mesa: GL_MESA_framebuffer_flip_y extension [v4]

Adds an extension to glFramebufferParameteri
that will specify if the framebuffer is vertically
flipped. Historically system framebuffers are
vertically flipped and user framebuffers are not.
Checking to see the state was done by looking at
the name field.  This adds an explicit field.

v2:
  * updated spec language [for chadv]
  * correctly specifying ES 3.1 [for chadv]
  * refactor access to rb->Name [for jason]
  * handle GetFramebufferParameteriv [for chadv]
v3:
  * correct _mesa_GetMultisamplefv [for kusmabite]
v4:
  * update spec language [for chadv]
  * s/GLboolean/bool/g [for chadv]
  * s/InvertedY/FlipY/g [for chadv]
  * s/inverted_y/flip_y/g [for chadv]
  * assert changes [for chadv]

Reviewed-by: Chad Versace <[email protected]>

1 files changed, 81 insertions, 0 deletions

diff --git a/docs/specs/MESA_framebuffer_flip_y.txt b/docs/specs/MESA_framebuffer_flip_y.txt
new file mode 100644
index 00000000000..697ab4e75d6
--- /dev/null
+++ b/docs/specs/MESA_framebuffer_flip_y.txt
@@ -0,0 +1,81 @@
+Name
+
+    MESA_framebuffer_flip_y
+
+Name Strings
+
+    GL_MESA_framebuffer_flip_y
+
+Contact
+
+    Fritz Koenig <[email protected]>
+
+Contributors
+
+    Fritz Koenig, Google
+    Kristian Høgsberg, Google
+    Chad Versace, Google
+
+Status
+
+    Proposal
+
+Version
+
+    Version 1, June 7, 2018
+
+Number
+
+    302
+
+Dependencies
+
+    OpenGL ES 3.1 is required, for FramebufferParameteri.
+
+Overview
+
+    This extension defines a new framebuffer parameter,
+    GL_FRAMEBUFFER_FLIP_Y_MESA, that changes the behavior of the reads and
+    writes to the framebuffer attachment points. When GL_FRAMEBUFFER_FLIP_Y_MESA
+    is GL_TRUE, render commands and pixel transfer operations access the
+    backing store of each attachment point with an y-inverted coordinate
+    system. This y-inversion is relative to the coordinate system set when
+    GL_FRAMEBUFFER_FLIP_Y_MESA is GL_FALSE.
+
+    Access through TexSubImage2D and similar calls will notice the effect of
+    the flip when they are not attached to framebuffer objects because
+    GL_FRAMEBUFFER_FLIP_Y_MESA is associated with the framebuffer object and
+    not the attachment points.
+
+IP Status
+
+    None
+
+Issues
+
+    None
+
+New Procedures and Functions
+
+    None
+
+New Types
+
+    None
+
+New Tokens
+
+    Accepted by the <pname> argument of FramebufferParameteri and
+    GetFramebufferParameteriv:
+
+        GL_FRAMEBUFFER_FLIP_Y_MESA                      0x8BBB
+
+Errors
+
+    An INVALID_OPERATION error is generated by GetFramebufferParameteriv if the
+    default framebuffer is bound to <target> and <pname> is FRAMEBUFFER_FLIP_Y_MESA.
+
+Revision History
+
+    Version 1, June, 2018
+        Initial draft (Fritz Koenig)