I think this fixes bug #261

Make sure that you don't use a wgl function after the context is deleted.

--HG--
branch : SDL-1.2
extra : convert_revision : svn%3Ac70aab31-4412-0410-b14c-859654838e24/branches/SDL-1.2%402476

src/video/wincommon/SDL_wingl.c

@@ -109,14 +109,15 @@ static int ExtensionSupported(const char *extension, const char *extensions)
 	return 0;
 }
 
-static void Init_WGL_ARB_extensions(_THIS)
+static int ChoosePixelFormatARB(_THIS, const int *iAttribs, const FLOAT *fAttribs)
 {
 	HWND hwnd;
 	HDC hdc;
 	HGLRC hglrc;
-	int pformat;
 	const char * (WINAPI *wglGetExtensionsStringARB)(HDC) = 0;
 	const char *extensions;
+	int pformat = 0;
+	UINT matches = 0;
 
 	hwnd = CreateWindow(SDL_Appname, SDL_Appname, WS_POPUP | WS_DISABLED,
 	                    0, 0, 10, 10,
@@ -125,8 +126,7 @@ static void Init_WGL_ARB_extensions(_THIS)
 
 	hdc = GetDC(hwnd);
 
-	pformat = ChoosePixelFormat(hdc, &GL_pfd);
-	SetPixelFormat(hdc, pformat, &GL_pfd);
+	SetPixelFormat(hdc, ChoosePixelFormat(hdc, &GL_pfd), &GL_pfd);
 
 	hglrc = this->gl_data->wglCreateContext(hdc);
 	if ( hglrc ) {
@@ -144,15 +144,12 @@ static void Init_WGL_ARB_extensions(_THIS)
 
 	this->gl_data->WGL_ARB_pixel_format = 0;
 	if( ExtensionSupported("WGL_ARB_pixel_format", extensions) ) {
-		this->gl_data->wglChoosePixelFormatARB =
+		BOOL (WINAPI *wglChoosePixelFormatARB)(HDC hdc, const int *piAttribIList, const FLOAT *pfAttribFList, UINT nMaxFormats, int *piFormats, UINT *nNumFormats);
+		wglChoosePixelFormatARB =
 			(BOOL (WINAPI *)(HDC, const int *, const FLOAT *, UINT, int *, UINT *))
 			this->gl_data->wglGetProcAddress("wglChoosePixelFormatARB");
-		this->gl_data->wglGetPixelFormatAttribivARB =
-			(BOOL (WINAPI *)(HDC, int, int, UINT, const int *, int *))
-			this->gl_data->wglGetProcAddress("wglGetPixelFormatAttribivARB");
-
-		if( (this->gl_data->wglChoosePixelFormatARB != NULL) &&
-		    (this->gl_data->wglGetPixelFormatAttribivARB != NULL) ) {
+		if( wglChoosePixelFormatARB &&
+		    wglChoosePixelFormatARB(hdc, iAttribs, fAttribs, 1, &pformat, &matches) && pformat ) {
 			this->gl_data->WGL_ARB_pixel_format = 1;
 		}
 	}
@@ -164,6 +161,8 @@ static void Init_WGL_ARB_extensions(_THIS)
 	ReleaseDC(hwnd, hdc);
 	DestroyWindow(hwnd);
 	WIN_FlushMessageQueue();
+
+	return pformat;
 }
 
 #endif /* SDL_VIDEO_OPENGL */
@@ -188,14 +187,6 @@ int WIN_GL_SetupWindow(_THIS)
 		}
 	}
 
-	for ( i=0; ; ++i ) {
-		/* Get the window device context for our OpenGL drawing */
-		GL_hdc = GetDC(SDL_Window);
-		if ( GL_hdc == NULL ) {
-			SDL_SetError("Unable to get DC for SDL_Window");
-			return(-1);
-		}
-
 	/* Set up the pixel format descriptor with our needed format */
 	SDL_memset(&GL_pfd, 0, sizeof(GL_pfd));
 	GL_pfd.nSize = sizeof(GL_pfd);
@@ -223,9 +214,6 @@ int WIN_GL_SetupWindow(_THIS)
 	GL_pfd.cDepthBits = this->gl_config.depth_size;
 	GL_pfd.cStencilBits = this->gl_config.stencil_size;
 
