weird rotation

I just edited the default program for the dev cpp new file...

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


/**************************
 * Function Declarations
 *
 **************************/

LRESULT CALLBACK WndProc (HWND hWnd, UINT message,
WPARAM wParam, LPARAM lParam);
void EnableOpenGL (HWND hWnd, HDC *hDC, HGLRC *hRC);
void DisableOpenGL (HWND hWnd, HDC hDC, HGLRC hRC);


/**************************
 * WinMain
 *
 **************************/

int WINAPI 
WinMain (HINSTANCE hInstance,
         HINSTANCE hPrevInstance,
         LPSTR lpCmdLine,
         int iCmdShow)
{
    WNDCLASS wc;
    HWND hWnd;
    HDC hDC;
    HGLRC hRC;        
    MSG msg;
    BOOL bQuit = FALSE;
    float theta = 0.0f;

    /* register window class */
    wc.style = CS_OWNDC;
    wc.lpfnWndProc = WndProc;
    wc.cbClsExtra = 0;
    wc.cbWndExtra = 0;
    wc.hInstance = hInstance;
    wc.hIcon = LoadIcon (NULL, IDI_APPLICATION);
    wc.hCursor = LoadCursor (NULL, IDC_ARROW);
    wc.hbrBackground = (HBRUSH) GetStockObject (BLACK_BRUSH);
    wc.lpszMenuName = NULL;
    wc.lpszClassName = "GLSample";
    RegisterClass (&wc);

    /* create main window */
    hWnd = CreateWindow (
      "GLSample", "OpenGL Sample", 
      WS_CAPTION | WS_POPUPWINDOW | WS_VISIBLE,
      0, 0, 256, 256,
      NULL, NULL, hInstance, NULL);

    /* enable OpenGL for the window */
    EnableOpenGL (hWnd, &hDC, &hRC);

    /* program main loop */
    while (!bQuit)
    {
        /* check for messages */
        if (PeekMessage (&msg, NULL, 0, 0, PM_REMOVE))
        {
            /* handle or dispatch messages */
            if (msg.message == WM_QUIT)
            {
                bQuit = TRUE;
            }
            else
            {
                TranslateMessage (&msg);
                DispatchMessage (&msg);
            }
        }
        else
        {
            /* OpenGL animation code goes here */

            glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
            glClear (GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT);
            
            glMatrixMode(GL_PROJECTION);
            glMatrixMode(GL_MODELVIEW);
            glLoadIdentity();
            glPushMatrix ();
            glDisable(GL_CULL_FACE);
            glRotatef (theta, 0.1f, 0.0f, 0.1f);
            glBegin (GL_TRIANGLES);
            
            glColor3f (1.0f, 0.0f, 0.0f);            glVertex3f (0.0f, 1.0f, 0.0f);
            glColor3f (0.0f, 1.0f, 0.0f);            glVertex3f (0.87f, -0.5f, 0.0f);
            glColor3f (1.0f, 0.0f,1.0f);             glVertex3f (-0.87f, -0.5f, 0.0f);
            glColor3f (1.0f, 0.0f,1.0f);             glVertex3f (-0.87f, -0.5f, 0.0f);
            glColor3f (0.0f, 1.0f, 0.0f);            glVertex3f (0.87f, -0.5f, 0.0f);
            glColor3f (0.0f, 0.0f, 1.0f);            glVertex3f (0.0f, 0.25f, 1.0f);
            glColor3f (0.0f, 0.0f, 1.0f);            glVertex3f (0.0f, 0.25f, 1.0f);
            glColor3f (0.0f, 1.0f, 0.0f);            glVertex3f (0.87f, -0.5f, 0.0f);
            glColor3f (1.0f, 0.0f, 0.0f);            glVertex3f (0.0f, 1.0f, 0.0f);
            glColor3f (1.0f, 0.0f,1.0f);             glVertex3f (-0.87f, -0.5f, 0.0f);
            glColor3f (1.0f, 0.0f, 0.0f);            glVertex3f (0.0f, 1.0f, 0.0f);
            glColor3f (0.0f, 0.0f, 1.0f);            glVertex3f (0.0f, 0.25f, 1.0f);
                       
