[Mesa-dev] [PATCH 1/3] gallium: add basic support for ARB_sample_shading

[Ilia Mirkin]

---
 src/gallium/auxiliary/tgsi/tgsi_strings.c  |  5 ++++-
 src/gallium/docs/source/context.rst        |  3 +++
 src/gallium/docs/source/screen.rst         |  3 +++
 src/gallium/docs/source/tgsi.rst           | 20 ++++++++++++++++++++
 src/gallium/include/pipe/p_context.h       |  3 +++
 src/gallium/include/pipe/p_defines.h       |  3 ++-
 src/gallium/include/pipe/p_shader_tokens.h |  5 ++++-
 7 files changed, 39 insertions(+), 3 deletions(-)

diff --git a/src/gallium/auxiliary/tgsi/tgsi_strings.c b/src/gallium/auxiliary/tgsi/tgsi_strings.c
index b0ba3ef..2be726c 100644
--- a/src/gallium/auxiliary/tgsi/tgsi_strings.c
+++ b/src/gallium/auxiliary/tgsi/tgsi_strings.c
@@ -81,7 +81,10 @@ const char *tgsi_semantic_names[TGSI_SEMANTIC_COUNT] =
    "PCOORD",
    "VIEWPORT_INDEX",
    "LAYER",
-   "CULLDIST"
+   "CULLDIST",
+   "SAMPLEID",
+   "SAMPLEPOS",
+   "SAMPLEMASK"
 };
 
 const char *tgsi_texture_names[TGSI_TEXTURE_COUNT] =
diff --git a/src/gallium/docs/source/context.rst b/src/gallium/docs/source/context.rst
index 8e14522..505995f 100644
--- a/src/gallium/docs/source/context.rst
+++ b/src/gallium/docs/source/context.rst
@@ -67,6 +67,9 @@ objects. They all follow simple, one-method binding calls, e.g.
   which are used as comparison values in stencil test.
 * ``set_blend_color``
 * ``set_sample_mask``
+* ``set_sample_shading`` sets the minimum percentage of samples that must be
+  run. 0 indicates per-fragment shading, while 1 should guarantee full
+  per-sample shading.
 * ``set_clip_state``
 * ``set_polygon_stipple``
 * ``set_scissor_states`` sets the bounds for the scissor test, which culls
diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index 09f809d..8530eb4 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -191,6 +191,9 @@ The integer capabilities:
 * ``PIPE_CAP_BUFFER_MAP_PERSISTENT_COHERENT``: Whether
   PIPE_TRANSFER_PERSISTENT and PIPE_TRANSFER_COHERENT are supported
   for buffers.
+* ``PIPE_CAP_SAMPLE_SHADING``: Whether there is support for per-sample
+  shading. The context->set_sample_shading function will be expected to be
+  implemented.
 
 
 .. _pipe_capf:
diff --git a/src/gallium/docs/source/tgsi.rst b/src/gallium/docs/source/tgsi.rst
index e184b2f..fa30d08 100644
--- a/src/gallium/docs/source/tgsi.rst
+++ b/src/gallium/docs/source/tgsi.rst
@@ -2600,6 +2600,26 @@ distances and by the PIPE_MAX_CLIP_OR_CULL_DISTANCE_ELEMENT_COUNT
 which specifies the maximum number of registers which can be
 annotated with those semantics.
 
+TGSI_SEMANTIC_SAMPLEID
+""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates that a system value
+contains the current sample id (i.e. gl_SampleID). Only the X value is used.
+
+TGSI_SEMANTIC_SAMPLEPOS
+"""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates that a system value
+contains the current sample's position (i.e. gl_SamplePosition). Only the X
+and Y values are used.
+
+TGSI_SEMANTIC_SAMPLEMASK
+""""""""""""""""""""""""
+
+For fragment shaders, this semantic label indicates that an output contains
+the sample mask used to disable further sample processing
+(i.e. gl_SampleMask). Only the X value is used, up to 32x MS.
+
 
 Declaration Interpolate
 ^^^^^^^^^^^^^^^^^^^^^^^
diff --git a/src/gallium/include/pipe/p_context.h b/src/gallium/include/pipe/p_context.h
index fe3045a..b753def 100644
--- a/src/gallium/include/pipe/p_context.h
+++ b/src/gallium/include/pipe/p_context.h
@@ -190,6 +190,9 @@ struct pipe_context {
    void (*set_sample_mask)( struct pipe_context *,
                             unsigned sample_mask );
 
+   void (*set_sample_shading)( struct pipe_context *,
+                               float samples );
+
    void (*set_clip_state)( struct pipe_context *,
                             const struct pipe_clip_state * );
 
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index a220de0..eb3bb98 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -551,7 +551,8 @@ enum pipe_cap {
    PIPE_CAP_MAX_GEOMETRY_TOTAL_OUTPUT_COMPONENTS = 89,
    PIPE_CAP_MAX_TEXTURE_GATHER_COMPONENTS = 90,
    PIPE_CAP_TEXTURE_GATHER_SM5 = 91,
-   PIPE_CAP_BUFFER_MAP_PERSISTENT_COHERENT = 92
+   PIPE_CAP_BUFFER_MAP_PERSISTENT_COHERENT = 92,
+   PIPE_CAP_SAMPLE_SHADING = 93
 };
 
 #define PIPE_QUIRK_TEXTURE_BORDER_COLOR_SWIZZLE_NV50 (1 << 0)
diff --git a/src/gallium/include/pipe/p_shader_tokens.h b/src/gallium/include/pipe/p_shader_tokens.h
index 8fa6a0a..2ce8b96 100644
--- a/src/gallium/include/pipe/p_shader_tokens.h
+++ b/src/gallium/include/pipe/p_shader_tokens.h
@@ -167,7 +167,10 @@ struct tgsi_declaration_interp
 #define TGSI_SEMANTIC_VIEWPORT_INDEX 21 /**< viewport index */
 #define TGSI_SEMANTIC_LAYER      22 /**< layer (rendertarget index) */
 #define TGSI_SEMANTIC_CULLDIST   23
-#define TGSI_SEMANTIC_COUNT      24 /**< number of semantic values */
+#define TGSI_SEMANTIC_SAMPLEID   24
+#define TGSI_SEMANTIC_SAMPLEPOS  25
+#define TGSI_SEMANTIC_SAMPLEMASK 26
+#define TGSI_SEMANTIC_COUNT      27 /**< number of semantic values */
 
 struct tgsi_declaration_semantic
 {
-- 
1.8.3.2