From 5db4c32035dea4e7782d83379962ae27516db2e5 Mon Sep 17 00:00:00 2001
From: Geoffrey McRae <geoff@hostfission.com>
Date: Mon, 6 Jan 2020 20:52:27 +1100
Subject: [PATCH] [c-host] dont use DX12 feature levels on Windows8

Fixes #218
---
 VERSION                                       |  2 +-
 .../platform/Windows/capture/DXGI/src/dxgi.c  | 28 +++++++++++++++++--
 common/include/common/windebug.h              |  3 ++
 common/src/platform/windows/windebug.c        | 22 +++++++++++++++
 4 files changed, 52 insertions(+), 3 deletions(-)

diff --git a/VERSION b/VERSION
index aa8ea2a0..209b1692 100644
--- a/VERSION
+++ b/VERSION
@@ -1 +1 @@
-B1-54-g5033d17990+1
\ No newline at end of file
+B1-55-g7469f54122+1
\ No newline at end of file
diff --git a/c-host/platform/Windows/capture/DXGI/src/dxgi.c b/c-host/platform/Windows/capture/DXGI/src/dxgi.c
index 623a6bb5..fc908145 100644
--- a/c-host/platform/Windows/capture/DXGI/src/dxgi.c
+++ b/c-host/platform/Windows/capture/DXGI/src/dxgi.c
@@ -307,7 +307,18 @@ static bool dxgi_init(void * pointerShape, const unsigned int pointerSize)
     goto fail;
   }
 
-  static const D3D_FEATURE_LEVEL featureLevels[] =
+  static const D3D_FEATURE_LEVEL win8[] =
+  {
+    D3D_FEATURE_LEVEL_11_1,
+    D3D_FEATURE_LEVEL_11_0,
+    D3D_FEATURE_LEVEL_10_1,
+    D3D_FEATURE_LEVEL_10_0,
+    D3D_FEATURE_LEVEL_9_3,
+    D3D_FEATURE_LEVEL_9_2,
+    D3D_FEATURE_LEVEL_9_1
+  };
+
+  static const D3D_FEATURE_LEVEL win10[] =
   {
     D3D_FEATURE_LEVEL_12_1,
     D3D_FEATURE_LEVEL_12_0,
@@ -320,6 +331,19 @@ static bool dxgi_init(void * pointerShape, const unsigned int pointerSize)
     D3D_FEATURE_LEVEL_9_1
   };
 
+  const D3D_FEATURE_LEVEL * featureLevels;
+  unsigned int featureLevelCount;
+  if (IsWindows8())
+  {
+    featureLevels     = win8;
+    featureLevelCount = sizeof(win8) / sizeof(D3D_FEATURE_LEVEL);
+  }
+  else
+  {
+    featureLevels     = win10;
+    featureLevelCount = sizeof(win10) / sizeof(D3D_FEATURE_LEVEL);
+  }
+
   IDXGIAdapter * tmp;
   status = IDXGIAdapter1_QueryInterface(this->adapter, &IID_IDXGIAdapter, (void **)&tmp);
   if (FAILED(status))
@@ -333,7 +357,7 @@ static bool dxgi_init(void * pointerShape, const unsigned int pointerSize)
     D3D_DRIVER_TYPE_UNKNOWN,
     NULL,
     D3D11_CREATE_DEVICE_VIDEO_SUPPORT,
-    featureLevels, sizeof(featureLevels) / sizeof(D3D_FEATURE_LEVEL),
+    featureLevels, featureLevelCount,
     D3D11_SDK_VERSION,
     &this->device,
     &this->featureLevel,
diff --git a/common/include/common/windebug.h b/common/include/common/windebug.h
index 729aa0d5..b897d697 100644
--- a/common/include/common/windebug.h
+++ b/common/include/common/windebug.h
@@ -21,6 +21,7 @@ Place, Suite 330, Boston, MA 02111-1307 USA
 
 #include "debug.h"
 #include <windows.h>
+#include <stdbool.h>
 
 #ifdef __cplusplus
 extern "C" {
@@ -30,6 +31,8 @@ void DebugWinError(const char * file, const unsigned int line, const char * func
 
 #define DEBUG_WINERROR(x, y) DebugWinError(STRIPPATH(__FILE__), __LINE__, __FUNCTION__, x, y)
 
+bool IsWindows8();
+
 #ifdef __cplusplus
 }
 #endif
\ No newline at end of file
diff --git a/common/src/platform/windows/windebug.c b/common/src/platform/windows/windebug.c
index 2ae65002..bee4bf4d 100644
--- a/common/src/platform/windows/windebug.c
+++ b/common/src/platform/windows/windebug.c
@@ -39,4 +39,26 @@ void DebugWinError(const char * file, const unsigned int line, const char * func
 
   fprintf(stderr, "[E] %20s:%-4u | %-30s | %s: 0x%08x (%s)\n", file, line, function, desc, (int)status, buffer);
   LocalFree(buffer);
+}
+
+/* credit for this function to: https://stackoverflow.com/questions/17399302/how-can-i-detect-windows-8-1-in-a-desktop-application */
+inline static BOOL CompareWindowsVersion(DWORD dwMajorVersion, DWORD dwMinorVersion)
+{
+  OSVERSIONINFOEX ver;
+  DWORDLONG dwlConditionMask = 0;
+
+  ZeroMemory(&ver, sizeof(OSVERSIONINFOEX));
+  ver.dwOSVersionInfoSize = sizeof(OSVERSIONINFOEX);
+  ver.dwMajorVersion = dwMajorVersion;
+  ver.dwMinorVersion = dwMinorVersion;
+
+  VER_SET_CONDITION(dwlConditionMask, VER_MAJORVERSION, VER_EQUAL);
+  VER_SET_CONDITION(dwlConditionMask, VER_MINORVERSION, VER_EQUAL);
+
+  return VerifyVersionInfo(&ver, VER_MAJORVERSION | VER_MINORVERSION, dwlConditionMask);
+}
+
+bool IsWindows8()
+{
+  return CompareWindowsVersion(6, 3) == TRUE;
 }
\ No newline at end of file