Add GLFW_NO_API for creating context-less windows

README.md

@@ -66,6 +66,7 @@ used by the tests and examples and are not required to build the library.
 
  - Added `glfwSetWindowSizeLimits` and `glfwSetWindowAspectRatio` for setting
    absolute and relative window size limits
+ - Added `GLFW_NO_API` for creating window without contexts
  - Added `GLFW_TRUE` and `GLFW_FALSE` as client API independent boolean values
  - Removed dependency on external OpenGL or OpenGL ES headers
  - [Cocoa] Removed support for OS X 10.6

include/GLFW/glfw3.h

@@ -613,6 +613,15 @@ extern "C" {
  *  the user, as appropriate.
  */
 #define GLFW_FORMAT_UNAVAILABLE     0x00010009
+/*! @brief The specified window does not have an OpenGL or OpenGL ES context.
+ *
+ *  A window that does not have an OpenGL or OpenGL ES context was passed to
+ *  a function that requires it to have one.
+ *
+ *  @par Analysis
+ *  Application programmer error.  Fix the offending call.
+ */
+#define GLFW_NO_WINDOW_CONTEXT      0x0001000A
 /*! @} */
 
 #define GLFW_FOCUSED                0x00020001
@@ -650,6 +659,7 @@ extern "C" {
 #define GLFW_OPENGL_PROFILE         0x00022008
 #define GLFW_CONTEXT_RELEASE_BEHAVIOR 0x00022009
 
+#define GLFW_NO_API                          0
 #define GLFW_OPENGL_API             0x00030001
 #define GLFW_OPENGL_ES_API          0x00030002
 

src/cocoa_window.m

@@ -887,10 +887,11 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
     if (!createWindow(window, wndconfig))
         return GLFW_FALSE;
 
-    if (!_glfwCreateContext(window, ctxconfig, fbconfig))
-        return GLFW_FALSE;
-
-    [window->nsgl.context setView:window->ns.view];
+    if (ctxconfig->api != GLFW_NO_API)
+    {
+        if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+            return GLFW_FALSE;
+    }
 
     if (wndconfig->monitor)
     {
@@ -909,7 +910,8 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
     if (window->monitor)
         leaveFullscreenMode(window);
 
-    _glfwDestroyContext(window);
+    if (window->context.api != GLFW_NO_API)
+        _glfwDestroyContext(window);
 
     [window->ns.object setDelegate:nil];
     [window->ns.delegate release];

src/context.c

@@ -89,7 +89,8 @@ static GLFWbool parseVersionString(int* api, int* major, int* minor, int* rev)
 
 GLFWbool _glfwIsValidContextConfig(const _GLFWctxconfig* ctxconfig)
 {
-    if (ctxconfig->api != GLFW_OPENGL_API &&
+    if (ctxconfig->api != GLFW_NO_API &&
+        ctxconfig->api != GLFW_OPENGL_API &&
         ctxconfig->api != GLFW_OPENGL_ES_API)
     {
         _glfwInputError(GLFW_INVALID_ENUM, "Invalid client API");
@@ -536,7 +537,15 @@ int _glfwStringInExtensionString(const char* string, const char* extensions)
 GLFWAPI void glfwMakeContextCurrent(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
+
     _GLFW_REQUIRE_INIT();
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return;
+    }
+
     _glfwPlatformMakeContextCurrent(window);
 }
 
@@ -549,7 +558,15 @@ GLFWAPI GLFWwindow* glfwGetCurrentContext(void)
 GLFWAPI void glfwSwapBuffers(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
+
     _GLFW_REQUIRE_INIT();
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return;
+    }
+
     _glfwPlatformSwapBuffers(window);
 }
 

src/egl_context.c

@@ -112,12 +112,6 @@ static GLFWbool chooseFBConfigs(const _GLFWctxconfig* ctxconfig,
         const EGLConfig n = nativeConfigs[i];
         _GLFWfbconfig* u = usableConfigs + usableCount;
 
-#if defined(_GLFW_X11)
-        // Only consider EGLConfigs with associated visuals
-        if (!getConfigAttrib(n, EGL_NATIVE_VISUAL_ID))
-            continue;
-#endif // _GLFW_X11
-
         // Only consider RGB(A) EGLConfigs
         if (!(getConfigAttrib(n, EGL_COLOR_BUFFER_TYPE) & EGL_RGB_BUFFER))
             continue;
@@ -126,6 +120,12 @@ static GLFWbool chooseFBConfigs(const _GLFWctxconfig* ctxconfig,
         if (!(getConfigAttrib(n, EGL_SURFACE_TYPE) & EGL_WINDOW_BIT))
             continue;
 
