From bcfcbd970ec7182b63cdda9421e475c85c1b2753 Mon Sep 17 00:00:00 2001
From: Stephen Gutekanst <stephen@hexops.com>
Date: Fri, 18 Feb 2022 13:13:19 -0700
Subject: [PATCH] dawn/native: add DAWN_NO_WINDOWS_UI option for Zig & MinGW
 compilers

In Mach engine, we're compiling Dawn using Zig as a C/C++
compiler. Zig provides it's own libc implementation, build
system, and system headers.

Dawn today makes use of newer `windows.ui.*.h` headers introduced in
more recent Windows versions. However, Zig relies on MinGW for it's
system headers and it is not straightforward/desirable to use the
official Windows SDK headers: Zig does not have these headers today.

Since Dawn does not truly require these headers, we are using a
preprocessor directive `DAWN_NO_WINDOWS_UI` to disable this functionality
and enable compilation of Dawn with Zig/MinGW compilers.

We do not consume Dawn's build system (cmake or otherwise), and so I have
not added integration with that. I ammhappy to do whatever is required in
order for such a patch to be accepted, however. I'm also happy to ensure
this works going forward well into the future should it break over time.

Signed-off-by: Stephen Gutekanst <stephen@hexops.com>
Change-Id: If41cafb95666946115b58567fef753df3fbe940a
---
 src/dawn/native/Surface.cpp              | 4 +++-
 src/dawn/native/d3d12/SwapChainD3D12.cpp | 6 ++++++
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/src/dawn/native/Surface.cpp b/src/dawn/native/Surface.cpp
index ff6fd07559d..e898547e794 100644
--- a/src/dawn/native/Surface.cpp
+++ b/src/dawn/native/Surface.cpp
@@ -19,7 +19,7 @@
 #include "dawn/native/Instance.h"
 #include "dawn/native/SwapChain.h"
 
-#if defined(DAWN_PLATFORM_WINDOWS)
+#if defined(DAWN_PLATFORM_WINDOWS) && !defined(DAWN_NO_WINDOWS_UI)
 #    include <windows.ui.core.h>
 #    include <windows.ui.xaml.controls.h>
 #endif  // defined(DAWN_PLATFORM_WINDOWS)
@@ -106,6 +106,7 @@ namespace dawn::native {
             return {};
         }
 #    endif  // defined(DAWN_PLATFORM_WIN32)
+#    if !defined(DAWN_NO_WINDOWS_UI)
         const SurfaceDescriptorFromWindowsCoreWindow* coreWindowDesc = nullptr;
         FindInChain(descriptor->nextInChain, &coreWindowDesc);
         if (coreWindowDesc) {
@@ -128,6 +129,7 @@ namespace dawn::native {
                             "Invalid SwapChainPanel");
             return {};
         }
+#endif  // !defined(DAWN_NO_WINDOWS_UI)
 #endif  // defined(DAWN_PLATFORM_WINDOWS)
 
 #if defined(DAWN_USE_X11)
diff --git a/src/dawn/native/d3d12/SwapChainD3D12.cpp b/src/dawn/native/d3d12/SwapChainD3D12.cpp
index 38d47d0eed9..6070e62ce87 100644
--- a/src/dawn/native/d3d12/SwapChainD3D12.cpp
+++ b/src/dawn/native/d3d12/SwapChainD3D12.cpp
@@ -14,7 +14,9 @@
 
 #include "dawn/native/d3d12/SwapChainD3D12.h"
 
+#if !defined(DAWN_NO_WINDOWS_UI)
 #include <windows.ui.xaml.media.dxinterop.h>
+#endif // !defined(DAWN_NO_WINDOWS_UI)
 
 #include <utility>
 
@@ -266,6 +268,7 @@ namespace dawn::native::d3d12 {
                     "Creating the IDXGISwapChain1"));
                 break;
             }
+#           if !defined(DAWN_NO_WINDOWS_UI)
             case Surface::Type::WindowsSwapChainPanel: {
                 DAWN_TRY(CheckHRESULT(
                     factory2->CreateSwapChainForComposition(device->GetCommandQueue().Get(),
@@ -279,6 +282,9 @@ namespace dawn::native::d3d12 {
                                       "Setting SwapChain"));
                 break;
             }
+#           else // !defined(DAWN_NO_WINDOWS_UI)
+            case Surface::Type::WindowsSwapChainPanel: UNREACHABLE();
+#           endif // !defined(DAWN_NO_WINDOWS_UI)
             default:
                 UNREACHABLE();
         }