Mesa (main): gallium: add PIPE_CAP_PREFER_POT_ALIGNED_VARYINGS
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gitlab-mirror at kemper.freedesktop.org
Mon Nov 15 23:23:13 UTC 2021
Module: Mesa
Branch: main
Commit: 3bb192a15bfd6bc676030a52e489e108f23d9de5
URL: http://cgit.freedesktop.org/mesa/mesa/commit/?id=3bb192a15bfd6bc676030a52e489e108f23d9de5
Author: Vasily Khoruzhick <anarsoul at gmail.com>
Date: Fri Oct 1 06:23:48 2021 -0700
gallium: add PIPE_CAP_PREFER_POT_ALIGNED_VARYINGS
Driver should enable this cap if it prefers varyings to be aligned
to power of two in a slot, i.e. vec4 in .xyzw, vec3 in .xyz, vec2 in .xy
or .zw
Reviewed-by: Tapani Pälli <tapani.palli at intel.com>
Signed-off-by: Vasily Khoruzhick <anarsoul at gmail.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/13151>
---
docs/gallium/screen.rst | 1 +
src/compiler/glsl/link_varyings.cpp | 20 +++++++++++++++++++-
src/gallium/auxiliary/util/u_screen.c | 3 +++
src/gallium/include/pipe/p_defines.h | 1 +
src/mesa/main/mtypes.h | 8 ++++++++
src/mesa/state_tracker/st_extensions.c | 3 +++
6 files changed, 35 insertions(+), 1 deletion(-)
diff --git a/docs/gallium/screen.rst b/docs/gallium/screen.rst
index 8458cada7a1..ab9087f68eb 100644
--- a/docs/gallium/screen.rst
+++ b/docs/gallium/screen.rst
@@ -629,6 +629,7 @@ The integer capabilities:
* ``PIPE_CAP_SUPPORTED_PRIM_MODES_WITH_RESTART``: A bitmask of the ``pipe_prim_type`` enum values that the driver can natively support for primitive restart. Only useful if ``PIPE_CAP_PRIMITIVE_RESTART`` is also exported.
* ``PIPE_CAP_PREFER_BACK_BUFFER_REUSE``: Only applies to DRI_PRIME. If 1, the driver prefers that DRI3 tries to use the same back buffer each frame. If 0, this means DRI3 will at least use 2 back buffers and ping-pong between them to allow the tiled->linear copy to run in parallel.
* ``PIPE_CAP_DRAW_VERTEX_STATE``: Driver supports `pipe_screen::create_vertex_state/vertex_state_destroy` and `pipe_context::draw_vertex_state`. Only used by display lists and designed to serve vbo_save.
+* ``PIPE_CAP_PREFER_POT_ALIGNED_VARYINGS``: Driver prefers varyings to be aligned to power of two in a slot. If this cap is enabled, vec4 varying will be placed in .xyzw components of the varying slot, vec3 in .xyz and vec2 in .xy or .zw
.. _pipe_capf:
diff --git a/src/compiler/glsl/link_varyings.cpp b/src/compiler/glsl/link_varyings.cpp
index 30f83b21d32..4f8e5566d1c 100644
--- a/src/compiler/glsl/link_varyings.cpp
+++ b/src/compiler/glsl/link_varyings.cpp
@@ -1719,6 +1719,7 @@ public:
bool disable_xfb_packing,
bool xfb_enabled,
bool enhanced_layouts_enabled,
+ bool prefer_pot_aligned_varyings,
gl_shader_stage producer_stage,
gl_shader_stage consumer_stage);
~varying_matches();
@@ -1760,6 +1761,12 @@ private:
const bool enhanced_layouts_enabled;
+ /**
+ * If true, this driver prefers varyings to be aligned to power of two
+ * in a slot.
+ */
+ const bool prefer_pot_aligned_varyings;
+
/**
* Enum representing the order in which varyings are packed within a
* packing class.
@@ -1838,12 +1845,14 @@ varying_matches::varying_matches(bool disable_varying_packing,
bool disable_xfb_packing,
bool xfb_enabled,
bool enhanced_layouts_enabled,
+ bool prefer_pot_aligned_varyings,
gl_shader_stage producer_stage,
gl_shader_stage consumer_stage)
: disable_varying_packing(disable_varying_packing),
disable_xfb_packing(disable_xfb_packing),
xfb_enabled(xfb_enabled),
enhanced_layouts_enabled(enhanced_layouts_enabled),
+ prefer_pot_aligned_varyings(prefer_pot_aligned_varyings),
producer_stage(producer_stage),
consumer_stage(consumer_stage)
{
@@ -2046,10 +2055,15 @@ varying_matches::assign_locations(struct gl_shader_program *prog,
* packing vec3 attributes can cause trouble because splitting a vec3
* effectively creates an additional transform feedback output. The
* extra TFB output may exceed device driver limits.
