-    // 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;
+    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
+    }