[idd] helper: fallback to default mode list

idd/LGCommon/DefaultDisplayModes.h

@@ -0,0 +1,17 @@
+#pragma once
+
+static const DWORD DefaultDisplayModes[][3] =
+{
+  {7680, 4800, 120}, {7680, 4320, 120}, {6016, 3384, 120}, {5760, 3600, 120},
+  {5760, 3240, 120}, {5120, 2800, 120}, {4096, 2560, 120}, {4096, 2304, 120},
+  {3840, 2400, 120}, {3840, 2160, 120}, {3200, 2400, 120}, {3200, 1800, 120},
+  {3008, 1692, 120}, {2880, 1800, 120}, {2880, 1620, 120}, {2560, 1600, 120},
+  {2560, 1440, 120}, {1920, 1440, 120}, {1920, 1200, 120}, {1920, 1080, 120},
+  {1600, 1200, 120}, {1600, 1024, 120}, {1600, 1050, 120}, {1600, 900 , 120},
+  {1440, 900 , 120}, {1400, 1050, 120}, {1366, 768 , 120}, {1360, 768 , 120},
+  {1280, 1024, 120}, {1280, 960 , 120}, {1280, 800 , 120}, {1280, 768 , 120},
+  {1280, 720 , 120}, {1280, 600 , 120}, {1152, 864 , 120}, {1024, 768 , 120},
+  {800 , 600 , 120}, {640 , 480 , 120}
+};
+
+static const DWORD DefaultPreferredDisplayMode = 19;

idd/LGIdd.sln

@@ -17,6 +17,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "LGCommon", "LGCommon", "{AC
 	ProjectSection(SolutionItems) = preProject
 		LGCommon\CDebug.cpp = LGCommon\CDebug.cpp
 		LGCommon\CDebug.h = LGCommon\CDebug.h
+		LGCommon\DefaultDisplayModes.h = LGCommon\DefaultDisplayModes.h
 		LGCommon\PipeMsg.h = LGCommon\PipeMsg.h
 	EndProjectSection
 EndProject

idd/LGIdd/CSettings.cpp

@@ -1,5 +1,6 @@
-#include "CSettings.h"
+#include "CSettings.h"
 #include "CDebug.h"
+#include "DefaultDisplayModes.h"
 
 #include <wdf.h>
 
@@ -7,22 +8,6 @@ CSettings g_settings;
 
 #define LGIDD_REGKEY L"SOFTWARE\\LookingGlass\\IDD"
 
-static const DWORD DefaultDisplayModes[][3] =
-{
-  {7680, 4800, 120}, {7680, 4320, 120}, {6016, 3384, 120}, {5760, 3600, 120},
-  {5760, 3240, 120}, {5120, 2800, 120}, {4096, 2560, 120}, {4096, 2304, 120},
-  {3840, 2400, 120}, {3840, 2160, 120}, {3200, 2400, 120}, {3200, 1800, 120},
-  {3008, 1692, 120}, {2880, 1800, 120}, {2880, 1620, 120}, {2560, 1600, 120},
-  {2560, 1440, 120}, {1920, 1440, 120}, {1920, 1200, 120}, {1920, 1080, 120},
-  {1600, 1200, 120}, {1600, 1024, 120}, {1600, 1050, 120}, {1600, 900 , 120},
-  {1440, 900 , 120}, {1400, 1050, 120}, {1366, 768 , 120}, {1360, 768 , 120},
-  {1280, 1024, 120}, {1280, 960 , 120}, {1280, 800 , 120}, {1280, 768 , 120},
-  {1280, 720 , 120}, {1280, 600 , 120}, {1152, 864 , 120}, {1024, 768 , 120},
-  {800 , 600 , 120}, {640 , 480 , 120}
-};
-
-static const DWORD DefaultPreferredDisplayMode = 19;
-
 CSettings::CSettings()
 {
 }

idd/LGIddHelper/CRegistrySettings.cpp

@@ -4,6 +4,8 @@
 #include <regex>
 #include <CDebug.h>
 
+#include "DefaultDisplayModes.h"
+
 #define LGIDD_REGKEY L"SOFTWARE\\LookingGlass\\IDD"
 
 CRegistrySettings::CRegistrySettings() : hKey(nullptr) {}
@@ -60,8 +62,25 @@ std::optional<std::vector<DisplayMode>> CRegistrySettings::getModes()
 
   DWORD type = 0, cb = 0;
   status = RegGetValue(hKey, nullptr, L"Modes", RRF_RT_REG_MULTI_SZ, &type, nullptr, &cb);
-  if (status != ERROR_SUCCESS)
+  switch (status)
   {
+  case ERROR_SUCCESS:
+    break;
+  case ERROR_FILE_NOT_FOUND:
+  {
+    std::vector<DisplayMode> result;
+    for (int i = 0; i < ARRAYSIZE(DefaultDisplayModes); ++i)
+    {
+      DisplayMode mode;
+      mode.width = DefaultDisplayModes[i][0];
+      mode.height = DefaultDisplayModes[i][1];
+      mode.refresh = DefaultDisplayModes[i][2];
+      mode.preferred = i == DefaultPreferredDisplayMode;
+      result.emplace_back(mode);
+    }
+    return result;
+  }
+  default:
     DEBUG_ERROR_HR(status, "RegGetValue(Modes) length computation");
     return {};
   }