Click here to Skip to main content
13,292,913 members (89,286 online)
Click here to Skip to main content
Add your own
alternative version


44 bookmarked
Posted 28 Sep 2002

How to add OpenGL support to ATL controls

, 28 Sep 2002
Rate this:
Please Sign up or sign in to vote.
An article describing the step-by-step process of adding basic OpenGL support to an ATL control


This tutorial will demonstrate how to add OpenGL support to an ATL control, and constitutes a cut-down, organized version of the ATL OpenGL demo that comes with Visual C++ in a more printable and easier-to-digest format. In order to work with this tutorial, you must create an ATL control in your project. What follows below is a step-by-step guide to adding the most basic OpenGL support to an ATL control.

Note: though I prefix function declarations with CMyControl::, I would recommend writing these functions inline (in the header file) and if you do that, the prefix must be removed.

  1. Add support for headers <gl/gl.h> and <gl/glu.h>; Add support for opengl32.lib and glu32.lib libraries.

    This can be done by adding the following four lines at the end of your stdafx.h file:

    <pre lang=c++>#include <gl/gl.h> #include <gl/glu.h> #pragma comment(lib, "opengl32.lib") #pragma comment(lib, "glu32.lib")
  2. Add an OpenGL rendering context variable to your control class: <pre lang=c++>// OpenGL rendering context HGLRC m_hRC; Now make a function to choose the OpenGL pixel format. This function will take a device context handle as a parameter and would set pixel format specifically for this device context. The function should look like the following: <pre lang=c++>// Set OpenGL pixel format for given DC BOOL MyControl::SetupPixelFormat(HDC hdc) { static PIXELFORMATDESCRIPTOR pfd = { sizeof(PIXELFORMATDESCRIPTOR), // size of this pfd 1, // version number PFD_DRAW_TO_WINDOW | // support window PFD_SUPPORT_OPENGL | // support OpenGL PFD_DOUBLEBUFFER, // double buffered PFD_TYPE_RGBA, // RGBA type 24, // 24-bit color depth 0, 0, 0, 0, 0, 0, // color bits ignored 0, // no alpha buffer 0, // shift bit ignored 0, // no accumulation buffer 0, 0, 0, 0, // accum bits ignored 32, // 32-bit z-buffer 0, // no stencil buffer 0, // no auxiliary buffer PFD_MAIN_PLANE, // main layer 0, // reserved 0, 0, 0 // layer masks ignored }; int pixelformat; if ((pixelformat = ChoosePixelFormat(hdc, &pfd)) == 0) { ATLASSERT(FALSE); return FALSE; } if (SetPixelFormat(hdc, pixelformat, &pfd) == FALSE) { ATLASSERT(FALSE); return FALSE; } return TRUE; }
  3. Make a function that would create an OpenGL rendering context and initialize the viewport. Note that after setting the current rendering context, we can begin calling OpenGL functions such as glViewport. <pre lang=c++>// Create rendering context given device context and control bounds void MyControl::CreateContext(HDC hdc, RECT& rc) { PIXELFORMATDESCRIPTOR pfd; if (!SetupPixelFormat(hdc)) return; int n = GetPixelFormat(hdc); DescribePixelFormat(hdc, n, sizeof(pfd), &pfd); m_hRC = wglCreateContext(hdc); wglMakeCurrent(hdc, m_hRC); // OpenGL code starts here - below is an example int width = rc.right - rc.left; int height = rc.bottom -; glViewport(0, 0, width, height); glMatrixMode(GL_PROJECTION); glLoadIdentity(); gluOrtho2D(-width/2, width/2, -height/2, height/2); glMatrixMode(GL_MODELVIEW); }
  4. Add a call to the above function from OnCreate. To do that, you first have to create a WM_CREATE handler. Use the Messages button on the Properties toolbar to add a handler. Then, find the function and add code similar to the following: <pre lang=c++>LRESULT CMyControl::OnCreate(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/) { HDC hdc = GetDC(); RECT rc; GetClientRect(&rc); CreateContext(hdc, rc); return 0; }
  5. In a similar fashion, add code for OnDestroy (WM_DESTROY) to clear the rendering context and delete it.
    LRESULT CMyControl::OnDestroy(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/)
      wglMakeCurrent(NULL, NULL);
      if (m_hRC)
        m_hRC = NULL;
      return 0;
  6. Handling WM_SIZE is also important. Whenever the window resizes, we must nullify the current OpenGL rendering context and recreate it from scratch. <pre lang=c++>LRESULT CMyControl::OnSize(UINT /*uMsg*/, WPARAM /*wParam*/, LPARAM /*lParam*/, BOOL& /*bHandled*/) { // when resized, recreate the device context wglMakeCurrent(NULL, NULL); if (m_hRC) { wglDeleteContext(m_hRC); m_hRC = NULL; } HDC hdc = GetDC(); RECT rc; GetClientRect(&rc); CreateContext(hdc, rc); return 0; }

    All done. Remember! You can use glaux library (glaux32.lib, <glaux.h>) to implement functionality equivalent to the GLUT library (though you probably won't need the windowing functions). For example, you can use auxDIBImageLoad to load bitmaps to use as textures. However, I would recommend using more advanced methods of texturing, for example using PNG files for textures that have an alpha channel.

