Propose WEBGL_present, allowing for early Present.

extensions/proposals/WEBGL_present/extension.xml

@@ -0,0 +1,57 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<proposal href="proposals/WEBGL_present/">
+  <name>WEBGL_present</name>
+
+  <contact> <a href="https://www.khronos.org/webgl/public-mailing-list/">WebGL
+  working group</a> (public_webgl 'at' khronos.org) </contact>
+
+  <contributors>
+    <contributor>Jeff Gilbert, Mozilla</contributor>
+  </contributors>
+
+  <number>NN</number>
+
+  <depends>
+    <api version="1.0"/>
+  </depends>
+
+  <overview>
+    <p>
+      This extension allows content to initiate a Present action early, instead of waiting for the
+      standard end-of-frame auto-Present mechanism.
+    </p>
+
+    <features>
+      <feature>
+        <code>present()</code> triggers canvas-related Present early, but does not immediately
+        trigger page composition.
+        After calling present, the context respects preserveDrawingBuffer like usual, and clears
+        the backbuffer-dirty bit, but does not clear the canvas-dirty bit.
+        The canvas-dirty bit means the now-frontbuffer (previously-backbuffer) will be composited
+        like normal at the end of the frame.
+      </feature>
+      <feature>
+        <code>autoPresent</code> disables (or re-enables) the default backbuffer-dirty auto-Present.
+        When disabled, the context will not automatically Present its backbuffer to the compositor
+        even if the backbuffer has been drawn into.
+        In this case, <code>present()</code> is the only way to trigger Presentation of the backbuffer
+        to the compositor.
+      </feature>
+    </features>
+  </overview>
+
+  <idl xml:space="preserve">
+    [NoInterfaceObject]
+    interface WEBGL_present {
+      attribute boolean autoPresent = true;
+
+      void present();
+    };
+  </idl>
+
+  <history>
+    <revision date="2017/12/19">
+      <change>Initial revision.</change>
+    </revision>
+  </history>
+</proposal>