+#if defined(_GLFW_X11)
+        // Only consider EGLConfigs with associated Visuals
+        if (!getConfigAttrib(n, EGL_NATIVE_VISUAL_ID))
+            continue;
+#endif // _GLFW_X11
+
         if (ctxconfig->api == GLFW_OPENGL_ES_API)
         {
             if (ctxconfig->major == 1)
@@ -311,55 +311,6 @@ int _glfwCreateContext(_GLFWwindow* window,
         return GLFW_FALSE;
     }
 
-#if defined(_GLFW_X11)
-    // Retrieve the visual corresponding to the chosen EGL config
-    {
-        EGLint count = 0;
-        int mask;
-        EGLint redBits, greenBits, blueBits, alphaBits, visualID = 0;
-        XVisualInfo info;
-
-        _glfw_eglGetConfigAttrib(_glfw.egl.display, config,
-                                 EGL_NATIVE_VISUAL_ID, &visualID);
-
-        info.screen = _glfw.x11.screen;
-        mask = VisualScreenMask;
-
-        if (visualID)
-        {
-            // The X window visual must match the EGL config
-            info.visualid = visualID;
-            mask |= VisualIDMask;
-        }
-        else
-        {
-            // Some EGL drivers do not implement the EGL_NATIVE_VISUAL_ID
-            // attribute, so attempt to find the closest match
-
-            _glfw_eglGetConfigAttrib(_glfw.egl.display, config,
-                                     EGL_RED_SIZE, &redBits);
-            _glfw_eglGetConfigAttrib(_glfw.egl.display, config,
-                                     EGL_GREEN_SIZE, &greenBits);
-            _glfw_eglGetConfigAttrib(_glfw.egl.display, config,
-                                     EGL_BLUE_SIZE, &blueBits);
-            _glfw_eglGetConfigAttrib(_glfw.egl.display, config,
-                                     EGL_ALPHA_SIZE, &alphaBits);
-
-            info.depth = redBits + greenBits + blueBits + alphaBits;
-            mask |= VisualDepthMask;
-        }
-
-        window->egl.visual = XGetVisualInfo(_glfw.x11.display,
-                                            mask, &info, &count);
-        if (!window->egl.visual)
-        {
-            _glfwInputError(GLFW_PLATFORM_ERROR,
-                            "EGL: Failed to retrieve visual for EGLConfig");
-            return GLFW_FALSE;
-        }
-    }
-#endif // _GLFW_X11
-
     if (ctxconfig->api == GLFW_OPENGL_ES_API)
     {
         if (!_glfw_eglBindAPI(EGL_OPENGL_ES_API))
@@ -453,6 +404,19 @@ int _glfwCreateContext(_GLFWwindow* window,
         return GLFW_FALSE;
     }
 
+    window->egl.surface =
+        _glfw_eglCreateWindowSurface(_glfw.egl.display,
+                                     config,
+                                     (EGLNativeWindowType)_GLFW_EGL_NATIVE_WINDOW,
+                                     NULL);
+    if (window->egl.surface == EGL_NO_SURFACE)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR,
+                        "EGL: Failed to create window surface: %s",
+                        getErrorString(_glfw_eglGetError()));
+        return GLFW_FALSE;
+    }
+
     window->egl.config = config;
 
     // Load the appropriate client library
@@ -541,14 +505,6 @@ void _glfwDestroyContext(_GLFWwindow* window)
         }
     }
 
-#if defined(_GLFW_X11)
-    if (window->egl.visual)
-    {
-       XFree(window->egl.visual);
-       window->egl.visual = NULL;
-    }
-#endif // _GLFW_X11
-
     if (window->egl.surface)
     {
         _glfw_eglDestroySurface(_glfw.egl.display, window->egl.surface);
@@ -564,16 +520,56 @@ void _glfwDestroyContext(_GLFWwindow* window)
 
