Add MULTISAMPLE_ARRAY format feature flag.

wgpu-core/src/device/resource.rs

@@ -1431,7 +1431,11 @@ impl Device {
                 });
             }
 
-            if desc.size.depth_or_array_layers != 1 {
+            if desc.size.depth_or_array_layers != 1
+                && !format_features
+                    .flags
+                    .contains(wgt::TextureFormatFeatureFlags::MULTISAMPLE_ARRAY)
+            {
                 return Err(CreateTextureError::InvalidDimension(
                     TextureDimensionError::MultisampledDepthOrArrayLayer(
                         desc.size.depth_or_array_layers,
@@ -1736,11 +1740,19 @@ impl Device {
 
         // check if multisampled texture is seen as anything but 2D
         if texture.desc.sample_count > 1 && resolved_dimension != TextureViewDimension::D2 {
-            return Err(
-                resource::CreateTextureViewError::InvalidMultisampledTextureViewDimension(
-                    resolved_dimension,
-                ),
-            );
+            // Multisample is allowed on 2D arrays, only if explicitly supported
+            let multisample_array_exception = resolved_dimension == TextureViewDimension::D2Array
+                && format_features
+                    .flags
+                    .contains(wgt::TextureFormatFeatureFlags::MULTISAMPLE_ARRAY);
+
+            if !multisample_array_exception {
+                return Err(
+                    resource::CreateTextureViewError::InvalidMultisampledTextureViewDimension(
+                        resolved_dimension,
+                    ),
+                );
+            }
         }
 
         // check if the dimension is compatible with the texture

wgpu-core/src/instance.rs

@@ -758,6 +758,11 @@ impl Adapter {
             caps.contains(Tfc::MULTISAMPLE_RESOLVE),
         );
 
+        flags.set(
+            wgt::TextureFormatFeatureFlags::MULTISAMPLE_ARRAY,
+            caps.contains(Tfc::MULTISAMPLE_ARRAY),
+        );
+
         wgt::TextureFormatFeatures {
             allowed_usages,
             flags,

wgpu-hal/src/lib.rs

@@ -1678,6 +1678,9 @@ bitflags!(
         const COPY_SRC = 1 << 15;
         /// Format can be copied to.
         const COPY_DST = 1 << 16;
+
+        /// Format can be used with both multisample and array at the same time.
+        const MULTISAMPLE_ARRAY = 1 << 17;
     }
 );
 

wgpu-hal/src/vulkan/adapter.rs

@@ -2616,6 +2616,9 @@ impl crate::Adapter for super::Adapter {
         // Vulkan is very permissive about MSAA
         flags.set(Tfc::MULTISAMPLE_RESOLVE, !format.is_compressed());
 
+        // Unless we're on a portability subset, this is always allowed
+        flags.set(Tfc::MULTISAMPLE_ARRAY, true);
+
         // get the supported sample counts
         let format_aspect = crate::FormatAspects::from(format);
         let limits = self.phd_capabilities.properties.limits;

wgpu-types/src/lib.rs

@@ -2058,6 +2058,9 @@ bitflags::bitflags! {
         const STORAGE_ATOMIC = 1 << 9;
         /// If not present, the texture can't be blended into the render target.
         const BLENDABLE = 1 << 10;
+        /// Allows a 2D texture of this format to have a `sample_count` higher than 1, and more
+        /// than 1 array layer at the same time.
+        const MULTISAMPLE_ARRAY = 1 << 11;
     }
 }