commit ef62b58cf96ea4d0f0f22fac1d0c768e15aab00c
author jchen10 <jie.a.chen@intel.com> Wed Jun 22 03:14:26 2022 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jun 22 03:14:26 2022 +0000
tree f7674a29d8dc0bc4f258d0f781702842eeb038d3
parent 797f0f82e0521a4aaaad3004dc281df6581c693e

Skip Gamma and Gamut conversions for BT.709->SRGB

This introduces a new field 'doYuvToRgbConversionOnly' in
ExternalTextureParams to have the WGSL only do yuv->rgb conversion for
better performance. User studies shows that users don't really care
about the Gamma difference between 2.4 and 2.2.
https://source.chromium.org/chromium/chromium/src/+/main:ui/gfx/color_space.cc;l=1022;drc=a1dbb594a6741a400db35fe3678e77bad2504ea4

Bug: dawn:1082
Bug: dawn:1466
Change-Id: I61c0fe65c5969d8a61c267c202c8dd64c259ed8a
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/92901
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Commit-Queue: Jie A Chen <jie.a.chen@intel.com>

src/tint/transform/multiplanar_external_texture.cc

diff --git a/src/tint/transform/multiplanar_external_texture.cc b/src/tint/transform/multiplanar_external_texture.cc
index 8b85573..cf5a5a6 100644
--- a/src/tint/transform/multiplanar_external_texture.cc
+++ b/src/tint/transform/multiplanar_external_texture.cc
@@ -251,6 +251,7 @@
         // Create ExternalTextureParams struct.
         ast::StructMemberList ext_tex_params_member_list = {
             b.Member("numPlanes", b.ty.u32()),
+            b.Member("doYuvToRgbConversionOnly", b.ty.u32()),
             b.Member("yuvToRgbConversionMatrix", b.ty.mat3x4(b.ty.f32())),
             b.Member("gammaDecodeParams", b.ty.type_name("GammaTransferParams")),
             b.Member("gammaEncodeParams", b.ty.type_name("GammaTransferParams")),
@@ -340,14 +341,20 @@
                               b.Mul(b.vec4<f32>(b.MemberAccessor(plane_0_call, "r"),
                                                 b.MemberAccessor(plane_1_call, "rg"), 1_f),
                                     b.MemberAccessor("params", "yuvToRgbConversionMatrix")))))),
-            // color = gammaConversion(color, gammaDecodeParams);
-            b.Assign("color", b.Call("gammaCorrection", "color",
-                                     b.MemberAccessor("params", "gammaDecodeParams"))),
-            // color = (params.gamutConversionMatrix * color);
-            b.Assign("color", b.Mul(b.MemberAccessor("params", "gamutConversionMatrix"), "color")),
-            // color = gammaConversion(color, gammaEncodeParams);
-            b.Assign("color", b.Call("gammaCorrection", "color",
-                                     b.MemberAccessor("params", "gammaEncodeParams"))),
+            // if (params.doYuvToRgbConversionOnly == 0u)
+            b.If(b.create<ast::BinaryExpression>(
+                     ast::BinaryOp::kEqual, b.MemberAccessor("params", "doYuvToRgbConversionOnly"),
+                     b.Expr(0_u)),
+                 b.Block(
+                     // color = gammaConversion(color, gammaDecodeParams);
+                     b.Assign("color", b.Call("gammaCorrection", "color",
+                                              b.MemberAccessor("params", "gammaDecodeParams"))),
+                     // color = (params.gamutConversionMatrix * color);
+                     b.Assign("color",
+                              b.Mul(b.MemberAccessor("params", "gamutConversionMatrix"), "color")),
+                     // color = gammaConversion(color, gammaEncodeParams);
+                     b.Assign("color", b.Call("gammaCorrection", "color",
+                                              b.MemberAccessor("params", "gammaEncodeParams"))))),
             // return vec4<f32>(color, 1.f);
             b.Return(b.vec4<f32>("color", 1_f))};
     }