[dxgi] Add option to expose composition swapchains

dxvk.conf

@@ -18,6 +18,17 @@
 # dxgi.enableHDR = True
 
 
+# Expose support for dcomp swap chains with a dummy window.
+#
+# This is not a valid implementation of DirectComposition swapchains,
+# however some games may rely on this functionality to be present while
+# others may require swap chain creation to fail.
+#
+# Supported values: True, False
+
+# dxgi.enableDummyCompositionSwapchain = False
+
+
 # Allows the Vulkan driver to opt-in to exclusive full-screen mode on
 # Windows. Certain features, such as variable refresh rate or HDR, will
 # not work without this setting, however enabling it will break certain

src/dxgi/dxgi_options.cpp

@@ -93,6 +93,9 @@ namespace dxvk {
     this->maxFrameRate = config.getOption<int32_t>("dxgi.maxFrameRate", 0);
     this->syncInterval = config.getOption<int32_t>("dxgi.syncInterval", -1);
 
+    // We don't support dcomp swapchains and some games may rely on them failing on creation
+    this->enableDummyCompositionSwapchain = config.getOption<bool>("dxgi.enableDummyCompositionSwapchain", false);
+
     // Expose Nvidia GPUs properly if NvAPI is enabled in environment
     this->hideNvidiaGpu = !isNvapiEnabled();
     applyTristate(this->hideNvidiaGpu, config.getOption<Tristate>("dxgi.hideNvidiaGpu", Tristate::Auto));

src/dxgi/dxgi_options.h

@@ -46,6 +46,9 @@ namespace dxvk {
     /// Enable HDR
     bool enableHDR;
 
+    /// Enable support for dummy composition swapchains
+    bool enableDummyCompositionSwapchain;
+
     /// Limit frame rate
     int32_t maxFrameRate;