Mesa (master): gallium: add a new cap PIPE_CAP_GLSL_ZERO_INIT

[GitLab Mirror]

Module: Mesa
Branch: master
Commit: 0ee1a724bf78baa3fe514036d77d3e96abc998f7
URL:    http://cgit.freedesktop.org/mesa/mesa/commit/?id=0ee1a724bf78baa3fe514036d77d3e96abc998f7

Author: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer at amd.com>
Date:   Fri Apr 24 18:14:40 2020 +0200

gallium: add a new cap PIPE_CAP_GLSL_ZERO_INIT

Allows driver to select a zero init mode between the 3 possible values.

Reviewed-by: Marek Olšák <marek.olsak at amd.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/4607>

---

 src/gallium/auxiliary/util/u_screen.c  | 1 +
 src/gallium/docs/source/screen.rst     | 1 +
 src/gallium/drivers/radeonsi/si_get.c  | 3 +++
 src/gallium/include/pipe/p_defines.h   | 1 +
 src/mesa/main/mtypes.h                 | 8 ++++++--
 src/mesa/state_tracker/st_extensions.c | 2 ++
 6 files changed, 14 insertions(+), 2 deletions(-)

diff --git a/src/gallium/auxiliary/util/u_screen.c b/src/gallium/auxiliary/util/u_screen.c
index ae024f0e650..a7fb85ca27b 100644
--- a/src/gallium/auxiliary/util/u_screen.c
+++ b/src/gallium/auxiliary/util/u_screen.c
@@ -345,6 +345,7 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
    case PIPE_CAP_SHADER_SAMPLES_IDENTICAL:
    case PIPE_CAP_TGSI_ATOMINC_WRAP:
    case PIPE_CAP_TGSI_TG4_COMPONENT_IN_SWIZZLE:
+   case PIPE_CAP_GLSL_ZERO_INIT:
       return 0;
 
    case PIPE_CAP_MAX_GS_INVOCATIONS:
diff --git a/src/gallium/docs/source/screen.rst b/src/gallium/docs/source/screen.rst
index e006ef19568..6832b999357 100644
--- a/src/gallium/docs/source/screen.rst
+++ b/src/gallium/docs/source/screen.rst
@@ -579,6 +579,7 @@ The integer capabilities:
 * ``PIPE_CAP_SYSTEM_SVM``: True if all application memory can be shared with the GPU without explicit mapping.
 * ``PIPE_CAP_VIEWPORT_MASK``: Whether ``TGSI_SEMANTIC_VIEWPORT_MASK`` and ``TGSI_PROPERTY_LAYER_VIEWPORT_RELATIVE`` are supported (see GL_NV_viewport_array2).
 * ``PIPE_CAP_MAP_UNSYNCHRONIZED_THREAD_SAFE``: Whether mapping a buffer as unsynchronized from any thread is safe.
+* ``PIPE_CAP_GLSL_ZERO_INIT``: Choose a default zero initialization some glsl variables. If `1`, then all glsl shader variables and gl_FragColor are initialized to zero. If `2`, then shader out variables are not initialized but function out variables are.
 
 .. _pipe_capf:
 
diff --git a/src/gallium/drivers/radeonsi/si_get.c b/src/gallium/drivers/radeonsi/si_get.c
index 9a10a82e052..fad46fa09ce 100644
--- a/src/gallium/drivers/radeonsi/si_get.c
+++ b/src/gallium/drivers/radeonsi/si_get.c
@@ -164,6 +164,9 @@ static int si_get_param(struct pipe_screen *pscreen, enum pipe_cap param)
    case PIPE_CAP_MAP_UNSYNCHRONIZED_THREAD_SAFE:
       return 1;
 
+   case PIPE_CAP_GLSL_ZERO_INIT:
+      return 2;
+
    case PIPE_CAP_QUERY_SO_OVERFLOW:
       return !sscreen->use_ngg_streamout;
 
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index dd0c7331b69..f1524b0cdb7 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -947,6 +947,7 @@ enum pipe_cap
    PIPE_CAP_VIEWPORT_MASK,
    PIPE_CAP_ALPHA_TO_COVERAGE_DITHER_CONTROL,
    PIPE_CAP_MAP_UNSYNCHRONIZED_THREAD_SAFE,
+   PIPE_CAP_GLSL_ZERO_INIT,
 };
 
 /**
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 7046e8adfa3..2fa06e7a570 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -3868,9 +3868,13 @@ struct gl_constants
    GLboolean ForceGLSLAbsSqrt;
 
    /**
-    * Types of variable to default initialized to zero.
+    * Types of variable to default initialized to zero. Supported values are:
+    *   - 0: no zero initialization
+    *   - 1: all shader variables and gl_FragColor are initialiazed to 0
+    *   - 2: same as 1, but shader out variables are *not* initialized, while
+    *        function out variables are now initialized.
     */
-   GLuint GLSLZeroInit;
+   GLchar GLSLZeroInit;
 
    /**
     * Treat integer textures using GL_LINEAR filters as GL_NEAREST.
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 2403bd60a8c..f13ded7c19d 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -1205,6 +1205,8 @@ void st_init_extensions(struct pipe_screen *screen,
 
    if (options->glsl_zero_init) {
       consts->GLSLZeroInit = 1;
+   } else {
+      consts->GLSLZeroInit = screen->get_param(screen, PIPE_CAP_GLSL_ZERO_INIT);
    }
 
    consts->ForceIntegerTexNearest = options->force_integer_tex_nearest;