From 3a004ecf9ab0bb2b3860d3ba0167692f107aa478 Mon Sep 17 00:00:00 2001
From: Dzmitry Malyshau <dmalyshau@mozilla.com>
Date: Thu, 29 Jul 2021 01:03:18 -0400
Subject: [PATCH] hal/dx12: fix depth formats and pipeline layout

---
 wgpu-hal/src/dx12/adapter.rs |  3 +++
 wgpu-hal/src/dx12/conv.rs    | 10 ++++++++++
 wgpu-hal/src/dx12/device.rs  | 18 ++++++++++++++++--
 3 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/wgpu-hal/src/dx12/adapter.rs b/wgpu-hal/src/dx12/adapter.rs
index 13b78198b..97be281a0 100644
--- a/wgpu-hal/src/dx12/adapter.rs
+++ b/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
diff --git a/wgpu-hal/src/dx12/conv.rs b/wgpu-hal/src/dx12/conv.rs
index b416ff69e..ea810d9f9 100644
--- a/wgpu-hal/src/dx12/conv.rs
+++ b/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,
diff --git a/wgpu-hal/src/dx12/device.rs b/wgpu-hal/src/dx12/device.rs
index a4c7a65be..994348d17 100644
--- a/wgpu-hal/src/dx12/device.rs
+++ b/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: conv::map_texture_format(desc.format),
+            Format: if crate::FormatAspects::from(desc.format).contains(crate::FormatAspects::COLOR)
+                || !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);