src/msw/glcanvas.cpp

   1 /////////////////////////////////////////////////////////////////////////////
   2 // Name:        src/msw/glcanvas.cpp
   3 // Purpose:     wxGLCanvas, for using OpenGL with wxWidgets under MS Windows
   4 // Author:      Julian Smart
   5 // Modified by:
   6 // Created:     04/01/98
   7 // RCS-ID:      $Id$
   8 // Copyright:   (c) Julian Smart
   9 // Licence:     wxWindows licence
  10 /////////////////////////////////////////////////////////////////////////////
  11
  12 #include "wx/wxprec.h"
  13
  14 #if defined(__BORLANDC__)
  15     #pragma hdrstop
  16 #endif
  17
  18 #if wxUSE_GLCANVAS
  19
  20 #ifndef WX_PRECOMP
  21     #include "wx/frame.h"
  22     #include "wx/settings.h"
  23     #include "wx/intl.h"
  24     #include "wx/log.h"
  25     #include "wx/app.h"
  26     #include "wx/module.h"
  27 #endif
  28
  29 #include "wx/msw/private.h"
  30
  31 // DLL options compatibility check:
  32 #include "wx/build.h"
  33 WX_CHECK_BUILD_OPTIONS("wxGL")
  34
  35 #include "wx/glcanvas.h"
  36
  37 #if GL_EXT_vertex_array
  38     #define WXUNUSED_WITHOUT_GL_EXT_vertex_array(name) name
  39 #else
  40     #define WXUNUSED_WITHOUT_GL_EXT_vertex_array(name) WXUNUSED(name)
  41 #endif
  42
  43 /*
  44   The following two compiler directives are specific to the Microsoft Visual
  45   C++ family of compilers
  46
  47   Fundementally what they do is instruct the linker to use these two libraries
  48   for the resolution of symbols. In essence, this is the equivalent of adding
  49   these two libraries to either the Makefile or project file.
  50
  51   This is NOT a recommended technique, and certainly is unlikely to be used
  52   anywhere else in wxWidgets given it is so specific to not only wxMSW, but
  53   also the VC compiler. However, in the case of opengl support, it's an
  54   applicable technique as opengl is optional in setup.h This code (wrapped by
  55   wxUSE_GLCANVAS), now allows opengl support to be added purely by modifying
  56   setup.h rather than by having to modify either the project or DSP fle.
  57
  58   See MSDN for further information on the exact usage of these commands.
  59 */
  60 #ifdef _MSC_VER
  61 #  pragma comment( lib, "opengl32" )
  62 #  pragma comment( lib, "glu32" )
  63 #endif
  64
  65
  66 static const wxChar *wxGLCanvasClassName = wxT("wxGLCanvasClass");
  67 static const wxChar *wxGLCanvasClassNameNoRedraw = wxT("wxGLCanvasClassNR");
  68
  69 LRESULT WXDLLEXPORT APIENTRY _EXPORT wxWndProc(HWND hWnd, UINT message,
  70                                    WPARAM wParam, LPARAM lParam);
  71
  72 // ----------------------------------------------------------------------------
  73 // wxGLModule is responsible for unregistering wxGLCanvasClass Windows class
  74 // ----------------------------------------------------------------------------
  75
  76 class wxGLModule : public wxModule
  77 {
  78 public:
  79     bool OnInit() { return true; }
  80     void OnExit() { UnregisterClasses(); }
  81
  82     // register the GL classes if not done yet, return true if ok, false if
  83     // registration failed
  84     static bool RegisterClasses();
  85
  86     // unregister the classes, done automatically on program termination
  87     static void UnregisterClasses();
  88
  89 private:
  90     // wxGLCanvas is only used from the main thread so this is MT-ok
  91     static bool ms_registeredGLClasses;
  92
  93     DECLARE_DYNAMIC_CLASS(wxGLModule)
  94 };
  95
  96 IMPLEMENT_DYNAMIC_CLASS(wxGLModule, wxModule)
  97
  98 bool wxGLModule::ms_registeredGLClasses = false;
  99
 100 /* static */
 101 bool wxGLModule::RegisterClasses()
 102 {
 103     if (ms_registeredGLClasses)
 104         return true;
 105
 106     // We have to register a special window class because we need the CS_OWNDC
 107     // style for GLCanvas.