 // Analyzes the specified context for possible recreation
 //
+#if defined(_GLFW_WIN32)
 int _glfwAnalyzeContext(const _GLFWwindow* window,
                         const _GLFWctxconfig* ctxconfig,
                         const _GLFWfbconfig* fbconfig)
 {
-#if defined(_GLFW_WIN32)
     return _GLFW_RECREATION_NOT_NEEDED;
-#else
-    return 0;
-#endif
 }
+#endif // _GLFW_WIN32
+
+// Returns the Visual and depth of the chosen EGLConfig
+//
+#if defined(_GLFW_X11)
+GLFWbool _glfwChooseVisual(const _GLFWctxconfig* ctxconfig,
+                           const _GLFWfbconfig* fbconfig,
+                           Visual** visual, int* depth)
+{
+    XVisualInfo* result;
+    XVisualInfo desired;
+    EGLConfig native;
+    EGLint visualID = 0, count = 0;
+    const long vimask = VisualScreenMask | VisualIDMask;
+
+    if (!chooseFBConfigs(ctxconfig, fbconfig, &native))
+    {
+        _glfwInputError(GLFW_FORMAT_UNAVAILABLE,
+                        "EGL: Failed to find a suitable EGLConfig");
+        return GLFW_FALSE;
+    }
+
+    _glfw_eglGetConfigAttrib(_glfw.egl.display, native,
+                             EGL_NATIVE_VISUAL_ID, &visualID);
+
+    desired.screen = _glfw.x11.screen;
+    desired.visualid = visualID;
+
+    result = XGetVisualInfo(_glfw.x11.display, vimask, &desired, &count);
+    if (!result)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR,
+                        "EGL: Failed to retrieve Visual for EGLConfig");
+        return GLFW_FALSE;
+    }
+
+    *visual = result->visual;
+    *depth = result->depth;
+
+    XFree(result);
+    return GLFW_TRUE;
+}
+#endif // _GLFW_X11
 
 
 //////////////////////////////////////////////////////////////////////////
@@ -584,21 +580,6 @@ void _glfwPlatformMakeContextCurrent(_GLFWwindow* window)
 {
     if (window)
     {
-        if (window->egl.surface == EGL_NO_SURFACE)
-        {
-            window->egl.surface =
-                _glfw_eglCreateWindowSurface(_glfw.egl.display,
-                                             window->egl.config,
-                                             (EGLNativeWindowType)_GLFW_EGL_NATIVE_WINDOW,
-                                             NULL);
-            if (window->egl.surface == EGL_NO_SURFACE)
-            {
-                _glfwInputError(GLFW_PLATFORM_ERROR,
-                                "EGL: Failed to create window surface: %s",
-                                getErrorString(_glfw_eglGetError()));
-            }
-        }
-
         _glfw_eglMakeCurrent(_glfw.egl.display,
                              window->egl.surface,
                              window->egl.surface,
@@ -667,6 +648,13 @@ GLFWAPI EGLContext glfwGetEGLContext(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
     _GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_CONTEXT);
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return EGL_NO_CONTEXT;
+    }
+
     return window->egl.context;
 }
 
@@ -674,6 +662,13 @@ GLFWAPI EGLSurface glfwGetEGLSurface(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
     _GLFW_REQUIRE_INIT_OR_RETURN(EGL_NO_SURFACE);
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return EGL_NO_SURFACE;
+    }
+
     return window->egl.surface;
 }
 

src/egl_context.h

@@ -147,10 +147,6 @@ typedef struct _GLFWcontextEGL
    EGLContext       context;
    EGLSurface       surface;
 
-#if defined(_GLFW_X11)
-   XVisualInfo*     visual;
-#endif
-
    void*            client;
 
 } _GLFWcontextEGL;
@@ -193,8 +189,15 @@ int _glfwCreateContext(_GLFWwindow* window,
                        const _GLFWctxconfig* ctxconfig,
                        const _GLFWfbconfig* fbconfig);
 void _glfwDestroyContext(_GLFWwindow* window);
+#if defined(_GLFW_WIN32)
 int _glfwAnalyzeContext(const _GLFWwindow* window,
                         const _GLFWctxconfig* ctxconfig,
                         const _GLFWfbconfig* fbconfig);
+#endif /*_GLFW_WIN32*/
+#if defined(_GLFW_X11)
+GLFWbool _glfwChooseVisual(const _GLFWctxconfig* ctxconfig,
+                           const _GLFWfbconfig* fbconfig,
+                           Visual** visual, int* depth);
+#endif /*_GLFW_X11*/
 
 #endif // _glfw3_egl_context_h_

src/glx_context.c

@@ -79,10 +79,6 @@ static GLFWbool chooseFBConfig(const _GLFWfbconfig* desired, GLXFBConfig* result
         const GLXFBConfig n = nativeConfigs[i];
         _GLFWfbconfig* u = usableConfigs + usableCount;
 
