From 9cff141d7f8c2fc4267b4472452c95aabf9ec361 Mon Sep 17 00:00:00 2001
From: Jinlei Li <grenlight@icloud.com>
Date: Fri, 28 Jan 2022 12:29:40 +0800
Subject: [PATCH] Add MULTISAMPLED_SHADING downlevel flag (#2425)

* Fix msaa-line example's unnecessary MSAA data store

* Add MULTISAMPLED_SHADING downlevel flag
---
 wgpu-hal/src/vulkan/adapter.rs | 12 ++++--------
 wgpu-types/src/lib.rs          |  3 +++
 2 files changed, 7 insertions(+), 8 deletions(-)

diff --git a/wgpu-hal/src/vulkan/adapter.rs b/wgpu-hal/src/vulkan/adapter.rs
index 0a03780697..bc03d8e7df 100644
--- a/wgpu-hal/src/vulkan/adapter.rs
+++ b/wgpu-hal/src/vulkan/adapter.rs
@@ -100,7 +100,9 @@ impl PhysicalDeviceFeatures {
             core: vk::PhysicalDeviceFeatures::builder()
                 .robust_buffer_access(private_caps.robust_buffer_access)
                 .independent_blend(true)
-                .sample_rate_shading(true)
+                .sample_rate_shading(
+                    downlevel_flags.contains(wgt::DownlevelFlags::MULTISAMPLED_SHADING),
+                )
                 .image_cube_array(
                     downlevel_flags.contains(wgt::DownlevelFlags::CUBE_ARRAY_TEXTURES),
                 )
@@ -342,6 +344,7 @@ impl PhysicalDeviceFeatures {
             Df::FRAGMENT_WRITABLE_STORAGE,
             self.core.fragment_stores_and_atomics != 0,
         );
+        dl_flags.set(Df::MULTISAMPLED_SHADING, self.core.sample_rate_shading != 0);
 
         features.set(
             F::INDIRECT_FIRST_INSTANCE,
@@ -929,13 +932,6 @@ impl super::Instance {
             );
             return None;
         }
-        if phd_features.core.sample_rate_shading == 0 {
-            log::warn!(
-                "sample_rate_shading feature is not supported, hiding adapter: {}",
-                info.name
-            );
-            return None;
-        }
         if !phd_capabilities.supports_extension(vk::AmdNegativeViewportHeightFn::name())
             && !phd_capabilities.supports_extension(vk::KhrMaintenance1Fn::name())
             && phd_capabilities.properties.api_version < vk::API_VERSION_1_2
diff --git a/wgpu-types/src/lib.rs b/wgpu-types/src/lib.rs
index d3290fe314..aee99070f2 100644
--- a/wgpu-types/src/lib.rs
+++ b/wgpu-types/src/lib.rs
@@ -909,6 +909,9 @@ bitflags::bitflags! {
 
         /// Supports storage buffers in fragment shaders.
         const FRAGMENT_STORAGE = 1 << 12;
+
+        ///  Supports sample shading and multisample interpolation.
+        const MULTISAMPLED_SHADING = 1 << 13;
     }
 }