 108
 109   /*
 110   From Angel Popov <jumpo@bitex.com>
 111
 112   Here are two snips from a dicussion in the OpenGL Gamedev list that explains
 113   how this problem can be fixed:
 114
 115   "There are 5 common DCs available in Win95. These are aquired when you call
 116   GetDC or GetDCEx from a window that does _not_ have the OWNDC flag.
 117   OWNDC flagged windows do not get their DC from the common DC pool, the issue
 118   is they require 800 bytes each from the limited 64Kb local heap for GDI."
 119
 120   "The deal is, if you hold onto one of the 5 shared DC's too long (as GL apps
 121   do), Win95 will actually "steal" it from you.  MakeCurrent fails,
 122   apparently, because Windows re-assigns the HDC to a different window.  The
 123   only way to prevent this, the only reliable means, is to set CS_OWNDC."
 124   */
 125
 126     WNDCLASS wndclass;
 127
 128     // the fields which are common to all classes
 129     wndclass.lpfnWndProc   = (WNDPROC)wxWndProc;
 130     wndclass.cbClsExtra    = 0;
 131     wndclass.cbWndExtra    = sizeof( DWORD ); // VZ: what is this DWORD used for?
 132     wndclass.hInstance     = wxhInstance;
 133     wndclass.hIcon         = (HICON) NULL;
 134     wndclass.hCursor       = ::LoadCursor((HINSTANCE)NULL, IDC_ARROW);
 135     wndclass.lpszMenuName  = NULL;
 136
 137     // Register the GLCanvas class name
 138     wndclass.hbrBackground = (HBRUSH)NULL;
 139     wndclass.lpszClassName = wxGLCanvasClassName;
 140     wndclass.style         = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS | CS_OWNDC;
 141
 142     if ( !::RegisterClass(&wndclass) )
 143     {
 144         wxLogLastError(wxT("RegisterClass(wxGLCanvasClass)"));
 145         return false;
 146     }
 147
 148     // Register the GLCanvas class name for windows which don't do full repaint
 149     // on resize
 150     wndclass.lpszClassName = wxGLCanvasClassNameNoRedraw;
 151     wndclass.style        &= ~(CS_HREDRAW | CS_VREDRAW);
 152
 153     if ( !::RegisterClass(&wndclass) )
 154     {
 155         wxLogLastError(wxT("RegisterClass(wxGLCanvasClassNameNoRedraw)"));
 156
 157         ::UnregisterClass(wxGLCanvasClassName, wxhInstance);
 158
 159         return false;
 160     }
 161
 162     ms_registeredGLClasses = true;
 163
 164     return true;
 165 }
 166
 167 /* static */
 168 void wxGLModule::UnregisterClasses()
 169 {
 170     // we need to unregister the classes in case we're in a DLL which is
 171     // unloaded and then loaded again because if we don't, the registration is
 172     // going to fail in wxGLCanvas::Create() the next time we're loaded
 173     if ( ms_registeredGLClasses )
 174     {
 175         ::UnregisterClass(wxGLCanvasClassName, wxhInstance);
 176         ::UnregisterClass(wxGLCanvasClassNameNoRedraw, wxhInstance);
 177
 178         ms_registeredGLClasses = false;
 179     }
 180 }
 181
 182 /*
 183  * GLContext implementation
 184  */
 185
 186 IMPLEMENT_CLASS(wxGLContext, wxObject)
 187
 188 wxGLContext::wxGLContext(wxGLCanvas* win, const wxGLContext* other /* for sharing display lists */)
 189 {
 190   m_glContext = wglCreateContext((HDC) win->GetHDC());
 191   wxCHECK_RET( m_glContext, wxT("Couldn't create OpenGL context") );
 192
 193   if( other != 0 )
 194     wglShareLists( other->m_glContext, m_glContext );
 195 }
 196
 197 wxGLContext::~wxGLContext()
 198 {
 199     // If this context happens to be the current context, wglDeleteContext() makes it un-current first.
