How to resize an openGL window created with wglCreateContext?
- by Nick
Is it possible to resize an openGL window (or device context) created with wglCreateContext without disabling it? If so how? Right now I have a function which resizes the DC but the only way I could get it to work was to call DisableOpenGL and then re-enable. This causes any textures and other state changes to be lost. I would like to do this without the disable so that I do not have to go through the tedious task of recreating the openGL DC state.
HWND hWnd;
HDC hDC;
void View_setSizeWin32(int width, int height) {
// resize the window
LPRECT rec = malloc(sizeof(RECT));
GetWindowRect(hWnd, rec);
SetWindowPos(
hWnd,
HWND_TOP,
rec->left,
rec->top,
rec->left+width,
rec->left+height,
SWP_NOMOVE
);
free(rec);
// sad panda
DisableOpenGL( hWnd, hDC, hRC );
EnableOpenGL( hWnd, &hDC, &hRC );
glMatrixMode(GL_PROJECTION);
glLoadIdentity();
glOrtho(-(width/2), width/2, -(height/2), height/2, -1.0, 1.0);
// have fun recreating the openGL state....
}
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 );
}
void DisableOpenGL(HWND hWnd, HDC hDC, HGLRC hRC) {
wglMakeCurrent( NULL, NULL );
wglDeleteContext( hRC );
ReleaseDC( hWnd, hDC );
}