-        // Only consider GLXFBConfigs with associated visuals
-        if (!getFBConfigAttrib(n, GLX_VISUAL_ID))
-            continue;
-
         // Only consider RGBA GLXFBConfigs
         if (!(getFBConfigAttrib(n, GLX_RENDER_TYPE) & GLX_RGBA_BIT))
             continue;
@@ -192,12 +188,12 @@ int _glfwInitContextAPI(void)
         dlsym(_glfw.glx.handle, "glXQueryExtensionsString");
     _glfw.glx.CreateNewContext =
         dlsym(_glfw.glx.handle, "glXCreateNewContext");
-    _glfw.glx.GetVisualFromFBConfig =
-        dlsym(_glfw.glx.handle, "glXGetVisualFromFBConfig");
     _glfw.glx.GetProcAddress =
         dlsym(_glfw.glx.handle, "glXGetProcAddress");
     _glfw.glx.GetProcAddressARB =
         dlsym(_glfw.glx.handle, "glXGetProcAddressARB");
+    _glfw.glx.GetVisualFromFBConfig =
+        dlsym(_glfw.glx.handle, "glXGetVisualFromFBConfig");
 
     if (!_glfw_glXQueryExtension(_glfw.x11.display,
                                  &_glfw.glx.errorBase,
@@ -326,15 +322,6 @@ int _glfwCreateContext(_GLFWwindow* window,
         return GLFW_FALSE;
     }
 
-    window->glx.visual = _glfw_glXGetVisualFromFBConfig(_glfw.x11.display,
-                                                        native);
-    if (!window->glx.visual)
-    {
-        _glfwInputError(GLFW_PLATFORM_ERROR,
-                        "GLX: Failed to retrieve visual for GLXFBConfig");
-        return GLFW_FALSE;
-    }
-
     if (ctxconfig->api == GLFW_OPENGL_ES_API)
     {
         if (!_glfw.glx.ARB_create_context ||
@@ -485,12 +472,6 @@ int _glfwCreateContext(_GLFWwindow* window,
 //
 void _glfwDestroyContext(_GLFWwindow* window)
 {
-    if (window->glx.visual)
-    {
-        XFree(window->glx.visual);
-        window->glx.visual = NULL;
-    }
-
     if (window->glx.context)
     {
         _glfw_glXDestroyContext(_glfw.x11.display, window->glx.context);
@@ -498,6 +479,37 @@ void _glfwDestroyContext(_GLFWwindow* window)
     }
 }
 
+// Returns the Visual and depth of the chosen GLXFBConfig
+//
+GLFWbool _glfwChooseVisual(const _GLFWctxconfig* ctxconfig,
+                           const _GLFWfbconfig* fbconfig,
+                           Visual** visual, int* depth)
+{
+    GLXFBConfig native;
+    XVisualInfo* result;
+
+    if (!chooseFBConfig(fbconfig, &native))
+    {
+        _glfwInputError(GLFW_FORMAT_UNAVAILABLE,
+                        "GLX: Failed to find a suitable GLXFBConfig");
+        return GLFW_FALSE;
+    }
+
+    result = _glfw_glXGetVisualFromFBConfig(_glfw.x11.display, native);
+    if (!result)
+    {
+        _glfwInputError(GLFW_PLATFORM_ERROR,
+                        "GLX: Failed to retrieve Visual for GLXFBConfig");
+        return GLFW_FALSE;
+    }
+
+    *visual = result->visual;
+    *depth = result->depth;
+
+    XFree(result);
+    return GLFW_TRUE;
+}
+
 
 //////////////////////////////////////////////////////////////////////////
 //////                       GLFW platform API                      //////
@@ -573,6 +585,13 @@ GLFWAPI GLXContext glfwGetGLXContext(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
     _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return NULL;
+    }
+
     return window->glx.context;
 }
 

src/glx_context.h

@@ -111,10 +111,7 @@ typedef XVisualInfo* (*PFNGLXGETVISUALFROMFBCONFIGPROC)(Display*,GLXFBConfig);
 //
 typedef struct _GLFWcontextGLX
 {
-    // Rendering context
     GLXContext      context;
-    // Visual of selected GLXFBConfig
-    XVisualInfo*    visual;
 
 } _GLFWcontextGLX;
 