 200     wglDeleteContext(m_glContext);
 201 }
 202
 203 void wxGLContext::SetCurrent(const wxGLCanvas& win) const
 204 {
 205     wglMakeCurrent((HDC) win.GetHDC(), m_glContext);
 206 }
 207
 208
 209 /*
 210  * wxGLCanvas implementation
 211  */
 212
 213 IMPLEMENT_CLASS(wxGLCanvas, wxWindow)
 214
 215 BEGIN_EVENT_TABLE(wxGLCanvas, wxWindow)
 216     EVT_SIZE(wxGLCanvas::OnSize)
 217     EVT_PALETTE_CHANGED(wxGLCanvas::OnPaletteChanged)
 218     EVT_QUERY_NEW_PALETTE(wxGLCanvas::OnQueryNewPalette)
 219 END_EVENT_TABLE()
 220
 221 wxGLCanvas::wxGLCanvas(wxWindow *parent, wxWindowID id, int *attribList,
 222     const wxPoint& pos, const wxSize& size, long style,
 223     const wxString& name, const wxPalette& palette) : wxWindow()
 224 {
 225     m_glContext = NULL;
 226
 227     if (Create(parent, id, pos, size, style, name))
 228     {
 229         SetBackgroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE));
 230     }
 231
 232     m_hDC = (WXHDC) ::GetDC((HWND) GetHWND());
 233
 234     SetupPixelFormat(attribList);
 235     SetupPalette(palette);
 236
 237     // This ctor does *not* create an instance of wxGLContext,
 238     // m_glContext intentionally remains NULL.
 239 }
 240
 241 wxGLCanvas::wxGLCanvas(wxWindow *parent, wxWindowID id,
 242     const wxPoint& pos, const wxSize& size, long style, const wxString& name,
 243     int *attribList, const wxPalette& palette) : wxWindow()
 244 {
 245   m_glContext = (wxGLContext*) NULL;
 246
 247   bool ret = Create(parent, id, pos, size, style, name);
 248
 249   if ( ret )
 250   {
 251     SetBackgroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE));
 252   }
 253
 254   m_hDC = (WXHDC) ::GetDC((HWND) GetHWND());
 255
 256   SetupPixelFormat(attribList);
 257   SetupPalette(palette);
 258
 259   m_glContext = new wxGLContext(this);
 260 }
 261
 262 wxGLCanvas::wxGLCanvas( wxWindow *parent,
 263               const wxGLContext *shared, wxWindowID id,
 264               const wxPoint& pos, const wxSize& size, long style, const wxString& name,
 265               int *attribList, const wxPalette& palette )
 266   : wxWindow()
 267 {
 268   m_glContext = (wxGLContext*) NULL;
 269
 270   bool ret = Create(parent, id, pos, size, style, name);
 271
 272   if ( ret )
 273   {
 274     SetBackgroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE));
 275   }
 276
 277   m_hDC = (WXHDC) ::GetDC((HWND) GetHWND());
 278
 279   SetupPixelFormat(attribList);
 280   SetupPalette(palette);
 281
 282   m_glContext = new wxGLContext(this, shared);
 283 }
 284
 285 // Not very useful for wxMSW, but this is to be wxGTK compliant
 286
 287 wxGLCanvas::wxGLCanvas( wxWindow *parent, const wxGLCanvas *shared, wxWindowID id,
 288                         const wxPoint& pos, const wxSize& size, long style, const wxString& name,
 289                         int *attribList, const wxPalette& palette ):
 290   wxWindow()
 291 {
 292   m_glContext = (wxGLContext*) NULL;
 293
 294   bool ret = Create(parent, id, pos, size, style, name);
 295
 296   if ( ret )
 297   {
 298     SetBackgroundColour(wxSystemSettings::GetColour(wxSYS_COLOUR_3DFACE));
 299   }
 300
 301   m_hDC = (WXHDC) ::GetDC((HWND) GetHWND());
 302
 303   SetupPixelFormat(attribList);
 304   SetupPalette(palette);
 305
