Chromium implementation of discardBackbuffer WebGraphicsContext3D extension.

content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h

Index: content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
diff --git a/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h b/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
index dd0620a79ba73ec1f33d970e9f2fc95243d7429b..0232edaa8d889f0905a527b4ca89641dd9437e69 100644
--- a/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
+++ b/content/common/gpu/client/webgraphicscontext3d_command_buffer_impl.h
@@ -443,6 +443,9 @@ class WebGraphicsContext3DCommandBufferImpl
 
   virtual void setVisibilityCHROMIUM(bool visible);
 
+  virtual void discardFramebufferEXT();

[apatrick_chromium, 2012/03/16 19:37:56]

This one takes some arguments.

[mmocny, 2012/03/16 20:25:20]

How closely should I duplicate the original arguments?

I assume target will simply be "WGC3Denum target", but I am not sure how best to
implement the attachements argument:

The only reference to values "COLOR_EXT" etc in our codebase is defined in
ANGLE, and WebGraphicsContext3D seems to use an Attributes struct of which
contains bools for these concepts.

Should I use an array of enum values and define these values somewhere, or use
something higher level?

On 2012/03/16 19:37:56, apatrick_chromium wrote:

[apatrick_chromium, 2012/03/16 21:08:19]

I think for the purposes of this patch, just make the signature:

void discardFramebufferEXT(WGC3Denum target, WGC3Dsizei numAttachments, const
WGC3Denum *attachments);

The constants are not used anywhere yet. But I think the appropriate place to
put them would be WebKit/Source/WebCore/platform/graphics/Extensions3D.h or
WebKit/Source/WebCore/platform/graphics/chromium/Extensions3DChromium.h. I don't
do a lot with WebKit though. You might want to check with someone more familiar
with it.

+  virtual void ensureFramebufferCHROMIUM();
+
   virtual void setMemoryAllocationChangedCallbackCHROMIUM(
       WebGraphicsMemoryAllocationChangedCallbackCHROMIUM* callback);