Unresolved external symbols?

EGD Eric · 2003-08-21T15:24:31

I copied this code exactly from the book, but I get unresolved external symbols. Its supposed to display a rotating red triangle on the screen. Can someone please copy/paste this into their compiler and tell me what you think? #define WIN32_LEAN_AND_MEAN #include <windows.h> #include <gl/gl.h> //Standard OpenGL include #include <gl/glu.h>//OpenGL utilities #include <gl/glaux.h> //OpenGL auxiliary functions //Global Variables float angle = 0.0f; //Current angle of the rotating triangle HDC g_HDC; //global device context //Function to set the pixel format for the device void SetupPixelFormat(HDC hDC) { int nPixelFormat; //your pixel format index static PIXELFORMATDESCRIPTOR pfd = { sizeof(PIXELFORMATDESCRIPTOR), //Size of the structure 1, //Version, always set to 1 PFD_DRAW_TO_WINDOW | //support window PFD_SUPPORT_OPENGL | //support openGL PFD_DOUBLEBUFFER, //support double buffering PFD_TYPE_RGBA, //RGBA color mode 32, //go for 32 bit color mode 0, 0, 0, 0, 0, 0, //Ignore color bits, not used 0, //No alpha buffer 0, //Ignore shift bit 0, //No accumulation buffer 0, 0, 0, 0, //Ignore accumulation bits 16, //16 bit Z buffer size 0, //no stencil buffer 0, //no auxiliary buffer PFD_MAIN_PLANE, //main drawing plane 0, //reserved 0, 0, 0 }; //layer masks ignored //Choose best matching pixel format, return index nPixelFormat = ChoosePixelFormat(hDC, &pfd;; //set pixel format to device context SetPixelFormat(hDC, nPixelFormat, &pfd;; } //Event handler LRESULT CALLBACK WndProc(HWND hwnd, UINT message, WPARAM wParam, LPARAM lParam) { static HGLRC hRC; //rendering context static HDC hDC; //device context char string[] = "Hello, world!"; //text to be displayed int width, height; //window width and height switch(message) { case WM_CREATE: hDC = GetDC(hwnd); //get current window''s device context g_HDC = hDC; SetupPixelFormat(hDC); //Call your pixel format setup function //create rendering context and make it current hRC = wglCreateContext(hDC); wglMakeCurrent(hDC, hRC); return 0; break; case WM_CLOSE: //deselect rendering context and delete it wglMakeCurrent(hDC, NULL); wglDeleteContext(hRC); //sent WM_QUIT to message queue PostQuitMessage(0); return 0; break; case WM_SIZE: height = HIWORD(lParam); //retrieve width and height width = LOWORD(lParam); if(height == 0) //don''t want a divide by zero { height = 1; } //Reset the viewport to new dimensions glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); //set projection matrix glLoadIdentity(); //reset projection matrix //calculate aspect ratio of window gluPerspective(45.0f, (GLfloat)width/(GLfloat)height, 1.0f, 1000.0f); glMatrixMode(GL_MODELVIEW); //Set modelview matrix glLoadIdentity(); //reset modelview matrix return 0; break; default: break; } return(DefWindowProc(hwnd, message, wParam, lParam)); } //main windows entry point int WINAPI WinMain(HINSTANCE hInstance, HINSTANCE hPrevInstance, LPSTR lpCmdLine, int nShowCmd) { WNDCLASSEX windowClass; //window class HWND hwnd; //Window handle MSG msg; //message bool done; //fill out the window class structure windowClass.style = sizeof(WNDCLASSEX); windowClass.style = CS_HREDRAW | CS_VREDRAW; windowClass.lpfnWndProc = WndProc; windowClass.cbClsExtra = 0; windowClass.cbWndExtra = 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 //Register the window class if(!RegisterClassEx(&windowClass)) return 0; //class registered, so now create your window hwnd = CreateWindowEx(NULL, //extended style "MyClass", //class name "The OpenGL Window Application!",//app name WS_OVERLAPPEDWINDOW | WS_VISIBLE| //window style WS_SYSMENU | WS_CLIPCHILDREN | // WS_CLIPSIBLINGS, 100, 100,//x, y coordinate 400, 400,//width, height NULL, //handle to parent NULL, //handle to menu hInstance, //application instance NULL); //no extra params //Check if window creation failed if(!hwnd) return 0; ShowWindow(hwnd, SW_SHOW); //display the window UpdateWindow(hwnd); //update the window done = false; //loop variable while(!done) { PeekMessage(&msg, hwnd, NULL, NULL, PM_REMOVE); if(msg.message == WM_QUIT) //if you receive a WM_QUIT message? { done = true; } else { //do rendering here //clear screen and depth buffer glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glLoadIdentity(); //Reset modelview matrix angle = angle + 0.1f;//Increase rotation angle counter if(angle >= 360.0f) { angle = 0.0f; //reset angle counter } glTranslatef(0.0f, 0.0f, -5.0f); //move back 5 units glRotatef(angle, 0.0f, 0.0f, 1.0f);//draw the rectangle glColor3f(1.0f, 0.0f, 0.0f); //set color to red glBegin(GL_TRIANGLES); //draw the triangle glVertex3f(0.0f, 0.0f, 0.0f); glVertex3f(1.0f, 0.0f, 0.0f); glVertex3f(1.0f, 1.0f, 0.0f); glEnd(); SwapBuffers(g_HDC); TranslateMessage(&msg;; //translate/dispatch to envent queue DispatchMessage(&msg;; } } return int(msg.wParam); // MessageBox(NULL, "\Hello, world!", "My first windows application", NULL); }