 306   wxGLContext *sharedContext=0;
 307   if (shared) sharedContext=shared->GetContext();
 308   m_glContext = new wxGLContext(this, sharedContext);
 309 }
 310
 311 wxGLCanvas::~wxGLCanvas()
 312 {
 313   delete m_glContext;
 314
 315   ::ReleaseDC((HWND) GetHWND(), (HDC) m_hDC);
 316 }
 317
 318 // Replaces wxWindow::Create functionality, since we need to use a different
 319 // window class
 320 bool wxGLCanvas::Create(wxWindow *parent,
 321                         wxWindowID id,
 322                         const wxPoint& pos,
 323                         const wxSize& size,
 324                         long style,
 325                         const wxString& name)
 326 {
 327     wxCHECK_MSG( parent, false, wxT("can't create wxWindow without parent") );
 328
 329     if ( !wxGLModule::RegisterClasses() )
 330     {
 331         wxLogError(_("Failed to register OpenGL window class."));
 332
 333         return false;
 334     }
 335
 336     if ( !CreateBase(parent, id, pos, size, style, wxDefaultValidator, name) )
 337         return false;
 338
 339     parent->AddChild(this);
 340
 341     DWORD msflags = 0;
 342
 343     /*
 344        A general rule with OpenGL and Win32 is that any window that will have a
 345        HGLRC built for it must have two flags:  WS_CLIPCHILDREN & WS_CLIPSIBLINGS.
 346        You can find references about this within the knowledge base and most OpenGL
 347        books that contain the wgl function descriptions.
 348      */
 349
 350     WXDWORD exStyle = 0;
 351     msflags |= WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;
 352     msflags |= MSWGetStyle(style, & exStyle) ;
 353
 354     return MSWCreate(wxGLCanvasClassName, NULL, pos, size, msflags, exStyle);
 355 }
 356
 357 static void AdjustPFDForAttributes(PIXELFORMATDESCRIPTOR& pfd, int *attribList)
 358 {
 359   if (attribList) {
 360     pfd.dwFlags &= ~PFD_DOUBLEBUFFER;
 361     pfd.iPixelType = PFD_TYPE_COLORINDEX;
 362     pfd.cColorBits = 0;
 363     int arg=0;
 364
 365     while( (attribList[arg]!=0) )
 366     {
 367       switch( attribList[arg++] )
 368       {
 369         case WX_GL_RGBA:
 370           pfd.iPixelType = PFD_TYPE_RGBA;
 371           break;
 372         case WX_GL_BUFFER_SIZE:
 373           pfd.cColorBits = (BYTE)attribList[arg++];
 374           break;
 375         case WX_GL_LEVEL:
 376           // this member looks like it may be obsolete
 377           if (attribList[arg] > 0) {
 378             pfd.iLayerType = (BYTE)PFD_OVERLAY_PLANE;
 379           } else if (attribList[arg] < 0) {
 380             pfd.iLayerType = (BYTE)PFD_UNDERLAY_PLANE;
 381           } else {
 382             pfd.iLayerType = (BYTE)PFD_MAIN_PLANE;
 383           }
 384           arg++;
 385           break;
 386         case WX_GL_DOUBLEBUFFER:
 387           pfd.dwFlags |= PFD_DOUBLEBUFFER;
 388           break;
 389         case WX_GL_STEREO:
 390           pfd.dwFlags |= PFD_STEREO;
 391           break;
 392         case WX_GL_AUX_BUFFERS:
 393           pfd.cAuxBuffers = (BYTE)attribList[arg++];
 394           break;
 395         case WX_GL_MIN_RED:
 396           pfd.cColorBits = (BYTE)(pfd.cColorBits + (pfd.cRedBits = (BYTE)attribList[arg++]));
 397           break;
 398         case WX_GL_MIN_GREEN:
