Proposing new CHROMIUM_sync_point API.

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt

Index: gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
diff --git a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
index 965cb44b0c066306163f84404232be632a42f644..719e2cbb9690683bc031ec4b8f33692bd7ab80e0 100644
--- a/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
+++ b/gpu/GLES2/extensions/CHROMIUM/CHROMIUM_sync_point.txt
@@ -8,7 +8,7 @@ Name Strings
 
 Version
 
-    Last Modifed Date: February 25, 2013
+    Last Modifed Date: September 8, 2015
 
 Dependencies
 
@@ -30,39 +30,56 @@ Issues
 
     None
 
-New Tokens
-
-    None
-
 New Procedures and Functions
 
     The command
 
         uint InsertSyncPointCHROMIUM()
 
-    flushes the stream of commands for the current context and creates and
-    inserts a sync point. The sync point acts as a fence, which is signaled when
-    previous commands have been submitted to the server, or when the context is
-    destroyed, whichever happens first. The sync point name is returned. The
-    sync point is implicitly deleted when it becomes signaled. The sync point
-    namespace is shared between all contexts on the same server, including other
-    context groups.
+    inserts a sync point insertion point in the current command stream. The

[piman, 2015/09/08 22:19:47]

nit: "inserts a sync point insertion point" doesn't read very well. I could be
useful to define our own terms, because we're using "sync point" a bit
loosely... I guess there's now 2 separated concepts:
1- the position in the current context that represents the point in the
execution that we will wait on (the uint)
2- an opaque token that globally represents that position, and that can be used
to wait (the GLbyte array)

I think if we put a name on each of them, this spec would read a little better.
We can rename the entrypoints in accordance too. Could be "execution point" (for
1) and "sync token" (for 2), but I'm not married to these names.

[David Yen, 2015/09/08 22:54:14]

Maybe just use "fence sync" and "sync object" to match how the ARB_sync spec is
written? So it would be InsertFenceSyncCHROMIUM, GenSyncObjectCHROMIUM, and
WaitSyncObjectCHROMIUM.

+    sync point acts as a fence, which is signaled when previous commands have been submitted to the server, or when the context is destroyed,

[piman, 2015/09/08 22:19:47]

nit: wrapping at 80 columns

[David Yen, 2015/09/08 22:54:14]

Done.

+    whichever happens first. The sync point name is only visible for the
+    current context. Before the returned sync point is waited upon, the command
+    must be flushed and converted to a sync point object using
+    GenSyncPointCHROMIUM. The opaque object returned from GenSyncPointCHROMIUM
+    is shared between all contexts.
+
+    The command
+
+        void GenSyncPointCHROMIUM (uint insertion, GLbyte *sync_point)
+
+    converts <insertion> which is only visible to the current context to a
+    sync point opaque object which is global between all contexts on the same
+    server. The <insertion> command must be flushed before this function may be
+    called, otherwise an INVALID_OPERATION error is generated. <sync_point> may
+    be passed to any other context on the same server to be waited upon.
 
+    <sync_point> returns a GL_SYNC_POINT_SIZE_CHROMIUM byte sized name

[piman, 2015/09/08 22:19:47]

nit: .

[David Yen, 2015/09/08 22:54:14]

Done.

 
     The command
 
-        void WaitSyncPointCHROMIUM(uint sync_point)
+        void WaitSyncPointCHROMIUM (GLbyte *sync_point)
 
     causes the current context to stop submitting commands until the specified
     sync point becomes signaled. This is implemented as a server-side wait.
-    <sync_point> is the name of the sync point to wait for. If <sync_point>
-    isn't a valid sync point returned by InsertSyncPointCHROMIUM, or if the sync
-    point has already been deleted, the command is equivalent to a no-op and no
-    error is generated.
+    <sync_point> is the name of the sync point to wait for that was generated
+    by GenSyncPointCHROMIUM. If <sync_point> isn't a valid sync point
+    returned by GenSyncPointCHROMIUM, the command is equivalent to a no-op
+    and no error is generated.
+
+New Tokens
+
+    The size of a mailbox name in bytes.
+
+        GL_SYNC_POINT_SIZE_CHROMIUM                         12
 
 Errors
 
-    None.
+    INVALID_VALUE is generated if the <insertion> parameter of
+    GenSyncPointCHROMIUM is not a valid local sync point insertion name.
+
+    INVALID_OPERATION is generated if the <insertion> parameter of
+    GenSyncPointCHROMIUM has not been flushed to the server.
 
 New State
 
@@ -71,3 +88,5 @@ New State
 Revision History
 
     2/25/2013    Documented the extension
+
+    9/8/2015     Added CHROMIUMsync, WaitSyncPointCHROMIUM