]> git.saurik.com Git - wxWidgets.git/blobdiff - src/msw/glcanvas.cpp
Fixed VC6 compilation - wxAny(const wxVariant&) ctor required a specific 'template<>')
[wxWidgets.git] / src / msw / glcanvas.cpp
index cefcac96a9b968997bbdc3e006ca3b31ff224f93..15ad41545b27d4e9a951f88e164add4f4bcced31 100644 (file)
@@ -29,7 +29,6 @@
     #include "wx/intl.h"
     #include "wx/log.h"
     #include "wx/app.h"
-    #include "wx/module.h"
 #endif
 
 #include "wx/msw/private.h"
@@ -46,6 +45,38 @@ LRESULT WXDLLEXPORT APIENTRY _EXPORT wxWndProc(HWND hWnd, UINT message,
     #define WXUNUSED_WITHOUT_GL_EXT_vertex_array(name) WXUNUSED(name)
 #endif
 
+// ----------------------------------------------------------------------------
+// define possibly missing WGL constants
+// ----------------------------------------------------------------------------
+
+#ifndef WGL_ARB_pixel_format
+#define WGL_DRAW_TO_WINDOW_ARB            0x2001
+#define WGL_ACCELERATION_ARB              0x2003
+#define WGL_NUMBER_OVERLAYS_ARB           0x2008
+#define WGL_NUMBER_UNDERLAYS_ARB          0x2009
+#define WGL_SUPPORT_OPENGL_ARB            0x2010
+#define WGL_DOUBLE_BUFFER_ARB             0x2011
+#define WGL_STEREO_ARB                    0x2012
+#define WGL_COLOR_BITS_ARB                0x2014
+#define WGL_RED_BITS_ARB                  0x2015
+#define WGL_GREEN_BITS_ARB                0x2017
+#define WGL_BLUE_BITS_ARB                 0x2019
+#define WGL_ALPHA_BITS_ARB                0x201B
+#define WGL_ACCUM_RED_BITS_ARB            0x201E
+#define WGL_ACCUM_GREEN_BITS_ARB          0x201F
+#define WGL_ACCUM_BLUE_BITS_ARB           0x2020
+#define WGL_ACCUM_ALPHA_BITS_ARB          0x2021
+#define WGL_DEPTH_BITS_ARB                0x2022
+#define WGL_STENCIL_BITS_ARB              0x2023
+#define WGL_AUX_BUFFERS_ARB               0x2024
+#define WGL_FULL_ACCELERATION_ARB         0x2027
+#endif
+
+#ifndef WGL_ARB_multisample
+#define WGL_SAMPLE_BUFFERS_ARB            0x2041
+#define WGL_SAMPLES_ARB                   0x2042
+#endif
+
 // ----------------------------------------------------------------------------
 // libraries
 // ----------------------------------------------------------------------------
@@ -72,110 +103,6 @@ LRESULT WXDLLEXPORT APIENTRY _EXPORT wxWndProc(HWND hWnd, UINT message,
 #  pragma comment( lib, "glu32" )
 #endif
 
