686083 - No way to switch between GL implementations for WebGL

Status: RESOLVED FIXED

(Core :: Graphics: CanvasWebGL, defect)

Description

[Kelsey Gilbert [:jgilbert]]

The implementations are tried in order, falling back to the next in line if an implementation fails to initialize. If one's system supports the first implementation, it's not possible to try other (later) implementations even if they are also supported by the system.

For windows, the order is:
ANGLE+EGL
WGL (PBuffers)
WGL (FBOs)

Comment 1

[Kelsey Gilbert [:jgilbert]]

A way of disabling each implementation would allow implementations below it to be tested.

Comment 2

[Benoit Jacob [:bjacob] (mostly away)]

We have webgl.prefer_native_gl in about:config, but we don't have a way of selecting between WGL+PBuffers and WGL+FBOs. But I think this is a bit too internal to warrant a pref. If you think this is useful, maybe the right balance is to make it a hidden pref: query it in c++ code like any other pref, but don't list it in all.js so that it doesn't show up in about:config unless the user explicitly created it.

Comment 3

[Kelsey Gilbert [:jgilbert]]

A hidden pref was my thought. It would help with testing and assuring that all the branches pass conformance tests while making changes.

Comment 4

[Kelsey Gilbert [:jgilbert]]

Attachment: Adds pref "wgl.prefer-fbo" (def: false)

Simple patch. Just adds a hidden pref called "wgl.prefer-fbo" which defaults to false (usually, we try PBuffers first, and only use FBOs if PBuffers fails to initialize). When enabled, it skips trying PBuffers, and tries FBOs.

Comment 5

[Kelsey Gilbert [:jgilbert]]

There's a need for a parallel pref for Mac's CGL path, so I added "cgl.prefer-fbo" to enable that.

Comment 6

[Kelsey Gilbert [:jgilbert]]

Attachment: Adds wgl.prefer-fbo and cgl.prefer-fbo

Comment 7

[Kelsey Gilbert [:jgilbert]]

Attachment: Adds hidden prefs wgl.prefer-fbo and cgl.prefer-fbo

Comment 8

[Kelsey Gilbert [:jgilbert]]

Try run: https://tbpl.mozilla.org/?tree=Try&usebuildbot=1&rev=bb7dd7636b4c

Comment 9

[Kelsey Gilbert [:jgilbert]]

Comment on attachment 562895 [details] [diff] [review]
Adds hidden prefs wgl.prefer-fbo and cgl.prefer-fbo

