From d8a4ca1162c397a09b4487b587d6d9c0e39671e3 Mon Sep 17 00:00:00 2001 From: "Stefanos A." Date: Wed, 18 Dec 2013 14:29:06 +0100 Subject: [PATCH] Cleaned up temporary context construction The temporary context is now retained until the actual context has been constructed. If we don't do this, then WGL_ARB_create_context may fail to work correctly on specific GPUs (e.g. Intel). This may affect issue #19. --- .../OpenTK/Platform/Windows/WinGLContext.cs | 217 ++++++++++-------- 1 file changed, 126 insertions(+), 91 deletions(-) diff --git a/Source/OpenTK/Platform/Windows/WinGLContext.cs b/Source/OpenTK/Platform/Windows/WinGLContext.cs index 92c21851..9d4bf4c5 100644 --- a/Source/OpenTK/Platform/Windows/WinGLContext.cs +++ b/Source/OpenTK/Platform/Windows/WinGLContext.cs @@ -28,88 +28,111 @@ namespace OpenTK.Platform.Windows internal sealed class WinGLContext : DesktopGraphicsContext { static readonly object LoadLock = new object(); - static readonly object SyncRoot = new object(); bool vsync_supported; readonly WinGraphicsMode ModeSelector; - #region --- Contructors --- - - static WinGLContext() + // We need to create a temp context in order to load + // wgl extensions (e.g. for multisampling or GL3). + // We cannot rely on any WGL extensions before + // we load them with the temporary context. + class TemporaryContext : IDisposable { - lock (LoadLock) + public ContextHandle Context; + + public TemporaryContext(INativeWindow native) { - // We need to create a temp context in order to load - // wgl extensions (e.g. for multisampling or GL3). - // We cannot rely on OpenTK.Platform.Wgl until we - // create the context and call Wgl.LoadAll(). - Debug.Print("Creating temporary context for wgl extensions."); - using (INativeWindow native = new NativeWindow()) + Debug.WriteLine("[WGL] Creating temporary context to load extensions"); + + if (native == null) + throw new ArgumentNullException(); + + // Create temporary context and load WGL entry points + // First, set a compatible pixel format to the device context + // of the temp window + WinWindowInfo window = native.WindowInfo as WinWindowInfo; + WinGraphicsMode selector = new WinGraphicsMode(window.DeviceContext); + WinGLContext.SetGraphicsModePFD(selector, GraphicsMode.Default, window); + + bool success = false; + + // Then, construct a temporary context and load all wgl extensions + Context = new ContextHandle(Wgl.CreateContext(window.DeviceContext)); + if (Context != ContextHandle.Zero) { - // Create temporary context and load WGL entry points - // First, set a compatible pixel format to the device context - // of the temp window - WinWindowInfo window = native.WindowInfo as WinWindowInfo; - WinGraphicsMode selector = new WinGraphicsMode(window.DeviceContext); - SetGraphicsModePFD(selector, GraphicsMode.Default, window); - - // Then, construct a temporary context and load all wgl extensions - ContextHandle temp_context = new ContextHandle(Wgl.CreateContext(window.DeviceContext)); - if (temp_context != ContextHandle.Zero) + // Make the context current. + // Note: on some video cards and on some virtual machines, wglMakeCurrent + // may fail with an errorcode of 6 (INVALID_HANDLE). The suggested workaround + // is to call wglMakeCurrent in a loop until it succeeds. + // See https://www.opengl.org/discussion_boards/showthread.php/171058-nVidia-wglMakeCurrent()-multiple-threads + // Sigh... + for (int retry = 0; retry < 5 && !success; retry++) { - // Make the context current. - // Note: on some video cards and on some virtual machines, wglMakeCurrent - // may fail with an errorcode of 6 (INVALID_HANDLE). The suggested workaround - // is to call wglMakeCurrent in a loop until it succeeds. - // See https://www.opengl.org/discussion_boards/showthread.php/171058-nVidia-wglMakeCurrent()-multiple-threads - // Sigh... - for (int retry = 0; retry < 5; retry++) - { - bool success = Wgl.MakeCurrent(window.DeviceContext, temp_context.Handle); - if (!success) - { - Debug.Print("wglMakeCurrent failed with error: {0}. Retrying", Marshal.GetLastWin32Error()); - System.Threading.Thread.Sleep(10); - } - else - { - // wglMakeCurrent succeeded, we are done here! - break; - } - } + success = Wgl.MakeCurrent(window.DeviceContext, Context.Handle); + if (!success) + { + Debug.Print("wglMakeCurrent failed with error: {0}. Retrying", Marshal.GetLastWin32Error()); + System.Threading.Thread.Sleep(10); + } + } + } + else + { + Debug.Print("[WGL] CreateContext failed with error: {0}", Marshal.GetLastWin32Error()); + } - // Load wgl extensions and destroy temporary context - Wgl.LoadAll(); - Wgl.MakeCurrent(IntPtr.Zero, IntPtr.Zero); - Wgl.DeleteContext(temp_context.Handle); - } - else - { - Debug.Print("wglCreateContext failed with error: {0}", Marshal.GetLastWin32Error()); - } + if (!success) + { + Debug.WriteLine("[WGL] Failed to create temporary context"); + } + } + + public void Dispose() + { + if (Context != ContextHandle.Zero) + { + Wgl.MakeCurrent(IntPtr.Zero, IntPtr.Zero); + Wgl.DeleteContext(Context.Handle); } } } + #region --- Contructors --- + public WinGLContext(GraphicsMode format, WinWindowInfo window, IGraphicsContext sharedContext, int major, int minor, GraphicsContextFlags flags) { // There are many ways this code can break when accessed by multiple threads. The