-// ----------------------------------------------------------------------------
-// constants
-// ----------------------------------------------------------------------------
-
-static const wxChar *wxGLCanvasClassName = wxT("wxGLCanvasClass");
-static const wxChar *wxGLCanvasClassNameNoRedraw = wxT("wxGLCanvasClassNR");
-
-// ============================================================================
-// implementation
-// ============================================================================
-
-// ----------------------------------------------------------------------------
-// wxGLModule is responsible for unregistering wxGLCanvasClass Windows class
-// ----------------------------------------------------------------------------
-
-class wxGLModule : public wxModule
-{
-public:
-    bool OnInit() { return true; }
-    void OnExit() { UnregisterClasses(); }
-
-    // register the GL classes if not done yet, return true if ok, false if
-    // registration failed
-    static bool RegisterClasses();
-
-    // unregister the classes, done automatically on program termination
-    static void UnregisterClasses();
-
-private:
-    // wxGLCanvas is only used from the main thread so this is MT-ok
-    static bool ms_registeredGLClasses;
-
-    DECLARE_DYNAMIC_CLASS(wxGLModule)
-};
-
-IMPLEMENT_DYNAMIC_CLASS(wxGLModule, wxModule)
-
-bool wxGLModule::ms_registeredGLClasses = false;
-
-/* static */
-bool wxGLModule::RegisterClasses()
-{
-    if ( ms_registeredGLClasses )
-        return true;
-
-    // We have to register a special window class because we need the CS_OWNDC
-    // style for GLCanvas: some OpenGL drivers are buggy and don't work with
-    // windows without this style
-    WNDCLASS wndclass;
-
-    // the fields which are common to all classes
-    wndclass.lpfnWndProc   = (WNDPROC)wxWndProc;
-    wndclass.cbClsExtra    = 0;
-    wndclass.cbWndExtra    = sizeof( DWORD ); // VZ: what is this DWORD used for?
-    wndclass.hInstance     = wxhInstance;
-    wndclass.hIcon         = (HICON) NULL;
-    wndclass.hCursor       = ::LoadCursor((HINSTANCE)NULL, IDC_ARROW);
-    wndclass.lpszMenuName  = NULL;
-
-    // Register the GLCanvas class name
-    wndclass.hbrBackground = (HBRUSH)NULL;
-    wndclass.lpszClassName = wxGLCanvasClassName;
-    wndclass.style         = CS_HREDRAW | CS_VREDRAW | CS_DBLCLKS | CS_OWNDC;
-
-    if ( !::RegisterClass(&wndclass) )
-    {
-        wxLogLastError(wxT("RegisterClass(wxGLCanvasClass)"));
-        return false;
-    }
-
-    // Register the GLCanvas class name for windows which don't do full repaint
-    // on resize
-    wndclass.lpszClassName = wxGLCanvasClassNameNoRedraw;
-    wndclass.style        &= ~(CS_HREDRAW | CS_VREDRAW);
-
-    if ( !::RegisterClass(&wndclass) )
-    {
-        wxLogLastError(wxT("RegisterClass(wxGLCanvasClassNameNoRedraw)"));
-
-        ::UnregisterClass(wxGLCanvasClassName, wxhInstance);
-
-        return false;
-    }
-
-    ms_registeredGLClasses = true;
-
-    return true;
-}
-
-/* static */
-void wxGLModule::UnregisterClasses()
-{
-    // we need to unregister the classes in case we're in a DLL which is
-    // unloaded and then loaded again because if we don't, the registration is
-    // going to fail in wxGLCanvas::Create() the next time we're loaded
-    if ( ms_registeredGLClasses )
-    {
-        ::UnregisterClass(wxGLCanvasClassName, wxhInstance);
-        ::UnregisterClass(wxGLCanvasClassNameNoRedraw, wxhInstance);
-
-        ms_registeredGLClasses = false;
-    }
-}
-
 // ----------------------------------------------------------------------------
 // wxGLContext
 // ----------------------------------------------------------------------------
@@ -190,7 +117,9 @@ wxGLContext::wxGLContext(wxGLCanvas *win, const wxGLContext* other)
     if ( other )
     {
         if ( !wglShareLists(other->m_glContext, m_glContext) )
-            wxLogLastError(_T("wglShareLists"));
+        {
+            wxLogLastError(wxT("wglShareLists"));
+        }
     }
 }
 
@@ -204,7 +133,7 @@ bool wxGLContext::SetCurrent(const wxGLCanvas& win) const
 {
     if ( !wglMakeCurrent(win.GetHDC(), m_glContext) )
     {
-        wxLogLastError(_T("wglMakeCurrent"));
+        wxLogLastError(wxT("wglMakeCurrent"));
         return false;
     }
     return true;
@@ -225,6 +154,8 @@ END_EVENT_TABLE()
 // wxGLCanvas construction
 // ----------------------------------------------------------------------------
 
+static int ChoosePixelFormatARB(HDC hdc, const int *attribList);
+
 void wxGLCanvas::Init()
 {
 #if WXWIN_COMPATIBILITY_2_8
@@ -254,24 +185,15 @@ wxGLCanvas::~wxGLCanvas()
 
 // Replaces wxWindow::Create functionality, since we need to use a different
 // window class
-bool wxGLCanvas::Create(wxWindow *parent,
-                        wxWindowID id,
-                        const wxPoint& pos,
-                        const wxSize& size,
-                        long style,
-                        const wxString& name,
-                        const int *attribList,
-                        const wxPalette& palette)
+bool wxGLCanvas::CreateWindow(wxWindow *parent,
+                              wxWindowID id,
+                              const wxPoint& pos,
+                              const wxSize& size,
+                              long style,
+                              const wxString& name)
 {
     wxCHECK_MSG( parent, false, wxT("can't create wxWindow without parent") );
 