Graphics and GPU Programming Programming

Started by EGD Eric August 07, 2003 07:40 AM

23 comments, last by EGD Eric 20 years, 7 months ago

MauMan

344

August 20, 2003 01:51 PM

1) Fired up dev studio 2002 Professional
2) File/New/Project
3) Selected C++/Win32 Project, Name: OpenGlTest, Location: C:\Source Code\C++\Test, then OK
4) Hit Application Settings, checked empty project, hit Finish
5) Right mouse on the project, Add/New Item, highlighted "C++ File", Name: OpenGlTest.cpp, hit Open
6) Pasted your code in (the code from your first post).
7) Right mouse click on the project select Properties, changed the configuration to be "All Configurations"
8) In the tree select Configuration Properties/Linker/Input. In the first field "Additional Dependencies" put:
opengl32.lib glu32.lib
9) hit OK
10) Hit F5 to run. Program exits early. Tracing in the debugger shows that RegisterClassEx is failing.
11) Fix the typo at line 115:

    windowClass.style = sizeof(WNDCLASSEX);

to be

    memset( &windowClass, 0, sizeof(WNDCLASSEX) );    windowClass.cbSize = sizeof(WNDCLASSEX);

in addition to zero initializing the structure. I also add a windows class name that matches the one in the CreateWindow() call:

    windowClass.lpszClassName = "MyClass";

12) I hit F5 and rebuild and it now runs.

[edited by - mauman on August 20, 2003 3:26:20 PM]

---CyberbrineDreamsSuspected implementation of the Windows idle loop: void idle_loop() { *((char*)rand()) = 0; }

Xero-X2

184

August 20, 2003 04:35 PM

In C++ builder 5, (includes opengl and stuff useing some weird mechanism on its own...)

I took first post code pasted it into a blank .cpp file.
changed the

windowClass.cbSize = sizeof(WNDCLASSEX);
windowClass.cbWndExtra = 0;
windowClass.lpszClassName = "MyClass";
windowClass.style = CS_HREDRAW | CS_VREDRAW;
windowClass.lpfnWndProc = WndProc;
windowClass.cbClsExtra = 0;
windowClass.cbWndExtra = 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

to be as it reads above, reloaded it to make a project file. hit run, it ran.

it shows a nifty red triangle rotating around the central z axis..

Before I changed the befoce code, it ran and closed itself with out doing anything. so in essence it did nothing.

"I seek knowledge and to help those who also seek it"

siaspete

208

August 21, 2003 04:05 AM

Time to learn how to program instead of copying and pasting.

