From 1358d93650bbfcc7ca585ad0f986b4969fc94a70 Mon Sep 17 00:00:00 2001
From: Ian Romanick <ian.d.romanick@intel.com>
Date: Wed, 10 Mar 2021 19:49:05 -0800
Subject: [PATCH] nir/lower_tex: Add support for lowering Y41x formats

These are similar to AYUV, but the channel ordering is different... in
such a way that there's no RGBA format that will make the channels line
up right.

v2: Rebase on bc438c91d9b ("nir/lower_tex: ignore texture_index if
tex_instr has deref src")

Reviewed-by: Emma Anholt <emma@anholt.net>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/9610>
---
 src/compiler/nir/nir.h           |  1 +
 src/compiler/nir/nir_lower_tex.c | 23 +++++++++++++++++++++++
 2 files changed, 24 insertions(+)

diff --git a/src/compiler/nir/nir.h b/src/compiler/nir/nir.h
index 71f8628423b..03fce223f5d 100644
--- a/src/compiler/nir/nir.h
+++ b/src/compiler/nir/nir.h
@@ -4721,6 +4721,7 @@ typedef struct nir_lower_tex_options {
    unsigned lower_ayuv_external;
    unsigned lower_xyuv_external;
    unsigned lower_yuv_external;
+   unsigned lower_y41x_external;
    unsigned bt709_external;
    unsigned bt2020_external;
 
diff --git a/src/compiler/nir/nir_lower_tex.c b/src/compiler/nir/nir_lower_tex.c
index 7af7d9d0f18..6f3df7d6282 100644
--- a/src/compiler/nir/nir_lower_tex.c
+++ b/src/compiler/nir/nir_lower_tex.c
@@ -436,6 +436,24 @@ lower_ayuv_external(nir_builder *b, nir_tex_instr *tex,
                      texture_index);
 }
 
+static void
+lower_y41x_external(nir_builder *b, nir_tex_instr *tex,
+                    const nir_lower_tex_options *options,
+                    unsigned texture_index)
+{
+  b->cursor = nir_after_instr(&tex->instr);
+
+  nir_ssa_def *y41x = sample_plane(b, tex, 0, options);
+
+  convert_yuv_to_rgb(b, tex,
+                     nir_channel(b, y41x, 1),
+                     nir_channel(b, y41x, 0),
+                     nir_channel(b, y41x, 2),
+                     nir_channel(b, y41x, 3),
+                     options,
+                     texture_index);
+}
+
 static void
 lower_xyuv_external(nir_builder *b, nir_tex_instr *tex,
                     const nir_lower_tex_options *options,
@@ -1209,6 +1227,11 @@ nir_lower_tex_block(nir_block *block, nir_builder *b,
          progress = true;
       }
 
+      if ((1 << tex->texture_index) & options->lower_y41x_external) {
+         lower_y41x_external(b, tex, options, texture_index);
+         progress = true;
+      }
+
       if (sat_mask) {
          tex = saturate_src(b, tex, sat_mask);
          progress = true;