[D3D12] Refactor root signature creation

src/xenia/ui/d3d12/d3d12_util.cc

@@ -0,0 +1,47 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2018 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#include "xenia/ui/d3d12/d3d12_util.h"
+
+#include "xenia/base/logging.h"
+
+namespace xe {
+namespace ui {
+namespace d3d12 {
+namespace util {
+
+ID3D12RootSignature* CreateRootSignature(
+    ID3D12Device* device, const D3D12_ROOT_SIGNATURE_DESC& desc) {
+  ID3DBlob* blob;
+  ID3DBlob* error_blob = nullptr;
+  if (FAILED(D3D12SerializeRootSignature(&desc, D3D_ROOT_SIGNATURE_VERSION_1,
+                                         &blob, &error_blob))) {
+    XELOGE("Failed to serialize a root signature");
+    if (error_blob != nullptr) {
+      XELOGE("%s",
+             reinterpret_cast<const char*>(error_blob->GetBufferPointer()));
+      error_blob->Release();
+    }
+    return nullptr;
+  }
+  if (error_blob != nullptr) {
+    error_blob->Release();
+  }
+  ID3D12RootSignature* root_signature = nullptr;
+  device->CreateRootSignature(0, blob->GetBufferPointer(),
+                              blob->GetBufferSize(),
+                              IID_PPV_ARGS(&root_signature));
+  blob->Release();
+  return root_signature;
+}
+
+}  // namespace util
+}  // namespace d3d12
+}  // namespace ui
+}  // namespace xe