == MessageBox( hwnd, caption, text, MBID_YESNO ) ;

I don't have VS installed on this puter, so I'm working from memory.