@@ -171,5 +168,8 @@ int _glfwCreateContext(_GLFWwindow* window,
                        const _GLFWctxconfig* ctxconfig,
                        const _GLFWfbconfig* fbconfig);
 void _glfwDestroyContext(_GLFWwindow* window);
+GLFWbool _glfwChooseVisual(const _GLFWctxconfig* ctxconfig,
+                           const _GLFWfbconfig* fbconfig,
+                           Visual** visual, int* depth);
 
 #endif // _glfw3_glx_context_h_

src/init.c

@@ -72,6 +72,8 @@ static const char* getErrorString(int error)
             return "A platform-specific error occurred";
         case GLFW_FORMAT_UNAVAILABLE:
             return "The requested format is unavailable";
+        case GLFW_NO_WINDOW_CONTEXT:
+            return "The specified window has no context";
     }
 
     return "ERROR: UNKNOWN ERROR TOKEN PASSED TO glfwErrorString";

src/mir_window.c

@@ -462,8 +462,11 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
                               const _GLFWctxconfig* ctxconfig,
                               const _GLFWfbconfig* fbconfig)
 {
-    if (!_glfwCreateContext(window, ctxconfig, fbconfig))
-        return GLFW_FALSE;
+    if (ctxconfig->api != GLFW_NO_API)
+    {
+        if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+            return GLFW_FALSE;
+    }
 
     if (wndconfig->monitor)
     {

src/nsgl_context.m

@@ -219,6 +219,7 @@ int _glfwCreateContext(_GLFWwindow* window,
         return GLFW_FALSE;
     }
 
+    [window->nsgl.context setView:window->ns.view];
     return GLFW_TRUE;
 }
 
@@ -291,6 +292,13 @@ GLFWAPI id glfwGetNSGLContext(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
     _GLFW_REQUIRE_INIT_OR_RETURN(nil);
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return NULL;
+    }
+
     return window->nsgl.context;
 }
 

src/wgl_context.c

@@ -672,6 +672,13 @@ GLFWAPI HGLRC glfwGetWGLContext(GLFWwindow* handle)
 {
     _GLFWwindow* window = (_GLFWwindow*) handle;
     _GLFW_REQUIRE_INIT_OR_RETURN(NULL);
+
+    if (window->context.api == GLFW_NO_API)
+    {
+        _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+        return NULL;
+    }
+
     return window->wgl.context;
 }
 

src/win32_window.c

@@ -665,10 +665,7 @@ static LRESULT CALLBACK windowProc(HWND hWnd, UINT uMsg,
 
 // Creates the GLFW window and rendering context
 //
-static GLFWbool createWindow(_GLFWwindow* window,
-                             const _GLFWwndconfig* wndconfig,
-                             const _GLFWctxconfig* ctxconfig,
-                             const _GLFWfbconfig* fbconfig)
+static int createWindow(_GLFWwindow* window, const _GLFWwndconfig* wndconfig)
 {
     int xpos, ypos, fullWidth, fullHeight;
     WCHAR* wideTitle;
@@ -742,9 +739,6 @@ static GLFWbool createWindow(_GLFWwindow* window,
 
     DragAcceptFiles(window->win32.handle, TRUE);
 
-    if (!_glfwCreateContext(window, ctxconfig, fbconfig))
-        return GLFW_FALSE;
-
     window->win32.minwidth  = GLFW_DONT_CARE;
     window->win32.minheight = GLFW_DONT_CARE;
     window->win32.maxwidth  = GLFW_DONT_CARE;
@@ -759,8 +753,6 @@ static GLFWbool createWindow(_GLFWwindow* window,
 //
 static void destroyWindow(_GLFWwindow* window)
 {
-    _glfwDestroyContext(window);
-
     if (window->win32.handle)
     {
         DestroyWindow(window->win32.handle);
@@ -830,43 +822,53 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
 {
     int status;
 
-    if (!createWindow(window, wndconfig, ctxconfig, fbconfig))
-        return GLFW_FALSE;
-
-    status = _glfwAnalyzeContext(window, ctxconfig, fbconfig);
-
-    if (status == _GLFW_RECREATION_IMPOSSIBLE)
+    if (!createWindow(window, wndconfig))
         return GLFW_FALSE;
 