-    if ( !wxGLModule::RegisterClasses() )
-    {
-        wxLogError(_("Failed to register OpenGL window class."));
-
-        return false;
-    }
-
     if ( !CreateBase(parent, id, pos, size, style, wxDefaultValidator, name) )
         return false;
 
@@ -287,16 +209,80 @@ bool wxGLCanvas::Create(wxWindow *parent,
     DWORD msflags = WS_CHILD | WS_VISIBLE | WS_CLIPSIBLINGS | WS_CLIPCHILDREN;
     msflags |= MSWGetStyle(style, &exStyle);
 
-    if ( !MSWCreate(wxGLCanvasClassName, NULL, pos, size, msflags, exStyle) )
+    if ( !MSWCreate(wxApp::GetRegisteredClassName(wxT("wxGLCanvas"), -1, CS_OWNDC),
+                    NULL, pos, size, msflags, exStyle) )
         return false;
 
     m_hDC = ::GetDC(GetHwnd());
     if ( !m_hDC )
         return false;
 
-    if ( !DoSetup(attribList) )
+    return true;
+}
+
+bool wxGLCanvas::Create(wxWindow *parent,
+                        wxWindowID id,
+                        const wxPoint& pos,
+                        const wxSize& size,
+                        long style,
+                        const wxString& name,
+                        const int *attribList,
+                        const wxPalette& palette)
+{
+    // Create the window first: we will either use it as is or use it to query
+    // for multisampling support and recreate it later with another pixel format
+    if ( !CreateWindow(parent, id, pos, size, style, name) )
         return false;
 
+    PIXELFORMATDESCRIPTOR pfd;
+    const int setupVal = DoSetup(pfd, attribList);
+    if ( setupVal == 0 ) // PixelFormat error
+        return false;
+
+    if ( setupVal == -1 ) // FSAA requested
+    {
+        // now that we have a valid OpenGL window, query it for FSAA support
+        int pixelFormat;
+        {
+            wxGLContext ctx(this);
+            ctx.SetCurrent(*this);
+            pixelFormat = ::ChoosePixelFormatARB(m_hDC, attribList);
+        }
+
+        if ( pixelFormat > 0 )
+        {
+            // from http://msdn.microsoft.com/en-us/library/ms537559(VS.85).aspx:
+            //
+            //      Setting the pixel format of a window more than once can
+            //      lead to significant complications for the Window Manager
+            //      and for multithread applications, so it is not allowed. An
+            //      application can only set the pixel format of a window one
+            //      time. Once a window's pixel format is set, it cannot be
+            //      changed.
+            //
+            // so we need to delete the old window and create the new one
+
+            // destroy Window
+            ::ReleaseDC(GetHwnd(), m_hDC);
+            m_hDC = 0;
+
+            parent->RemoveChild(this);
+            const HWND hwnd = GetHwnd();
+            DissociateHandle(); // will do SetHWND(0);
+            ::DestroyWindow(hwnd);
+
+            // now recreate with FSAA pixelFormat
+            if ( !CreateWindow(parent, id, pos, size, style, name) )
+                return false;
+
+            if ( !::SetPixelFormat(m_hDC, pixelFormat, &pfd) )
+            {
+                wxLogLastError(wxT("SetPixelFormat"));
+                return false;
+            }
+        }
+    }
+
 #if wxUSE_PALETTE
     if ( !SetupPalette(palette) )
         return false;
@@ -315,27 +301,226 @@ bool wxGLCanvas::SwapBuffers()
 {
     if ( !::SwapBuffers(m_hDC) )
     {
-        wxLogLastError(_T("SwapBuffers"));
+        wxLogLastError(wxT("SwapBuffers"));
         return false;
     }
 
