Add warning if vive layers are present, but not using SteamVR

fixes #27

Author: fredemmott

src/Architectures.hpp

@@ -47,6 +47,13 @@ class Architectures {
     return std::to_underlying(mValue);
   }
 
+  constexpr Architecture get_only() const {
+    if (std::popcount(underlying()) != 1) {
+      return Architecture::Invalid;
+    }
+    return mValue;
+  }
+
   std::generator<Architecture> enumerate() const {
     for (auto arch: magic_enum::enum_values<Architecture>()) {
       if (arch == Architecture::Invalid) {

src/lib.cmake

@@ -93,6 +93,7 @@ if (WIN32)
     linters/windows/ProgramFilesLinter.cpp
     linters/windows/UltraleapLastLinter.cpp
     linters/windows/UnsignedDllLinter.cpp
+    linters/windows/ViveLayersLinter.cpp
     linters/windows/XRNeckSaferLinter.cpp
   )
 

src/linters/windows/ViveLayersLinter.cpp

@@ -0,0 +1,57 @@
+// Copyright 2026 Fred Emmott <fred@fredemmott.com>
+// SPDX-License-Identifier: MIT
+
+#include <fmt/core.h>
+
+#include <unordered_set>
+
+#include "APILayerStore.hpp"
+#include "Linter.hpp"
+
+// Warn about a registry value that is not a DWORD
+namespace FredEmmott::OpenXRLayers {
+
+class ViveLayersLinter final : public Linter {
+  std::vector<std::shared_ptr<LintError>> Lint(
+    const APILayerStore* store,
+    const std::vector<std::tuple<APILayer, APILayerDetails>>& layers) override {
+    const auto arch = store->GetArchitectures().get_only();
+    if (arch == Architecture::Invalid) {
+      return {};
+    }
+    const auto runtime = Platform::Get().GetActiveRuntime(arch);
+    if (!runtime) {
+      return {};
+    }
+    if (runtime->mName == "SteamVR") {
+      return {};
+    }
+    const auto runtimeName = runtime->mName.value_or(runtime->mPath.string());
+
+    static const std::unordered_set<std::string_view> LayerNames {
+      "XR_APILAYER_VIVE_hand_tracking",
+      "XR_APILAYER_VIVE_facial_tracking",
+      "XR_APILAYER_VIVE_srworks",
+    };
+
+    std::vector<std::shared_ptr<LintError>> ret;
+    for (const auto& [layer, details]: layers) {
+      if (!LayerNames.contains(details.mName)) {
+        continue;
+      }
+      ret.push_back(
+        std::make_shared<InvalidLayerStateLintError>(
+          fmt::format(
+            "{} requires the SteamVR runtime, but you are currently using "
+            "'{}'; this can cause game crashes or other issues.",
+            details.mName,
+            runtimeName),
+          layer));
+    }
+    return ret;
+  }
+};
+
+static ViveLayersLinter gInstance;
+
+}// namespace FredEmmott::OpenXRLayers