  7. Rendering can be done in OnDraw. Here is an example: <pre lang=c++>HRESULT OnDraw(ATL_DRAWINFO& di) { HDC hdc = di.hdcDraw; RECT& rc = *(RECT*)di.prcBounds; wglMakeCurrent(hdc, m_hRC); glClearColor(1.0f, 0.0f, 0.0f, 10.0f); glClear(GL_COLOR_BUFFER_BIT | GL_DEPTH_BUFFER_BIT); glPushMatrix(); // compute dimensions of a quarter of the control SIZE qtrSize = { (rc.right - rc.left) / 2, (rc.bottom - / 2 }; glBegin(GL_QUADS); glColor3ub(255, 0, 0); glVertex3s(,, 0); glColor3ub(0, 255, 0); glVertex3s(,, 0); glColor3ub(0, 0, 255); glVertex3s(,, 0); glColor3ub(255, 255, 255); glVertex3s(,, 0); glEnd(); glPopMatrix(); glFinish(); SwapBuffers(wglGetCurrentDC()); return S_OK; }

Possible Improvements

I believe it is possible to create a mixin class/abstract superclass that will add OpenGL functionality to an ATL control in a much cleaner fashion than a bunch of functions/message handlers inside every control class. Writing all this code for each ATL control (if you have many in your project) is tedious: it would be better if you could specify that your control inherits from some CControlOpenGL<YourControl> class. This functionality, as well as more advanced OpenGL modes and options may make up material for another tutorial.


This article, along with any associated source code and files, is licensed under The Code Project Open License (CPOL)


About the Author

Dmitri Nеstеruk
Founder ActiveMesa
United Kingdom United Kingdom
I work primarily with the .NET technology stack, and specialize in accelerated code production via code generation (static or dynamic), aspect-oriented programming, MDA, domain-specific languages and anything else that gets products out the door faster. My languages of choice are C# and F#, though I'm open to suggestions.

I'm a Microsoft MVP (Visual C#) since 2009. I run a collective tech blog at I use my own editor called TypograFix to typeset articles and blog posts.

Like the article and want this implemented in your product? Got a project that can benefit from Microsoft.Net goodness? Then get in touch!

You may also be interested in...


Comments and Discussions

QuestionDoesn't render anything Pin
DrkAngr7-Jan-09 13:21
memberDrkAngr7-Jan-09 13:21 
QuestionNo hardware acceleration Pin
blaless27-Aug-07 6:22
memberblaless27-Aug-07 6:22 
QuestionActiveX control crashes Pin
PabloMano22-Sep-06 6:04
memberPabloMano22-Sep-06 6:04 
AnswerRe: ActiveX control crashes Pin
Dmitri Nesteruk27-Feb-07 20:15
memberDmitri Nesteruk27-Feb-07 20:15 
GeneralRe: ActiveX control crashes Pin
vyacheslav avdeyev4-Nov-07 23:11
membervyacheslav avdeyev4-Nov-07 23:11 
GeneralRe: ActiveX control crashes Pin
Dmitri Nesteruk5-Nov-07 2:20
memberDmitri Nesteruk5-Nov-07 2:20 
AnswerRe: ActiveX control crashes Pin
luisperdigao26-Jul-08 1:29
memberluisperdigao26-Jul-08 1:29 
Questionhow to create a activex control that can be used in vb6? such as an example of atlopengldemo Pin
ictory18-May-05 3:40
memberictory18-May-05 3:40 
GeneralAdding ATL wizard setup Pin
rbtoaks4-Jun-04 7:14
memberrbtoaks4-Jun-04 7:14 
GeneralRe: Adding ATL wizard setup Pin
Anonymous23-Jul-04 2:08
sussAnonymous23-Jul-04 2:08 
GeneralRe: Adding ATL wizard setup Pin
rbtoaks23-Jul-04 7:31
memberrbtoaks23-Jul-04 7:31 
Questionpossible to create transparent opengl windows? Pin
BugByter23-Feb-04 12:14
memberBugByter23-Feb-04 12:14 
AnswerRe: possible to create transparent opengl windows? Pin
Anonymous25-May-04 2:09
sussAnonymous25-May-04 2:09 
I think the easiest way to have live OpenGL content on your desktop is to put a COM control on a webpage and set that webpage as your background.
Generalresize Pin
Mikko Mononen29-Sep-02 23:43
memberMikko Mononen29-Sep-02 23:43 
QuestionWindowOnly ? Pin
Anonymous29-Sep-02 13:24
sussAnonymous29-Sep-02 13:24 
AnswerRe: WindowOnly ? Pin
Anonymous4-Feb-03 2:06
sussAnonymous4-Feb-03 2:06 

General General    News News    Suggestion Suggestion    Question Question    Bug Bug    Answer Answer    Joke Joke    Praise Praise    Rant Rant    Admin Admin   

Use Ctrl+Left/Right to switch messages, Ctrl+Up/Down to switch threads, Ctrl+Shift+Left/Right to switch pages.

Permalink | Advertise | Privacy | Terms of Use | Mobile
Web04 | 2.8.171207.1 | Last Updated 29 Sep 2002
Article Copyright 2002 by Dmitri Nеstеruk
Everything else Copyright © CodeProject, 1999-2017
Layout: fixed | fluid