     return true;
 }
 
+
+// ----------------------------------------------------------------------------
+// multi sample support
+// ----------------------------------------------------------------------------
+
+// this macro defines a variable of type "name_t" called "name" and initializes
+// it with the pointer to WGL function "name" (which may be NULL)
+#define wxDEFINE_WGL_FUNC(name) \
+    name##_t name = (name##_t)wglGetProcAddress(#name)
+
+/* static */
+bool wxGLCanvasBase::IsExtensionSupported(const char *extension)
+{
+    static const char *s_extensionsList = (char *)wxUIntPtr(-1);
+    if ( s_extensionsList == (char *)wxUIntPtr(-1) )
+    {
+        typedef const char * (WINAPI *wglGetExtensionsStringARB_t)(HDC hdc);
+
+        wxDEFINE_WGL_FUNC(wglGetExtensionsStringARB);
+        if ( wglGetExtensionsStringARB )
+        {
+            s_extensionsList = wglGetExtensionsStringARB(wglGetCurrentDC());
+        }
+        else
+        {
+            typedef const char * (WINAPI * wglGetExtensionsStringEXT_t)();
+
+            wxDEFINE_WGL_FUNC(wglGetExtensionsStringEXT);
+            if ( wglGetExtensionsStringEXT )
+            {
+                s_extensionsList = wglGetExtensionsStringEXT();
+            }
+            else
+            {
+                s_extensionsList = NULL;
+            }
+        }
+    }
+
+    return s_extensionsList && IsExtensionInList(s_extensionsList, extension);
+}
+
+// this is a wrapper around wglChoosePixelFormatARB(): returns the pixel format
+// index matching the given attributes on success or 0 on failure
+static int ChoosePixelFormatARB(HDC hdc, const int *attribList)
+{
+    if ( !wxGLCanvas::IsExtensionSupported("WGL_ARB_multisample") )
+        return 0;
+
+    typedef BOOL (WINAPI * wglChoosePixelFormatARB_t)
+                 (HDC hdc,
+                  const int *piAttribIList,
+                  const FLOAT *pfAttribFList,
+                  UINT nMaxFormats,
+                  int *piFormats,
+                  UINT *nNumFormats
+                 );
+
+    wxDEFINE_WGL_FUNC(wglChoosePixelFormatARB);
+    if ( !wglChoosePixelFormatARB )
+        return 0; // should not occur if extension is supported
+
+    int iAttributes[128];
+    int dst = 0; // index in iAttributes array
+
+    #define ADD_ATTR(attr, value) \
+        iAttributes[dst++] = attr; iAttributes[dst++] = value
+
+    ADD_ATTR( WGL_DRAW_TO_WINDOW_ARB,    GL_TRUE );
+    ADD_ATTR( WGL_SUPPORT_OPENGL_ARB,    GL_TRUE );
+    ADD_ATTR( WGL_ACCELERATION_ARB,      WGL_FULL_ACCELERATION_ARB );
+
+    if ( !attribList )
+    {
+        ADD_ATTR( WGL_COLOR_BITS_ARB,          24 );
+        ADD_ATTR( WGL_ALPHA_BITS_ARB,           8 );
+        ADD_ATTR( WGL_DEPTH_BITS_ARB,          16 );
+        ADD_ATTR( WGL_STENCIL_BITS_ARB,         0 );
+        ADD_ATTR( WGL_DOUBLE_BUFFER_ARB,  GL_TRUE );
+        ADD_ATTR( WGL_SAMPLE_BUFFERS_ARB, GL_TRUE );
+        ADD_ATTR( WGL_SAMPLES_ARB,              4 );
+    }
+    else // have custom attributes
+    {
+        #define ADD_ATTR_VALUE(attr) ADD_ATTR(attr, attribList[src++])
+
+        int src = 0;
+        while ( attribList[src] )
+        {
+            switch ( attribList[src++] )
+            {
+                case WX_GL_RGBA:
+                    ADD_ATTR( WGL_COLOR_BITS_ARB, 24 );
+                    ADD_ATTR( WGL_ALPHA_BITS_ARB,  8 );
+                    break;
+
+                case WX_GL_BUFFER_SIZE:
+                    ADD_ATTR_VALUE( WGL_COLOR_BITS_ARB);
+                    break;
+
+                case WX_GL_LEVEL:
+                    if ( attribList[src] > 0 )
+                    {
+                        ADD_ATTR( WGL_NUMBER_OVERLAYS_ARB, 1 );
+                    }
+                    else if ( attribList[src] <0 )
+                    {
+                        ADD_ATTR( WGL_NUMBER_UNDERLAYS_ARB, 1 );
+                    }
+                    //else: ignore it
+
+                    src++; // skip the value in any case
+                    break;
+
+                case WX_GL_DOUBLEBUFFER:
+                    ADD_ATTR( WGL_DOUBLE_BUFFER_ARB, GL_TRUE );
+                    break;
+
+                case WX_GL_STEREO:
+                    ADD_ATTR( WGL_STEREO_ARB, GL_TRUE );
+                    break;
+
+                case WX_GL_AUX_BUFFERS:
+                    ADD_ATTR_VALUE( WGL_AUX_BUFFERS_ARB );
+                    break;
+
+                case WX_GL_MIN_RED:
+                    ADD_ATTR_VALUE( WGL_RED_BITS_ARB );
+                    break;
+
+                case WX_GL_MIN_GREEN:
+                    ADD_ATTR_VALUE( WGL_GREEN_BITS_ARB );
+                    break;
+
+                case WX_GL_MIN_BLUE:
+                    ADD_ATTR_VALUE( WGL_BLUE_BITS_ARB );
+                    break;
+
+                case WX_GL_MIN_ALPHA:
+                    ADD_ATTR_VALUE( WGL_ALPHA_BITS_ARB );
+                   break;
+
+                case WX_GL_DEPTH_SIZE:
+                    ADD_ATTR_VALUE( WGL_DEPTH_BITS_ARB );
+                    break;
+
+                case WX_GL_STENCIL_SIZE:
+                    ADD_ATTR_VALUE( WGL_STENCIL_BITS_ARB );
+                    break;
+
+               case WX_GL_MIN_ACCUM_RED:
+                    ADD_ATTR_VALUE( WGL_ACCUM_RED_BITS_ARB );
+                    break;
+
+                case WX_GL_MIN_ACCUM_GREEN:
+                    ADD_ATTR_VALUE( WGL_ACCUM_GREEN_BITS_ARB );
+                    break;
+
+                case WX_GL_MIN_ACCUM_BLUE:
+                    ADD_ATTR_VALUE( WGL_ACCUM_BLUE_BITS_ARB );
+                    break;
+
+                case WX_GL_MIN_ACCUM_ALPHA:
+                    ADD_ATTR_VALUE( WGL_ACCUM_ALPHA_BITS_ARB );
+                    break;
+
+                case WX_GL_SAMPLE_BUFFERS:
+                    ADD_ATTR_VALUE( WGL_SAMPLE_BUFFERS_ARB );
+                    break;
+
+                case WX_GL_SAMPLES:
+                    ADD_ATTR_VALUE( WGL_SAMPLES_ARB );
+                    break;
+            }
+        }
+
+        #undef ADD_ATTR_VALUE
+    }
+
+    #undef ADD_ATTR
+
+    iAttributes[dst++] = 0;
+
+    int pf;
+    UINT numFormats = 0;
+    if ( !wglChoosePixelFormatARB(hdc, iAttributes, NULL, 1, &pf, &numFormats) )
+    {
+        wxLogLastError(wxT("wglChoosePixelFormatARB"));
+        return 0;
+    }
+
+    return pf;
+}
+
 // ----------------------------------------------------------------------------
 // pixel format stuff
 // ----------------------------------------------------------------------------
 