                                                                                           
            glEnd ();
            glPopMatrix ();

            SwapBuffers (hDC);

            theta += 1.0f;
            Sleep (1);
        }
    }

    /* shutdown OpenGL */
    DisableOpenGL (hWnd, hDC, hRC);

    /* destroy the window explicitly */
    DestroyWindow (hWnd);

    return msg.wParam;
}


/********************
 * Window Procedure
 *
 ********************/

LRESULT CALLBACK 
WndProc (HWND hWnd, UINT message,
         WPARAM wParam, LPARAM lParam)
{

    switch (message)
    {
    case WM_CREATE:
        return 0;
    case WM_CLOSE:
        PostQuitMessage (0);
        return 0;

    case WM_DESTROY:
        return 0;

    case WM_KEYDOWN:
        switch (wParam)
        {
        case VK_ESCAPE:
            PostQuitMessage(0);
            return 0;
        }
        return 0;

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


/*******************
 * Enable OpenGL
 *
 *******************/

void
EnableOpenGL (HWND hWnd, HDC *hDC, HGLRC *hRC)
{
    PIXELFORMATDESCRIPTOR pfd;
    int iFormat;

    /* get the device context (DC) */
    *hDC = GetDC (hWnd);

    /* set the pixel format for the DC */
    ZeroMemory (&pfd, sizeof (pfd));
    pfd.nSize = sizeof (pfd);
    pfd.nVersion = 1;
    pfd.dwFlags = PFD_DRAW_TO_WINDOW | 
      PFD_SUPPORT_OPENGL | PFD_DOUBLEBUFFER;
    pfd.iPixelType = PFD_TYPE_RGBA;
    pfd.cColorBits = 24;
    pfd.cDepthBits = 16;
    pfd.iLayerType = PFD_MAIN_PLANE;
    iFormat = ChoosePixelFormat (*hDC, &pfd);
    SetPixelFormat (*hDC, iFormat, &pfd);

    /* create and enable the render context (RC) */
    *hRC = wglCreateContext( *hDC );
    wglMakeCurrent( *hDC, *hRC );

}


/******************
 * Disable OpenGL
 *
 ******************/

void
DisableOpenGL (HWND hWnd, HDC hDC, HGLRC hRC)
{
    wglMakeCurrent (NULL, NULL);
    wglDeleteContext (hRC);
    ReleaseDC (hWnd, hDC);
}

[edited by - Infuscare on July 11, 2003 5:33:56 PM]

You''re missing out on alot of things in your initialisation - namely gluPerspective, glViewport.

You need to enable depth testing - that''s why the sides of your pyramid keep dissapearing.

where did you get this code? because it reminds me of some really terrible tutorials someone posted here...

glMatrixMode(GL_PROJECTION);
glMatrixMode(GL_MODELVIEW);

whats to point in changing the mode to projection, not doing anything and changing back to modelview? thats like someone walking to the door and opening and closing it for no reason.

glPushMatrix ();

usually good, but youre not doing anything else, so its also pointless.

glClearColor (0.0f, 0.0f, 0.0f, 0.0f);
glDisable(GL_CULL_FACE);

do this once when you init opengl (backface if you really need to change it, but you dont)

glPopMatrix ();

together with push its pointless.. youre not doing anything with the restored matrix and in the next step its overwritten with the identity anyway.

numbers are giving me a headache, so id rather check it on paper.
edit: ok.. not quite the orientation i would want to specify the points, but looks ok.

[edited by - Trienco on July 12, 2003 3:14:57 AM]

I would try Luke''s suggestion, glEnable(GL_DEPTH_TEST); after you have enabled your render context.

excellent, thanks all