-    if (status == _GLFW_RECREATION_REQUIRED)
+    if (ctxconfig->api != GLFW_NO_API)
     {
-        // Some window hints require us to re-create the context using WGL
-        // extensions retrieved through the current context, as we cannot check
-        // for WGL extensions or retrieve WGL entry points before we have a
-        // current context (actually until we have implicitly loaded the ICD)
-
-        // Yes, this is strange, and yes, this is the proper way on Win32
-
-        // As Windows only allows you to set the pixel format once for a
-        // window, we need to destroy the current window and create a new one
-        // to be able to use the new pixel format
-
-        // Technically, it may be possible to keep the old window around if
-        // we're just creating an OpenGL 3.0+ context with the same pixel
-        // format, but it's not worth the added code complexity
-
-        // First we clear the current context (the one we just created)
-        // This is usually done by glfwDestroyWindow, but as we're not doing
-        // full GLFW window destruction, it's duplicated here
-        _glfwPlatformMakeContextCurrent(NULL);
+        if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+            return GLFW_FALSE;
 
-        // Next destroy the Win32 window and WGL context (without resetting or
-        // destroying the GLFW window object)
-        destroyWindow(window);
+        status = _glfwAnalyzeContext(window, ctxconfig, fbconfig);
 
-        // ...and then create them again, this time with better APIs
-        if (!createWindow(window, wndconfig, ctxconfig, fbconfig))
+        if (status == _GLFW_RECREATION_IMPOSSIBLE)
             return GLFW_FALSE;
+
+        if (status == _GLFW_RECREATION_REQUIRED)
+        {
+            // Some window hints require us to re-create the context using WGL
+            // extensions retrieved through the current context, as we cannot
+            // check for WGL extensions or retrieve WGL entry points before we
+            // have a current context (actually until we have implicitly loaded
+            // the vendor ICD)
+
+            // Yes, this is strange, and yes, this is the proper way on Win32
+
+            // As Windows only allows you to set the pixel format once for
+            // a window, we need to destroy the current window and create a new
+            // one to be able to use the new pixel format
+
+            // Technically, it may be possible to keep the old window around if
+            // we're just creating an OpenGL 3.0+ context with the same pixel
+            // format, but it's not worth the added code complexity
+
+            // First we clear the current context (the one we just created)
+            // This is usually done by glfwDestroyWindow, but as we're not doing
+            // full GLFW window destruction, it's duplicated here
+            _glfwPlatformMakeContextCurrent(NULL);
+
+            // Next destroy the Win32 window and WGL context (without resetting
+            // or destroying the GLFW window object)
+            _glfwDestroyContext(window);
+            destroyWindow(window);
+
+            // ...and then create them again, this time with better APIs
+            if (!createWindow(window, wndconfig))
+                return GLFW_FALSE;
+            if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+                return GLFW_FALSE;
+        }
     }
 
     if (window->monitor)
@@ -884,6 +886,9 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
     if (window->monitor)
         leaveFullscreenMode(window);
 
+    if (window->context.api != GLFW_NO_API)
+        _glfwDestroyContext(window);
+
     destroyWindow(window);
 }
 

src/window.c

@@ -142,6 +142,15 @@ GLFWAPI GLFWwindow* glfwCreateWindow(int width, int height,
     wndconfig.monitor = (_GLFWmonitor*) monitor;
     ctxconfig.share   = (_GLFWwindow*) share;
 
+    if (ctxconfig.share)
+    {
+        if (ctxconfig.share->context.api == GLFW_NO_API)
+        {
+            _glfwInputError(GLFW_NO_WINDOW_CONTEXT, NULL);
+            return NULL;
+        }
+    }
+
     if (wndconfig.monitor)
     {
         wndconfig.resizable = GLFW_TRUE;
@@ -181,27 +190,30 @@ GLFWAPI GLFWwindow* glfwCreateWindow(int width, int height,
         return NULL;
     }
 
-    _glfwPlatformMakeContextCurrent(window);
-
-    // Retrieve the actual (as opposed to requested) context attributes
-    if (!_glfwRefreshContextAttribs(&ctxconfig))
+    if (ctxconfig.api != GLFW_NO_API)
     {
-        glfwDestroyWindow((GLFWwindow*) window);
-        _glfwPlatformMakeContextCurrent(previous);
-        return NULL;
-    }
+        _glfwPlatformMakeContextCurrent(window);
 
