[Mesa-dev] [PATCH 4/4] st/mesa: add OES_sample_variables support

[Ilia Mirkin]

Basically the same thing as ARB_sample_shading except that it also needs
gl_SampleMaskIn support as well as not enable per-sample interpolation
whenever doing per-sample shading. This is done explicitly in another
extension.

Signed-off-by: Ilia Mirkin <imirkin at alum.mit.edu>
---

I get 16 failures with dEQP tests, these fall into 2 categories:

 - 1-sample multisample surfaces don't behave the way it likes (it considers
   them non-multisampled even though they're created through gl*Multisample*

 - gl_SampleMaskIn is reporting the whole pixel's worth of mask rather than
   just the fragment in question. Looking back, it appears that
   ARB_gpu_shader5 also wants it for only the current fragment.

 docs/GL3.txt                                | 2 +-
 src/mesa/state_tracker/st_atom_rasterizer.c | 2 ++
 src/mesa/state_tracker/st_atom_shader.c     | 2 ++
 src/mesa/state_tracker/st_extensions.c      | 4 ++++
 src/mesa/state_tracker/st_program.c         | 5 ++++-
 5 files changed, 13 insertions(+), 2 deletions(-)

diff --git a/docs/GL3.txt b/docs/GL3.txt
index 26847b9..ae439f6 100644
--- a/docs/GL3.txt
+++ b/docs/GL3.txt
@@ -248,7 +248,7 @@ GLES3.2, GLSL ES 3.2
   GL_OES_gpu_shader5                                   not started (based on parts of GL_ARB_gpu_shader5, which is done for some drivers)
   GL_OES_primitive_bounding box                        not started
   GL_OES_sample_shading                                not started (based on parts of GL_ARB_sample_shading, which is done for some drivers)
-  GL_OES_sample_variables                              not started (based on parts of GL_ARB_sample_shading, which is done for some drivers)
+  GL_OES_sample_variables                              DONE (nvc0, r600, radeonsi)
   GL_OES_shader_image_atomic                           not started (based on parts of GL_ARB_shader_image_load_store, which is done for some drivers)
   GL_OES_shader_io_blocks                              not started (based on parts of GLSL 1.50, which is done)
   GL_OES_shader_multisample_interpolation              not started (based on parts of GL_ARB_gpu_shader5, which is done)
diff --git a/src/mesa/state_tracker/st_atom_rasterizer.c b/src/mesa/state_tracker/st_atom_rasterizer.c
index c20cadf..d42d512 100644
--- a/src/mesa/state_tracker/st_atom_rasterizer.c
+++ b/src/mesa/state_tracker/st_atom_rasterizer.c
@@ -31,6 +31,7 @@
   */
  
 #include "main/macros.h"
+#include "main/context.h"
 #include "st_context.h"
 #include "st_atom.h"
 #include "st_debug.h"
@@ -239,6 +240,7 @@ static void update_raster_state( struct st_context *st )
 
    /* _NEW_MULTISAMPLE | _NEW_BUFFERS */
    raster->force_persample_interp =
+         !_mesa_is_gles(ctx) &&
          !st->force_persample_in_shader &&
          ctx->Multisample._Enabled &&
          ctx->Multisample.SampleShading &&
diff --git a/src/mesa/state_tracker/st_atom_shader.c b/src/mesa/state_tracker/st_atom_shader.c
index a88f035..8cfe756 100644
--- a/src/mesa/state_tracker/st_atom_shader.c
+++ b/src/mesa/state_tracker/st_atom_shader.c
@@ -36,6 +36,7 @@
  */
 
 #include "main/imports.h"
+#include "main/context.h"
 #include "main/mtypes.h"
 #include "program/program.h"
 
@@ -76,6 +77,7 @@ update_fp( struct st_context *st )
     * Ignore sample qualifier while computing this flag.
     */
    key.persample_shading =
+      !_mesa_is_gles(st->ctx) &&
       st->force_persample_in_shader &&
       !(stfp->Base.Base.SystemValuesRead & (SYSTEM_BIT_SAMPLE_ID |
                                             SYSTEM_BIT_SAMPLE_POS)) &&
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index eff3a2d..49d5a2c 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -861,6 +861,10 @@ void st_init_extensions(struct pipe_screen *screen,
       extensions->OES_copy_image = GL_TRUE;
    }
 
+   /* Needs PIPE_CAP_SAMPLE_SHADING + gl_SampleMaskIn.
+    */
+   extensions->OES_sample_variables = extensions->ARB_gpu_shader5;
+
    /* Maximum sample count. */
    {
       enum pipe_format color_formats[] = {
diff --git a/src/mesa/state_tracker/st_program.c b/src/mesa/state_tracker/st_program.c
index 2e21d02..de628d7 100644
--- a/src/mesa/state_tracker/st_program.c
+++ b/src/mesa/state_tracker/st_program.c
@@ -32,6 +32,7 @@
 
 
 #include "main/imports.h"
+#include "main/context.h"
 #include "main/hash.h"
 #include "main/mtypes.h"
 #include "program/prog_parameter.h"
@@ -573,7 +574,9 @@ st_translate_fragment_program(struct st_context *st,
          else
             interpLocation[slot] = TGSI_INTERPOLATE_LOC_CENTER;
 
-         if (stfp->Base.Base.SystemValuesRead & (SYSTEM_BIT_SAMPLE_ID |
+         /* GLES specifies that only the sample keyword alters interpolation */
+         if (!_mesa_is_gles(st->ctx) &&
+             stfp->Base.Base.SystemValuesRead & (SYSTEM_BIT_SAMPLE_ID |
                                                  SYSTEM_BIT_SAMPLE_POS))
             interpLocation[slot] = TGSI_INTERPOLATE_LOC_SAMPLE;
 
-- 
2.4.10