Merge #1744

1744: hal/dx12: fix depth formats and pipeline layout r=kvark a=kvark

**Connections**
Closes #1727

**Description**
There were 2 problems. One was that the reversing of the pipeline layout was done wrong (again). I don't know how it still worked on one of my machines :/
The other was that the backend relied on the depth format reinterpretation without using a typeless format. This is OK on higher-level platforms, but we should be doing it more careful. I tried to approach this maximally efficient: we only use the typeless format if all of the following are true:
  1. it's a depth/stencil format
  2. it needs to be seen as SRV/UAV

So in the case of a simple depth texture, we are still going to be using a fully-qualified format, and therefore get all of the benefit of HW compression on it.

**Testing**
Ran the examples on Intel


Co-authored-by: Dzmitry Malyshau <dmalyshau@mozilla.com>

wgpu-hal/src/dx12/adapter.rs

@@ -121,6 +121,9 @@ impl super::Adapter {
             hr == 0 && features2.DepthBoundsTestSupported != 0
         };
 
+        //Note: `D3D12_FEATURE_D3D12_OPTIONS3::CastingFullyTypedFormatSupported` can be checked
+        // to know if we can skip "typeless" formats entirely.
+
         let private_caps = super::PrivateCapabilities {
             instance_flags,
             heterogeneous_resource_heaps: options.ResourceHeapTier

wgpu-hal/src/dx12/conv.rs

@@ -129,6 +129,16 @@ pub fn map_texture_format_nodepth(format: wgt::TextureFormat) -> dxgiformat::DXG
     }
 }
 
+pub fn map_texture_format_depth_typeless(format: wgt::TextureFormat) -> dxgiformat::DXGI_FORMAT {
+    match format {
+        wgt::TextureFormat::Depth32Float => dxgiformat::DXGI_FORMAT_R32_TYPELESS,
+        wgt::TextureFormat::Depth24Plus | wgt::TextureFormat::Depth24PlusStencil8 => {
+            dxgiformat::DXGI_FORMAT_R24G8_TYPELESS
+        }
+        _ => unreachable!(),
+    }
+}
+
 pub fn map_index_format(format: wgt::IndexFormat) -> dxgiformat::DXGI_FORMAT {
     match format {
         wgt::IndexFormat::Uint16 => dxgiformat::DXGI_FORMAT_R16_UINT,

wgpu-hal/src/dx12/device.rs

@@ -393,8 +393,20 @@ impl crate::Device<super::Api> for super::Device {
             Height: desc.size.height,
             DepthOrArraySize: desc.size.depth_or_array_layers as u16,
             MipLevels: desc.mip_level_count as u16,
-            //TODO: map to surface format to allow view casting
+            Format: if crate::FormatAspects::from(desc.format).contains(crate::FormatAspects::COLOR)
-            Format: conv::map_texture_format(desc.format),
+                || !desc.usage.intersects(
+                    crate::TextureUses::RESOURCE
+                        | crate::TextureUses::STORAGE_READ
+                        | crate::TextureUses::STORAGE_WRITE,
+                ) {
+                conv::map_texture_format(desc.format)
+            } else {
+                // This branch is needed if it's a depth texture, and it's ever needed to be viewed as SRV or UAV,
+                // because then we'd create a non-depth format view of it.
+                // Note: we can skip this branch if
+                // `D3D12_FEATURE_D3D12_OPTIONS3::CastingFullyTypedFormatSupported`
+                conv::map_texture_format_depth_typeless(desc.format)
+            },
             SampleDesc: dxgitype::DXGI_SAMPLE_DESC {
                 Count: desc.sample_count,
                 Quality: 0,
@@ -912,6 +924,8 @@ impl crate::Device<super::Api> for super::Device {
             bind_group_infos.push(info);
         }
 
+        //Note: we populated them in reverse
+        bind_group_infos.reverse();
         // Ensure that we didn't reallocate!
         debug_assert_eq!(ranges.len(), total_non_dynamic_entries);