>From: Jeff Gilbert <[e-mail]>
>Fix for 686083: Adds method to disable GL implementations
>
>diff --git a/gfx/thebes/GLContextProviderCGL.mm b/gfx/thebes/GLContextProviderCGL.mm
>--- a/gfx/thebes/GLContextProviderCGL.mm
>+++ b/gfx/thebes/GLContextProviderCGL.mm
>@@ -41,16 +41,17 @@
> #include <OpenGL/gl.h>
> #include <AppKit/NSOpenGL.h>
> #include "gfxASurface.h"
> #include "gfxImageSurface.h"
> #include "gfxQuartzSurface.h"
> #include "gfxPlatform.h"
> #include "gfxFailure.h"
> #include "prenv.h"
>+#include "mozilla/Preferences.h"
> 
> namespace mozilla {
> namespace gl {
> 
> static PRBool gUseDoubleBufferedWindows = PR_TRUE;
> 
> class CGLLibrary
> {
>@@ -553,26 +554,31 @@ CreateOffscreenFBOContext(const gfxIntSi
>     return glContext.forget();
> }
> 
> already_AddRefed<GLContext>
> GLContextProviderCGL::CreateOffscreen(const gfxIntSize& aSize,
>                                       const ContextFormat& aFormat)
> {
>     nsRefPtr<GLContextCGL> glContext;
>-
>-    glContext = CreateOffscreenPBufferContext(aSize, aFormat);
>-    if (glContext &&
>-        glContext->Init())
>+	
>+    NS_ENSURE_TRUE(Preferences::GetRootBranch(), nsnull);
>+    PRBool preferFBOs = Preferences::GetBool("cgl.prefer-fbo", PR_FALSE);
>+    if (!preferFBOs)
>     {
>-        glContext->mOffscreenSize = aSize;
>-        glContext->mOffscreenActualSize = aSize;
>-
>-        return glContext.forget();
>-    }
>+        glContext = CreateOffscreenPBufferContext(aSize, aFormat);
>+        if (glContext &&
>+            glContext->Init())
>+        {
>+            glContext->mOffscreenSize = aSize;
>+            glContext->mOffscreenActualSize = aSize;
>+    
>+            return glContext.forget();
>+        }
>+    }
> 
>     // try a FBO as second choice
>     glContext = CreateOffscreenFBOContext(aSize, aFormat);
>     if (glContext &&
>         glContext->Init() &&
>         glContext->ResizeOffscreenFBO(aSize))
>     {
>         return glContext.forget();
>diff --git a/gfx/thebes/GLContextProviderWGL.cpp b/gfx/thebes/GLContextProviderWGL.cpp
>--- a/gfx/thebes/GLContextProviderWGL.cpp
>+++ b/gfx/thebes/GLContextProviderWGL.cpp
>@@ -43,16 +43,18 @@
> #include "gfxImageSurface.h"
> #include "gfxPlatform.h"
> #include "gfxWindowsSurface.h"
> 
> #include "gfxCrashReporterUtils.h"
> 
> #include "prenv.h"
> 
>+#include "mozilla/Preferences.h"
>+
> namespace mozilla {
> namespace gl {
> 
> WGLLibrary sWGLLibrary;
> 
> static HWND gSharedWindow = 0;
> static HDC gSharedWindowDC = 0;
> static HGLRC gSharedWindowGLContext = 0;
>@@ -611,17 +613,20 @@ GLContextProviderWGL::CreateOffscreen(co
>     if (!sWGLLibrary.EnsureInitialized()) {
>         return nsnull;
>     }
> 
>     nsRefPtr<GLContextWGL> glContext;
> 
>     // Always try to create a pbuffer context first, because we
>     // want the context isolation.
>-    if (sWGLLibrary.fCreatePbuffer &&
>+    NS_ENSURE_TRUE(Preferences::GetRootBranch(), nsnull);
>+    PRBool preferFBOs = Preferences::GetBool("wgl.prefer-fbo", PR_FALSE);
>+    if (!preferFBOs &&
>+        sWGLLibrary.fCreatePbuffer &&
>         sWGLLibrary.fChoosePixelFormat)
>     {
>         glContext = CreatePBufferOffscreenContext(aSize, aFormat);
>     }
> 
>     // If it failed, then create a window context and use a FBO.
>     if (!glContext) {
>         glContext = CreateWindowOffscreenContext(aSize, aFormat);

Comment 10

[Kelsey Gilbert [:jgilbert]]

Derp, that didn't do what I thought it would do.

There are some tabs which snuck in to the patch. Will reupload shortly.

Comment 11

[Kelsey Gilbert [:jgilbert]]

Attachment: Adds hidden prefs wgl.prefer-fbo and cgl.prefer-fbo (without tabs)

Here's the patch with the tabs fixed.

Comment 12

[Kelsey Gilbert [:jgilbert]]

Attachment: Adds hidden prefs wgl.prefer-fbo and cgl.prefer-fbo

Carryover r+ from bjacob, updated to include conversion from PRBool to bool.

Comment 13

[Benoit Jacob [:bjacob] (mostly away)]

http://hg.mozilla.org/integration/mozilla-inbound/rev/30454fc8f442

Comment 14

[Benoit Jacob [:bjacob] (mostly away)]

Re-landed with proper commit message (sorry, should have checked that):
http://hg.mozilla.org/integration/mozilla-inbound/rev/f5f1228fc7ab

Comment 15

[Marco Bonardo [:mak]]

https://hg.mozilla.org/mozilla-central/rev/f5f1228fc7ab