-static void
+// returns true if pfd was adjusted accordingly to attributes provided, false
+// if there is an error with attributes or -1 if the attributes indicate
+// features not supported by ChoosePixelFormat() at all (currently only multi
+// sampling)
+static int
 AdjustPFDForAttributes(PIXELFORMATDESCRIPTOR& pfd, const int *attribList)
 {
     if ( !attribList )
-        return;
+        return 1;
 
     // remove default attributes
     pfd.dwFlags &= ~PFD_DOUBLEBUFFER;
     pfd.iPixelType = PFD_TYPE_COLORINDEX;
 
+    bool requestFSAA = false;
     for ( int arg = 0; attribList[arg]; )
     {
         switch ( attribList[arg++] )
@@ -411,8 +596,17 @@ AdjustPFDForAttributes(PIXELFORMATDESCRIPTOR& pfd, const int *attribList)
             case WX_GL_MIN_ACCUM_ALPHA:
                 pfd.cAccumBits += (pfd.cAccumAlphaBits = attribList[arg++]);
                 break;
+
+            case WX_GL_SAMPLE_BUFFERS:
+            case WX_GL_SAMPLES:
+                // There is no support for multisample when using PIXELFORMATDESCRIPTOR
+                requestFSAA = true; // Remember that multi sample is requested.
+                arg++;              // will call ChoosePixelFormatARB() later
+                break;
         }
     }
+
+    return requestFSAA ? -1 : 1;
 }
 
 /* static */
@@ -448,9 +642,27 @@ wxGLCanvas::ChooseMatchingPixelFormat(HDC hdc,
     else
         *ppfd = pfd;
 
-    AdjustPFDForAttributes(*ppfd, attribList);
+    // adjust the PFD using the provided attributes and also check if we can
+    // use PIXELFORMATDESCRIPTOR at all: if multisampling is requested, we
+    // can't as it's not supported by ChoosePixelFormat()
+    switch ( AdjustPFDForAttributes(*ppfd, attribList) )
+    {
+        case 1:
+            return ::ChoosePixelFormat(hdc, ppfd);
+
+        default:
+            wxFAIL_MSG( "unexpected AdjustPFDForAttributes() return value" );
+            // fall through
 
