mesa: Add GL/GLSL plumbing for INTEL_fragment_shader_ordering

This extension provides new GLSL built-in function
beginFragmentShaderOrderingIntel() that guarantees
(taking wording of GL_INTEL_fragment_shader_ordering
extension) that any memory transactions issued by
shader invocations from previous primitives mapped to
same xy window coordinates (and same sample when
per-sample shading is active), complete and are visible
to the shader invocation that called
beginFragmentShaderOrderingINTEL().

One advantage of INTEL_fragment_shader_ordering over
ARB_fragment_shader_interlock is that it provides a
function that operates as a memory barrie (instead
of a defining a critcial section) that can be called
under arbitary control flow from any function (in
contrast the begin/end of ARB_fragment_shader_interlock
may only be called once, from main(), under no control
flow.

Signed-off-by: Kevin Rogovin <[email protected]>
Reviewed-by: Plamena Manolova <[email protected]>

2 files changed, 2 insertions, 0 deletions

diff --git a/src/mesa/main/extensions_table.h b/src/mesa/main/extensions_table.h
index 115af796bcc..7072fa46ad8 100644
--- a/src/mesa/main/extensions_table.h
+++ b/src/mesa/main/extensions_table.h
@@ -316,6 +316,7 @@ EXT(IBM_texture_mirrored_repeat             , dummy_true
 EXT(INGR_blend_func_separate                , EXT_blend_func_separate                , GLL,  x ,  x ,  x , 1999)
 
 EXT(INTEL_conservative_rasterization        , INTEL_conservative_rasterization       ,  x , GLC,  x ,  31, 2013)
+EXT(INTEL_fragment_shader_ordering          , INTEL_fragment_shader_ordering         , GLL, GLC,  x ,  x , 2013)
 EXT(INTEL_performance_query                 , INTEL_performance_query                , GLL, GLC,  x , ES2, 2013)
 EXT(INTEL_shader_atomic_float_minmax        , INTEL_shader_atomic_float_minmax       , GLL, GLC,  x ,  x , 2018)
 
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 9d058cef6d9..f247b125e7e 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -4271,6 +4271,7 @@ struct gl_extensions
    GLboolean ATI_fragment_shader;
    GLboolean GREMEDY_string_marker;
    GLboolean INTEL_conservative_rasterization;
+   GLboolean INTEL_fragment_shader_ordering;
    GLboolean INTEL_performance_query;
    GLboolean INTEL_shader_atomic_float_minmax;
    GLboolean KHR_blend_equation_advanced;