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View Full Version : Undefined Reference using OpenGL and FLTK



CokeCola
03-27-2005, 09:52 AM
Hello all. I have a feeling this is one of those types of problems that gets posted regularly, but a search didn't answer the question.

I'm trying to compile a program with an OpenGL FLTK window, and I'm getting

[Linker error] undefined reference to FL_GL_Window... everything

I'm using Dev-C++ on Windows XP.

Here is the Dev-C++ FLTK demo that does work:
__________________________________________________
#include <FL/Fl.H>
#include <FL/Fl_Window.H>
#include <FL/Fl_Box.H>

int
main (int argc, char *argv[])
{
Fl_Window *window;
Fl_Box *box;

window = new Fl_Window (300, 180);
box = new Fl_Box (20, 40, 260, 100, "Hello World!");

box->box (FL_UP_BOX);
box->labelsize (36);
box->labelfont (FL_BOLD+FL_ITALIC);
box->labeltype (FL_SHADOW_LABEL);
window->end ();
window->show (argc, argv);

return Fl::run();
}
__________________________________________________
Linker Parameters: -lfltk -lole32 -luuid -lcomctl32 -lwsock32 -lm

Here is the Dev-C++ OpenGL demo that does work:
__________________________________________________
/**************************
* Includes
*
**************************/

#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);

glPushMatrix ();
glRotatef (theta, 0.0f, 0.0f, 1.0f);
glBegin (GL_TRIANGLES);
glColor3f (1.0f, 0.0f, 0.0f); glVertex2f (0.0f, 1.0f);
glColor3f (0.0f, 1.0f, 0.0f); glVertex2f (0.87f, -0.5f);
glColor3f (0.0f, 0.0f, 1.0f); glVertex2f (-0.87f, -0.5f);
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);
}
__________________________________________________
Linker Parameters: -lopengl32

And here's the simple OpenGL FLTK program from
http://www.cs.wisc.edu/graphics/Courses/cs-638-1999/Examples/GL/simple.cpp
that does not work:
__________________________________________________
// simple OpenGL / FlTk program
// written 10/16/99, Michael L Gleicher

#include <FL/Fl_Gl_Window.h>
#include <Fl/Fl.h>
#include <windows.h>
#include <gl/gl.h>

// make a Gl window that draws something:
class MyGlWindow : public Fl_Gl_Window {
public:
MyGlWindow(int x, int y, int w, int h) :
Fl_Gl_Window(x,y,w,h,"My GL Window")
{
}
private:
void draw() { // the draw method must be private
glClearColor(0,0,0,0); // clear the window to black
glClear(GL_COLOR_BUFFER_BIT); // clear the window

glColor3f(1,1,0); // draw in yellow
glRectf(-.5,-.5,.5,.5); // draw a filled rectangle
};
};

// the main routine makes the window, and then runs an even loop
// until the window is closed
main()
{
MyGlWindow* gl = new MyGlWindow(100,100,500,500);
gl->show(); // this actually opens the window

Fl::run();
delete gl;

return 1;
}
__________________________________________________
Linker Parameters: -lopengl32 -lfltk -lole32 -luuid -lcomctl32 -lwsock32 -lm

Errors:

[Linker error] undefined reference to `vtable for Fl_Gl_Window'
[Linker error] undefined reference to `Fl_Gl_Window::init()'
[Linker error] undefined reference to `Fl_Gl_Window::resize(int, int, int, int)'
[Linker error] undefined reference to `Fl_Gl_Window::flush()'
[Linker error] undefined reference to `Fl_Gl_Window::show()'
[Linker error] undefined reference to `Fl_Gl_Window::hide()'
[Linker error] undefined reference to `Fl_Gl_Window::draw_overlay()'
[Linker error] undefined reference to `Fl_Gl_Window::~Fl_Gl_Window()'
[Linker error] undefined reference to `Fl_Gl_Window::~Fl_Gl_Window()'
ld returned 1 exit status

Other OpenGL FLTK windows give similar results. What am I missing?

mikael_aronsson
03-27-2005, 11:14 PM
Hi !

One of two problems, you have not added to fltk import library to the linker options, something like -lfltk, or if you have done that it may not be in the right order, the list of libraries to the linker must be in correct order, reference before implementation.