Share Group plumbing in Blink; Remove WebGL from default share group

Source/platform/graphics/ImageBuffer.cpp

 /*
  * Copyright (c) 2008, Google Inc. All rights reserved.
  * Copyright (C) 2009 Dirk Schulze <krit@webkit.org>
  * Copyright (C) 2010 Torch Mobile (Beijing) Co. Ltd. All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without
  * modification, are permitted provided that the following conditions are
  * met:
  *
  *     * Redistributions of source code must retain the above copyright
@@ skipping 29 matching lines @@
 #include "platform/graphics/GraphicsTypes3D.h"
 #include "platform/graphics/UnacceleratedImageBufferSurface.h"
 #include "platform/graphics/gpu/DrawingBuffer.h"
 #include "platform/graphics/gpu/Extensions3DUtil.h"
 #include "platform/graphics/skia/NativeImageSkia.h"
 #include "platform/graphics/skia/SkiaUtils.h"
 #include "platform/image-encoders/skia/JPEGImageEncoder.h"
 #include "platform/image-encoders/skia/PNGImageEncoder.h"
 #include "platform/image-encoders/skia/WEBPImageEncoder.h"
 #include "public/platform/Platform.h"
+#include "public/platform/WebExternalTextureMailbox.h"
 #include "public/platform/WebGraphicsContext3D.h"
 #include "public/platform/WebGraphicsContext3DProvider.h"
 #include "third_party/skia/include/effects/SkTableColorFilter.h"
 #include "wtf/MathExtras.h"
 #include "wtf/text/Base64.h"
 #include "wtf/text/WTFString.h"
 
 using namespace std;
 
 namespace WebCore {
@@ skipping 71 matching lines @@
 blink::WebLayer* ImageBuffer::platformLayer() const
 {
     return m_surface->layer();
 }
 
 bool ImageBuffer::copyToPlatformTexture(blink::WebGraphicsContext3D* context, Platform3DObject texture, GLenum internalFormat, GLenum destType, GLint level, bool premultiplyAlpha, bool flipY)
 {
     if (!m_surface->isAccelerated() || !platformLayer() || !isValid())
         return false;
 
+    if (!Extensions3DUtil::canUseCopyTextureCHROMIUM(internalFormat, destType, level))
+        return false;
+
+    OwnPtr<blink::WebGraphicsContext3DProvider> provider = adoptPtr(blink::Platform::current()->createSharedOffscreenGraphicsContext3DProvider());
+    if (!provider)
+        return false;
+    blink::WebGraphicsContext3D* sharedContext = provider->context3d();
+    if (!sharedContext || !sharedContext->makeContextCurrent())
+        return false;
+
+    OwnPtr<blink::WebExternalTextureMailbox> mailbox = adoptPtr(new blink::WebExternalTextureMailbox);
+
+    // Contexts may be in a different share group. We must transfer the texture through a mailbox first
+    sharedContext->genMailboxCHROMIUM(mailbox->name);
+    sharedContext->bindTexture(GL_TEXTURE_2D, getBackingTexture());

[Ken Russell (switch to Gerrit), 2014/03/13 19:35:54]

I recall you mentioned that it was always necessary to preserve the TEXTURE_2D
binding on the shared context. Was that not actually necessary here?

+    sharedContext->produceTextureCHROMIUM(GL_TEXTURE_2D, mailbox->name);
+    sharedContext->flush();
+
+    mailbox->syncPoint = sharedContext->insertSyncPoint();
+
     if (!context->makeContextCurrent())
         return false;
 
-    if (!Extensions3DUtil::canUseCopyTextureCHROMIUM(internalFormat, destType, level))
-        return false;
+    Platform3DObject sourceTexture = context->createTexture();
+
+    context->bindTexture(GL_TEXTURE_2D, sourceTexture);
+
+    context->waitSyncPoint(mailbox->syncPoint);
+    context->consumeTextureCHROMIUM(GL_TEXTURE_2D, mailbox->name);
 
     // The canvas is stored in a premultiplied format, so unpremultiply if necessary.
     context->pixelStorei(GC3D_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM, !premultiplyAlpha);
 
     // The canvas is stored in an inverted position, so the flip semantics are reversed.
     context->pixelStorei(GC3D_UNPACK_FLIP_Y_CHROMIUM, !flipY);
-    context->copyTextureCHROMIUM(GL_TEXTURE_2D, getBackingTexture(), texture, level, internalFormat, destType);
+    context->copyTextureCHROMIUM(GL_TEXTURE_2D, sourceTexture, texture, level, internalFormat, destType);
 
     context->pixelStorei(GC3D_UNPACK_FLIP_Y_CHROMIUM, false);
     context->pixelStorei(GC3D_UNPACK_UNPREMULTIPLY_ALPHA_CHROMIUM, false);
+
+    context->bindTexture(GL_TEXTURE_2D, 0);

[dshwang, 2014/03/14 21:47:54]

If changing context->bindTexture(GL_TEXTURE_2D, texture),
ImageBuffer::copyToPlatformTexture() seems to be not changed from client's
perspective. So clients don't need to call restoreCurrentTexture2D().
So imo, we can remove to query bound texture in DrawingBuffer.

+    context->deleteTexture(sourceTexture);
+
     context->flush();
+    sharedContext->waitSyncPoint(context->insertSyncPoint());
+
     return true;
 }
 
 static bool drawNeedsCopy(GraphicsContext* src, GraphicsContext* dst)
 {
     ASSERT(dst);
     return (src == dst);
 }
 
 Platform3DObject ImageBuffer::getBackingTexture()
@@ skipping 216 matching lines @@
     if (!encodeImage(imageData, mimeType, quality, &encodedImage))
         return "data:,";
 
     Vector<char> base64Data;
     base64Encode(encodedImage, base64Data);
 
     return "data:" + mimeType + ";base64," + base64Data;
 }
 
 } // namespace WebCore