 399           pfd.cColorBits = (BYTE)(pfd.cColorBits + (pfd.cGreenBits = (BYTE)attribList[arg++]));
 400           break;
 401         case WX_GL_MIN_BLUE:
 402           pfd.cColorBits = (BYTE)(pfd.cColorBits + (pfd.cBlueBits = (BYTE)attribList[arg++]));
 403           break;
 404         case WX_GL_MIN_ALPHA:
 405           // doesn't count in cColorBits
 406           pfd.cAlphaBits = (BYTE)attribList[arg++];
 407           break;
 408         case WX_GL_DEPTH_SIZE:
 409           pfd.cDepthBits = (BYTE)attribList[arg++];
 410           break;
 411         case WX_GL_STENCIL_SIZE:
 412           pfd.cStencilBits = (BYTE)attribList[arg++];
 413           break;
 414         case WX_GL_MIN_ACCUM_RED:
 415           pfd.cAccumBits = (BYTE)(pfd.cAccumBits + (pfd.cAccumRedBits = (BYTE)attribList[arg++]));
 416           break;
 417         case WX_GL_MIN_ACCUM_GREEN:
 418           pfd.cAccumBits = (BYTE)(pfd.cAccumBits + (pfd.cAccumGreenBits = (BYTE)attribList[arg++]));
 419           break;
 420         case WX_GL_MIN_ACCUM_BLUE:
 421           pfd.cAccumBits = (BYTE)(pfd.cAccumBits + (pfd.cAccumBlueBits = (BYTE)attribList[arg++]));
 422           break;
 423         case WX_GL_MIN_ACCUM_ALPHA:
 424           pfd.cAccumBits = (BYTE)(pfd.cAccumBits + (pfd.cAccumAlphaBits = (BYTE)attribList[arg++]));
 425           break;
 426         default:
 427           break;
 428       }
 429     }
 430   }
 431 }
 432
 433 void wxGLCanvas::SetupPixelFormat(int *attribList) // (HDC hDC)
 434 {
 435   PIXELFORMATDESCRIPTOR pfd = {
 436         sizeof(PIXELFORMATDESCRIPTOR),    /* size */
 437         1,                /* version */
 438         PFD_SUPPORT_OPENGL |
 439         PFD_DRAW_TO_WINDOW |
 440         PFD_DOUBLEBUFFER,        /* support double-buffering */
 441         PFD_TYPE_RGBA,            /* color type */
 442         16,                /* preferred color depth */
 443         0, 0, 0, 0, 0, 0,        /* color bits (ignored) */
 444         0,                /* no alpha buffer */
 445         0,                /* alpha bits (ignored) */
 446         0,                /* no accumulation buffer */
 447         0, 0, 0, 0,            /* accum bits (ignored) */
 448         16,                /* depth buffer */
 449         0,                /* no stencil buffer */
 450         0,                /* no auxiliary buffers */
 451         PFD_MAIN_PLANE,            /* main layer */
 452         0,                /* reserved */
 453         0, 0, 0,            /* no layer, visible, damage masks */
 454     };
 455
 456   AdjustPFDForAttributes(pfd, attribList);
 457
 458   int pixelFormat = ChoosePixelFormat((HDC) m_hDC, &pfd);
 459   if (pixelFormat == 0) {
 460     wxLogLastError(_T("ChoosePixelFormat"));
 461   }
 462   else {
 463     if ( !::SetPixelFormat((HDC) m_hDC, pixelFormat, &pfd) ) {
 464       wxLogLastError(_T("SetPixelFormat"));
 465     }
 466   }
 467 }
 468
 469 void wxGLCanvas::SetupPalette(const wxPalette& palette)
 470 {
 471     int pixelFormat = GetPixelFormat((HDC) m_hDC);
 472     PIXELFORMATDESCRIPTOR pfd;
 473
 474     DescribePixelFormat((HDC) m_hDC, pixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pfd);
 475
 476     if (pfd.dwFlags & PFD_NEED_PALETTE)
 477     {
 478     }
 479     else
 480     {
 481       return;
