nvapi: Allow switching ShowDlssIndicator registry setting

src/nvapi.cpp

@@ -5,6 +5,7 @@
 #include "util/util_string.h"
 #include "util/util_env.h"
 #include "util/util_log.h"
+#include "util/util_dlss.h"
 #include "../version.h"
 #include "../config.h"
 
@@ -384,6 +385,8 @@ extern "C" {
         nvapiD3dInstance = std::make_unique<NvapiD3dInstance>(*resourceFactory);
         nvapiD3dInstance->Initialize();
 
+        setDlssIndicator();
+
         return Ok(n);
     }
 }

src/util/util_dlss.h

@@ -0,0 +1,38 @@
+#pragma once
+
+#include "../nvapi_private.h"
+#include "util_log.h"
+#include "util_env.h"
+
+namespace dxvk {
+    inline void setDlssIndicator() {
+        constexpr static auto showDLSSIndicatorEnvName = "DXVK_NVAPI_SET_DLSS_INDICATOR";
+        const static auto showDLSSIndicator = env::getEnvVariable(showDLSSIndicatorEnvName);
+
+        if (showDLSSIndicator.empty())
+            return;
+
+        NvU32 showDLSSIndicatorValue;
+        if (!str::parsedword(std::string_view(showDLSSIndicator), showDLSSIndicatorValue)) {
+            log::info(str::format(showDLSSIndicatorEnvName, " is set to '", showDLSSIndicator, "', but this value is invalid, please set a number"));
+            return;
+        }
+
+        if (showDLSSIndicatorValue != 0)
+            log::info(str::format(showDLSSIndicatorEnvName, " is set, enable ShowDlssIndicator in registry"));
+        else
+            log::info(str::format(showDLSSIndicatorEnvName, " is set to 0, disable ShowDlssIndicator in registry"));
+
+        HKEY key{};
+        auto status = RegOpenKeyExW(HKEY_LOCAL_MACHINE, L"SOFTWARE\\NVIDIA Corporation\\Global\\NGXCore", REG_OPTION_NON_VOLATILE, KEY_ALL_ACCESS, &key);
+        if (status != NO_ERROR || !key) {
+            log::info(str::format(R"(Failed to open SOFTWARE\NVIDIA Corporation\Global\NGXCore registry key: )", status));
+            return;
+        }
+
+        if (RegSetValueExW(key, L"ShowDlssIndicator", 0, REG_DWORD, reinterpret_cast<const BYTE*>(&showDLSSIndicatorValue), sizeof(DWORD)) != NO_ERROR)
+            log::info(str::format("Failed to set ShowDlssIndicator registry key"));
+
+        RegCloseKey(key);
+    }
+}