biggest offender is // the sharedContext stuff, which will only become valid *after* this constructor returns. // The easiest solution is to serialize all context construction - hence the big lock, below. - lock (SyncRoot) + lock (LoadLock) { if (window == null) throw new ArgumentNullException("window", "Must point to a valid window."); if (window.Handle == IntPtr.Zero) throw new ArgumentException("window", "Must be a valid window."); - Debug.Print("OpenGL will be bound to window:{0} on thread:{1}", window.Handle, - System.Threading.Thread.CurrentThread.ManagedThreadId); - - lock (LoadLock) + IntPtr current_context = Wgl.GetCurrentContext(); + INativeWindow temp_window = null; + TemporaryContext temp_context = null; + try { + if (current_context == IntPtr.Zero) + { + // Create temporary context to load WGL extensions + temp_window = new NativeWindow(); + temp_context = new TemporaryContext(temp_window); + current_context = Wgl.GetCurrentContext(); + if (current_context != IntPtr.Zero && current_context == temp_context.Context.Handle) + { + Wgl.LoadAll(); + } + } + + Debug.Print("OpenGL will be bound to window:{0} on thread:{1}", window.Handle, + System.Threading.Thread.CurrentThread.ManagedThreadId); + ModeSelector = new WinGraphicsMode(window.DeviceContext); Mode = SetGraphicsModePFD(ModeSelector, format, (WinWindowInfo)window); @@ -146,43 +169,56 @@ namespace OpenTK.Platform.Windows if (Handle == ContextHandle.Zero) Debug.Print("failed. (Error: {0})", Marshal.GetLastWin32Error()); } - catch (EntryPointNotFoundException e) { Debug.Print(e.ToString()); } - catch (NullReferenceException e) { Debug.Print(e.ToString()); } + catch (Exception e) { Debug.Print(e.ToString()); } + } + + if (Handle == ContextHandle.Zero) + { + // Failed to create GL3-level context, fall back to GL2. + Debug.Write("Falling back to GL2... "); + Handle = new ContextHandle(Wgl.CreateContext(window.DeviceContext)); + if (Handle == ContextHandle.Zero) + Handle = new ContextHandle(Wgl.CreateContext(window.DeviceContext)); + if (Handle == ContextHandle.Zero) + throw new GraphicsContextException( + String.Format("Context creation failed. Wgl.CreateContext() error: {0}.", + Marshal.GetLastWin32Error())); + } + + Debug.WriteLine(String.Format("success! (id: {0})", Handle)); + } + finally + { + if (temp_context != null) + { + temp_context.Dispose(); + temp_context = null; + } + if (temp_window != null) + { + temp_window.Dispose(); + temp_window = null; } } + } - if (Handle == ContextHandle.Zero) - { - // Failed to create GL3-level context, fall back to GL2. - Debug.Write("Falling back to GL2... "); - Handle = new ContextHandle(Wgl.CreateContext(window.DeviceContext)); - if (Handle == ContextHandle.Zero) - Handle = new ContextHandle(Wgl.CreateContext(window.DeviceContext)); - if (Handle == ContextHandle.Zero) - throw new GraphicsContextException( - String.Format("Context creation failed. Wgl.CreateContext() error: {0}.", - Marshal.GetLastWin32Error())); - } + // Todo: is this comment still true? + // On intel drivers, wgl entry points appear to change + // when creating multiple contexts. As a workaround, + // we reload Wgl entry points every time we create a + // new context - this solves the issue without any apparent + // side-effects (i.e. the old contexts can still be handled + // using the new entry points.) + // Sigh... + Wgl.MakeCurrent(window.DeviceContext, Handle.Handle); + Wgl.LoadAll(); - Debug.WriteLine(String.Format("success! (id: {0})", Handle)); - - // Todo: is this comment still true? - // On intel drivers, wgl entry points appear to change - // when creating multiple contexts. As a workaround, - // we reload Wgl entry points every time we create a - // new context - this solves the issue without any apparent - // side-effects (i.e. the old contexts can still be handled - // using the new entry points.) - // Sigh... - Wgl.LoadAll(); - - if (sharedContext != null) - { - Marshal.GetLastWin32Error(); - Debug.Write(String.Format("Sharing state with context {0}: ", sharedContext)); - bool result = Wgl.ShareLists((sharedContext as IGraphicsContextInternal).Context.Handle, Handle.Handle); - Debug.WriteLine(result ? "success!" : "failed with win32 error " + Marshal.GetLastWin32Error()); - } + if (sharedContext != null) + { + Marshal.GetLastWin32Error(); + Debug.Write(String.Format("Sharing state with context {0}: ", sharedContext)); + bool result = Wgl.ShareLists((sharedContext as IGraphicsContextInternal).Context.Handle, Handle.Handle); + Debug.WriteLine(result ? "success!" : "failed with win32 error " + Marshal.GetLastWin32Error()); } } @@ -231,7 +267,6 @@ namespace OpenTK.Platform.Windows public override void MakeCurrent(IWindowInfo window) { - lock (SyncRoot) lock (LoadLock) { bool success; @@ -347,7 +382,7 @@ namespace OpenTK.Platform.Windows { // See https://www.opengl.org/wiki/Load_OpenGL_Functions long a = address.ToInt64(); - bool is_valid = (a < -1 )|| (a > 3); + bool is_valid = (a < -1) || (a > 3); return is_valid; } @@ -379,7 +414,7 @@ namespace OpenTK.Platform.Windows Functions.DescribePixelFormat( window.DeviceContext, (int)mode.Index.Value, API.PixelFormatDescriptorSize, ref pfd); - + Debug.WriteLine(mode.Index.ToString()); if (!Functions.SetPixelFormat(window.DeviceContext, (int)mode.Index.Value, ref pfd))