 482     }
 483
 484     m_palette = palette;
 485
 486     if ( !m_palette.Ok() )
 487     {
 488         m_palette = CreateDefaultPalette();
 489     }
 490
 491     if (m_palette.Ok())
 492     {
 493         ::SelectPalette((HDC) m_hDC, (HPALETTE) m_palette.GetHPALETTE(), FALSE);
 494         ::RealizePalette((HDC) m_hDC);
 495     }
 496 }
 497
 498 wxPalette wxGLCanvas::CreateDefaultPalette()
 499 {
 500     PIXELFORMATDESCRIPTOR pfd;
 501     int paletteSize;
 502     int pixelFormat = GetPixelFormat((HDC) m_hDC);
 503
 504     DescribePixelFormat((HDC) m_hDC, pixelFormat, sizeof(PIXELFORMATDESCRIPTOR), &pfd);
 505
 506     paletteSize = 1 << pfd.cColorBits;
 507
 508     LOGPALETTE* pPal =
 509      (LOGPALETTE*) malloc(sizeof(LOGPALETTE) + paletteSize * sizeof(PALETTEENTRY));
 510     pPal->palVersion = 0x300;
 511     pPal->palNumEntries = (WORD)paletteSize;
 512
 513     /* build a simple RGB color palette */
 514     {
 515     int redMask = (1 << pfd.cRedBits) - 1;
 516     int greenMask = (1 << pfd.cGreenBits) - 1;
 517     int blueMask = (1 << pfd.cBlueBits) - 1;
 518     int i;
 519
 520     for (i=0; i<paletteSize; ++i) {
 521         pPal->palPalEntry[i].peRed =
 522             (BYTE)((((i >> pfd.cRedShift) & redMask) * 255) / redMask);
 523         pPal->palPalEntry[i].peGreen =
 524             (BYTE)((((i >> pfd.cGreenShift) & greenMask) * 255) / greenMask);
 525         pPal->palPalEntry[i].peBlue =
 526             (BYTE)((((i >> pfd.cBlueShift) & blueMask) * 255) / blueMask);
 527         pPal->palPalEntry[i].peFlags = 0;
 528     }
 529     }
 530
 531     HPALETTE hPalette = CreatePalette(pPal);
 532     free(pPal);
 533
 534     wxPalette palette;
 535     palette.SetHPALETTE((WXHPALETTE) hPalette);
 536
 537     return palette;
 538 }
 539
 540 void wxGLCanvas::SwapBuffers()
 541 {
 542     ::SwapBuffers((HDC) m_hDC);
 543 }
 544
 545 void wxGLCanvas::OnSize(wxSizeEvent& WXUNUSED(event))
 546 {
 547 }
 548
 549 void wxGLCanvas::SetCurrent(const wxGLContext& RC) const
 550 {
 551     // although on MSW it works even if the window is still hidden, it doesn't
 552         // under wxGTK and documentation mentions that SetCurrent() can only be
 553         // called for a shown window, so check it
 554         wxASSERT_MSG( GetParent()->IsShown(), _T("can't make hidden GL canvas current") );
 555
 556     RC.SetCurrent(*this);
 557 }
 558
 559 void wxGLCanvas::SetCurrent()
 560 {
 561   // although on MSW it works even if the window is still hidden, it doesn't
 562   // under wxGTK and documentation mentions that SetCurrent() can only be
 563   // called for a shown window, so check it
 564   wxASSERT_MSG( GetParent()->IsShown(),
 565                     _T("can't make hidden GL canvas current") );
 566
 567   if (m_glContext)
 568   {
 569     m_glContext->SetCurrent(*this);
 570   }
 571 }
 572
 573 void wxGLCanvas::SetColour(const wxChar *colour)
 574 {
 575     wxColour col = wxTheColourDatabase->Find(colour);
 576
 577     if (col.Ok())
 578     {
 579         float r = (float)(col.Red()/256.0);
 580         float g = (float)(col.Green()/256.0);
 581         float b = (float)(col.Blue()/256.0);
 582         glColor3f( r, g, b);
 583     }
 584 }
 585
 586 // TODO: Have to have this called by parent frame (?)
