[Mesa-dev] [PATCH 00/12] ARB_fragment_layer_viewport for i965

[Chris Forbes]

This series adds support for ARB_fragment_layer_viewport on i965 Gen7, in
core contexts [the same conditions as for ARB_viewport_array being exposed].

This is another tiny piece of GL4.3, allowing the GS- [or with
AMD_vertex_shader_*, VS- ] written values of gl_Layer and gl_ViewportIndex
to be read by the fragment shader.

Note that there are a few oddities in the spec, which I've assumed hopefully
reasonable corrections for:

- Dependencies section specifies that ARB_geometry_shader4 is required, but
  should probably be 'geometry shaders are required', or perhaps 'GL 3.2 or
  ARB_geometry_shader4 is required'.
- In the description of gl_Layer's behavior, there is a stray reference to
  `gl_Value` which should be `gl_Layer`.
- The extension doesn't list a new define for shaders to test for presence.
  I've assumed the usual pattern in 6/12.