+ *
+ * Also don't pack vec3 if the driver prefers power of two aligned
+ * varyings. Packing order guarantees that vec4, vec2 and vec1 will be
+ * pot-aligned, we only need to take care of vec3s
*/
const bool dont_pack_vec3 =
(prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
- prog->TransformFeedback.NumVarying > 0);
+ prog->TransformFeedback.NumVarying > 0) ||
+ this->prefer_pot_aligned_varyings;
for (unsigned i = 0; i < this->num_matches; i++) {
unsigned *location = &generic_location;
@@ -2794,10 +2808,14 @@ assign_varying_locations(struct gl_context *ctx,
if (prog->SeparateShader && (producer == NULL || consumer == NULL))
disable_varying_packing = true;
+ bool prefer_pot_aligned_varyings =
+ ctx->Const.PreferPOTAlignedVaryings;
+
varying_matches matches(disable_varying_packing,
disable_xfb_packing,
xfb_enabled,
ctx->Extensions.ARB_enhanced_layouts,
+ prefer_pot_aligned_varyings,
producer ? producer->Stage : MESA_SHADER_NONE,
consumer ? consumer->Stage : MESA_SHADER_NONE);
void *hash_table_ctx = ralloc_context(NULL);
diff --git a/src/gallium/auxiliary/util/u_screen.c b/src/gallium/auxiliary/util/u_screen.c
index c7e26d54da4..399c8c7c815 100644
--- a/src/gallium/auxiliary/util/u_screen.c
+++ b/src/gallium/auxiliary/util/u_screen.c
@@ -476,6 +476,9 @@ u_pipe_screen_get_param_defaults(struct pipe_screen *pscreen,
case PIPE_CAP_DRAW_VERTEX_STATE:
return 0;
+ case PIPE_CAP_PREFER_POT_ALIGNED_VARYINGS:
+ return 0;
+
default:
unreachable("bad PIPE_CAP_*");
}
diff --git a/src/gallium/include/pipe/p_defines.h b/src/gallium/include/pipe/p_defines.h
index 0bcc5de7e26..46220b00423 100644
--- a/src/gallium/include/pipe/p_defines.h
+++ b/src/gallium/include/pipe/p_defines.h
@@ -998,6 +998,7 @@ enum pipe_cap
PIPE_CAP_SUPPORTED_PRIM_MODES_WITH_RESTART,
PIPE_CAP_PREFER_BACK_BUFFER_REUSE,
PIPE_CAP_DRAW_VERTEX_STATE,
+ PIPE_CAP_PREFER_POT_ALIGNED_VARYINGS,
PIPE_CAP_LAST,
/* XXX do not add caps after PIPE_CAP_LAST! */
diff --git a/src/mesa/main/mtypes.h b/src/mesa/main/mtypes.h
index 85672a63892..acf28cbd6cc 100644
--- a/src/mesa/main/mtypes.h
+++ b/src/mesa/main/mtypes.h
@@ -4155,6 +4155,14 @@ struct gl_constants
*/
GLboolean DisableTransformFeedbackPacking;
+ /**
+ * Align varyings to POT in a slot
+ *
+ * Drivers that prefer varyings to be aligned to POT must set this value to GL_TRUE
+ */
+ GLboolean PreferPOTAlignedVaryings;
+
+
/**
* UBOs and SSBOs can be packed tightly by the OpenGL implementation when
* layout is set as shared (the default) or packed. However most Mesa drivers
diff --git a/src/mesa/state_tracker/st_extensions.c b/src/mesa/state_tracker/st_extensions.c
index 214c38e1349..850dd1236e8 100644
--- a/src/mesa/state_tracker/st_extensions.c
+++ b/src/mesa/state_tracker/st_extensions.c
@@ -1550,6 +1550,9 @@ void st_init_extensions(struct pipe_screen *screen,
if (!screen->get_param(screen, PIPE_CAP_PACKED_STREAM_OUTPUT))
consts->DisableTransformFeedbackPacking = GL_TRUE;
+ if (screen->get_param(screen, PIPE_CAP_PREFER_POT_ALIGNED_VARYINGS))
+ consts->PreferPOTAlignedVaryings = GL_TRUE;
+
unsigned max_fb_fetch_rts = screen->get_param(screen, PIPE_CAP_FBFETCH);
bool coherent_fb_fetch =
screen->get_param(screen, PIPE_CAP_FBFETCH_COHERENT);
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