From f64712f2770b2230e9bb7f8b5e9d498404593251 Mon Sep 17 00:00:00 2001
From: Cameron Gutman <aicommander@gmail.com>
Date: Wed, 17 Jan 2024 17:15:21 -0600
Subject: [PATCH] Always reset the thread desktop before calling
 DuplicateOutput()

Otherwise capture will fail if the thread desktop is different than the current input desktop (ex: UAC secure desktop is active)
---
 src/platform/windows/display_base.cpp | 15 +++++++++++----
 tools/ddprobe.cpp                     | 20 ++++++++++++++++++++
 2 files changed, 31 insertions(+), 4 deletions(-)

diff --git a/src/platform/windows/display_base.cpp b/src/platform/windows/display_base.cpp
index 50f72698..d76a2e0a 100644
--- a/src/platform/windows/display_base.cpp
+++ b/src/platform/windows/display_base.cpp
@@ -376,11 +376,15 @@ namespace platf::dxgi {
     // Check if we can use the Desktop Duplication API on this output
     for (int x = 0; x < 2; ++x) {
       dup_t dup;
+
+      // Ensure we can duplicate the current display
+      syncThreadDesktop();
+
       status = output1->DuplicateOutput((IUnknown *) device.get(), &dup);
       if (SUCCEEDED(status)) {
         return true;
       }
-      Sleep(200);
+      std::this_thread::sleep_for(200ms);
     }
 
     BOOST_LOG(error) << "DuplicateOutput() test failed [0x"sv << util::hex(status).to_string_view() << ']';
@@ -405,9 +409,6 @@ namespace platf::dxgi {
       FreeLibrary(user32);
     });
 
-    // Ensure we can duplicate the current display
-    syncThreadDesktop();
-
     // Get rectangle of full desktop for absolute mouse coordinates
     env_width = GetSystemMetrics(SM_CXVIRTUALSCREEN);
     env_height = GetSystemMetrics(SM_CYVIRTUALSCREEN);
@@ -679,6 +680,9 @@ namespace platf::dxgi {
 
         // We try this twice, in case we still get an error on reinitialization
         for (int x = 0; x < 2; ++x) {
+          // Ensure we can duplicate the current display
+          syncThreadDesktop();
+
           status = output5->DuplicateOutput1((IUnknown *) device.get(), 0, supported_formats.size(), supported_formats.data(), &dup.dup);
           if (SUCCEEDED(status)) {
             break;
@@ -705,6 +709,9 @@ namespace platf::dxgi {
         }
 
         for (int x = 0; x < 2; ++x) {
+          // Ensure we can duplicate the current display
+          syncThreadDesktop();
+
           status = output1->DuplicateOutput((IUnknown *) device.get(), &dup.dup);
           if (SUCCEEDED(status)) {
             break;
diff --git a/tools/ddprobe.cpp b/tools/ddprobe.cpp
index 423a1f13..68b2da87 100644
--- a/tools/ddprobe.cpp
+++ b/tools/ddprobe.cpp
@@ -52,6 +52,23 @@ set_gpu_preference(int preference) {
   return ERROR_SUCCESS;
 }
 
+void
+syncThreadDesktop() {
+  auto hDesk = OpenInputDesktop(DF_ALLOWOTHERACCOUNTHOOK, FALSE, GENERIC_ALL);
+  if (!hDesk) {
+    auto err = GetLastError();
+    std::cout << "Failed to Open Input Desktop [0x"sv << util::hex(err).to_string_view() << ']' << std::endl;
+    return;
+  }
+
+  if (!SetThreadDesktop(hDesk)) {
+    auto err = GetLastError();
+    std::cout << "Failed to sync desktop to thread [0x"sv << util::hex(err).to_string_view() << ']' << std::endl;
+  }
+
+  CloseDesktop(hDesk);
+}
+
 HRESULT
 test_dxgi_duplication(dxgi::adapter_t &adapter, dxgi::output_t &output) {
   D3D_FEATURE_LEVEL featureLevels[] {
@@ -87,6 +104,9 @@ test_dxgi_duplication(dxgi::adapter_t &adapter, dxgi::output_t &output) {
     return status;
   }
 
+  // Ensure we can duplicate the current display
+  syncThreadDesktop();
+
   // Return the result of DuplicateOutput() to Sunshine
   dxgi::dup_t dup;
   return output1->DuplicateOutput((IUnknown *) device.get(), &dup);