Why you shouldn''t use iostream.h - ever! | A Good free online C++ book

Saurus Games, home of the Independent Game Engine

EGD Eric

106

Author

August 21, 2003 01:24 PM

If you want to save time, skip the first 2 paragraphs.
They are directed at Siaspete and Trienco.

Actually, I already know how to program. I'm just wet around the ears. I've already have a good grasp of the C++ language. I once made a 2-player chess program in C that was a bitch for me to debug (at the time). I've done file writing, operator overloading and templated linked lists, among other things. I've only worked in simple console before. When I learn something new, I like to start off with theory, then mimicking (copying and pasting) then tweaking with it, then More theory, then either repeat the steps or do whatever else I decide to do.
As I go, I use less and less "Crutches". This may not be how you learn, but its how I learn. You may have taught yourself, but ALL of MY programming skill comes from school. I just finished my first year, before which I didn't know much at all about computers.

Don't take your knowledge for granted. Some people just aren't as knowledgable and/or possessing as much "Computer sense" as you do. It doesn't mean I'm taking shortcuts or being lazy, its because its the only way I know how for now. If you can tell me a better way of doing it, maybe I'll try that.

I've implemented the changes in the C++6 project and it still exits early. This happens at line 131:

if(!RegisterClassEx(&windowClass))
return 0;

it seems to register the class okay, but then it skips
to the bottom line of this function call:

hwnd = CreateWindowEx(NULL,//extended style "MyClass",//class name "The OpenGL Window Application!",//app name
WS_OVERLAPPEDWINDOW | WS_VISIBLE| //window style
WS_SYSMENU | WS_CLIPCHILDREN | //
WS_CLIPSIBLINGS,
100, 100,//x, y coordinate
400, 400,//width, height
NULL, //handle to parent
NULL, //handle to menu
hInstance, //application instance
NULL); //no extra parameters

At this point hwnd is still NULL, which means it must not have Created the window. I can't step into the CreateWindowEx function because the compiler skips the lines for some reason.

if(!hwnd)
return 0;
This is where the program ends.

I tried this with C++6.

I'm gonna look into the .net development environment now, read the docs and stuff.

Edit: I just ran into something on the .net docs!
Its a Direct 3D tutorial! It showed the CreateWindow function, instead of the CreateWindowEx function, I tried this and it worked!

hwnd = CreateWindow("My Class", "The OpenGL Window Application!", WS_OVERLAPPEDWINDOW,
100, 100, 400, 400, GetDesktopWindow(), NULL, windowClass.hInstance, NULL);

[edited by - EGD Eric on August 21, 2003 2:37:34 PM]

MauMan

344

August 21, 2003 03:22 PM

If you use the same code from before you had two bugs in your window class code which may have caused your CreateWindow() call to fail. One was your window class name was missing. This is what the 1st argument to CreateWindow and the 2nd argument to CreateWindowEx use to find the class you registered. Second, you were setting the stype field to be the structure size not the cbSize field. Aslo, you should zero initialize your structures in windows in case you do not explicitly set all of the fields.

With that said your registration code should look like:

//fill out the window class structurememset( &windowClass, 0, sizeof(WNDCLASSEX));windowClass.cbSize = sizeof(WNDCLASSEX);windowClass.lpszClassName = "MyClass";windowClass.style = CS_HREDRAW | CS_VREDRAW;windowClass.lpfnWndProc = WndProc;windowClass.cbClsExtra = 0;windowClass.cbWndExtra = 0;windowClass.cbWndExtra = 0;windowClass.hInstance = hInstance;windowClass.hIcon = LoadIcon(NULL, IDI_APPLICATION); //default iconwindowClass.hCursor = LoadCursor(NULL, IDC_ARROW); //default arrowwindowClass.hbrBackground = NULL; //don't need backgroundwindowClass.lpszMenuName = NULL; //no menu//Register the window classif(!RegisterClassEx(&windowClass))   return 0;

You should find that this works on VC6, VC7 (Visual Studio .Net 2002), and VC7.1 (Visual Studio .Net 2003)

[edited by - mauman on August 21, 2003 4:24:31 PM]

---CyberbrineDreamsSuspected implementation of the Windows idle loop: void idle_loop() { *((char*)rand()) = 0; }

Unresolved external symbols?

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