Add a separate thread for rendering and add texture mailbox and shared context to SDL

src/citra/citra.cpp

@@ -35,6 +35,7 @@
 #include "core/file_sys/cia_container.h"
 #include "core/frontend/applets/default_applets.h"
 #include "core/frontend/framebuffer_layout.h"
+#include "core/frontend/scope_acquire_context.h"
 #include "core/gdbstub/gdbstub.h"
 #include "core/hle/service/am/am.h"
 #include "core/hle/service/cfg/cfg.h"
@@ -347,7 +348,7 @@ int main(int argc, char** argv) {
     Core::System::GetInstance().RegisterImageInterface(std::make_shared<LodePNGImageInterface>());
 
     std::unique_ptr<EmuWindow_SDL2> emu_window{std::make_unique<EmuWindow_SDL2>(fullscreen)};
-
+    Frontend::ScopeAcquireContext scope(*emu_window);
     Core::System& system{Core::System::GetInstance()};
 
     const Core::System::ResultStatus load_result{system.Load(*emu_window, filepath)};
@@ -411,9 +412,11 @@ int main(int argc, char** argv) {
         system.VideoDumper().StartDumping(dump_video, "webm", layout);
     }
 
+    std::thread render_thread([&emu_window] { emu_window->Present(); });
     while (emu_window->IsOpen()) {
         system.RunLoop();
     }
+    render_thread.join();
 
     Core::Movie::GetInstance().Shutdown();
     if (system.VideoDumper().IsDumping()) {