From 890a32bd98c05e77c9134370ae3c988bcbde4ecb Mon Sep 17 00:00:00 2001
From: Triang3l <triang3l@yandex.ru>
Date: Sat, 3 Aug 2019 22:33:09 +0300
Subject: [PATCH] [App] Only start D3D12 if DLL exists

---
 src/xenia/app/xenia_main.cc                  | 10 ++++++----
 src/xenia/gpu/d3d12/d3d12_graphics_system.cc |  4 ++++
 src/xenia/gpu/d3d12/d3d12_graphics_system.h  |  2 ++
 src/xenia/ui/d3d12/d3d12_provider.cc         | 10 ++++++++++
 src/xenia/ui/d3d12/d3d12_provider.h          |  2 ++
 5 files changed, 24 insertions(+), 4 deletions(-)

diff --git a/src/xenia/app/xenia_main.cc b/src/xenia/app/xenia_main.cc
index 887f1cb4f..7e779b460 100644
--- a/src/xenia/app/xenia_main.cc
+++ b/src/xenia/app/xenia_main.cc
@@ -105,10 +105,12 @@ std::unique_ptr<gpu::GraphicsSystem> CreateGraphicsSystem() {
     std::unique_ptr<gpu::GraphicsSystem> best;
 
 #if XE_PLATFORM_WIN32
-    best = std::unique_ptr<gpu::GraphicsSystem>(
-        new xe::gpu::d3d12::D3D12GraphicsSystem());
-    if (best) {
-      return best;
+    if (xe::gpu::d3d12::D3D12GraphicsSystem::IsD3D12APIAvailable()) {
+      best = std::unique_ptr<gpu::GraphicsSystem>(
+          new xe::gpu::d3d12::D3D12GraphicsSystem());
+      if (best) {
+        return best;
+      }
     }
 #endif  // XE_PLATFORM_WIN32
     best = std::unique_ptr<gpu::GraphicsSystem>(
diff --git a/src/xenia/gpu/d3d12/d3d12_graphics_system.cc b/src/xenia/gpu/d3d12/d3d12_graphics_system.cc
index ef425a12f..87fa23445 100644
--- a/src/xenia/gpu/d3d12/d3d12_graphics_system.cc
+++ b/src/xenia/gpu/d3d12/d3d12_graphics_system.cc
@@ -27,6 +27,10 @@ D3D12GraphicsSystem::D3D12GraphicsSystem() {}
 
 D3D12GraphicsSystem::~D3D12GraphicsSystem() {}
 
+bool D3D12GraphicsSystem::IsD3D12APIAvailable() {
+  return xe::ui::d3d12::D3D12Provider::IsD3D12APIAvailable();
+}
+
 std::wstring D3D12GraphicsSystem::name() const {
   auto d3d12_command_processor =
       static_cast<D3D12CommandProcessor*>(command_processor());
diff --git a/src/xenia/gpu/d3d12/d3d12_graphics_system.h b/src/xenia/gpu/d3d12/d3d12_graphics_system.h
index 47ea9a71d..812d63126 100644
--- a/src/xenia/gpu/d3d12/d3d12_graphics_system.h
+++ b/src/xenia/gpu/d3d12/d3d12_graphics_system.h
@@ -26,6 +26,8 @@ class D3D12GraphicsSystem : public GraphicsSystem {
   D3D12GraphicsSystem();
   ~D3D12GraphicsSystem() override;
 
+  static bool IsD3D12APIAvailable();
+
   std::wstring name() const override;
 
   X_STATUS Setup(cpu::Processor* processor, kernel::KernelState* kernel_state,
diff --git a/src/xenia/ui/d3d12/d3d12_provider.cc b/src/xenia/ui/d3d12/d3d12_provider.cc
index 7031f4fb1..5779b7dd2 100644
--- a/src/xenia/ui/d3d12/d3d12_provider.cc
+++ b/src/xenia/ui/d3d12/d3d12_provider.cc
@@ -27,6 +27,15 @@ namespace xe {
 namespace ui {
 namespace d3d12 {
 
+bool D3D12Provider::IsD3D12APIAvailable() {
+  HMODULE library_d3d12 = LoadLibrary(L"D3D12.dll");
+  if (!library_d3d12) {
+    return false;
+  }
+  FreeLibrary(library_d3d12);
+  return true;
+}
+
 std::unique_ptr<D3D12Provider> D3D12Provider::Create(Window* main_window) {
   std::unique_ptr<D3D12Provider> provider(new D3D12Provider(main_window));
   InitializationResult result = provider->Initialize();
@@ -81,6 +90,7 @@ D3D12Provider::InitializationResult D3D12Provider::Initialize() {
   library_d3dcompiler_ = LoadLibrary(L"D3DCompiler_47.dll");
   if (library_dxgi_ == nullptr || library_d3d12_ == nullptr ||
       library_d3dcompiler_ == nullptr) {
+    XELOGE("Failed to load dxgi.dll, D3D12.dll and D3DCompiler_47.dll.");
     return InitializationResult::kLibraryLoadFailed;
   }
   bool libraries_loaded = true;
diff --git a/src/xenia/ui/d3d12/d3d12_provider.h b/src/xenia/ui/d3d12/d3d12_provider.h
index 861405f38..b527189c0 100644
--- a/src/xenia/ui/d3d12/d3d12_provider.h
+++ b/src/xenia/ui/d3d12/d3d12_provider.h
@@ -23,6 +23,8 @@ class D3D12Provider : public GraphicsProvider {
  public:
   ~D3D12Provider() override;
 
+  static bool IsD3D12APIAvailable();
+
   static std::unique_ptr<D3D12Provider> Create(Window* main_window);
 
   std::unique_ptr<GraphicsContext> CreateContext(