VideoBackends: Add Metal renderer

Source/Core/VideoBackends/Metal/MTLUtil.h

@@ -0,0 +1,54 @@
+// Copyright 2022 Dolphin Emulator Project
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#pragma once
+
+#include <Metal/Metal.h>
+#include <vector>
+
+#include "VideoCommon/AbstractShader.h"
+#include "VideoCommon/TextureConfig.h"
+#include "VideoCommon/VideoConfig.h"
+
+#include "VideoBackends/Metal/MRCHelpers.h"
+
+namespace Metal
+{
+struct DeviceFeatures
+{
+  bool unified_memory;
+  bool subgroup_ops;
+};
+
+extern DeviceFeatures g_features;
+
+namespace Util
+{
+struct Viewport
+{
+  float x;
+  float y;
+  float width;
+  float height;
+  float near_depth;
+  float far_depth;
+};
+
+/// Gets the list of Metal devices, ordered so the system default device is first
+std::vector<MRCOwned<id<MTLDevice>>> GetAdapterList();
+void PopulateBackendInfo(VideoConfig* config);
+void PopulateBackendInfoAdapters(VideoConfig* config,
+                                 const std::vector<MRCOwned<id<MTLDevice>>>& adapters);
+void PopulateBackendInfoFeatures(VideoConfig* config, id<MTLDevice> device);
+
+AbstractTextureFormat ToAbstract(MTLPixelFormat format);
+MTLPixelFormat FromAbstract(AbstractTextureFormat format);
+static inline bool HasStencil(AbstractTextureFormat format)
+{
+  return format == AbstractTextureFormat::D24_S8 || format == AbstractTextureFormat::D32F_S8;
+}
+
+std::optional<std::string> TranslateShaderToMSL(ShaderStage stage, std::string_view source);
+
+}  // namespace Util
+}  // namespace Metal