Implement Pull #3528 from citra: use nvidia graphics automatically on laptops with optimus (with AMD support) (#271)

* Port 3528: use nvidia graphics automatically on laptops with optimus

* Force dedicated AMD Card for switchable Graphics

* Ran clang-format

src/yuzu/main.cpp

@@ -44,6 +44,15 @@
 Q_IMPORT_PLUGIN(QWindowsIntegrationPlugin);
 #endif
 
+#ifdef _WIN32
+extern "C" {
+// tells Nvidia and AMD drivers to use the dedicated GPU by default on laptops with switchable
+// graphics
+__declspec(dllexport) unsigned long NvOptimusEnablement = 0x00000001;
+__declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
+}
+#endif
+
 /**
  * "Callouts" are one-time instructional messages shown to the user. In the config settings, there
  * is a bitfield "callout_flags" options, used to track if a message has already been shown to the

src/yuzu_cmd/yuzu.cpp

@@ -37,6 +37,15 @@
 #include "yuzu_cmd/config.h"
 #include "yuzu_cmd/emu_window/emu_window_sdl2.h"
 
+#ifdef _WIN32
+extern "C" {
+// tells Nvidia and AMD drivers to use the dedicated GPU by default on laptops with switchable
+// graphics
+__declspec(dllexport) unsigned long NvOptimusEnablement = 0x00000001;
+__declspec(dllexport) int AmdPowerXpressRequestHighPerformance = 1;
+}
+#endif
+
 static void PrintHelp(const char* argv0) {
     std::cout << "Usage: " << argv0
               << " [options] <filename>\n"