Support stencil-only views and copying to/from combined depth-stencil…

… textures

- break down `describe` into `block_dimensions`, `required_features`, `guaranteed_format_features`, `sample_type` and `block_size`
- `sample_type` and `block_size` now take an optional `TextureAspect`

To enable copying to/from combined depth-stencil textures:
- [validation] copy aspect must refer to a single aspect of format
- [validation] update `validate_linear_texture_data` according to the WebGPU spec
- [validation] require missing `DEPTH_TEXTURE_AND_BUFFER_COPIES` downlevel flag for `queue_write_texture` and `command_encoder_copy_buffer_to_texture`
- [metal] set the right `MTLBlitOption` for texture/buffer copies
- [dx12] use the aspect specific texture format for the copy

To create stencil-only views from combined depth-stencil textures:
- [metal] set the right format `X24_Stencil8`/`X32_Stencil8` for the view and `MTLTextureUsage::PixelFormatView` for the texture
- [gles] set the right `DEPTH_STENCIL_TEXTURE_MODE` to either `DEPTH_COMPONENT` or `STENCIL_INDEX`
- [dx12] set the right formats `DXGI_FORMAT_X32_TYPELESS_G8X24_UINT` and `DXGI_FORMAT_X24_TYPELESS_G8_UINT`

CHANGELOG.md

@@ -42,6 +42,34 @@ Bottom level categories:
 
 ### Major changes
 
+#### TextureFormat info API
+
+The `describe` fn was removed in favor of separate functions: `block_dimensions`, `is_compressed`, `is_srgb`, `required_features`, `guaranteed_format_features`, `sample_type` and `block_size`.
+
+```diff
+- let block_dimensions = format.describe().block_dimensions;
++ let block_dimensions = format.block_dimensions();
+- let is_compressed = format.describe().is_compressed();
++ let is_compressed = format.is_compressed();
+- let is_srgb = format.describe().srgb;
++ let is_srgb = format.is_srgb();
+- let required_features = format.describe().required_features;
++ let required_features = format.required_features();
+- let guaranteed_format_features = format.describe().guaranteed_format_features;
++ let guaranteed_format_features = format.guaranteed_format_features();
+```
+
+Additionally `sample_type` and `block_size` now take an optional `TextureAspect` and return `Option`s.
+
+```diff
+- let sample_type = format.describe().sample_type;
++ let sample_type = format.sample_type(None).expect("combined depth-stencil format requires specifying a TextureAspect");
+- let block_size = format.describe().block_size;
++ let block_size = format.block_size(None).expect("combined depth-stencil format requires specifying a TextureAspect");
+```
+
+By @teoxoy in [#3436](https://github.com/gfx-rs/wgpu/pull/3436)
+
 #### General
 
 - Change type of `mip_level_count` and `array_layer_count` (members of `TextureViewDescriptor` and `ImageSubresourceRange`) from `Option<NonZeroU32>` to `Option<u32>`. By @teoxoy in [#3445](https://github.com/gfx-rs/wgpu/pull/3445)
@@ -51,6 +79,7 @@ Bottom level categories:
 #### General
 
 - Added `TextureFormatFeatureFlags::MULTISAMPLE_X16`. By @Dinnerbone in [#3454](https://github.com/gfx-rs/wgpu/pull/3454)
+- Support stencil-only views and copying to/from combined depth-stencil textures. By @teoxoy in [#3436](https://github.com/gfx-rs/wgpu/pull/3436)
 
 #### WebGPU
 

wgpu-core/src/command/clear.rs

@@ -178,8 +178,8 @@ impl<G: GlobalIdentityHandlerFactory> Global<G> {
             .map_err(|_| ClearError::InvalidTexture(dst))?;
 
         // Check if subresource aspects are valid.
-        let requested_aspects = hal::FormatAspects::from(subresource_range.aspect);
-        let clear_aspects = hal::FormatAspects::from(dst_texture.desc.format) & requested_aspects;
+        let clear_aspects =
+            hal::FormatAspects::new(dst_texture.desc.format, subresource_range.aspect);
         if clear_aspects.is_empty() {
             return Err(ClearError::MissingTextureAspect {
                 texture_format: dst_texture.desc.format,
@@ -310,29 +310,33 @@ fn clear_texture_via_buffer_copies<A: hal::Api>(
     encoder: &mut A::CommandEncoder,
     dst_raw: &A::Texture,
 ) {
+    assert_eq!(
+        hal::FormatAspects::from(texture_desc.format),
+        hal::FormatAspects::COLOR
+    );
+
     // Gather list of zero_buffer copies and issue a single command then to perform them
     let mut zero_buffer_copy_regions = Vec::new();
     let buffer_copy_pitch = alignments.buffer_copy_pitch.get() as u32;
-    let format_desc = texture_desc.format.describe();
+    let (block_width, block_height) = texture_desc.format.block_dimensions();
+    let block_size = texture_desc.format.block_size(None).unwrap();
 
-    let bytes_per_row_alignment =
-        get_lowest_common_denom(buffer_copy_pitch, format_desc.block_size as u32);
+    let bytes_per_row_alignment = get_lowest_common_denom(buffer_copy_pitch, block_size);
 
     for mip_level in range.mip_range {
         let mut mip_size = texture_desc.mip_level_size(mip_level).unwrap();
         // Round to multiple of block size
-        mip_size.width = align_to(mip_size.width, format_desc.block_dimensions.0 as u32);
-        mip_size.height = align_to(mip_size.height, format_desc.block_dimensions.1 as u32);
+        mip_size.width = align_to(mip_size.width, block_width);
+        mip_size.height = align_to(mip_size.height, block_height);
 
         let bytes_per_row = align_to(
-            mip_size.width / format_desc.block_dimensions.0 as u32 * format_desc.block_size as u32,
+            mip_size.width / block_width * block_size,
             bytes_per_row_alignment,
         );
 
         let max_rows_per_copy = crate::device::ZERO_BUFFER_SIZE as u32 / bytes_per_row;
         // round down to a multiple of rows needed by the texture format
-        let max_rows_per_copy = max_rows_per_copy / format_desc.block_dimensions.1 as u32
-            * format_desc.block_dimensions.1 as u32;
+        let max_rows_per_copy = max_rows_per_copy / block_height * block_height;
         assert!(
             max_rows_per_copy > 0,
             "Zero buffer size is too small to fill a single row \
@@ -370,7 +374,7 @@ fn clear_texture_via_buffer_copies<A: hal::Api>(
                                 y: mip_size.height - num_rows_left,
                                 z,
                             },
-                            aspect: hal::FormatAspects::all(),
+                            aspect: hal::FormatAspects::COLOR,
                         },
                         size: hal::CopyExtent {
                             width: mip_size.width, // full row