Add subscribeUniform extension pipeline

gpu/GLES2/extensions/CHROMIUM/CHROMIUM_subscribe_uniform.txt

+Name
+
+    CHROMIUM_subscribe_uniform
+
+Name Strings
+
+    CHROMIUM_subscribe_uniform
+
+Version
+
+    Last Modifed Date: October 30, 2014
+
+Dependencies
+
+    OpenGL ES 2.0 is required.
+
+Overview
+
+    Allows clients to subscribe to a set of input uniforms which can
+    be populated within buffers and used to modify uniform variables within
+    their programs.
+
+    Decreases percieved latency for operations performed against these
+    uniforms.
+
+New Tokens
+
+    Accepted by the <target> parameter of glBindValueBufferCHROMIUM,
+    glSubscribeValueCHROMIUM, glPopulateSubscribedValuesCHROMIUM and
+    glUniformValueBufferCHROMIUM
+
+    SUBSCRIBED_VALUES_BUFFER_CHROMIUM                        0x924B
+
+    Accepted by the <subscription> parameter of glSubscribeValueCHROMIUM and
+    glUniformValueBufferCHROMIUM:
+
+    MOUSE_POSITION_CHROMIUM                                  0x924C
+
+New Procedures and Functions
+
+    The command
+
+       void glCreateValuebufferCHROMIUM()

[piman, 2014/11/04 02:38:22]

update to current implemenation? glGenValuebuffersCHROMIUM

[orglofch, 2014/11/04 19:53:28]

This reflects the current implementation of the user facing API, the calls get
translated into gen calls further down the pipeline which is similar to existing
buffer creation mechanisms. Is this document meant to reflect the command buffer
API?

[piman, 2014/11/04 21:10:06]

Why do we have a different API? Let's pick one way and just do it that way. You
can either model it after the Gen/Delete APIs (like Buffers) or Create/Delete
(like Programs), both of which are supported by the command buffer generator
(GENn/DELn or Create/Delete respectively).

What matters to document is what we expose at the GL level (gl2extchromium.h).
The WebGraphicsContext3D wrappers are different in many aspects anyway.

[orglofch, 2014/11/04 21:28:33]

Oh I see. This is currently reflecting a WebGraphicsContext3D wrapper.
Internally it already uses GENn/DELn. I've modified the document.

+
+    Returns a value buffer object.
+
+   The command
+
+      void glDeleteValuebufferCHROMIUM(GLuint buffer)

[piman, 2014/11/04 02:38:22]

glDeleteValuebuffers, update prototype & doc

[orglofch, 2014/11/04 19:53:28]

Same as above

+
+   Deletes a value buffer object.
+   <buffer> Specifies the name of a buffer object.
+
+   The command
+
+      boolean glIsValuebufferCHROMIUM(GLuint buffer);
+
+   Returns whether an object is a value buffer object.
+   <buffer> Specifies the name of a buffer object.
+
+   The command
+
+      void glBindValuebufferCHROMIUM(GLenum target, GLuint buffer);
+
+   Lets you use a named value buffer object.
+   <target> Specifies the target to which the buffer object is bound.
+   <buffer> Specifies the name of a buffer object.
+
+   The command
+
+      void glSubscribeValueCHROMIUM(GLenum target, GLenum subscription)
+
+   Subscribes the currently bound buffer object to a subscription target.
+   <target> Specifies the target to which the buffer object is bound.
+   <subscription> Specifies the subscription to which the currently bound
+                  buffer object should be subscribed.
+
+   The command
+
+      void glPopulateSubscribedValuesCHROMIUM(GLenum target)
+
+   Populates the currently bound buffer object with all subscription states
+   to which it is subscribed.
+   <target> Specifies the target to which the buffer object is bound.
+
+   The command
+ 
+      void glUniformValueBufferCHROMIUM(GLint location, GLenum target,
+                                       GLenum subscription)
+
+   Populates the uniform specified by location within the currently bound
+   program with the value in the currently bound buffer for the subscription
+   target.
+   <location> Specifies the location of the uniform variable to by modified.
+   <target> Specifies the target to which the buffer object is bound.
+   <subscription> Specifies the subscription in the currently bound buffer
+                  whose value should be used to populate the uniform.
+
+Errors
+
+    None.
+
+New State
+
+    None.
+
+Revision History
+
+    10/30/2014    Documented the extension