From 5486a2fba596ca15c45acac42df5f110dc24b5bb Mon Sep 17 00:00:00 2001
From: shrekshao <shrekshao@google.com>
Date: Fri, 13 Aug 2021 00:08:50 +0000
Subject: [PATCH] Remove some validation for alpha.src/dstFactor

Validation rules revised at
https://github.com/gpuweb/gpuweb/issues/2013#issuecomment-897364617

Bug: dawn:1063
Change-Id: I8ae1cd00f75c8049206a8c5f6fcdb879e1b6a469
Reviewed-on: https://dawn-review.googlesource.com/c/dawn/+/61821
Reviewed-by: Kai Ninomiya <kainino@chromium.org>
Reviewed-by: Shrek Shao <shrekshao@google.com>
Reviewed-by: Austin Eng <enga@chromium.org>
Commit-Queue: Shrek Shao <shrekshao@google.com>
---
 src/dawn_native/RenderPipeline.cpp                   | 12 ------------
 .../validation/RenderPipelineValidationTests.cpp     | 10 +---------
 2 files changed, 1 insertion(+), 21 deletions(-)

diff --git a/src/dawn_native/RenderPipeline.cpp b/src/dawn_native/RenderPipeline.cpp
index 8ad0b8f070..c1c33356d1 100644
--- a/src/dawn_native/RenderPipeline.cpp
+++ b/src/dawn_native/RenderPipeline.cpp
@@ -259,11 +259,6 @@ namespace dawn_native {
                    blendFactor == wgpu::BlendFactor::SrcAlphaSaturated;
         }
 
-        bool BlendFactorContainsSrc(const wgpu::BlendFactor& blendFactor) {
-            return blendFactor == wgpu::BlendFactor::Src ||
-                   blendFactor == wgpu::BlendFactor::OneMinusSrc;
-        }
-
         MaybeError ValidateColorTargetState(
             DeviceBase* device,
             const ColorTargetState* descriptor,
@@ -312,13 +307,6 @@ namespace dawn_native {
                                 "Color blending factor is reading alpha but it is missing from "
                                 "fragment output");
                         }
-                        if (descriptor->blend->alpha.srcFactor != wgpu::BlendFactor::Zero ||
-                            BlendFactorContainsSrc(descriptor->blend->alpha.dstFactor) ||
-                            BlendFactorContainsSrcAlpha(descriptor->blend->alpha.dstFactor)) {
-                            return DAWN_VALIDATION_ERROR(
-                                "Alpha blending factor is reading alpha but it is missing from "
-                                "fragment output");
-                        }
                     }
                 }
             } else {
diff --git a/src/tests/unittests/validation/RenderPipelineValidationTests.cpp b/src/tests/unittests/validation/RenderPipelineValidationTests.cpp
index 0809fe4c23..5efc8410d3 100644
--- a/src/tests/unittests/validation/RenderPipelineValidationTests.cpp
+++ b/src/tests/unittests/validation/RenderPipelineValidationTests.cpp
@@ -329,15 +329,7 @@ TEST_F(RenderPipelineValidationTest, FragmentOutputComponentCountCompatibility)
                                 if (BlendFactorContainsSrcAlpha(
                                         descriptor.cTargets[0].blend->color.srcFactor) ||
                                     BlendFactorContainsSrcAlpha(
-                                        descriptor.cTargets[0].blend->color.dstFactor) ||
-                                    descriptor.cTargets[0].blend->alpha.srcFactor !=
-                                        wgpu::BlendFactor::Zero ||
-                                    descriptor.cTargets[0].blend->alpha.dstFactor ==
-                                        wgpu::BlendFactor::Src ||
-                                    descriptor.cTargets[0].blend->alpha.dstFactor ==
-                                        wgpu::BlendFactor::OneMinusSrc ||
-                                    BlendFactorContainsSrcAlpha(
-                                        descriptor.cTargets[0].blend->alpha.dstFactor)) {
+                                        descriptor.cTargets[0].blend->color.dstFactor)) {
                                     valid = componentCount == 4;
                                 }
                             } else {