commit be367b73ae9c5d043fd9934c87636b09a9da9099
author Ben Clayton <bclayton@google.com> Wed Jan 04 12:29:56 2023 +0000
committer Dawn LUCI CQ <dawn-scoped@luci-project-accounts.iam.gserviceaccount.com> Wed Jan 04 12:29:56 2023 +0000
tree 8ca10ac64e8df193b1de8a30b53b71483ecbfa8c
parent b6fb41cc32030bf4eb6c54cd0fbc78b6266c5d37

Reduce shader complexity for external textures

Do more math on the CPU to avoid per-fragment ALU operations.
Use a mat3x2 instead of mat2x3 to avoid padding.

Fixed: dawn:1614
Change-Id: Ib0e0f7d44ed9aa16eaca712f6553214fad141feb
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/116060
Kokoro: Kokoro <noreply+kokoro@google.com>
Reviewed-by: Corentin Wallez <cwallez@chromium.org>
Reviewed-by: Brandon1 Jones <brandon1.jones@intel.com>
Commit-Queue: Ben Clayton <bclayton@google.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 f8c927b1..f5770fb 100644
--- a/src/tint/transform/multiplanar_external_texture.cc
+++ b/src/tint/transform/multiplanar_external_texture.cc
@@ -263,7 +263,7 @@
             b.Member("gammaDecodeParams", b.ty.type_name("GammaTransferParams")),
             b.Member("gammaEncodeParams", b.ty.type_name("GammaTransferParams")),
             b.Member("gamutConversionMatrix", b.ty.mat3x3<f32>()),
-            b.Member("coordTransformationMatrix", b.ty.mat2x3<f32>())};
+            b.Member("coordTransformationMatrix", b.ty.mat3x2<f32>())};
 
         params_struct_sym = b.Symbols().New("ExternalTextureParams");
 
@@ -316,12 +316,9 @@
         const ast::CallExpression* plane_1_call = nullptr;
         switch (call_type) {
             case sem::BuiltinType::kTextureSampleBaseClampToEdge:
-                // TODO(dawn:1614): Change this statement to incorporate the "- 0.5" into the
-                // matrix.
-                stmts.Push(
-                    b.Decl(b.Let("modifiedCoords",
-                                 b.Mul(b.vec3<f32>(b.Sub("coord", f32(0.5)), f32(1.0f)),
-                                       b.MemberAccessor("params", "coordTransformationMatrix")))));
+                stmts.Push(b.Decl(b.Let(
+                    "modifiedCoords", b.Mul(b.MemberAccessor("params", "coordTransformationMatrix"),
+                                            b.vec3<f32>("coord", 1_a)))));
 
                 stmts.Push(b.Decl(b.Let(
                     "plane0_dims",