-    // Verify the context against the requested parameters
-    if (!_glfwIsValidContext(&ctxconfig))
-    {
-        glfwDestroyWindow((GLFWwindow*) window);
+        // Retrieve the actual (as opposed to requested) context attributes
+        if (!_glfwRefreshContextAttribs(&ctxconfig))
+        {
+            glfwDestroyWindow((GLFWwindow*) window);
+            _glfwPlatformMakeContextCurrent(previous);
+            return NULL;
+        }
+
+        // Verify the context against the requested parameters
+        if (!_glfwIsValidContext(&ctxconfig))
+        {
+            glfwDestroyWindow((GLFWwindow*) window);
+            _glfwPlatformMakeContextCurrent(previous);
+            return NULL;
+        }
+
+        // Restore the previously current context (or NULL)
         _glfwPlatformMakeContextCurrent(previous);
-        return NULL;
     }
 
-    // Restore the previously current context (or NULL)
-    _glfwPlatformMakeContextCurrent(previous);
-
     if (wndconfig.monitor)
     {
         int width, height;

src/wl_window.c

@@ -238,8 +238,11 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
                               const _GLFWctxconfig* ctxconfig,
                               const _GLFWfbconfig* fbconfig)
 {
-    if (!_glfwCreateContext(window, ctxconfig, fbconfig))
-        return GLFW_FALSE;
+    if (ctxconfig->api != GLFW_NO_API)
+    {
+        if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+            return GLFW_FALSE;
+    }
 
     if (!createSurface(window, wndconfig))
         return GLFW_FALSE;

src/x11_platform.h

@@ -62,10 +62,8 @@
 #include "xkb_unicode.h"
 
 #if defined(_GLFW_GLX)
- #define _GLFW_X11_CONTEXT_VISUAL window->glx.visual
  #include "glx_context.h"
 #elif defined(_GLFW_EGL)
- #define _GLFW_X11_CONTEXT_VISUAL window->egl.visual
  #define _GLFW_EGL_NATIVE_WINDOW  window->x11.handle
  #define _GLFW_EGL_NATIVE_DISPLAY _glfw.x11.display
  #include "egl_context.h"

src/x11_window.c

@@ -248,17 +248,16 @@ static char** parseUriList(char* text, int* count)
 // Create the X11 window (and its colormap)
 //
 static GLFWbool createWindow(_GLFWwindow* window,
-                             const _GLFWwndconfig* wndconfig)
+                             const _GLFWwndconfig* wndconfig,
+                             Visual* visual, int depth)
 {
-    XVisualInfo* vi = _GLFW_X11_CONTEXT_VISUAL;
-
     // Every window needs a colormap
     // Create one based on the visual used by the current context
     // TODO: Decouple this from context creation
 
     window->x11.colormap = XCreateColormap(_glfw.x11.display,
                                            _glfw.x11.root,
-                                           vi->visual,
+                                           visual,
                                            AllocNone);
 
     // Create the actual window
@@ -279,10 +278,10 @@ static GLFWbool createWindow(_GLFWwindow* window,
                                            _glfw.x11.root,
                                            0, 0,
                                            wndconfig->width, wndconfig->height,
-                                           0,          // Border width
-                                           vi->depth,  // Color depth
+                                           0,      // Border width
+                                           depth,  // Color depth
                                            InputOutput,
-                                           vi->visual,
+                                           visual,
                                            wamask,
                                            &wa);
 
@@ -1467,12 +1466,21 @@ int _glfwPlatformCreateWindow(_GLFWwindow* window,
                               const _GLFWctxconfig* ctxconfig,
                               const _GLFWfbconfig* fbconfig)
 {
-    if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+    Visual* visual;
+    int depth;
+
+    if (!_glfwChooseVisual(ctxconfig, fbconfig, &visual, &depth))
         return GLFW_FALSE;
 
-    if (!createWindow(window, wndconfig))
+    if (!createWindow(window, wndconfig, visual, depth))
         return GLFW_FALSE;
 
+    if (ctxconfig->api != GLFW_NO_API)
+    {
+        if (!_glfwCreateContext(window, ctxconfig, fbconfig))
+            return GLFW_FALSE;
+    }
+
     if (wndconfig->monitor)
     {
         _glfwPlatformShowWindow(window);
@@ -1493,7 +1501,8 @@ void _glfwPlatformDestroyWindow(_GLFWwindow* window)
         window->x11.ic = NULL;
     }
 
-    _glfwDestroyContext(window);
+    if (window->context.api != GLFW_NO_API)
+        _glfwDestroyContext(window);
 
     if (window->x11.handle)
     {