-    return ::ChoosePixelFormat(hdc, ppfd);
+        case 0:
+            // error in attributes
+            return 0;
+
+        case -1:
+            // requestFSAA == true, will continue as normal
+            // in order to query later for a FSAA pixelformat
+            return -1;
+    }
 }
 
 /* static */
@@ -461,23 +673,27 @@ bool wxGLCanvasBase::IsDisplaySupported(const int *attribList)
     return wxGLCanvas::ChooseMatchingPixelFormat(ScreenHDC(), attribList) > 0;
 }
 
-bool wxGLCanvas::DoSetup(const int *attribList)
+int wxGLCanvas::DoSetup(PIXELFORMATDESCRIPTOR &pfd, const int *attribList)
 {
-    PIXELFORMATDESCRIPTOR pfd;
-    const int pixelFormat = ChooseMatchingPixelFormat(m_hDC, attribList, &pfd);
+    int pixelFormat = ChooseMatchingPixelFormat(m_hDC, attribList, &pfd);
+
+    const bool requestFSAA = pixelFormat == -1;
+    if ( requestFSAA )
+        pixelFormat = ::ChoosePixelFormat(m_hDC, &pfd);
+
     if ( !pixelFormat )
     {
-        wxLogLastError(_T("ChoosePixelFormat"));
-        return false;
+        wxLogLastError(wxT("ChoosePixelFormat"));
+        return 0;
     }
 
     if ( !::SetPixelFormat(m_hDC, pixelFormat, &pfd) )
     {
-        wxLogLastError(_T("SetPixelFormat"));
-        return false;
+        wxLogLastError(wxT("SetPixelFormat"));
+        return 0;
     }
 
-    return true;
+    return requestFSAA ? -1 : 1;
 }
 
 // ----------------------------------------------------------------------------
@@ -491,14 +707,14 @@ bool wxGLCanvas::SetupPalette(const wxPalette& palette)
     const int pixelFormat = ::GetPixelFormat(m_hDC);
     if ( !pixelFormat )
     {
-        wxLogLastError(_T("GetPixelFormat"));
+        wxLogLastError(wxT("GetPixelFormat"));
         return false;
     }
 
     PIXELFORMATDESCRIPTOR pfd;
     if ( !::DescribePixelFormat(m_hDC, pixelFormat, sizeof(pfd), &pfd) )
     {
-        wxLogLastError(_T("DescribePixelFormat"));
+        wxLogLastError(wxT("DescribePixelFormat"));
         return false;
     }
 
@@ -516,13 +732,13 @@ bool wxGLCanvas::SetupPalette(const wxPalette& palette)
 
     if ( !::SelectPalette(m_hDC, GetHpaletteOf(m_palette), FALSE) )
     {
-        wxLogLastError(_T("SelectPalette"));
+        wxLogLastError(wxT("SelectPalette"));
         return false;
     }
 
     if ( ::RealizePalette(m_hDC) == GDI_ERROR )
     {
-        wxLogLastError(_T("RealizePalette"));
+        wxLogLastError(wxT("RealizePalette"));
         return false;
     }
 
@@ -545,13 +761,12 @@ wxPalette wxGLCanvas::CreateDefaultPalette()
     pPal->palNumEntries = (WORD)paletteSize;
 
     /* build a simple RGB color palette */
-    {
     int redMask = (1 << pfd.cRedBits) - 1;
     int greenMask = (1 << pfd.cGreenBits) - 1;
     int blueMask = (1 << pfd.cBlueBits) - 1;
-    int i;
 
-    for (i=0; i<paletteSize; ++i) {
+    for (int i=0; i<paletteSize; ++i)
+    {
         pPal->palPalEntry[i].peRed =
             (BYTE)((((i >> pfd.cRedShift) & redMask) * 255) / redMask);
         pPal->palPalEntry[i].peGreen =
@@ -560,7 +775,6 @@ wxPalette wxGLCanvas::CreateDefaultPalette()
             (BYTE)((((i >> pfd.cBlueShift) & blueMask) * 255) / blueMask);
         pPal->palPalEntry[i].peFlags = 0;
     }
-    }
 
     HPALETTE hPalette = CreatePalette(pPal);
     free(pPal);