 587 // So we need wxFrame to call OnQueryNewPalette for all children...
 588 void wxGLCanvas::OnQueryNewPalette(wxQueryNewPaletteEvent& event)
 589 {
 590   /* realize palette if this is the current window */
 591   if ( GetPalette()->Ok() ) {
 592     ::UnrealizeObject((HPALETTE) GetPalette()->GetHPALETTE());
 593     ::SelectPalette((HDC) GetHDC(), (HPALETTE) GetPalette()->GetHPALETTE(), FALSE);
 594     ::RealizePalette((HDC) GetHDC());
 595     Refresh();
 596     event.SetPaletteRealized(true);
 597   }
 598   else
 599     event.SetPaletteRealized(false);
 600 }
 601
 602 // I think this doesn't have to be propagated to child windows.
 603 void wxGLCanvas::OnPaletteChanged(wxPaletteChangedEvent& event)
 604 {
 605   /* realize palette if this is *not* the current window */
 606   if ( GetPalette() &&
 607        GetPalette()->Ok() && (this != event.GetChangedWindow()) )
 608   {
 609     ::UnrealizeObject((HPALETTE) GetPalette()->GetHPALETTE());
 610     ::SelectPalette((HDC) GetHDC(), (HPALETTE) GetPalette()->GetHPALETTE(), FALSE);
 611     ::RealizePalette((HDC) GetHDC());
 612     Refresh();
 613   }
 614 }
 615
 616
 617 //---------------------------------------------------------------------------
 618 // wxGLApp
 619 //---------------------------------------------------------------------------
 620
 621 IMPLEMENT_CLASS(wxGLApp, wxApp)
 622
 623 bool wxGLApp::InitGLVisual(int *attribList)
 624 {
 625   int pixelFormat;
 626   PIXELFORMATDESCRIPTOR pfd = {
 627         sizeof(PIXELFORMATDESCRIPTOR),    /* size */
 628         1,                /* version */
 629         PFD_SUPPORT_OPENGL |
 630         PFD_DRAW_TO_WINDOW |
 631         PFD_DOUBLEBUFFER,        /* support double-buffering */
 632         PFD_TYPE_RGBA,            /* color type */
 633         16,                /* preferred color depth */
 634         0, 0, 0, 0, 0, 0,        /* color bits (ignored) */
 635         0,                /* no alpha buffer */
 636         0,                /* alpha bits (ignored) */
 637         0,                /* no accumulation buffer */
 638         0, 0, 0, 0,            /* accum bits (ignored) */
 639         16,                /* depth buffer */
 640         0,                /* no stencil buffer */
 641         0,                /* no auxiliary buffers */
 642         PFD_MAIN_PLANE,            /* main layer */
 643         0,                /* reserved */
 644         0, 0, 0,            /* no layer, visible, damage masks */
 645     };
 646
 647   AdjustPFDForAttributes(pfd, attribList);
 648
 649   // use DC for whole (root) screen, since no windows have yet been created
 650   pixelFormat = ChoosePixelFormat(ScreenHDC(), &pfd);
 651
 652   if (pixelFormat == 0) {
 653     wxLogError(_("Failed to initialize OpenGL"));
 654     return false;
 655   }
 656
 657   return true;
 658 }
 659
 660 wxGLApp::~wxGLApp()
 661 {
 662 }
 663
 664 #endif
 665     // wxUSE_GLCANVAS