-		/* initialize WGL_ARB_pixel_format */
-		Init_WGL_ARB_extensions(this);
-
 	/* setup WGL_ARB_pixel_format attribs */
 	iAttr = &iAttribs[0];
 
@@ -298,12 +286,18 @@ int WIN_GL_SetupWindow(_THIS)
 
 	*iAttr = 0;
 
+	for ( i=0; ; ++i ) {
+		/* Get the window device context for our OpenGL drawing */
+		GL_hdc = GetDC(SDL_Window);
+		if ( GL_hdc == NULL ) {
+			SDL_SetError("Unable to get DC for SDL_Window");
+			return(-1);
+		}
+
 		/* Choose and set the closest available pixel format */
-		if ( !this->gl_data->WGL_ARB_pixel_format ||
-		     !this->gl_data->wglChoosePixelFormatARB(GL_hdc, iAttribs, fAttribs, 1, &pixel_format, &matching) ||
-		     !matching ) {
+		pixel_format = ChoosePixelFormatARB(this, iAttribs, fAttribs);
+		if ( !pixel_format ) {
 			pixel_format = ChoosePixelFormat(GL_hdc, &GL_pfd);
-			this->gl_data->WGL_ARB_pixel_format = 0;
 		}
 		if ( !pixel_format ) {
 			SDL_SetError("No matching GL pixel format available");
@@ -335,6 +329,15 @@ int WIN_GL_SetupWindow(_THIS)
 	}
 	gl_active = 1;
 
+	/* Get the wglGetPixelFormatAttribivARB pointer for the context */
+	if ( this->gl_data->WGL_ARB_pixel_format ) {
+		this->gl_data->wglGetPixelFormatAttribivARB =
+			(BOOL (WINAPI *)(HDC, int, int, UINT, const int *, int *))
+			this->gl_data->wglGetProcAddress("wglGetPixelFormatAttribivARB");
+	} else {
+		this->gl_data->wglGetPixelFormatAttribivARB = NULL;
+	}
+
 	/* Vsync control under Windows.  Checking glGetString here is
 	 * somewhat a documented and reliable hack - it was originally
 	 * as a feature added by mistake, but since so many people rely
@@ -416,7 +419,7 @@ int WIN_GL_GetAttribute(_THIS, SDL_GLattr attrib, int* value)
 		return -1;
 	}
 
-	if ( this->gl_data->WGL_ARB_pixel_format ) {
+	if ( this->gl_data->wglGetPixelFormatAttribivARB ) {
 		int wgl_attrib;
 
 		switch(attrib) {
@@ -566,7 +569,6 @@ void WIN_GL_UnloadLibrary(_THIS)
 		this->gl_data->wglCreateContext = NULL;
 		this->gl_data->wglDeleteContext = NULL;
 		this->gl_data->wglMakeCurrent = NULL;
-		this->gl_data->wglChoosePixelFormatARB = NULL;
 		this->gl_data->wglGetPixelFormatAttribivARB = NULL;
 		this->gl_data->wglSwapIntervalEXT = NULL;
 		this->gl_data->wglGetSwapIntervalEXT = NULL;

src/video/wincommon/SDL_wingl_c.h

@@ -44,10 +44,6 @@ struct SDL_PrivateGLData {
 
     BOOL (WINAPI *wglMakeCurrent)(HDC hdc, HGLRC hglrc);
    
-    BOOL (WINAPI *wglChoosePixelFormatARB)(HDC hdc, const int *piAttribIList,
-                                           const FLOAT *pfAttribFList,
-                                           UINT nMaxFormats, int *piFormats,
-                                           UINT *nNumFormats);
     BOOL (WINAPI *wglGetPixelFormatAttribivARB)(HDC hdc, int iPixelFormat,
                                                 int iLayerPlane,
                                                 UINT nAttributes,