Show menu on Window with Opengl - c++

Question

I made an Edit Box in my window, but when I try to draw something with OpenGl in dissapears. What should I change?
Here is the code:
#include <windows.h>
#include <gl/gl.h>
#include <math.h>
#define IDC_MAIN_EDIT 102
HWND hEdit;
// Function Declarations
HMENU men;
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 quit = 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, 800, 800,
NULL, NULL, hInstance, NULL );
// enable OpenGL for the window
EnableOpenGL( hWnd, &hDC, &hRC );
// program main loop
while ( !quit )
{
// check for messages
if ( PeekMessage( &msg, NULL, 0, 0, PM_REMOVE ) )
{
// handle or dispatch messages
if ( msg.message == WM_QUIT )
{
quit = TRUE;
}
else
{
TranslateMessage( &msg );
DispatchMessage( &msg );
}
}
else
{
// OpenGL animation code goes here
glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
glClear(GL_COLOR_BUFFER_BIT);
glPushMatrix();
glRotatef( theta, 0.0f, 0.0f, 1.0f );
glBegin( GL_TRIANGLES );
glColor3f( 1.0f, 0.0f, 0.0f ); glVertex2f( 0.0f, 0.25f );
glColor3f( 0.0f, 1.0f, 0.0f ); glVertex2f( 0.21f, -0.12f );
glColor3f( 0.0f, 0.0f, 1.0f ); glVertex2f( -0.21f, -0.12f );
glEnd();
glPopMatrix();
SwapBuffers( hDC );
theta += 1.0f;
}
}
// 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:
{
hEdit=CreateWindowEx(WS_EX_CLIENTEDGE,
"EDIT",
"",
WS_CHILD|WS_VISIBLE|
ES_MULTILINE|ES_AUTOVSCROLL|ES_AUTOHSCROLL,
50,
20,
60,
30,
hWnd,
(HMENU)IDC_MAIN_EDIT,
GetModuleHandle(NULL),
NULL);
HGDIOBJ hfDefault=GetStockObject(DEFAULT_GUI_FONT);
SendMessage(hEdit,
WM_SETFONT,
(WPARAM)hfDefault,
MAKELPARAM(FALSE,0));
SendMessage(hEdit,
WM_SETTEXT,
NULL,
(LPARAM)"Length");
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 format;
// 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;
format = ChoosePixelFormat( *hDC, &pfd );
SetPixelFormat( *hDC, format, &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 );
}

Answer 1

The answer is very simple - I just changed the parametrs of function CreateWindow to
hWnd = CreateWindow(
"GLSample", "OpenGL Sample",
WS_SYSMENU|WS_VISIBLE|WS_MINIMIZEBOX|WS_OVERLAPPED|WS_BORDER|WS_CAPTION|
WS_CLIPCHILDREN|WS_CLIPSIBLINGS,
0, 0, 800, 800,
NULL, NULL, hInstance, NULL );
this and voila- it all works^_^

Answer 2

It could be overwriting your painting in the default WM_ERASEBKGND code. One way to fix it is to move your OpenGL code to WM_PAINT handler, and then invalidate your window each time you want the animation to advance.